- Email: [email protected]
CNTs nanocomposite feedstock powders produced by chemical vapor deposition for thermal spray coatings
Fe-Cr/CNTs ¡!–[INS][N]–¿n¡!–[/INS]–¿anocomposite ¡!–[INS][F]–¿f¡!– [/INS]–¿eedstock ¡!–[INS][P]–¿p¡!–[/INS]–¿owders ¡!–[INS][P]–¿p¡!– [/INS]–¿roduced by ¡!–[INS][C]–¿c¡!–[/INS]–¿hemical ¡!–[INS][V]–¿v¡!– [/INS]–¿apor ¡!–[INS][D]–¿d¡!–[/INS]–¿eposition for ¡!–[INS][T]–¿t¡!– [/INS]–¿hermal ¡!–[INS][S]–¿s¡!–[/INS]–¿pray ¡!–[INS][C]–¿c¡!–[/INS]– ¿oatings S. Moonngam, P. Tunjina, D. Deesom, C. Banjongprasert PII: DOI: Reference:
S0257-8972(16)30604-1 doi: 10.1016/j.surfcoat.2016.07.024 SCT 21354
To appear in:
Surface & Coatings Technology
Received date: Revised date: Accepted date:
15 January 2016 5 July 2016 8 July 2016
Please cite this article as: S. Moonngam, P. Tunjina, D. Deesom, C. Banjongprasert, Fe-Cr/CNTs ¡!–[INS][N]–¿n¡!–[/INS]–¿anocomposite ¡!–[INS][F]–¿f¡!–[/INS]–¿eedstock ¡!–[INS][P]–¿p¡!–[/INS]–¿owders ¡!–[INS][P]–¿p¡!–[/INS]–¿roduced by ¡!–[INS][C]–¿c¡!– [/INS]–¿hemical ¡!–[INS][V]–¿v¡!–[/INS]–¿apor ¡!–[INS][D]–¿d¡!–[/INS]–¿eposition for ¡!–[INS][T]–¿t¡!–[/INS]–¿hermal ¡!–[INS][S]–¿s¡!–[/INS]–¿pray ¡!–[INS][C]–¿c¡!–[/INS]– ¿oatings, Surface & Coatings Technology (2016), doi: 10.1016/j.surfcoat.2016.07.024
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Fe-Cr/CNTs Nanocomposite Feedstock Powders Produced by Chemical Vapor Deposition for Thermal Spray Coatings S. Moonngama, P. Tunjinaa, D. Deesoma, and C. Banjongpraserta* Department of Physics and Materials Science, Faculty of Science, Chiang Mai University,
RI P
T
a
SC
Chiang Mai 50200, Thailand
* Corresponding author: Email: [email protected]; Tel.: +66 (0) 53941915; Postal
MA
University, Chiang Mai 50200, Thailand
NU
address: Department of Physics and Materials Science, Faculty of Science, Chiang Mai
Abstract
ED
The carbon nanotubes (CNTs) were synthesized using a traditional chemical vapor deposition technique directly on Fe-13Cr (wt%) feedstock powder for thermal spray coating
PT
without catalyst. CNTs were grown at a temperature of 500, 550, 600, 650, 700, 750 and
AC CE
800°C for 60 mins and at 650°C for 30, 45, 60 and 90 mins under a controlled atmosphere with ethanol as a carbon source. The synthesized powders were characterized using various techniques: (1) Scanning Electron Microscope (SEM); (2) X-ray Diffraction (XRD); (3) Raman Spectroscopy; (4) Energy-dispersive Spectroscopy (EDS); and (5) Transmission Electron Microscope (TEM). The presence and quality of the CNTs were analyzed by Raman Spectroscopy in which D band and G band were clearly seen at 2187 cm-1 and 2653 cm-1 respectively. It was found that the CNTs had an average diameter of 32 to 81nm and a length of 7 to more than 100nm. The results show that CNTs can be grown on Fe-13Cr thermal sprayed feedstock powder with an optimal condition for the synthetization of CNTs was at 600-650°C for 60 mins with homogeneous and uniform distribution of CNTs. The FeCr/CNTs composite powder was successfully sprayed using Low Velocity Oxy-Fuel (LVOF) that confirmed the potential for use as a new coating.
ACCEPTED MANUSCRIPT Keywords: Carbon nanotubes; Chemical vapor deposition; Thermal spray coating; Fe-13Cr; Surface technology; Composite.
RI P
T
Abstract code: B022
SC
1. Introduction
Thermal spray coating technology is widely used to provide wear and corrosion
NU
protections for machinery parts or to change the surface properties of the sprayed items such as an improvement of wear resistance and thermal conductivity [1]. This technology provides
MA
many advantages: easy and fast process, a high coating rate and little effect on the microstructure of the substrate. Raw materials for coating production are usually in the form
ED
of powder or wire [2]. Recently, the composite feedstock powder especially with nanoparticles as reinforcements has been developing to extend the applications of thermal
PT
spray coating in a more demanding environment [3-6] and CNTs are among the strong
AC CE
reinforcements [7-11]. These composites can be used in structural applications for high specific strength. However, CNT-reinforced metal matrix composites (MMCs) are applied in a limited application due to the difficulty to producing a uniform distribution of CNTs in the matrix. For thermal spray coating, Agarwal et al. [8] studied the CNTs-AlSi composite coatings produced by plasma spraying from ball-milled composite feedstock powder. The results confirmed that CNTs improved mechanical properties of the coatings and CNTs could effectively act as reinforcement. However, feedstock powder preparation by ball milling may cause an agglomeration of CNTs. Bakshi et al. [12] synthesized Al-CNTs nanocomposite with improved CNTs dispersion by spray drying causing uniform distribution of CNTs. Most of the previous research reported the CNTs reinforced composite coatings from composite feedstock powders prepared by mechanical mixing methods. Chemical vapor deposition (CVD) is one of the most common methods for growing CNTs due to its low cost, high purity
ACCEPTED MANUSCRIPT with robust process. It is also reported that CNTs can be grown directly on some metal substrates such as Co, Ni, Fe and they are typically used as catalysts. Kumar et al. [13] reported a review on growing CNTs on a large scale with and without catalysts. Talapatra et
RI P
T
al. [14] reviewed the direct growth of CNTs in some metallic materials. It is shown that CNTs can be grown on some commercial alloys such as stainless steels and cobalt alloys.
SC
Nevertheless, very few works studied on the CNTs composite coatings using CVD to synthesize CNTs directly on the commercial feedstock powders. In this study, Fe-13Cr/CNTs
NU
feedstock powder was fabricated by CVD without catalyst in order to prevent agglomeration of CNTs in the final coating microstructure and to save production cost in thermal spray
MA
composite coating. In addition, the optimum condition for growing CNTs will be determined by varying synthesized time and temperature. The optimum condition was used to prepare the
ED
FeCr/CNTs feedstock powder for thermal spray coating by Low Velocity Oxy-Fuel (LVOF)
PT
technique for corrosion and wear resistance in industrial parts in the future.
AC CE
2. Material and methods
Fe-13Cr powder is a specially formulated stainless steel alloy powder by Dura-Metal® for wear and corrosion resistance. It provides many advantages such as good abrasion and corrosion resistance and low temperature particle erosion and fretting [15]. The carbon nanotubes (CNTs) were synthesized using a Chemical Vapor Deposition (CVD) technique without catalyst on the Fe-13Cr powder. CNTs were synthesized at a temperature of 500, 550, 600, 650, 700, 750 and 800°C for 60 mins and at 650°C for 30, 45, 60 and 90 mins. The apparatus of the CVD unit is shown in Fig.1. The gas inlets were connected to one side and the other was connected to a rotary vacuum pump. Fe-13Cr powder (10g) with an average diameter of 50µm was placed on a ceramic boat in a tube furnace (quartz diameter = 35mm), In order to reduce oxides and impurities on the particle, Fe-13Cr powder was thermally pretreated under Ar (300 mLmin-1) and H2 (50 mLmin-1) gases at 450°C for 30 mins. After
ACCEPTED MANUSCRIPT that, temperature was increased until it reached synthesis temperature. The CNTs were grown by using ethanol (C2H5OH) vapor as a carbon source at the pressure of 10 Torr. Finally, the powder was cooled down to room temperature. The synthesized powders were characterized
RI P
T
using various techniques: (1) Scanning Electron Microscope (SEM, JEOL JSM-6335F); (2) X-ray diffraction (XRD, Philips Diffractometer); (3) Raman Spectroscopy (Jobin Yvon,
SC
T64000) was carried out with 514.5nm argon ion laser; (4) Energy-Dispersive X-ray spectroscopy (EDS); and Transmission Electron Microscope (TEM, JEOL JEM 2010).
NU
The FeCr/CNTs powders synthesized by the optimum condition were then sprayed onto mild steel substrates (25mm × 40mm × 5mm) using a Low Velocity Oxy–Fuel (LVOF)
MA
spraying under atmospheric condition and spray parameters are listed in Table 3. The coated specimens were cross-sectioned, mounted in resin, ground using a series of SiC papers (400,
ED
600, 800, 1000 and 1200 grit) and finally polished with 5μm and 1μm alumina suspensions. Microstructure and composition of the coatings were studied using SEM and Energy
AC CE
PT
Dispersive Spectroscopy (EDS) analysis.
3. Results and discussion Fe-13Cr feedstock powder was characterized by SEM indicating the spherical powder due to gas atomization as shown in Fig. 2 (a). Fig. 2 (b) shows the SEM micrograph of Fe13Cr/CNTs synthesized using the CVD process. CNTs were synthesized at the temperature range of 500-800°C for 60 mins leading to a 1.56-70.67% (area fraction, unless otherwise stated) of carbon nanotubes with a diameter of 32-81nm and a length of more than 100nm (Table.1). For CVD at 500-550ºC, CNTs grew a little on Fe-13Cr powder with 1.56-3% CNTs due to low synthesized temperature. When the synthesized temperature was increased to 650ºC, the amount of CNTs increased to 70.63% with a length of more than 100µm. Compared with the results from Kaewsai et al., [16], CNTs were grown on 413 stainless steel (SS/CNTs) particles at 550-800°C for 60 mins with diameters of 31-44nm when synthesized
ACCEPTED MANUSCRIPT at 800°C for 120 mins, the amount of carbon nanotubes was highest at 65.5% (area fraction) with the largest diameter of 44nm suggesting that CNTs can be grown on Fe-13Cr powder quicker than those grown on 413 stainless steel. At synthesized temperature of 750-800°C, the
RI P
T
growth of CNTs was small at 0-18% since the CNTs encapsulated at a high temperature in accordance with Byshkin et al. [17]. The work illustrated the effect of encapsulation in carbon
SC
nanotubes on properties of Fe-Ni nanoalloys with cubic and helical structure at about 700°C. Thus, the optimum condition to grow CNTs directly on Fe-13Cr was at 600-650°C for 60
NU
mins. TEM micrograph of CNTs is shown in Fig. 4. The diffraction patterns from TEM indicated multi-walled type of carbon nanotubes and it was a typical hexagonal structure.
MA
The effects of synthesized time at the temperature of 650°C for 30-90 mins on the diameter of CNTs are shown in Table 2. At synthesized temperature of 650°C for 60 mins, the
ED
amount of carbon nanotubes was at 70.6% with the largest diameter of 81.0nm in Fig. 3 and
nanotubes.
PT
that an increase of synthesized time at 650°C resulted in an increase in the amount of carbon
AC CE
The X-ray diffraction pattern in Fig. 6 show no intermetallic compounds between Fe and Cr or carbides. All X-ray diffraction patterns represented peaks corresponding to Fe. The position angles of diffraction were at 44.8 and 65 degree and corresponding to peaks of Fe and C from Joint Committee on Powder Diffraction Standard (JCPDS) Fe No. 87-0721 and JCPDS C No. 80-0017. The presence and quality of the CNTs were studied by Raman Spectroscopy. Raman spectrum was observed and the result is shown in Fig. 5, in which disorder band (D band) and graphite spectrum (G band) were clearly seen at 1330cm-1 and 1580cm-1 respectively. The Raman spectrum of multiwall carbon nanotubes (MWCNTs) is very similar to those of single wall carbon nanotubes (SWCNTs). The primary differences are the lack of radial breathing modes (RBM) in MWCNTs and a much more prominent D band in MWCNTs [18]. Radial Breathing Mode or RBM modes are unique to SWCNTs, corresponding to the expansion and
ACCEPTED MANUSCRIPT contraction of the tubes. The D band indicates disorder features in graphite sheet and the G band is characteristic of original graphite features. If both bands have similar intensity, this indicates a high quantity of structural defects [19]. The ratio between intensity of D band and
RI P
T
intensity of G band (ID/IG) of the Raman spectra (as shown in Fig 5(c)) from CNTs synthesized at various temperatures was in the range of 0.53 to 1.15 and the ID/IG of the
SC
Raman spectra (as shown in Fig 5(d)) from CNTs synthesized at 600 °C for 30-90 mins was in the range of 0.64 to 1.17. These ID/IG values were less than 1 demonstrating that the
NU
crystalline perfection of CNTs is good. Compared with the results from Kaewsai et al. [16], the ratios of ID/IG varied between 0.97-1.01. The intensity of Raman spectrum increased with
MA
an increase of synthesized temperature, suggesting that higher CNTs content was achieved at a higher temperature. Compared with the research of Laha et al. [8], Raman spectroscopy
ED
shows the peaks for multi-walled carbon nanotubes along with the Si peak from pre-alloyed. The D-line in the spectrum represents the structure defect while the G-line represents of
PT
graphene structure [20] and the D band and G band were clearly seen at 1300cm-1 and
AC CE
1600cm-1 respectively and the ratio between the D band and G band was 1.61. The synthesized powder was thermally sprayed on a mild steel substrate by Low Velocity Oxy-Fuel (LVOF) spraying with spray parameters listed in Table 3. The thickness of Fe13Cr/CNTs coating was 280-330µm. The coating consisted of lamellar splats, oxide layers, and porosity that are typical coating microstructure of thermal sprayed coating as seen from SEM image in Fig. 7 (a). This confirmed that Fe-Cr/CNTs composite powders synthesized directly on thermal spray graded powder can be used as typical feedstock powder. In addition, the evidence of CNTs inside the coatings was clearly seen on the fracture surface of the composite coating in Figure 7(b) and it is similar to those sprayed by other techniques with different powder preparation methods [8, 11-12].
ACCEPTED MANUSCRIPT 4. Conclusion The Fe-Cr/CNTs composite feedstock powder can be directly produced by traditional CVD without catalyst. Optimal conditions for the synthesis of CNTs on Fe-13Cr by the
RI P
T
thermal CVD method was at a temperature of 600-650 °C for 60 mins; the amount of CNTs was at 70.6% (area fraction) with the largest diameter of 80.9 nm and CNTs were high quality
SC
confirmed by ID/IG values less than 1 revealing that the crystalline perfection of CNTs is good by Raman spectroscopy and CNTs can be grown without using a catalyst with homogeneous
NU
and uniform distribution of CNTs. The FeCr/CNTs powders prepared by the optimum
MA
condition were successfully thermal sprayed by LVOF.
Acknowledgements
ED
The authors would like to thank the Thailand Research Fund (TRF) under the project: Research and Researchers for Industries Scholarship (RRI) for Master Degree in 2014 and
PT
Advance Surface Technology Co., Ltd. National Research University Project under
AC CE
Thailand’s Office of the Higher Education Commission and Thailand Research Fund (IRG5780013) are also acknowledged for financial supports.
ACCEPTED MANUSCRIPT References [1] J.R. Davis, Handbook of Thermal Spray Technology, ASM International, Materials Park, USA, 2004.
RI P
T
[2] L. Pawlowski, The Science and Engineering of Thermal Spray Coatings, 2nd edition, John Wiley & Sons Ltd., UK, 2008.
– A review, Int. Mater. Rev. 55 (2010) 41-64.
SC
[3] S.R. Bakshi, D. Lahiri, A. Agarwal , Carbon nanotube reinforced metal matrix composites
NU
[4] C. Banjongprasert, P. Jaimeewong, S. Jiansirisomboon, Investigation of thermal Sprayed stainless steel/WC-12wt%Co nanocomposite coatings, Mater. Sci. Forum. 695 (2011) 441-
MA
444.
[5] A. Limpichaipanit, C. Banjongprasert, P. Jaiban, and S. Jiansirisomboon, Fabrication and
ED
properties of thermal sprayed AlSi-based coatings from nanocomposite powders, J. Therm. Spray. Techn. 22 (2013) 18-26.
PT
[6] J.A. Gan, C.C. Berndt, Nanocomposite coatings: thermal spray processing, microstructure
AC CE
and performance, Int. Mater. Rev. 60 (2015) 195-244. [7] R. Zhong, H. Cong, P. Hou, Fabrication of nano-Al based composites reinforced by single-walled carbon nanotubes, Carbon, 41 (2013) 848-851. [8] T. Laha, A. Agarwal, T. McKechnie, S. Seal, Synthesis and characterization of plasma spray formed carbon nanotube reinforced aluminum composite, Mat. Sci. Eng. A-Struct. 381(1-2) (2004) 249–258. [9] D. Deesom, S. Moonngam, K. Charoenrut, C. Banjongprasert (2016) Fabrication and properties of NiCr/CNTs nanocomposite coatings prepared by high velocity oxy-fuel spraying, Surf. Coat.Tech. doi: 10.1016/j.surfcoat.2016.06.016. [10] P. Daram, C. Banjongprasert, W. Thongsuwan, S. Jiansirisomboon (2016) Microstructure and photocatalytic activities of thermal sprayed titanium dioxide/carbon nanotubes composite coatings, Surf. Coat.Tech. doi: 10.1016/j.surfcoat.2016.06.068.
ACCEPTED MANUSCRIPT [11] A. Agarwal, T. McKenzie, S. Seal, Net shape nanostructured aluminum oxide structures fabricated by plasma spray forming, J. Therm. Spray. Techn. 12(3) (2003) 350-359. [12] S.R. Bakshi, V. Singh, S. Seal, A. Agarwal, Aluminum composite reinforced with
RI P
T
multiwalled carbon nanotubes from plasma spraying of spray dried powders, Surf. Coat. Tech. 203 (2009) 1544-1554.
SC
[13] M. Kumar, Y. Ando, Chemical Vapor Deposition of Carbon Nanotubes: A Review on Growth Mechanism and Mass Production, J. Nanosci. Nanotechnol. 10(6) (2010) 3739-3758.
NU
[14] S. Talapatra, S. Kar, S.K. Pal, R. Vajtai, L. Ci, P. Victor, M. M. Shaijumon, S. Kaur, O.
Nanotechnol. 1 (2006) 112-116.
MA
Nalamasu, P.M. Ajayan, Direct growth of aligned carbon nanotubes on bulk metals, Nat.
[15] Dura Metal, Product Information, Dura Metal Alloy Products Group LLC 3581 Centre
ED
Circle Suite 102, 2003, 1-3.
[16] D. Kaewsai, P. Singjai, A. Watcharapasorn, P. Niranartlumpong, S. Jiansirisomboon,
AC CE
(2010) 2014-2112.
PT
Thermal sprayed stainless steel/carbon nanotubes composite coating, Surf. Coat. Tech. 205
[17] M. Byshkin, B. Zhu, M. Hou, The effect of encapsulation in carbon nanotubes on properties of Fe–Ni nanoalloys with cubic and helical structures, J. Mater. Sci. 48 (2013) 866875.
[18] J. Hodkiewicz, Characterizing Carbon Materials with Raman Spectroscopy, Thermo Fisher Scientific, Madison, WI, USA, 2010. [19] S. Costa, E. Borowiak-Palen, M. Kruszynska, A. Bachmatiuk, R.J. Kalenczuk, Characterization of Carbon Nanotubes by Raman spectroscopy, Mater. Sci-Poland. 26 (2008) 433-441. [20] W. Li, H. Zhang, C. Wang, Y. Zhang, L. Xu, K. Zhu, S. Xie, Raman characterization of aligned carbon nanotubes produced by thermal decomposition of hydrocarbon vapor, Appl. Phys. Lett. 70 (1997) 2684-2686.
ACCEPTED MANUSCRIPT List of Table captions Table. I The effects of synthesized temperature on the amount of CNTs (area fraction, %), Diameter of CNTs, and ID/IG.
RI P
T
Table. II The effect of synthesized time on the amount of CNTs (area fraction, %), diameter of CNTs, and ID/IG.
AC CE
PT
ED
MA
NU
SC
Table. III Thermal spray parameters.
ACCEPTED MANUSCRIPT Table. I The effects of synthesized temperature on the amount of CNTs (area fraction, %), diameter of CNTs, and ID/IG. CNTs (area fraction, %)
Diameter of CNTs (nm)
ID/IG
500
1.56
32 ± 6
1.15
550
3.00
33 ± 9
0.89
600
70.63
48 ± 14
0.94
650
70.67
700
64.86
750
18.00
800
0.00
RI P
SC 81 ± 19
0.70
55 ± 15
0.64
70 ± 17
0.53
0
1.04
NU MA
ED PT AC CE
T
Temperature (°C)
ACCEPTED MANUSCRIPT Table. II The effect of synthesized time on the amount of CNTs (area fraction, %), diameter of CNTs, and ID/IG. CNTs (area fraction, %)
Diameter of CNTs (nm)
ID/IG
30
25.00
46 ± 9
1.12
45
65.62
58 ± 17
1.17
60
70.67
81 ± 19
0.70
90
70.31
RI P
SC MA
NU
47 ± 7
ED PT AC CE
T
Time (mins)
0.64
ACCEPTED MANUSCRIPT
Value
C2H2 flow rate (l/min)
25.95
C2H2 pressure (psi)
14.50
O2 flow rate (l/min)
T
Parameter
RI P
Table III Thermal spray parameters.
21.23 34.80
SC
O2 pressure (psi) N2 flow rate (l/min)
33.03 104.42
Spray distance (mm)
AC CE
PT
ED
MA
Spray rate (g/min)
NU
N2 pressure (psi)
200 108
ACCEPTED MANUSCRIPT List of figure captions Fig. 1 Schematic diagram of CVD system. Fig. 2 SEM micrographs of (a) the as-received Fe-13Cr powder and (b) as-synthesized Fe-
RI P
T
13Cr/CNTs feedstock powder at 650 °C for 60 min.
Fig. 3 SEM micrograph of Fe-13Cr/CNTs synthesized using the CVD at 650 °C for 60 min.
SC
Fig. 4 TEM micrograph of CNTs.
Fig. 5 Relationships of diameter of CNTs and amount of CNTs (surface area %) from different
NU
synthesized temperature and time (a) at 500-800 °C for 60 mins, (b) at 650 °C for 30-90 mins and Raman spectroscopy of synthesized powders at (c) temperature of 550-800 °C with 60
MA
mins and (d) temperature 650 °C with 30-90 mins.
Fig. 6 XRD pattern of the as-received Fe-13Cr powder and as-synthesized Fe-13Cr powder.
ED
Fig. 7 SEM micrographs of (a) LVOF Fe-13Cr/CNTs coating (b) fracture surface of the
AC CE
PT
coating showing remained CNTs.
NU
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
Fig. 1
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
NU
Fig. 2
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
NU
Fig. 3
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
NU
Fig. 4
AC CE
PT
ED
MA
NU
SC
RI P
T
ACCEPTED MANUSCRIPT
Fig. 5
MA
NU
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
Fig. 6
NU
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
Fig. 7
ACCEPTED MANUSCRIPT
Highlights
RI P
T
Homogeneous CNTs can be successfully synthesized directly on a FeCr commercial thermal sprayed feedstock powder. The optimum condition for growing CNTs on the FeCr powder was at 600-650 °C for 1h by chemical vapor deposition.
AC CE
PT
ED
MA
NU
SC
The FeCr/CNTs composite powder was successfully sprayed by LVOF using standard industrial processing parameters.
S0257-8972(16)30604-1 doi: 10.1016/j.surfcoat.2016.07.024 SCT 21354
To appear in:
Surface & Coatings Technology
Received date: Revised date: Accepted date:
15 January 2016 5 July 2016 8 July 2016
Please cite this article as: S. Moonngam, P. Tunjina, D. Deesom, C. Banjongprasert, Fe-Cr/CNTs ¡!–[INS][N]–¿n¡!–[/INS]–¿anocomposite ¡!–[INS][F]–¿f¡!–[/INS]–¿eedstock ¡!–[INS][P]–¿p¡!–[/INS]–¿owders ¡!–[INS][P]–¿p¡!–[/INS]–¿roduced by ¡!–[INS][C]–¿c¡!– [/INS]–¿hemical ¡!–[INS][V]–¿v¡!–[/INS]–¿apor ¡!–[INS][D]–¿d¡!–[/INS]–¿eposition for ¡!–[INS][T]–¿t¡!–[/INS]–¿hermal ¡!–[INS][S]–¿s¡!–[/INS]–¿pray ¡!–[INS][C]–¿c¡!–[/INS]– ¿oatings, Surface & Coatings Technology (2016), doi: 10.1016/j.surfcoat.2016.07.024
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Fe-Cr/CNTs Nanocomposite Feedstock Powders Produced by Chemical Vapor Deposition for Thermal Spray Coatings S. Moonngama, P. Tunjinaa, D. Deesoma, and C. Banjongpraserta* Department of Physics and Materials Science, Faculty of Science, Chiang Mai University,
RI P
T
a
SC
Chiang Mai 50200, Thailand
* Corresponding author: Email: [email protected]; Tel.: +66 (0) 53941915; Postal
MA
University, Chiang Mai 50200, Thailand
NU
address: Department of Physics and Materials Science, Faculty of Science, Chiang Mai
Abstract
ED
The carbon nanotubes (CNTs) were synthesized using a traditional chemical vapor deposition technique directly on Fe-13Cr (wt%) feedstock powder for thermal spray coating
PT
without catalyst. CNTs were grown at a temperature of 500, 550, 600, 650, 700, 750 and
AC CE
800°C for 60 mins and at 650°C for 30, 45, 60 and 90 mins under a controlled atmosphere with ethanol as a carbon source. The synthesized powders were characterized using various techniques: (1) Scanning Electron Microscope (SEM); (2) X-ray Diffraction (XRD); (3) Raman Spectroscopy; (4) Energy-dispersive Spectroscopy (EDS); and (5) Transmission Electron Microscope (TEM). The presence and quality of the CNTs were analyzed by Raman Spectroscopy in which D band and G band were clearly seen at 2187 cm-1 and 2653 cm-1 respectively. It was found that the CNTs had an average diameter of 32 to 81nm and a length of 7 to more than 100nm. The results show that CNTs can be grown on Fe-13Cr thermal sprayed feedstock powder with an optimal condition for the synthetization of CNTs was at 600-650°C for 60 mins with homogeneous and uniform distribution of CNTs. The FeCr/CNTs composite powder was successfully sprayed using Low Velocity Oxy-Fuel (LVOF) that confirmed the potential for use as a new coating.
ACCEPTED MANUSCRIPT Keywords: Carbon nanotubes; Chemical vapor deposition; Thermal spray coating; Fe-13Cr; Surface technology; Composite.
RI P
T
Abstract code: B022
SC
1. Introduction
Thermal spray coating technology is widely used to provide wear and corrosion
NU
protections for machinery parts or to change the surface properties of the sprayed items such as an improvement of wear resistance and thermal conductivity [1]. This technology provides
MA
many advantages: easy and fast process, a high coating rate and little effect on the microstructure of the substrate. Raw materials for coating production are usually in the form
ED
of powder or wire [2]. Recently, the composite feedstock powder especially with nanoparticles as reinforcements has been developing to extend the applications of thermal
PT
spray coating in a more demanding environment [3-6] and CNTs are among the strong
AC CE
reinforcements [7-11]. These composites can be used in structural applications for high specific strength. However, CNT-reinforced metal matrix composites (MMCs) are applied in a limited application due to the difficulty to producing a uniform distribution of CNTs in the matrix. For thermal spray coating, Agarwal et al. [8] studied the CNTs-AlSi composite coatings produced by plasma spraying from ball-milled composite feedstock powder. The results confirmed that CNTs improved mechanical properties of the coatings and CNTs could effectively act as reinforcement. However, feedstock powder preparation by ball milling may cause an agglomeration of CNTs. Bakshi et al. [12] synthesized Al-CNTs nanocomposite with improved CNTs dispersion by spray drying causing uniform distribution of CNTs. Most of the previous research reported the CNTs reinforced composite coatings from composite feedstock powders prepared by mechanical mixing methods. Chemical vapor deposition (CVD) is one of the most common methods for growing CNTs due to its low cost, high purity
ACCEPTED MANUSCRIPT with robust process. It is also reported that CNTs can be grown directly on some metal substrates such as Co, Ni, Fe and they are typically used as catalysts. Kumar et al. [13] reported a review on growing CNTs on a large scale with and without catalysts. Talapatra et
RI P
T
al. [14] reviewed the direct growth of CNTs in some metallic materials. It is shown that CNTs can be grown on some commercial alloys such as stainless steels and cobalt alloys.
SC
Nevertheless, very few works studied on the CNTs composite coatings using CVD to synthesize CNTs directly on the commercial feedstock powders. In this study, Fe-13Cr/CNTs
NU
feedstock powder was fabricated by CVD without catalyst in order to prevent agglomeration of CNTs in the final coating microstructure and to save production cost in thermal spray
MA
composite coating. In addition, the optimum condition for growing CNTs will be determined by varying synthesized time and temperature. The optimum condition was used to prepare the
ED
FeCr/CNTs feedstock powder for thermal spray coating by Low Velocity Oxy-Fuel (LVOF)
PT
technique for corrosion and wear resistance in industrial parts in the future.
AC CE
2. Material and methods
Fe-13Cr powder is a specially formulated stainless steel alloy powder by Dura-Metal® for wear and corrosion resistance. It provides many advantages such as good abrasion and corrosion resistance and low temperature particle erosion and fretting [15]. The carbon nanotubes (CNTs) were synthesized using a Chemical Vapor Deposition (CVD) technique without catalyst on the Fe-13Cr powder. CNTs were synthesized at a temperature of 500, 550, 600, 650, 700, 750 and 800°C for 60 mins and at 650°C for 30, 45, 60 and 90 mins. The apparatus of the CVD unit is shown in Fig.1. The gas inlets were connected to one side and the other was connected to a rotary vacuum pump. Fe-13Cr powder (10g) with an average diameter of 50µm was placed on a ceramic boat in a tube furnace (quartz diameter = 35mm), In order to reduce oxides and impurities on the particle, Fe-13Cr powder was thermally pretreated under Ar (300 mLmin-1) and H2 (50 mLmin-1) gases at 450°C for 30 mins. After
ACCEPTED MANUSCRIPT that, temperature was increased until it reached synthesis temperature. The CNTs were grown by using ethanol (C2H5OH) vapor as a carbon source at the pressure of 10 Torr. Finally, the powder was cooled down to room temperature. The synthesized powders were characterized
RI P
T
using various techniques: (1) Scanning Electron Microscope (SEM, JEOL JSM-6335F); (2) X-ray diffraction (XRD, Philips Diffractometer); (3) Raman Spectroscopy (Jobin Yvon,
SC
T64000) was carried out with 514.5nm argon ion laser; (4) Energy-Dispersive X-ray spectroscopy (EDS); and Transmission Electron Microscope (TEM, JEOL JEM 2010).
NU
The FeCr/CNTs powders synthesized by the optimum condition were then sprayed onto mild steel substrates (25mm × 40mm × 5mm) using a Low Velocity Oxy–Fuel (LVOF)
MA
spraying under atmospheric condition and spray parameters are listed in Table 3. The coated specimens were cross-sectioned, mounted in resin, ground using a series of SiC papers (400,
ED
600, 800, 1000 and 1200 grit) and finally polished with 5μm and 1μm alumina suspensions. Microstructure and composition of the coatings were studied using SEM and Energy
AC CE
PT
Dispersive Spectroscopy (EDS) analysis.
3. Results and discussion Fe-13Cr feedstock powder was characterized by SEM indicating the spherical powder due to gas atomization as shown in Fig. 2 (a). Fig. 2 (b) shows the SEM micrograph of Fe13Cr/CNTs synthesized using the CVD process. CNTs were synthesized at the temperature range of 500-800°C for 60 mins leading to a 1.56-70.67% (area fraction, unless otherwise stated) of carbon nanotubes with a diameter of 32-81nm and a length of more than 100nm (Table.1). For CVD at 500-550ºC, CNTs grew a little on Fe-13Cr powder with 1.56-3% CNTs due to low synthesized temperature. When the synthesized temperature was increased to 650ºC, the amount of CNTs increased to 70.63% with a length of more than 100µm. Compared with the results from Kaewsai et al., [16], CNTs were grown on 413 stainless steel (SS/CNTs) particles at 550-800°C for 60 mins with diameters of 31-44nm when synthesized
ACCEPTED MANUSCRIPT at 800°C for 120 mins, the amount of carbon nanotubes was highest at 65.5% (area fraction) with the largest diameter of 44nm suggesting that CNTs can be grown on Fe-13Cr powder quicker than those grown on 413 stainless steel. At synthesized temperature of 750-800°C, the
RI P
T
growth of CNTs was small at 0-18% since the CNTs encapsulated at a high temperature in accordance with Byshkin et al. [17]. The work illustrated the effect of encapsulation in carbon
SC
nanotubes on properties of Fe-Ni nanoalloys with cubic and helical structure at about 700°C. Thus, the optimum condition to grow CNTs directly on Fe-13Cr was at 600-650°C for 60
NU
mins. TEM micrograph of CNTs is shown in Fig. 4. The diffraction patterns from TEM indicated multi-walled type of carbon nanotubes and it was a typical hexagonal structure.
MA
The effects of synthesized time at the temperature of 650°C for 30-90 mins on the diameter of CNTs are shown in Table 2. At synthesized temperature of 650°C for 60 mins, the
ED
amount of carbon nanotubes was at 70.6% with the largest diameter of 81.0nm in Fig. 3 and
nanotubes.
PT
that an increase of synthesized time at 650°C resulted in an increase in the amount of carbon
AC CE
The X-ray diffraction pattern in Fig. 6 show no intermetallic compounds between Fe and Cr or carbides. All X-ray diffraction patterns represented peaks corresponding to Fe. The position angles of diffraction were at 44.8 and 65 degree and corresponding to peaks of Fe and C from Joint Committee on Powder Diffraction Standard (JCPDS) Fe No. 87-0721 and JCPDS C No. 80-0017. The presence and quality of the CNTs were studied by Raman Spectroscopy. Raman spectrum was observed and the result is shown in Fig. 5, in which disorder band (D band) and graphite spectrum (G band) were clearly seen at 1330cm-1 and 1580cm-1 respectively. The Raman spectrum of multiwall carbon nanotubes (MWCNTs) is very similar to those of single wall carbon nanotubes (SWCNTs). The primary differences are the lack of radial breathing modes (RBM) in MWCNTs and a much more prominent D band in MWCNTs [18]. Radial Breathing Mode or RBM modes are unique to SWCNTs, corresponding to the expansion and
ACCEPTED MANUSCRIPT contraction of the tubes. The D band indicates disorder features in graphite sheet and the G band is characteristic of original graphite features. If both bands have similar intensity, this indicates a high quantity of structural defects [19]. The ratio between intensity of D band and
RI P
T
intensity of G band (ID/IG) of the Raman spectra (as shown in Fig 5(c)) from CNTs synthesized at various temperatures was in the range of 0.53 to 1.15 and the ID/IG of the
SC
Raman spectra (as shown in Fig 5(d)) from CNTs synthesized at 600 °C for 30-90 mins was in the range of 0.64 to 1.17. These ID/IG values were less than 1 demonstrating that the
NU
crystalline perfection of CNTs is good. Compared with the results from Kaewsai et al. [16], the ratios of ID/IG varied between 0.97-1.01. The intensity of Raman spectrum increased with
MA
an increase of synthesized temperature, suggesting that higher CNTs content was achieved at a higher temperature. Compared with the research of Laha et al. [8], Raman spectroscopy
ED
shows the peaks for multi-walled carbon nanotubes along with the Si peak from pre-alloyed. The D-line in the spectrum represents the structure defect while the G-line represents of
PT
graphene structure [20] and the D band and G band were clearly seen at 1300cm-1 and
AC CE
1600cm-1 respectively and the ratio between the D band and G band was 1.61. The synthesized powder was thermally sprayed on a mild steel substrate by Low Velocity Oxy-Fuel (LVOF) spraying with spray parameters listed in Table 3. The thickness of Fe13Cr/CNTs coating was 280-330µm. The coating consisted of lamellar splats, oxide layers, and porosity that are typical coating microstructure of thermal sprayed coating as seen from SEM image in Fig. 7 (a). This confirmed that Fe-Cr/CNTs composite powders synthesized directly on thermal spray graded powder can be used as typical feedstock powder. In addition, the evidence of CNTs inside the coatings was clearly seen on the fracture surface of the composite coating in Figure 7(b) and it is similar to those sprayed by other techniques with different powder preparation methods [8, 11-12].
ACCEPTED MANUSCRIPT 4. Conclusion The Fe-Cr/CNTs composite feedstock powder can be directly produced by traditional CVD without catalyst. Optimal conditions for the synthesis of CNTs on Fe-13Cr by the
RI P
T
thermal CVD method was at a temperature of 600-650 °C for 60 mins; the amount of CNTs was at 70.6% (area fraction) with the largest diameter of 80.9 nm and CNTs were high quality
SC
confirmed by ID/IG values less than 1 revealing that the crystalline perfection of CNTs is good by Raman spectroscopy and CNTs can be grown without using a catalyst with homogeneous
NU
and uniform distribution of CNTs. The FeCr/CNTs powders prepared by the optimum
MA
condition were successfully thermal sprayed by LVOF.
Acknowledgements
ED
The authors would like to thank the Thailand Research Fund (TRF) under the project: Research and Researchers for Industries Scholarship (RRI) for Master Degree in 2014 and
PT
Advance Surface Technology Co., Ltd. National Research University Project under
AC CE
Thailand’s Office of the Higher Education Commission and Thailand Research Fund (IRG5780013) are also acknowledged for financial supports.
ACCEPTED MANUSCRIPT References [1] J.R. Davis, Handbook of Thermal Spray Technology, ASM International, Materials Park, USA, 2004.
RI P
T
[2] L. Pawlowski, The Science and Engineering of Thermal Spray Coatings, 2nd edition, John Wiley & Sons Ltd., UK, 2008.
– A review, Int. Mater. Rev. 55 (2010) 41-64.
SC
[3] S.R. Bakshi, D. Lahiri, A. Agarwal , Carbon nanotube reinforced metal matrix composites
NU
[4] C. Banjongprasert, P. Jaimeewong, S. Jiansirisomboon, Investigation of thermal Sprayed stainless steel/WC-12wt%Co nanocomposite coatings, Mater. Sci. Forum. 695 (2011) 441-
MA
444.
[5] A. Limpichaipanit, C. Banjongprasert, P. Jaiban, and S. Jiansirisomboon, Fabrication and
ED
properties of thermal sprayed AlSi-based coatings from nanocomposite powders, J. Therm. Spray. Techn. 22 (2013) 18-26.
PT
[6] J.A. Gan, C.C. Berndt, Nanocomposite coatings: thermal spray processing, microstructure
AC CE
and performance, Int. Mater. Rev. 60 (2015) 195-244. [7] R. Zhong, H. Cong, P. Hou, Fabrication of nano-Al based composites reinforced by single-walled carbon nanotubes, Carbon, 41 (2013) 848-851. [8] T. Laha, A. Agarwal, T. McKechnie, S. Seal, Synthesis and characterization of plasma spray formed carbon nanotube reinforced aluminum composite, Mat. Sci. Eng. A-Struct. 381(1-2) (2004) 249–258. [9] D. Deesom, S. Moonngam, K. Charoenrut, C. Banjongprasert (2016) Fabrication and properties of NiCr/CNTs nanocomposite coatings prepared by high velocity oxy-fuel spraying, Surf. Coat.Tech. doi: 10.1016/j.surfcoat.2016.06.016. [10] P. Daram, C. Banjongprasert, W. Thongsuwan, S. Jiansirisomboon (2016) Microstructure and photocatalytic activities of thermal sprayed titanium dioxide/carbon nanotubes composite coatings, Surf. Coat.Tech. doi: 10.1016/j.surfcoat.2016.06.068.
ACCEPTED MANUSCRIPT [11] A. Agarwal, T. McKenzie, S. Seal, Net shape nanostructured aluminum oxide structures fabricated by plasma spray forming, J. Therm. Spray. Techn. 12(3) (2003) 350-359. [12] S.R. Bakshi, V. Singh, S. Seal, A. Agarwal, Aluminum composite reinforced with
RI P
T
multiwalled carbon nanotubes from plasma spraying of spray dried powders, Surf. Coat. Tech. 203 (2009) 1544-1554.
SC
[13] M. Kumar, Y. Ando, Chemical Vapor Deposition of Carbon Nanotubes: A Review on Growth Mechanism and Mass Production, J. Nanosci. Nanotechnol. 10(6) (2010) 3739-3758.
NU
[14] S. Talapatra, S. Kar, S.K. Pal, R. Vajtai, L. Ci, P. Victor, M. M. Shaijumon, S. Kaur, O.
Nanotechnol. 1 (2006) 112-116.
MA
Nalamasu, P.M. Ajayan, Direct growth of aligned carbon nanotubes on bulk metals, Nat.
[15] Dura Metal, Product Information, Dura Metal Alloy Products Group LLC 3581 Centre
ED
Circle Suite 102, 2003, 1-3.
[16] D. Kaewsai, P. Singjai, A. Watcharapasorn, P. Niranartlumpong, S. Jiansirisomboon,
AC CE
(2010) 2014-2112.
PT
Thermal sprayed stainless steel/carbon nanotubes composite coating, Surf. Coat. Tech. 205
[17] M. Byshkin, B. Zhu, M. Hou, The effect of encapsulation in carbon nanotubes on properties of Fe–Ni nanoalloys with cubic and helical structures, J. Mater. Sci. 48 (2013) 866875.
[18] J. Hodkiewicz, Characterizing Carbon Materials with Raman Spectroscopy, Thermo Fisher Scientific, Madison, WI, USA, 2010. [19] S. Costa, E. Borowiak-Palen, M. Kruszynska, A. Bachmatiuk, R.J. Kalenczuk, Characterization of Carbon Nanotubes by Raman spectroscopy, Mater. Sci-Poland. 26 (2008) 433-441. [20] W. Li, H. Zhang, C. Wang, Y. Zhang, L. Xu, K. Zhu, S. Xie, Raman characterization of aligned carbon nanotubes produced by thermal decomposition of hydrocarbon vapor, Appl. Phys. Lett. 70 (1997) 2684-2686.
ACCEPTED MANUSCRIPT List of Table captions Table. I The effects of synthesized temperature on the amount of CNTs (area fraction, %), Diameter of CNTs, and ID/IG.
RI P
T
Table. II The effect of synthesized time on the amount of CNTs (area fraction, %), diameter of CNTs, and ID/IG.
AC CE
PT
ED
MA
NU
SC
Table. III Thermal spray parameters.
ACCEPTED MANUSCRIPT Table. I The effects of synthesized temperature on the amount of CNTs (area fraction, %), diameter of CNTs, and ID/IG. CNTs (area fraction, %)
Diameter of CNTs (nm)
ID/IG
500
1.56
32 ± 6
1.15
550
3.00
33 ± 9
0.89
600
70.63
48 ± 14
0.94
650
70.67
700
64.86
750
18.00
800
0.00
RI P
SC 81 ± 19
0.70
55 ± 15
0.64
70 ± 17
0.53
0
1.04
NU MA
ED PT AC CE
T
Temperature (°C)
ACCEPTED MANUSCRIPT Table. II The effect of synthesized time on the amount of CNTs (area fraction, %), diameter of CNTs, and ID/IG. CNTs (area fraction, %)
Diameter of CNTs (nm)
ID/IG
30
25.00
46 ± 9
1.12
45
65.62
58 ± 17
1.17
60
70.67
81 ± 19
0.70
90
70.31
RI P
SC MA
NU
47 ± 7
ED PT AC CE
T
Time (mins)
0.64
ACCEPTED MANUSCRIPT
Value
C2H2 flow rate (l/min)
25.95
C2H2 pressure (psi)
14.50
O2 flow rate (l/min)
T
Parameter
RI P
Table III Thermal spray parameters.
21.23 34.80
SC
O2 pressure (psi) N2 flow rate (l/min)
33.03 104.42
Spray distance (mm)
AC CE
PT
ED
MA
Spray rate (g/min)
NU
N2 pressure (psi)
200 108
ACCEPTED MANUSCRIPT List of figure captions Fig. 1 Schematic diagram of CVD system. Fig. 2 SEM micrographs of (a) the as-received Fe-13Cr powder and (b) as-synthesized Fe-
RI P
T
13Cr/CNTs feedstock powder at 650 °C for 60 min.
Fig. 3 SEM micrograph of Fe-13Cr/CNTs synthesized using the CVD at 650 °C for 60 min.
SC
Fig. 4 TEM micrograph of CNTs.
Fig. 5 Relationships of diameter of CNTs and amount of CNTs (surface area %) from different
NU
synthesized temperature and time (a) at 500-800 °C for 60 mins, (b) at 650 °C for 30-90 mins and Raman spectroscopy of synthesized powders at (c) temperature of 550-800 °C with 60
MA
mins and (d) temperature 650 °C with 30-90 mins.
Fig. 6 XRD pattern of the as-received Fe-13Cr powder and as-synthesized Fe-13Cr powder.
ED
Fig. 7 SEM micrographs of (a) LVOF Fe-13Cr/CNTs coating (b) fracture surface of the
AC CE
PT
coating showing remained CNTs.
NU
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
Fig. 1
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
NU
Fig. 2
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
NU
Fig. 3
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
NU
Fig. 4
AC CE
PT
ED
MA
NU
SC
RI P
T
ACCEPTED MANUSCRIPT
Fig. 5
MA
NU
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
Fig. 6
NU
SC
RI P
T
ACCEPTED MANUSCRIPT
AC CE
PT
ED
MA
Fig. 7
ACCEPTED MANUSCRIPT
Highlights
RI P
T
Homogeneous CNTs can be successfully synthesized directly on a FeCr commercial thermal sprayed feedstock powder. The optimum condition for growing CNTs on the FeCr powder was at 600-650 °C for 1h by chemical vapor deposition.
AC CE
PT
ED
MA
NU
SC
The FeCr/CNTs composite powder was successfully sprayed by LVOF using standard industrial processing parameters.