Normal spectral emissivity measurement on five aeronautical alloys

Journal of Alloys and Compounds 703 (2017) 125e138

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Normal spectral emissivity measurement on five aeronautical alloys Bo Kong a, Ting Li b, Qitai Eri a, * a b

School of Energy and Power Engineering, Beihang University, Beijing, 100191, China Collaborative Innovation Center for Advanced Aero-Engine, 100191, Beijing, China

a r t i c l e i n f o

a b s t r a c t

Article history: Received 14 August 2016 Received in revised form 13 January 2017 Accepted 24 January 2017 Available online 30 January 2017

Aeronautical alloys have a good performance on resisting oxidization, corrosion and fatigue in high temperature environments. Therefore, they are not only widely employed in aero-engine but also in nuclear and petroleum industries. The normal spectral emissivity of five alloys in the wavelength ranging 1e15 mm at moderate and high temperature (400e1200 K) is measured. It is found that the emissivity decreases with the increasing of wavelength and increases when temperature rises. The effects of oxidation and flame treatment process are also studied. The results of the oxidized samples indicate that oxidation can enhance the emissivity significantly and alter the wavelength dependent trend. The results of the flame treatment processed samples show that the impurities and defects caused by the flame treatment process moderately increase the emissivity. The experimental data presented in this paper can be used directly to improve the accuracy of radiation computation and other relevant applications. © 2017 Elsevier B.V. All rights reserved.

Keywords: High-temperature alloy Infrared emissivity Surface conditions FT-IR

1. Introduction Radiation is an important heat transfer mode for the hot parts of aero-engines, which significantly affects the structure and strength of aircraft parts. To describe the capacity of emitting radiation of a certain material, emissivity is defined by the ratio of the emissive power of the material and blackbody at the same temperature. The emissivity generally varies with wavelength, temperature and surface conditions. Even for the same material, different surface conditions, such as oxidation, contaminate and different surface micromorphology, have considerable effects on it [1]. However, there are limited theories to predict emissivity accurately, especially for the real material surfaces [2e5]. Therefore, measuring emissivity in a certain material with different surface conditions is significant for high fidelity radiation computation and improving the understanding of radiation heat transfer. Aeronautical alloys are not only widely employed in hot parts of aero-engines but also in nuclear and petroleum industries because of their good performance in resisting oxidization, corrosion and fatigue in high temperature environment. So some researches have already been carried on. Campo investigated the normal and directional emissivity of three kinds of Ni and Co based aeronautical alloys, Inconel 718 (GH169), Rene41 and Haynes 25, on wavelength (2e22 mm), sample temperature (200e650  C) and emission angle

(0e85 ). The effects of the following surface conditions, brushed, sandblast, wire-cut EDM and oxidation, on emissivity were taken into consideration [6]. Keller measured the hemispherical emissivity of Inconel 718 in four different surface types from 650 K to 1275 K, and found that the hemispherical emissivity increased with the increase of temperature and oxidation [7]. Greene measured the hemispherical emissivity of Inconel 718 for the as-received sample and oxidized sample [8]. The normal emissivity of two nickel-based superalloys at the melting transition and in the molten state at 684.5 nm was reported [9]. In this paper, the normal emissivity of GH169, K417G, K77, DZ125 and DD5 in the range of 1e15 mm at 400e1200 K has been measured. Almost all radiation is covered in this range, when these alloys are employed. So emissivity acquired in this experiment is applicable. It can be seen that the emissivity of GH169 has been widely studied and the current experiment extents its temperature range. No emissivity data of K417G, K77, DZ125 and DD5 can be found in literature. Thus the experiment results presented in this paper will show the data for the first time. In addition, when these alloys are used in aero-engine, two typical surface conditions, oxidation and heated by flame, are also considered. 2. Experimental 2.1. Samples

* Corresponding author. E-mail address: [email protected] (Q. Eri). http://dx.doi.org/10.1016/j.jallcom.2017.01.288 0925-8388/© 2017 Elsevier B.V. All rights reserved.

Table 1 shows the composition of each alloy in weight percentage. Alloys are machined into disk samples with the dimension

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of 30 mm in diameter and 2 mm in thickness and then polished using sandpaper. Then these samples are washed by acetone to clean the surfaces and then dried in the air. After that, some of them are heated in a high-temperature air muffle furnace at the temperature of 900  C for 10 h then cooled down to the room temperature in the open air. Some are processed in a kerosene flame for 20 min. So we get three kinds of samples with different surface conditions of each alloy: polished, oxidized and flame treatment processed. These samples can be easily distinguished by their appearance. The polished surfaces are silver-white and shiny. The oxidized surfaces are black and rough. The flame treatment processed surfaces are brown. We measure the roughness of these samples using a conventional roughmeter. Table 2 shows the average roughness (Ra) of each sample. Seen from their appearance, the oxidized samples have the roughest surfaces and the flame treatment processed samples increase not much in roughness. Then a scanning electron microscope (SEM) is used to observe the detail surface micromorphology of each sample. The images in different magnifications are shown in Fig. 1. It can be seen that the polished surfaces are relatively smooth and clean but some tool marks still exist. The oxidized surfaces are covered by continuous oxide films which consist of many cubic crystals. There are some differences between alloys that the films of K417G, DD5 and DZ125 are more uniform than that of GH169 and K77. The flame treatment process introduces some impurities and defects on the surfaces. And X-ray diffraction (XRD) is performed on oxidized and flame treatment processed surfaces to detect products generated. The patterns are displayed in Fig. 2. Analyzing the position and relative intensity of these peaks, we can see that the products on the oxidized samples are almost the same which are Cr2O3 in a higher proportion and fewer NiCrMnO4. The XRD results also show that oxides quantity in the film of GH169 and K77 are higher than K417G, DD5 and DZ125, which indicates that K417G, DD5 and DZ125 have a better oxidation resistance than GH169 and K77. It agrees with the oxidized rate of these alloys reported in literature [10]. There is no oxide detected on the flame treatment processed surfaces. Since the diffusion flame consumed most oxygen in the air and the flame treatment processing time is not long enough.

2.2. Apparatus and measurements The normal spectral emissivity of each sample is measured by a high-temperature normal spectral emissivity measurement system, which mainly consists of a FTeIR spectrometer, a sample heating chamber, a blackbody chamber a rotation disk and a vacuum system [11]. The FTeIR spectrometer (Nicolet iS50) rapidly and accurately detects and processes the signals from the sample and blackbody. The heating chamber heats up the sample by a

Table 2 Roughness average (Ra) of each sample. Ra (mm)

Polished Oxidized Flame treated

GH169

K417G

K77

DD5

DZ125

0.66 1.84 0.78

0.44 1.41 0.59

0.55 2.13 0.61

0.43 1.38 0.52

0.52 1.51 0.57

Silicon Nitride plate and the temperature is measured by a S-type thermocouple wire with the diameter of 0.5 mm. Temperature is controlled by a PID device with the accuracy of 1  C. The blackbody (ISDC, IR-564) is used to calibrate the radiometer. When temperature is stable, the rotation disk rotates to ensure the radiation emitted from sample and blackbody transmits through the same optical path successively. The vacuum system evacuates the chamber to 10 2 Pa to avoid oxidation and the absorption by CO2 and vapor during measuring. Because of the radiation of background, emissivity value can't be obtained by direct division of the radiation signals of the sample and the blackbody. Therefore, a calibration procedure should be done before all measurements. This method involves measuring the output radiation signals of the blackbody at low and high temperatures. A water-cooling system is set at 20  C to keep temperature of the background. So its radiation can be determined. The uncertainty sources of this system come from the temperature measurement, containing the measurement and the stability of the sample temperature and the blackbody temperature, the blackbody cavity effective emissivity, the none-linearity of FTIR and the noise signal. The uncertainty of the temperature is 0.0121. The blackbody cavity effective emissivity uncertainty is 0.0065 and the uncertainty of FTIR is 0.0043, according to the maximum nonlinearity provided by the manufacturer. Hence, the combined uncertainty of this system is 0.0147 and the expended uncertainty is 0.0294 at the 95% confidence level. More details can be found in Ref. [11]. Since surface stress generated during machine process raise emissivity considerably, this effect should be eliminated before measurement [12]. It is also reported that annealing at high temperature is effective to relieve the stress [13]. Therefore, the polished samples were heated for 1 h at 900  C in vacuum before experiment. The oxidation and flame treatment process have already severed as a relieving step, therefore, their emittance can be measured directly. After all preparations, the emissivity of each sample is measured from 400 K to 1200 K in the interval of 200 K. Every temperature step is kept for 20 min to ensure thermal equilibrium before the FT-IR begins to acquire the sample and blackbody radiation spectrum.

Table 1 Nominal composition of each alloy in weight percentage.

GH169 K77 K417G DZ125 DD5

GH169 K77 K417G DZ125 DD5

C

Cr

Ni

Co

W

Mo

Al

Ti

Fe

Ta

Hf

B

Nb

Mg

Ca

0.08 0.05e0.09 0.13e0.22 0.07e0.12 0.05

17.0e21.0 14.0e15.2 8.50e9.50 8.4e9.4 7

50.0e55.0 bal. bal. bal. bal.

1.0 14.0e16.0 9.0e11.0 9.4e10.5 7.5

e e e 6.5e7.5 5

2.80e3.30 3.9e4.5 2.50e3.50 1.5e2.5 1.5

0.30e0.70 4.0e4.6 4.80e5.70 4.8e5.4 6.2

0.75e1.15 3.0e3.7 4.10e4.70 0.7e1.2 e

bal. 0.5 1.0 0.30 0.30

e e e 3.6e4.1 6.5

e e e 1.2e1.8 0.15

0.006 0.012e0.20 0.012e0.024 0.01e0.02 e

4.75e5.50 2.5e3.3 e e 1.2

0.01 0.003 e e e

0.01 e e e e

Re

Zr

Si

Mn

S

P

Ag

Pb

Bi

As

Sn

Sb

V

Cu

e e e e 3

e 0.04 0.05e0.09 0.08 e

0.35 0.20 0.20 0.15 0.20

0.35 0.20 0.20 0.15 0.15

0.015 0.015 0.010 0.01 0.004

0.015 0.0005 0.015 0.01 0.018

e 0.0005 e 0.0005 0.005

0.0005 0.00005 0.0005 0.01 0.0005

e e 0.0001 0.00005 0.00005

e e 0.005 0.001 0.001

e e 0.002 0.001 0.001

e 0.10 0.001 0.001 0.001

e 0.30 0.1 0.60e0.90 e e e d 0.1

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Fig. 1. SEM images of each alloy in different magnification factors. Images in each row are polished sample in 2.5 K magnification factor, oxidized sample in 2.5 K and 10 K factors and flame treatment processed sample in 2.5 K and 10 K factors.

3. Results & discussion The normal emissivity of five aeronautical alloys, GH169, K77, K417G, DD5 and DZ125 is acquired in the wavelength range of 1e15 mm at medium to high temperature (400e1200 K). In addition, the emittance of oxide and flame treatment processed samples in the same ranges is also measured to investigate their effects on radiation properties.

except K77. The emissivity of K77 becomes higher when temperature is beyond 800 K. This is probably caused by oxidation during measuring. Although it is measured almost in a vacuum, there still exists some oxygen reacting with the alloy, which can be proved by some oxides in grey color formed on the surface after measurement. It is also clear that the emissivity value of GH169 increases more with temperature than other alloys. 3.2. Effects of oxidation

3.1. The normal emissivity of polished samples Fig. 3 shows the normal spectral emissivity of the polished samples as a function of wavelength at different temperatures. It can be seen that the wavelength and temperature dependence of these alloys are almost the same that the emissivity decreases with increasing wavelength and increases as temperature rise. These trends are well predicted by the electromagnetic wave theory. But the emissivity values among them still have some differences. DZ125 has a relatively lower emissivity than other alloys, while GH169 and K77 have higher values in long wavelengths. The emissivity at different temperatures in three specific wavelengths (2 mm, 8 mm and 14 mm) is shown in Fig. 4. As seen, the value of emissivity is nearly in liner relation with temperature

Fig. 5 shows the normal spectral emittance of the oxidized samples as a function of wavelength at different temperatures. As seen, their emittance changes significantly in value and profile that the values become higher and the wavelength dependence become irregular compared with the polished samples. The wavelength dependence trends of oxidized K417G, DZ125 and DD5 are almost the same. The oscillation observed in their short wavelength is due to the interference effect of radiation between the oxide film and the alloy surface [6,14,15]. Interference of radiation depends on the thickness of the oxide film and the frequency of incident radiation. The peak shifts to the longer wavelength as the thickness of the oxide film increases. As the growing of the film, the interference effect will disappear when the thickness reaches a certain value

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Fig. 2. XRD patterns of oxidized and flame treatment processed samples. Red, blue and green peaks are identified respectively for Cr2O3 phase Cr2Ni3 phase and NiCrMnO4 phase. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

that incident radiation will be absorbed completely in the film. Consequently, no radiation approaches the substrate and interferes with radiation reflected from oxide film surface. Therefore, it can be concluded that the oxide film of K77 is the thickest. It also agrees with the fact mentioned above that K417G, DZ125 and DD5 have a better oxidation resistance than GH169 and K77, for they experienced the same oxidized process. The oscillations in long wavelength are related to the absorption bands caused by oxide crystal vibrational transitions. In the band the absorptive index is relatively high, while it decreases sharply on both sides [1]. Metals are high reflection and poor absorption to incident radiation because of an abundance of free electrons so that they are usually low in emissivity, since the absorptivity is equal to

emissivity according to the Kirchhoff law. While an oxide film formed on metal, the mechanism of absorption is changed and becomes similar to nonconductors. In infrared, the radiative properties are dominant by the photon excitation of the vibrational energy levels of the solid's crystal lattice [1]. This vibration can produce some electric dipole moment which can interact with electromagnetic wave, triggering strong absorption [16]. This is the main reason that the emittance of these oxidized samples is much higher than polished samples. The other reason is the change of surface micromorphology. The SEM images show the oxide crystals on the film make the surface rougher and more complicated. Roughness average increases significantly, especially for K77 oxide sample. As a result, incident radiation is reflected and absorbed

B. Kong et al. / Journal of Alloys and Compounds 703 (2017) 125e138

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Fig. 3. Normal spectral emissivity of polished samples as a function of wavelength at different temperatures. Fig. 4. Normal emissivity of S1 sample as a function of temperature at different wavelengths.

more times between the crystals, leading to the increase of emittance. XRD results reveal that the compositions of the oxide film are almost the same for these alloys, which are Cr2O3 and NiCrMnO4. The results also show Cr2O3 is in higher proportion than NiCrMnO4. This reason is that Cr is more active and has a stronger outward

transmitting capacity through grain boundary. In addition, Cr2O3 is more stable than the oxides of other elements in the Ni-Cr alloy systems [17] [18]. The generated Cr2O3 and NiCrMnO4 form a continuous and compact oxide film then will prevent oxygen from further oxidizing alloy.

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Fig. 5. Normal spectral emissivity of S2 sample as a function of wavelength at different temperatures.

The temperature dependence of emittance in three wavelengths (2 mm, 8 mm and 14 mm) is displayed in Fig. 6. As seen, temperature rise, emittance in these wavelengths increases with the nearly same rate. The difference among samples is very small.

Fig. 6. Normal emissivity of oxidized samples as a function of temperature at different wavelengths.

3.3. Effect of flame treatment process Fig. 7 is the spectral normal emittance of the flame treatment processed samples in different temperatures as a function of wavelength. It shows that the emittance increases moderately and

B. Kong et al. / Journal of Alloys and Compounds 703 (2017) 125e138

Fig. 7. Normal spectral emittance of flame treatment samples as a function of wavelength at different temperatures.

the wavelength dependence of these samples varies not too much compared with polished samples, i.e., the emittance decreases as increasing wavelength. It indicates most of the radiation is still emitted from the alloy self. There is no interference effect appeared in short wavelength, which reveals no oxides film formed after the flame treatment process. This is accordance with the XRD results that no oxides peaks are identified. Although the process is

131

Fig. 8. Normal emittance of flame treatment samples as a function of temperature at different wavelengths.

conducted in high temperature in the air, oxygen is consumed by the diffusion flame so it can be hardly react with alloys. It is also remarkable that the emittance has a slight increase in long wavelength. The SEM images in Fig. 2 show the surfaces become coarser with some impurities and defects after the flame treatment process. These

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combustion residual particles such as soot have a higher emissivity than alloy. The roughness average of these surfaces also have slight increased. It is reported that the increase of surface roughness affects the emissivity at longer wavelengths more than at shorter wavelengths [19] [20]. These combined effects lead to the increase of emittance, especially in long wavelength. The temperature dependence of emittance in three wavelengths (2 mm, 8 mm and 14 mm) is displayed in Fig. 8. It is notable that there is a sudden increase of emittance at high temperature. On the one hand, this is due to impurities which may have different temperature dependence and on the other hand oxidation during measurement is also a reason. Although a vacuum atmosphere is made before measuring, there still remains some oxygen. When temperature increases highly, oxidation occurs. This is accordance with the observation that some grey oxide spots are formed on some samples after measurement.

near IR to middle IR is measured. It is found these polished alloys all have low emissivity. As theories predict, the emissivity decreases with increasing wavelength and increases as temperature rise. In addition, oxide film formed on samples increase the emissivity significantly because of the change of absorption mechanism and surface micromorphology. The effects of interference and absorption band are observed clearly, which make the wavelength dependence irregular. The flame treatment process also increases the emissivity, especially in long wavelength. This is mainly caused by impurities left on the surface after the process. These surface conditions are typical conditions when these alloys are used in aero-engine, and temperature and wavelength ranges are wide enough to cover their working conditions. Therefore, data acquired in this experiment is practical in relevant industrial applications.

4. Conclusion Appendix In this paper, the normal spectral emissivity of five aeronautical alloys in a wide temperature range (400e1200 K) from

Table 3 Some data extracted from original experimental data. Wavelength

Emissivity of polished GH169

14.9658 13.86568 12.90993 12.07188 11.33105 10.67145 10.08042 9.54779 9.06531 8.62623 8.22492 7.85674 7.51772 7.20454 6.91437 6.64473 6.39355 6.15897 5.93941 5.73347 5.53993 5.35769 5.18579 5.02338 4.86969 4.58581 4.45446 4.2104 3.98841 3.78562 3.42849 3.19585 2.98804 2.80127 2.57981 2.3395 2.1712 1.97288 1.66775 1.42516 1.22765 1.06374

0.09274 0.08477 0.08859 0.08453 0.08452 0.0977 0.09636 0.09942 0.10623 0.10406 0.10489 0.10951 0.10673 0.11696 0.11842 0.11574 0.1231 0.1221 0.12103 0.12301 0.12946 0.13269 0.13069 0.13259 0.13884 0.14584 0.14376 0.14895 0.1564 0.16664 0.18448 0.18995 0.19893 0.21812 0.23335 0.25676 0.27216 0.29659 0.32985 0.35823 0.38101 0.40896

Wavelength

Emissivity of polished K77

14.9658 13.86568 12.90993

0.08477 0.07786 0.07377

0.10816 0.1079 0.10679 0.10433 0.10613 0.11355 0.11792 0.12087 0.12369 0.1246 0.12688 0.12753 0.13044 0.13511 0.13758 0.13865 0.14149 0.14375 0.14171 0.14384 0.14907 0.15145 0.15135 0.15374 0.15703 0.16284 0.16691 0.17115 0.17774 0.18678 0.19775 0.20941 0.22047 0.23686 0.25199 0.27485 0.29246 0.31793 0.34322 0.37022 0.39442 0.42338

0.09334 0.08624 0.08272

Emissivity of polished K417G 0.12494 0.12495 0.12397 0.12143 0.12322 0.13065 0.13502 0.13797 0.14079 0.1417 0.14398 0.14463 0.14754 0.15221 0.15469 0.15574 0.1586 0.16084 0.15881 0.16095 0.16616 0.16855 0.16845 0.17083 0.17413 0.17994 0.18402 0.18825 0.19483 0.20388 0.21485 0.2265 0.23757 0.25396 0.26909 0.29196 0.30957 0.33573 0.36146 0.38956 0.41786 0.45303

0.14569 0.14591 0.14501 0.14242 0.14422 0.15164 0.15603 0.15897 0.16178 0.16271 0.16498 0.16562 0.16854 0.17322 0.17569 0.17674 0.1796 0.18184 0.17981 0.18195 0.18716 0.18955 0.18945 0.19184 0.19513 0.20095 0.20502 0.20924 0.21582 0.22488 0.23584 0.24751 0.25857 0.27496 0.29009 0.31295 0.33057 0.35692 0.38021 0.40658 0.43612 0.47572

0.16666 0.1669 0.16601 0.16344 0.16521 0.17264 0.17703 0.17997 0.18278 0.18371 0.18598 0.18663 0.18954 0.19422 0.19668 0.19774 0.20059 0.20284 0.2008 0.20296 0.20816 0.21055 0.21045 0.21284 0.21613 0.22196 0.22602 0.23025 0.23682 0.24589 0.25683 0.26852 0.27956 0.29597 0.3111 0.33395 0.35157 0.37714 0.40477 0.43605 0.47233 0.52137

0.04439 0.04365 0.04383 0.04555 0.05154 0.06185 0.06954 0.07793 0.08274 0.08665 0.09098 0.09344 0.09871 0.10669 0.11152 0.11597 0.1212 0.12613 0.12816 0.13226 0.13902 0.1434 0.14417 0.14665 0.15125 0.15995 0.16573 0.17385 0.18423 0.19682 0.21892 0.23387 0.25115 0.27493 0.29525 0.32462 0.34499 0.37811 0.40835 0.43783 0.46351 0.49056

0.05078 0.04978 0.04975 0.05148 0.05883 0.06891 0.07831 0.08578 0.0907 0.09441 0.09869 0.10131 0.10628 0.11497 0.12023 0.12377 0.12884 0.13442 0.13579 0.14035 0.14695 0.15201 0.15223 0.15472 0.15888 0.16758 0.17393 0.18148 0.19213 0.20423 0.22688 0.24249 0.25929 0.28226 0.30275 0.33219 0.35258 0.38549 0.41489 0.44674 0.47213 0.4972

0.06019 0.05907 0.05993 0.06123 0.06884 0.07957 0.088 0.09514 0.10133 0.10428 0.10878 0.11149 0.11632 0.12521 0.13015 0.13343 0.13922 0.14458 0.14547 0.15019 0.1573 0.16199 0.16223 0.16434 0.1685 0.17794 0.18392 0.19122 0.20188 0.21437 0.23618 0.25216 0.26919 0.29284 0.3125 0.34219 0.36287 0.39677 0.42522 0.45535 0.48026 0.50631

0.06665 0.06647 0.06742 0.06834 0.07576 0.08628 0.09535 0.1031 0.10774 0.11148 0.11604 0.11784 0.12355 0.13215 0.13681 0.14055 0.14576 0.15164 0.15259 0.1568 0.1639 0.169 0.16932 0.17179 0.17586 0.18504 0.19119 0.19913 0.20937 0.22153 0.24315 0.25975 0.27658 0.29921 0.3196 0.34939 0.36965 0.40389 0.43216 0.4621 0.48764 0.51364

0.07762 0.07722 0.07804 0.0797 0.08671 0.09736 0.10615 0.11361 0.11913 0.12255 0.12707 0.12915 0.13478 0.14311 0.14792 0.15158 0.1571 0.16243 0.1638 0.168 0.17505 0.17968 0.18062 0.18284 0.18679 0.19591 0.20213 0.20966 0.22019 0.23241 0.25458 0.27032 0.28716 0.31048 0.33096 0.36037 0.38107 0.41464 0.44304 0.47326 0.49832 0.52388

0.08331 0.08632 0.09075

0.09329 0.09632 0.10075

0.11029 0.11259 0.11666

Emissivity of polished DD5 0.10248 0.09622 0.09166

0.12498 0.11853 0.11506

0.14316 0.14129 0.13893

0.06541 0.06828 0.07266

0.07962 0.08232 0.08673

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Table 3 (continued ) Wavelength

Emissivity of polished K77

12.07188 11.33105 10.67145 10.08042 9.54779 9.06531 8.62623 8.22492 7.85674 7.51772 7.20454 6.91437 6.64473 6.39355 6.15897 5.93941 5.73347 5.53993 5.35769 5.18579 5.02338 4.86969 4.58581 4.45446 4.2104 3.98841 3.78562 3.42849 3.19585 2.98804 2.80127 2.57981 2.3395 2.1712 1.97288 1.66775 1.42516 1.22765 1.06374

0.07272 0.07577 0.08259 0.08805 0.0935 0.09771 0.09901 0.10075 0.10025 0.10341 0.10957 0.11221 0.11386 0.11822 0.12189 0.12147 0.12426 0.12984 0.13257 0.13073 0.13027 0.13261 0.1384 0.1431 0.14793 0.15574 0.16449 0.18084 0.19264 0.20554 0.22531 0.24063 0.26693 0.285 0.31426 0.34171 0.37603 0.40735 0.43876

0.08086 0.08432 0.09088 0.09703 0.10209 0.10603 0.10784 0.10926 0.10885 0.11227 0.11847 0.12064 0.12282 0.12659 0.13072 0.13023 0.13285 0.13826 0.14097 0.13941 0.13904 0.14154 0.14713 0.15179 0.15625 0.16389 0.17348 0.18941 0.20156 0.21364 0.23408 0.24961 0.275 0.29376 0.32171 0.34938 0.38224 0.41301 0.44917

Emissivity of polished DD5 0.09089 0.09373 0.10093 0.10643 0.11165 0.1157 0.11698 0.11878 0.11863 0.12117 0.12728 0.13062 0.13192 0.13639 0.13941 0.13906 0.14194 0.1477 0.15014 0.1491 0.14834 0.1508 0.1563 0.1609 0.16584 0.1738 0.18235 0.19847 0.21018 0.22368 0.24377 0.25856 0.2845 0.30323 0.33202 0.36266 0.39881 0.43072 0.46366

Wavelength

Emissivity of polished DZ125

14.9658 13.86568 12.90993 12.07188 11.33105 10.67145 10.08042 9.54779 9.06531 8.62623 8.22492 7.85674 7.51772 7.20454 6.91437 6.64473 6.39355 6.15897 5.93941 5.73347 5.53993 5.35769 5.18579 5.02338 4.86969 4.58581 4.45446 4.2104 3.98841 3.78562 3.42849 3.19585 2.98804

0.053 0.05579 0.05983 0.06386 0.06658 0.06989 0.07397 0.07804 0.08144 0.08385 0.08923 0.09236 0.09529 0.0983 0.1028 0.10664 0.10868 0.11071 0.11329 0.11557 0.12099 0.12529 0.12713 0.12975 0.13267 0.14334 0.14613 0.15232 0.16029 0.16843 0.18276 0.19763 0.20815

0.11326 0.11695 0.12354 0.12913 0.13421 0.13886 0.14031 0.14169 0.14094 0.14451 0.15102 0.15342 0.15471 0.15947 0.16238 0.16218 0.16506 0.17088 0.17404 0.17215 0.17137 0.17316 0.17947 0.18366 0.18904 0.19676 0.20555 0.22193 0.23413 0.24649 0.26604 0.28186 0.30757 0.3259 0.35532 0.38342 0.41543 0.44524 0.47922

0.05993 0.06296 0.06633 0.07171 0.07423 0.07697 0.08199 0.08583 0.09 0.09153 0.09675 0.10085 0.10218 0.10639 0.10883 0.11341 0.11547 0.11885 0.12099 0.12408 0.12751 0.13196 0.13402 0.137 0.13976 0.14911 0.15202 0.15912 0.16841 0.17419 0.19026 0.20228 0.21409

0.13797 0.14096 0.145 0.15095 0.15595 0.15948 0.16169 0.16248 0.1656 0.16819 0.17087 0.17467 0.17811 0.18101 0.18305 0.18652 0.18836 0.19146 0.1933 0.19428 0.19521 0.19563 0.20127 0.20472 0.21117 0.21893 0.22673 0.24385 0.25561 0.2694 0.28676 0.30262 0.32865 0.34837 0.38584 0.40857 0.43861 0.47188 0.50382

0.0771 0.08089 0.08196 0.08798 0.09155 0.09433 0.09609 0.09936 0.1001 0.10414 0.10832 0.11202 0.11439 0.11807 0.1216 0.12108 0.12212 0.12716 0.13055 0.13296 0.13455 0.13785 0.14402 0.14927 0.15398 0.16294 0.17141 0.1861 0.20079 0.2132 0.23073 0.24882 0.27389 0.29335 0.32439 0.35004 0.37578 0.39506 0.41813

0.06633 0.06845 0.07383 0.07707 0.08035 0.08233 0.08608 0.09133 0.09543 0.0971 0.10243 0.10496 0.10897 0.11177 0.11551 0.12022 0.12153 0.12392 0.12714 0.12789 0.13455 0.13865 0.14064 0.14196 0.14541 0.15666 0.15936 0.16507 0.17421 0.1816 0.19608 0.21132 0.22029

0.0911 0.09479 0.09575 0.1027 0.10465 0.10838 0.1088 0.11205 0.11289 0.11755 0.12187 0.12548 0.1284 0.1328 0.13621 0.1336 0.13627 0.14245 0.14563 0.14534 0.14892 0.15303 0.15815 0.16219 0.1688 0.17647 0.18639 0.19985 0.21463 0.22626 0.24546 0.26222 0.28761 0.30783 0.33694 0.36397 0.38822 0.41048 0.43248

0.09525 0.09853 0.09977 0.10685 0.11 0.11195 0.11312 0.11559 0.11744 0.12161 0.12762 0.13067 0.13171 0.13646 0.13924 0.13848 0.13984 0.14596 0.14949 0.15082 0.15282 0.15591 0.16308 0.1664 0.17304 0.18136 0.18971 0.20531 0.21685 0.2308 0.24791 0.26721 0.29188 0.31258 0.34194 0.36738 0.39259 0.41315 0.43599

0.07465 0.07662 0.08191 0.08511 0.08715 0.09151 0.09506 0.09993 0.10305 0.10541 0.11045 0.11398 0.11633 0.11888 0.12436 0.12819 0.12926 0.1331 0.13435 0.13625 0.14175 0.14745 0.14791 0.15226 0.15497 0.16404 0.16805 0.1738 0.18223 0.18924 0.20366 0.21941 0.22865

0.10611 0.10881 0.10982 0.11678 0.11854 0.12333 0.1246 0.12541 0.12715 0.13124 0.13579 0.13919 0.14126 0.14613 0.14851 0.14818 0.14959 0.15637 0.15869 0.15905 0.1618 0.16536 0.17326 0.17736 0.18258 0.1911 0.20087 0.21535 0.2283 0.24163 0.258 0.27739 0.30165 0.32253 0.35178 0.37802 0.40259 0.42409 0.44613

0.12214 0.12486 0.12575 0.13285 0.13542 0.13832 0.13968 0.14231 0.14394 0.14745 0.15276 0.15596 0.15783 0.16187 0.16508 0.16416 0.16621 0.17166 0.17506 0.176 0.17861 0.18204 0.18858 0.19307 0.19823 0.2065 0.21592 0.23055 0.24387 0.25696 0.2747 0.2926 0.31782 0.33817 0.36758 0.39376 0.4186 0.43881 0.46058

0.08264 0.08524 0.08842 0.09254 0.0971 0.09847 0.10353 0.10838 0.11179 0.11416 0.11906 0.12082 0.12586 0.12712 0.13148 0.13659 0.13902 0.1391 0.14277 0.14425 0.14953 0.15486 0.15606 0.15826 0.1622 0.17258 0.17642 0.18107 0.19012 0.19773 0.21141 0.2267 0.23862 (continued on next page)

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B. Kong et al. / Journal of Alloys and Compounds 703 (2017) 125e138

Table 3 (continued ) Wavelength

Emissivity of polished DZ125

2.80127 2.57981 2.3395 2.1712 1.97288 1.66775 1.42516 1.22765 1.06374

0.21941 0.23696 0.26128 0.2783 0.30471 0.32576 0.34937 0.3686 0.38673

Wavelength

Emissivity of oxidized GH169

14.9658 13.86568 12.90993 12.07188 11.33105 10.67145 10.08042 9.54779 9.06531 8.62623 8.22492 7.85674 7.51772 7.20454 6.91437 6.64473 6.39355 6.15897 5.93941 5.73347 5.53993 5.35769 5.18579 5.02338 4.86969 4.58581 4.45446 4.2104 3.98841 3.78562 3.42849 3.19585 2.98804 2.80127 2.57981 2.3395 2.1712 1.97288 1.66775 1.42516 1.22765 1.06374

0.28141 0.28639 0.39185 0.32929 0.39331 0.53766 0.61991 0.65912 0.66709 0.65376 0.63385 0.61577 0.59948 0.59573 0.59295 0.58936 0.59285 0.59328 0.59451 0.59599 0.60055 0.60651 0.60914 0.6152 0.62339 0.6378 0.64351 0.65864 0.67663 0.69432 0.71912 0.72573 0.73008 0.73859 0.74488 0.75417 0.76013 0.7701 0.78365 0.79565 0.80561 0.81229

Wavelength

Emissivity of oxidized K77

14.9658 13.86568 12.90993 12.07188 11.33105 10.67145 10.08042 9.54779 9.06531 8.62623 8.22492 7.85674 7.51772 7.20454 6.91437 6.64473 6.39355 6.15897 5.93941

0.29514 0.31821 0.39115 0.41505 0.447 0.51859 0.57012 0.60969 0.62834 0.62963 0.62846 0.62876 0.62669 0.63302 0.63512 0.63563 0.6412 0.64357 0.64568

0.29569 0.30168 0.40682 0.34433 0.40833 0.55251 0.63495 0.67394 0.68213 0.66879 0.64896 0.63094 0.61435 0.61097 0.60777 0.60461 0.60784 0.60846 0.60949 0.61088 0.6154 0.62148 0.62383 0.63012 0.63825 0.65295 0.6585 0.67378 0.69186 0.70943 0.73405 0.74097 0.745 0.75354 0.75979 0.76893 0.77493 0.78458 0.79922 0.81005 0.82048 0.82706

0.3143 0.33853 0.41112 0.43515 0.46701 0.53838 0.59018 0.62955 0.6484 0.64964 0.64858 0.64891 0.64658 0.65325 0.65494 0.65587 0.66124 0.66373 0.6657

0.2277 0.24536 0.26945 0.28582 0.32014 0.33576 0.35569 0.37496 0.39183

0.23163 0.24943 0.27495 0.29114 0.31895 0.34227 0.36399 0.38118 0.39895

0.24176 0.25797 0.28235 0.29999 0.32711 0.35103 0.37296 0.38855 0.40662

0.24956 0.26756 0.29058 0.30782 0.33606 0.35865 0.3798 0.3966 0.41634

Emissivity of oxidized K417G 0.31517 0.32174 0.42675 0.3643 0.4283 0.57252 0.65499 0.6939 0.70203 0.68874 0.66911 0.65103 0.63436 0.63104 0.62771 0.62456 0.62766 0.62869 0.62948 0.6308 0.63542 0.64144 0.64396 0.65019 0.65824 0.67294 0.6783 0.69392 0.71198 0.72943 0.75413 0.76095 0.76507 0.77357 0.77971 0.78877 0.79496 0.80495 0.819 0.82934 0.84079 0.84689

0.32834 0.33452 0.4397 0.37725 0.4412 0.5856 0.66807 0.70693 0.71498 0.70167 0.68207 0.66401 0.64736 0.64403 0.64074 0.63752 0.64061 0.64181 0.64255 0.6438 0.64843 0.65439 0.65706 0.66328 0.67124 0.6859 0.69133 0.70689 0.72506 0.74242 0.76717 0.7739 0.77816 0.78651 0.79268 0.80171 0.80794 0.81755 0.83205 0.84244 0.85355 0.86018

0.34991 0.35511 0.46053 0.39826 0.46214 0.60664 0.68911 0.72796 0.73596 0.72262 0.70302 0.68502 0.66835 0.66503 0.66178 0.6585 0.66162 0.66288 0.66358 0.66475 0.66947 0.67528 0.67813 0.68436 0.69221 0.7069 0.71234 0.72785 0.74613 0.7634 0.78819 0.79483 0.79921 0.80738 0.81367 0.82268 0.82887 0.83848 0.8531 0.86335 0.87446 0.88136

0.22951 0.31076 0.40246 0.24962 0.21935 0.24628 0.26701 0.29982 0.34661 0.36632 0.39547 0.43974 0.4914 0.55502 0.61372 0.65982 0.69804 0.71947 0.73191 0.73458 0.73277 0.72577 0.712 0.69816 0.68655 0.6633 0.65215 0.63832 0.63216 0.6321 0.63712 0.64164 0.64824 0.66299 0.67829 0.70292 0.72168 0.75132 0.77995 0.7895 0.7959 0.80131

0.32699 0.3516 0.4241 0.44822 0.47999 0.55136 0.60324 0.6425 0.66131 0.66262 0.66169 0.66196 0.6596 0.66628 0.66789 0.66882 0.67416 0.67683 0.67867

0.3499 0.37454 0.44708 0.47118 0.50288 0.57442 0.62639 0.66549 0.68421 0.6855 0.68475 0.68494 0.68257 0.68929 0.69089 0.69172 0.69707 0.69999 0.70172

0.36454 0.38199 0.45652 0.48185 0.51272 0.58432 0.63663 0.67557 0.69409 0.69518 0.69491 0.69511 0.69272 0.69923 0.70103 0.70156 0.70744 0.71007 0.71205

0.27955 0.37966 0.47164 0.28782 0.25207 0.27378 0.29402 0.31786 0.36159 0.38725 0.41788 0.4589 0.51199 0.57348 0.64292 0.70931 0.75646 0.78852 0.80874

0.23603 0.31797 0.40948 0.2567 0.22642 0.2531 0.27407 0.3067 0.35361 0.37332 0.40246 0.44685 0.49824 0.56214 0.62057 0.66696 0.70508 0.72661 0.73891 0.74153 0.73957 0.73272 0.71872 0.70509 0.69345 0.67041 0.65917 0.64544 0.6393 0.6392 0.64407 0.64883 0.65533 0.66997 0.68535 0.70969 0.72851 0.75705 0.7867 0.79724 0.80233 0.80756

0.24635 0.32914 0.42055 0.2679 0.23739 0.26401 0.28511 0.31764 0.36465 0.38432 0.41368 0.45801 0.50932 0.57331 0.63149 0.67797 0.71595 0.73787 0.74991 0.75246 0.75062 0.74374 0.72985 0.71614 0.70437 0.68143 0.66991 0.65662 0.65053 0.65019 0.6552 0.65988 0.66623 0.68094 0.69617 0.72052 0.73959 0.76878 0.7977 0.80726 0.81262 0.81833

0.26758 0.34997 0.44151 0.28906 0.25833 0.28507 0.30624 0.33866 0.38559 0.4052 0.43464 0.47896 0.5303 0.59428 0.65251 0.69888 0.73691 0.759 0.77096 0.77344 0.77163 0.76471 0.75094 0.73722 0.72539 0.70239 0.69095 0.67758 0.67162 0.67121 0.67629 0.6808 0.6873 0.70189 0.71713 0.74148 0.7606 0.78945 0.81873 0.82836 0.83334 0.83949

0.29033 0.37372 0.46359 0.32196 0.28325 0.30952 0.33158 0.3644 0.41006 0.43016 0.46006 0.50417 0.55579 0.61923 0.67762 0.72407 0.76231 0.78426 0.7963 0.79864 0.79732 0.78924 0.77626 0.76263 0.75036 0.72723 0.71611 0.70246 0.69705 0.69632 0.70089 0.70534 0.71309 0.72639 0.74197 0.76602 0.78561 0.81458 0.84366 0.85343 0.85779 0.86447

0.33183 0.42927 0.52168 0.33776 0.30214 0.32389 0.34423 0.36769 0.41183 0.43734 0.46807 0.50897 0.56207 0.6234 0.69297 0.75947 0.80622 0.83842 0.85896

0.36205 0.45924 0.55173 0.36775 0.33216 0.35385 0.37423 0.39769 0.44181 0.4674 0.49808 0.53896 0.59205 0.65347 0.723 0.78951 0.83616 0.86846 0.889

0.37316 0.46893 0.56182 0.37774 0.34219 0.3639 0.38434 0.40766 0.4518 0.47757 0.50803 0.54914 0.60198 0.66368 0.73319 0.79939 0.84603 0.87858 0.89907

Emissivity of oxidized DD5 0.30184 0.39925 0.49163 0.30776 0.27211 0.29391 0.31425 0.33773 0.38185 0.40732 0.43807 0.47896 0.53205 0.59334 0.66298 0.72944 0.77623 0.80842 0.82894

B. Kong et al. / Journal of Alloys and Compounds 703 (2017) 125e138

135

Table 3 (continued ) Wavelength

Emissivity of oxidized K77

5.73347 5.53993 5.35769 5.18579 5.02338 4.86969 4.58581 4.45446 4.2104 3.98841 3.78562 3.42849 3.19585 2.98804 2.80127 2.57981 2.3395 2.1712 1.97288 1.66775 1.42516 1.22765 1.06374

0.64865 0.65067 0.65551 0.65634 0.6576 0.66224 0.66495 0.66487 0.66683 0.67004 0.67465 0.68015 0.67881 0.67734 0.6818 0.68105 0.68236 0.6814 0.684 0.68535 0.68592 0.68775 0.68867

0.66855 0.67053 0.67548 0.67605 0.6775 0.6821 0.68508 0.68487 0.68698 0.69027 0.69477 0.7001 0.69904 0.69728 0.70176 0.70096 0.70213 0.70123 0.70313 0.70558 0.70571 0.70783 0.70823

Emissivity of oxidized DD5 0.68151 0.68356 0.68846 0.68913 0.69055 0.69509 0.69809 0.69775 0.70008 0.70334 0.70777 0.71318 0.71205 0.71031 0.71478 0.71394 0.71502 0.71427 0.71633 0.71821 0.71871 0.72095 0.72128

Wavelength

Emissivity of oxidized DZ125

14.95502 13.81537 12.82768 11.96345 11.2009 10.52307 9.91659 9.37076 8.87691 8.42797 8.01805 7.6423 7.29661 6.97751 6.68205 6.40769 6.15225 5.91384 5.69082 5.48173 5.28531 5.10045 4.92615 4.76153 4.60582 4.4583 4.31834 4.18538 4.05891 3.93846 3.71398 3.50903 3.23296 3.14831 2.9135 2.70384 2.45692 2.191 2.00602 1.79084 1.45986 1.19906

0.24456 0.33715 0.44606 0.3128 0.21665 0.22969 0.24873 0.26116 0.29289 0.31851 0.34262 0.37696 0.41244 0.46014 0.51986 0.57557 0.64025 0.6896 0.7307 0.76258 0.78543 0.7929 0.78892 0.78261 0.77216 0.75509 0.74407 0.73454 0.71767 0.71041 0.69094 0.6831 0.67823 0.67417 0.68005 0.68379 0.69598 0.71863 0.73015 0.75226 0.79436 0.81374

0.7143 0.71703 0.72094 0.72257 0.72402 0.72795 0.73096 0.73081 0.73284 0.73674 0.74087 0.74598 0.74469 0.74381 0.74728 0.74684 0.7476 0.74721 0.74898 0.75087 0.75157 0.75371 0.75412

0.25648 0.35025 0.45868 0.32625 0.22951 0.24253 0.26159 0.2745 0.30594 0.33157 0.35555 0.38986 0.42503 0.47282 0.53336 0.5884 0.65345 0.70265 0.7437 0.77545 0.79838 0.80582 0.80177 0.79566 0.78503 0.76789 0.75719 0.74764 0.73052 0.72361 0.70406 0.69627 0.69118 0.68681 0.69326 0.69727 0.70929 0.73153 0.74323 0.76754 0.80837 0.826

Wavelength

Emissivity of flame processed GH169

14.9658 13.86568 12.90993 12.07188

0.16165 0.17109 0.15835 0.1469

0.17129 0.18133 0.16834 0.15699

0.70445 0.70658 0.71143 0.71228 0.71366 0.71809 0.72105 0.7207 0.72309 0.72647 0.73081 0.73625 0.73497 0.73338 0.73774 0.73687 0.7379 0.73728 0.73909 0.74109 0.74157 0.74388 0.74433

0.20334 0.21332 0.20033 0.18899

0.81671 0.81271 0.80674 0.79131 0.77198 0.75245 0.72493 0.71535 0.69796 0.6898 0.68726 0.689 0.69162 0.70499 0.7152 0.73354 0.75768 0.78145 0.8112 0.84366 0.85793 0.8625 0.87121

0.83664 0.83289 0.82681 0.81183 0.79218 0.77278 0.74476 0.73528 0.7181 0.70985 0.70723 0.70918 0.71131 0.72508 0.73521 0.75391 0.77754 0.8013 0.83062 0.86479 0.88024 0.88232 0.89252

0.26577 0.35909 0.46757 0.33527 0.23866 0.2514 0.27054 0.2836 0.31498 0.34053 0.36452 0.39895 0.43392 0.48191 0.54226 0.59736 0.66232 0.71172 0.75269 0.78453 0.80734 0.81485 0.81069 0.80484 0.79405 0.77679 0.76603 0.75662 0.7396 0.73258 0.71297 0.70532 0.70007 0.69574 0.70225 0.70613 0.7184 0.74056 0.75212 0.77636 0.81629 0.83565

0.86671 0.86286 0.85679 0.84179 0.82213 0.80275 0.77474 0.76533 0.74806 0.73985 0.73721 0.73914 0.74128 0.75506 0.76522 0.78389 0.80751 0.83133 0.8607 0.89465 0.91004 0.9118 0.9217

0.89678 0.89284 0.88677 0.8718 0.85213 0.83272 0.80469 0.79536 0.77801 0.76985 0.76715 0.76914 0.77126 0.785 0.79517 0.81388 0.83744 0.86131 0.8908 0.92464 0.94008 0.9416 0.95154

0.27694 0.37001 0.47846 0.34627 0.24973 0.26237 0.28151 0.29468 0.32602 0.35155 0.37548 0.40994 0.44487 0.49292 0.55326 0.6083 0.67331 0.72276 0.76367 0.79549 0.81837 0.82587 0.82164 0.81589 0.80505 0.78776 0.77698 0.76768 0.75061 0.7436 0.72392 0.71631 0.71106 0.70668 0.71324 0.71713 0.72949 0.75156 0.76313 0.78771 0.82728 0.84678

0.90676 0.90282 0.89664 0.8818 0.86189 0.84262 0.81469 0.80554 0.78787 0.77988 0.77703 0.77918 0.78139 0.79502 0.80495 0.82388 0.8472 0.87124 0.90052 0.93511 0.94915 0.95188 0.9612

0.29107 0.38394 0.49238 0.36024 0.26378 0.27635 0.29549 0.30874 0.34005 0.36556 0.38944 0.42392 0.45885 0.50694 0.56724 0.62226 0.6873 0.73679 0.77764 0.80946 0.8324 0.8399 0.8356 0.82994 0.81905 0.80173 0.79092 0.78171 0.76464 0.7576 0.73788 0.7303 0.72503 0.72064 0.72722 0.73111 0.74356 0.76557 0.77712 0.80181 0.84114 0.86093

Emissivity of flame processed K417G 0.21489 0.22553 0.21228 0.20106

0.25901 0.26949 0.25666 0.24463

0.13918 0.1548 0.14753 0.13675

0.15059 0.16709 0.15954 0.14883

0.15991 0.17729 0.16946 0.1589

0.16859 0.18639 0.17855 0.16782

0.17994 0.1975 0.19012 0.17794

(continued on next page)

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B. Kong et al. / Journal of Alloys and Compounds 703 (2017) 125e138

Table 3 (continued ) Wavelength

Emissivity of flame processed GH169

11.33105 10.67145 10.08042 9.54779 9.06531 8.62623 8.22492 7.85674 7.51772 7.20454 6.91437 6.64473 6.39355 6.15897 5.93941 5.73347 5.53993 5.35769 5.18579 5.02338 4.86969 4.58581 4.45446 4.2104 3.98841 3.78562 3.42849 3.19585 2.98804 2.80127 2.57981 2.3395 2.1712 1.97288 1.66775 1.42516 1.22765 1.06374

0.15161 0.1651 0.16912 0.17676 0.18843 0.18818 0.19238 0.19272 0.19316 0.20226 0.20273 0.20123 0.20924 0.20967 0.20959 0.212 0.21796 0.22316 0.21694 0.21754 0.22282 0.22988 0.23007 0.23553 0.24378 0.25411 0.27254 0.28109 0.29116 0.31354 0.32699 0.35249 0.36441 0.3889 0.42366 0.44694 0.47162 0.49721

Wavelength

Emissivity of flame processed K77

14.9658 13.86568 12.90993 12.07188 11.33105 10.67145 10.08042 9.54779 9.06531 8.62623 8.22492 7.85674 7.51772 7.20454 6.91437 6.64473 6.39355 6.15897 5.93941 5.73347 5.53993 5.35769 5.18579 5.02338 4.86969 4.58581 4.45446 4.2104 3.98841 3.78562 3.42849 3.19585 2.98804 2.80127

0.16602 0.17963 0.17071 0.15866 0.16143 0.17578 0.17793 0.18365 0.19307 0.19158 0.19451 0.19767 0.19722 0.2063 0.20723 0.20533 0.21365 0.21444 0.21494 0.21738 0.22225 0.22656 0.22486 0.22568 0.23247 0.23919 0.2393 0.24554 0.25414 0.26603 0.28533 0.29541 0.30631 0.3276

0.16167 0.17487 0.17917 0.18659 0.1984 0.19817 0.20238 0.20289 0.20293 0.21245 0.21251 0.21143 0.21926 0.21983 0.21955 0.22191 0.22772 0.23307 0.22655 0.22741 0.23269 0.24004 0.2401 0.2457 0.25396 0.26425 0.28248 0.29134 0.30128 0.32352 0.33707 0.36217 0.37416 0.39704 0.43362 0.45797 0.48114 0.50557

0.17491 0.18941 0.18023 0.16826 0.17103 0.18504 0.18752 0.19295 0.20256 0.20106 0.20401 0.20734 0.20646 0.21599 0.21647 0.21506 0.22319 0.22412 0.22441 0.22678 0.23146 0.23597 0.23394 0.23504 0.24184 0.24887 0.24882 0.25523 0.26383 0.27569 0.29477 0.3052 0.31594 0.33708

0.19362 0.20687 0.21117 0.21859 0.23045 0.23019 0.23443 0.2349 0.23499 0.2445 0.24453 0.24348 0.25124 0.25183 0.25158 0.2539 0.2598 0.2651 0.25858 0.25942 0.26467 0.27203 0.2721 0.27769 0.28598 0.29623 0.31447 0.32333 0.33316 0.35549 0.36897 0.39423 0.40619 0.42962 0.46604 0.48911 0.51328 0.53763

0.19856 0.21417 0.20475 0.19297 0.19546 0.20952 0.21211 0.21732 0.22714 0.22557 0.22881 0.23206 0.23111 0.24068 0.24085 0.2397 0.24756 0.24883 0.24897 0.25119 0.25611 0.26052 0.25849 0.2596 0.26623 0.27341 0.27314 0.27993 0.28859 0.30016 0.31937 0.32982 0.34021 0.36151

Emissivity of flame processed K417G 0.20547 0.21883 0.2233 0.23046 0.2424 0.24208 0.24672 0.24712 0.24701 0.25668 0.25644 0.25549 0.26298 0.26414 0.26356 0.26577 0.27184 0.27708 0.27068 0.27153 0.27656 0.28405 0.28382 0.28996 0.29826 0.30823 0.32664 0.33536 0.34513 0.3675 0.38084 0.40596 0.41828 0.44226 0.47809 0.50009 0.52499 0.54801

0.2491 0.26298 0.26761 0.27457 0.2863 0.28567 0.29062 0.29118 0.2909 0.30065 0.30067 0.29925 0.30697 0.30843 0.30787 0.30956 0.31594 0.32072 0.31501 0.31588 0.32041 0.32794 0.32798 0.33373 0.34261 0.35219 0.37084 0.37909 0.3895 0.41099 0.42476 0.44974 0.46211 0.4858 0.52184 0.54429 0.5672 0.59231

0.14047 0.1545 0.15605 0.16223 0.16925 0.17027 0.1732 0.17693 0.17654 0.18697 0.18964 0.19028 0.19919 0.19959 0.2027 0.20529 0.20939 0.21424 0.2141 0.21516 0.22107 0.22778 0.22777 0.23357 0.24215 0.25315 0.27132 0.28025 0.29071 0.31032 0.32565 0.35024 0.36504 0.38887 0.41712 0.43278 0.44572 0.46492

0.2083 0.22424 0.21485 0.20294 0.20536 0.21953 0.2222 0.22733 0.23703 0.23544 0.23892 0.24204 0.24102 0.2507 0.25085 0.24958 0.25737 0.25903 0.25903 0.26116 0.26607 0.2705 0.26861 0.26967 0.27626 0.28337 0.28302 0.28999 0.29869 0.3102 0.32946 0.3397 0.3503 0.37153

0.22876 0.24413 0.23537 0.2226 0.22505 0.23969 0.24259 0.24738 0.25679 0.2551 0.25875 0.26217 0.26091 0.27065 0.27104 0.26938 0.27741 0.27925 0.2793 0.28104 0.28624 0.29015 0.2889 0.29003 0.29618 0.30333 0.30313 0.30974 0.31907 0.33013 0.3495 0.35937 0.37059 0.39098

0.21428 0.22602 0.21718 0.20591 0.21011 0.22211 0.22472 0.2285 0.23509 0.2375 0.23967 0.24195 0.24201 0.24907 0.25147 0.25282 0.2615 0.26428 0.25986 0.2654 0.26811 0.27087 0.27026 0.27225 0.27768 0.28522 0.28575 0.29219 0.29988 0.30973 0.32815 0.33766 0.34873 0.36887

0.15256 0.16626 0.1681 0.17404 0.1812 0.18225 0.18517 0.18909 0.18828 0.19915 0.20138 0.20249 0.21122 0.21177 0.21467 0.21721 0.22108 0.22616 0.22567 0.22702 0.23294 0.23995 0.2398 0.24576 0.25435 0.2653 0.28324 0.29254 0.30284 0.3223 0.33773 0.36189 0.37676 0.3989 0.4289 0.44561 0.45741 0.47574

0.16244 0.17625 0.17813 0.1839 0.19131 0.1923 0.19546 0.19931 0.19842 0.20936 0.21127 0.2126 0.22106 0.22195 0.22469 0.22718 0.23119 0.23624 0.2357 0.23708 0.24283 0.24999 0.24963 0.25594 0.26459 0.27526 0.29331 0.30266 0.31265 0.33224 0.34756 0.37175 0.38677 0.4101 0.43886 0.45274 0.46803 0.4851

0.17135 0.18527 0.18722 0.19291 0.20023 0.20117 0.20456 0.20829 0.20733 0.21837 0.22027 0.22149 0.22988 0.23116 0.23372 0.23615 0.24017 0.24522 0.24484 0.24618 0.25187 0.25896 0.25852 0.26501 0.2737 0.28429 0.30242 0.31152 0.32175 0.34125 0.35647 0.3806 0.3958 0.41885 0.44761 0.46169 0.4768 0.49407

0.18161 0.19537 0.1987 0.20421 0.21065 0.21174 0.21615 0.21941 0.21883 0.22917 0.23154 0.2327 0.2412 0.24267 0.24545 0.24749 0.25203 0.25554 0.25626 0.25792 0.26287 0.26973 0.26982 0.27565 0.28541 0.29537 0.31281 0.32179 0.33391 0.3514 0.36721 0.39093 0.40671 0.42979 0.45815 0.47229 0.48691 0.50455

0.24903 0.26195 0.25279 0.24164 0.24574 0.25752 0.26038 0.2639 0.27076 0.27314 0.27535 0.27775 0.2775 0.28489 0.28685 0.28867 0.2971 0.30001 0.29546 0.30091 0.3036 0.30646 0.30553 0.30776 0.3131 0.32097 0.32135 0.32795 0.33571 0.34545 0.36367 0.37354 0.38429 0.40439

0.29865 0.31208 0.30277 0.29164 0.2957 0.30764 0.3105 0.31383 0.32069 0.32296 0.32561 0.32783 0.32742 0.33497 0.33681 0.33857 0.3468 0.35036 0.34549 0.35078 0.3535 0.3564 0.35574 0.3579 0.36307 0.37093 0.37112 0.37809 0.38593 0.39548 0.41377 0.42343 0.43439 0.45442

Emissivity of flame processed DD5 0.23042 0.24309 0.23401 0.22274 0.22692 0.2387 0.24157 0.24517 0.25195 0.25433 0.2565 0.25889 0.25865 0.26609 0.26808 0.26986 0.27833 0.28118 0.27665 0.28211 0.28475 0.28764 0.28671 0.28893 0.29434 0.30218 0.30259 0.3091 0.31685 0.32667 0.34485 0.35467 0.36549 0.38562

0.23913 0.25191 0.24279 0.23162 0.23574 0.24754 0.25038 0.25392 0.26075 0.26313 0.26532 0.26771 0.2675 0.27486 0.27687 0.27866 0.28711 0.29 0.28546 0.29092 0.29359 0.29646 0.29554 0.29776 0.30311 0.31095 0.31138 0.31792 0.32569 0.33545 0.35367 0.36351 0.37431 0.39439

B. Kong et al. / Journal of Alloys and Compounds 703 (2017) 125e138

137

Table 3 (continued ) Wavelength

Emissivity of flame processed K77

2.57981 2.3395 2.1712 1.97288 1.66775 1.42516 1.22765 1.06374

0.34522 0.37159 0.38939 0.41807 0.45429 0.4794 0.50576 0.53805

0.3548 0.38074 0.39865 0.42549 0.46362 0.49001 0.5152 0.54611

0.3791 0.40509 0.42325 0.45113 0.48844 0.51252 0.54055 0.56888

Emissivity of flame processed DD5 0.38903 0.41496 0.43329 0.46084 0.49828 0.5226 0.55022 0.5789

Wavelength

Emissivity of flame processed DZ125

14.9658 13.86568 12.90993 12.07188 11.33105 10.67145 10.08042 9.54779 9.06531 8.62623 8.22492 7.85674 7.51772 7.20454 6.91437 6.64473 6.39355 6.15897 5.93941 5.73347 5.53993 5.35769 5.18579 5.02338 4.86969 4.58581 4.45446 4.2104 3.98841 3.78562 3.42849 3.19585 2.98804 2.80127 2.57981 2.3395 2.1712 1.97288 1.66775 1.42516 1.22765 1.06374

0.20806 0.2085 0.20399 0.18803 0.18829 0.19951 0.1984 0.20429 0.2081 0.20779 0.2094 0.21459 0.21366 0.22186 0.22324 0.22026 0.22768 0.22825 0.22907 0.23011 0.23557 0.2408 0.24067 0.24158 0.24726 0.25277 0.25254 0.25749 0.26516 0.27559 0.29355 0.30057 0.30997 0.32957 0.34456 0.36891 0.38432 0.40837 0.43898 0.45373 0.46847 0.48493

0.40903 0.43472 0.45309 0.48053 0.51815 0.54268 0.56943 0.59864

0.21741 0.21881 0.21401 0.19813 0.19838 0.20926 0.20847 0.21409 0.21807 0.21777 0.2194 0.22475 0.2234 0.23205 0.23299 0.23048 0.23772 0.23842 0.23903 0.24001 0.24529 0.25071 0.25024 0.25144 0.25712 0.26295 0.26257 0.26768 0.27535 0.28574 0.30348 0.31085 0.3201 0.33955 0.35465 0.37857 0.39407 0.41634 0.44885 0.46471 0.47797 0.49403

0.23237 0.23382 0.22901 0.21312 0.21332 0.22427 0.22347 0.2291 0.23313 0.2328 0.23447 0.23976 0.23847 0.2471 0.24801 0.24552 0.25272 0.25342 0.25406 0.25501 0.26037 0.26574 0.26528 0.26645 0.2721 0.27794 0.27755 0.28267 0.29038 0.30073 0.31847 0.32585 0.33496 0.35451 0.36955 0.39363 0.4091 0.432 0.46425 0.47879 0.49328 0.50955

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0.38413 0.4098 0.42596 0.45148 0.48461 0.50639 0.52819 0.55376

[9]

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[13]

0.40089 0.4264 0.44258 0.46697 0.50183 0.52321 0.5449 0.56988

0.40972 0.43516 0.4514 0.47607 0.51034 0.53187 0.55392 0.57864

0.25808 0.26129 0.25615 0.24004 0.23999 0.25129 0.25083 0.256 0.25996 0.25951 0.26186 0.2669 0.26539 0.27425 0.27486 0.27239 0.27931 0.28105 0.28125 0.2819 0.28733 0.29265 0.29256 0.29371 0.29905 0.30484 0.30424 0.30994 0.31789 0.3278 0.34567 0.35277 0.36211 0.38142 0.39629 0.42018 0.43626 0.45907 0.49077 0.50529 0.52026 0.5366

0.41972 0.44514 0.46141 0.48615 0.52035 0.54176 0.564 0.58863

0.46962 0.49489 0.51148 0.53621 0.57022 0.59116 0.61409 0.63907

0.28728 0.2897 0.28529 0.27205 0.26754 0.28129 0.27969 0.28802 0.29264 0.28591 0.29077 0.2971 0.29062 0.30734 0.30728 0.3017 0.31332 0.31283 0.31369 0.31302 0.31748 0.32285 0.32439 0.32105 0.33048 0.33319 0.3301 0.33636 0.34643 0.35791 0.37711 0.38404 0.38902 0.41221 0.42674 0.44942 0.46684 0.48763 0.52037 0.53319 0.55177 0.56648

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