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Wettability of Ti6Al4V on calcia-stabilized zirconia
Materials Letters 73 (2012) 40–42
Contents lists available at SciVerse ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Wettability of Ti6Al4V on calcia-stabilized zirconia Aihui Liu a, b,⁎, Bangsheng Li b, Dinggen Yan a, Jingjie Guo b a b
Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai'an 223003, China School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001
a r t i c l e
i n f o
Article history: Received 22 December 2011 Accepted 2 January 2012 Available online 8 January 2012 Keywords: Interfaces Ceramics Metals and alloys
a b s t r a c t The wettability between liquid Ti6Al4V alloy and calcia-stabilized zirconia was studied by the self-designed measuring apparatus in argon atmosphere. By means of the testing device, a kinetic and interfacial study on the wettability and spreading behavior of Ti6Al4V alloy melt on calcia-stabilized zirconia is presented. The micrographic observation made on cross sections perpendicular to the interface using map analyses shows that the interfacial reaction occurred at high temperature. However, the contact angles are relative stable and larger than 90° within experimental duration, and the equilibrium contact angle is 110°. The influence of interfacial reaction on the wettability can be explained by the total free energy at the liquid/solid interface. © 2012 Elsevier B.V. All rights reserved.
1. Introduction
2. Experimental procedure
Titanium alloys have been widely used in the aerospace, automobile applications, and relative industries for their excellent properties, such as high specific strength, good corrosion resistance, and appropriate high temperature properties [1–3]. Thanks to the efforts of different researchers, various methods have been applied in titanium alloys processing such as forging, forming, casting, powder metallurgy, welding etc. On the other hand, the investing casting is the optimal processing method for titanium alloy complex components. Wettability is crucial factor for making titanium alloy castings. The wetting of ceramic surface by molten metal is one of the most important phenomena to consider when a titanium alloy casting is produced. The sessile drop [4,5] is the most extensive method used to measure the contact angle. But it is usually applied in the measurement of low-activity alloys, such as Al, Cu, Ni, Zn and Fe [6–8]. Titanium alloy is metal with high melting point and high reactivity. The conventional sessile drop method is not suitable to measure the contact angle of molten titanium alloy/ceramic molds; it is because liquid metal reacts with ceramics resulting in a new ceramic surface before titanium alloy melts into droplet. The contact angle measured after titanium alloy melting is not that between molten titanium alloys and initial ceramic substrates [9,10]. In this work, a testing device to measure the contact angle of high-activity metal melt on ceramics is developed. By means of the testing device, a kinetic and interfacial study on the wettability and spreading behavior of Ti6Al4V alloy melt on calcia-stabilized zirconia (ZrO2 (CaO stabilized)) is presented. On the basis of thermodynamics, the wetting mechanism is analyzed.
In this study, ZrO2 (CaO stabilized) was used as the substrate, which was plate with 20 mm in diameter and 10 mm in thickness. The ceramic substrate was put on the resistance heating element, and then put into the testing device to measure the contact angle of high-activity metal melt on ceramic. Fig. 1 shows the apparatus for wetting experiments. Ti6Al4V alloy bar (5 mm in diameter) was employed in this study. It was ultrasound cleaned by acetone and ethanol and then dried in an air blast. Ti6Al4V alloy sample was held in the clamp of lift placed directly above the ceramic substrate. Before the heating cycle, the furnace chamber was evacuated down to 0.001 Pa and back-filled with argon gas three times, in order to reduce the oxygen content to a minimum level. After that, when the ceramic substrate was heated up to the Ti6Al4V alloy melting point by the resistance heating element, the end of Ti6Al4V alloy sample was put into the coil by lift. The high frequency induction coil in 50 kHz was used to heat Ti6Al4V alloy sample. As soon as the melting metal liquid dropped onto the ceramic substrate, the Ti6Al4V alloy sample was lift from the coil to avoid the liquid metal dropping again. At the same time, the metal drop was held in the liquid state by the resistance heating element, and images were obtained using the CCD camera and recorded on videotape at a speed of 6.3 frame/s. The contact angle was measured directly from the image of drop sections with an accuracy of ±5°. 3. Results and discussion 3.1. Contact angle
⁎ Corresponding author at: Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai'an 223003, China. Tel.: + 86 51783559150; fax: + 86 51783559150. E-mail address: [email protected] (A. Liu). 0167-577X/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2012.01.002
Fig. 2 shows the video images of Ti6Al4V alloy droplet on the ZrO2 (CaO stabilized) substrate at various time. From Fig. 2, it can be seen that the shape of the droplet is relatively smooth at initial contact
A. Liu et al. / Materials Letters 73 (2012) 40–42
41
1:Furnace
5: CCD video camera
9: Metal drop
13: Lift
2: Vacuum pump
6: Resistance heater
10: Quartz glass window
3: Spotlight
7: Ceramic insulating sleeve
11: Induction coil
4: Image processing system
8: Substrate
12: Metal sample
Fig. 1. Schematic diagram of experimental apparatus.
stage, and the contact angle changes as time goes on. Fig. 3 presents the change of contact angle with time. The curve exhibits two characteristic regions of the contact angle with respect to time: the first region presents a rapid slope (chemical reaction), and another where the value of θ is nearly constant and reaches a “steady state”. The examined system revealed unwetted states, θ > 90° at all time.
oxide compound is not clear yet, it may play an important role in inhibiting wetting of Ti on ZrO2 substrate. Furthermore, the stability of the CaO controls the rate of chemical reaction, which blocks the spreading of the droplet.
3.2. Interface
The dispersion force and Van der Waals force are the main driving forces during wetting, when the liquid metal/solid ceramic interface is nonreactive. In this case, the wettability for the system is poor. The contact angel depends mainly on the surface energy of liquid metal/ceramic substrate, liquid metal/vapor, and ceramic substrate/ vapor, which can be expressed as the Young equation for the conventional non-reactive wetting system:
In reactive systems, wetting frequently occurs with extensive chemical reaction and the forms of a new solid compound at the metal/substrate. After the experiment, it is found that the solidified droplet adheres well to ZrO2 (CaO stabilized) substrate. The micrographic observation made on the cross section perpendicular to the interface of sample using EPMA shows that there are two distinct layers between Ti6Al4Vand ZrO2 (CaO stabilized), as illustrated in Fig. 4a. The observed area is situated near the drop center. The unaffected ZrO2 (CaO stabilized) is located at the right end, while the unaffected Ti6Al4V is at the left end of the micrograph. To the left side of the unaffected ZrO2 (CaO stabilized) is a layer of the oxygen deficient zirconia (indicated as Zone A). At high temperature, the liquid metal infiltrated into ZrO2 (CaO stabilized) forming a thick chemical reaction zone (indicated as B) at the interface. Zone C (dark gray phase around zone B) is to the right of the unaffected Ti6Al4V [9]. The map analyses of Ti, Al, Zr, Ca, and O elements on cross section [Fig. 4a] are given in Fig. 4b. It can be seen that the reactive products formed near the interface and Ca displays a high concentration along the interface contrary to Zr. Although the composition of the reactive
1s
7s
3.3. Influence of the interfacial reaction on the wetting properties
cosθ ¼
σ sl −σ sg σ lg
ð1Þ
where θ is the contact angle; σlg, σsg and σsl are the surface tensions of liquid metal-vapor, ceramic-vapor and liquid metal-ceramic substrate, respectively. However, besides physical action, there is chemical action between high-activity Ti6Al4V alloy melt and ceramic materials. On the basis of physical chemistry fundamentals, for the reactive system, the free energy change is induced because the nature of matter is changed through the chemical reaction, and the interaction between reactive product and liquid metal occurs. At a high temperature, highly chemical active Ti ions in molten Ti6Al4V alloy attract intensively O
13s
32s
Fig. 2. Images of Ti6Al4V alloy droplet on ZrO2 (CaO stabilized) substrate at different holding times.
42
A. Liu et al. / Materials Letters 73 (2012) 40–42
the main driving force for improving the system wettability is the interfacial reaction free energy change of the molten Ti6Al4V alloy/ oxide ceramic system. The stability of the CaO controls the rate of chemical reaction, which blocks the spreading of the droplet.
132
Contact angle, deg
128 124
4. Conclusions
120
The study of high temperature wetting properties of molten Ti6Al4V on the ZrO2 (CaO stabilized) substrate, carried out by the self-designed measuring apparatus. Although the interfacial reaction between Ti6Al4V and ZrO2 (CaO stabilized) occurs at high temperature, the contact angle of molten Ti6Al4V on ZrO2 (CaO stabilized) substrate is larger than 90° and reaches stable in 10 s. The CaO exhibits a higher stability in contact with molten Ti6Al4V than ZrO2 and slows down the rate of Ti6Al4V/ZrO2 reaction.
116 112 108 0
5
10
15
20
25
30
35
Time, s Fig. 3. Variation of contact angle with time for the Ti6Al4V/ZrO2 (CaO stabilized) system.
ion in ceramic materials. The greater the affinity of liquid metal and O, the greater the adhesive work, the smaller the contact angle, based on the reference [11]. When liquid metal reacts with ceramic materials resulting in the formation of a continuous reactive product layer, the total free energy change at the liquid/solid interface, caused by interfacial reaction, is equal to the sum of free energy change produced by liquid metal reacting with ceramic materials and the interfacial energy of liquid metal/reactive product. Laurent et al. [12] introduced the chemical reaction free energy into Young equation and established the new contact angle formula in the reactive-wetting system: ′
cosθ ¼ cosθ−ΔGr =σ lg −Δσ r =σ lg
ð2Þ
where θ ' is the contact angle of the high-activity liquid metal and ceramic mold after interfacial reaction, Δσr is interfacial energy change caused by interfacial composition change, and ΔGr is the Gibbs free energy change of interfacial reaction in the gravitational field. According to Eq. (2), though the interfacial reaction free energy change and the interfacial energy change caused by ceramic matrix composition are key factors affecting the system wettability, the interfacial reactive product is the covalent compound with stability close to ceramic matrix for the molten Ti6Al4V alloy/oxide ceramics system. Thus, at the interface the change of surface component of ceramic matrix is small, that is to say, the effect of Δσr on the system wettability is weak, but the interfacial reaction free energy is large. Consequently,
Ti6Al4V
C
B
A
Acknowledgments The authors gratefully acknowledge financial support from the National Natural Science Foundation of China (51004051, 51175212), and the Natural Science Foundation of Jiangsu Province (BE2011726). References [1] Boyer RR. An overview on the use of titanium in aerospace industry. [J]Mater Sci Eng 1996;A213:103–14. [2] Schutz RW, Watkins HB. Recent developments in titanium alloy application in the energy industry. [J]Mater Sci Eng 1998;A243:305–15. [3] Joaquim Barbosaa, Ribeirob C Silva, Monteiro A Caetano. Influence of superheating on casting of γ-TiAl. Intermetallics 2007;15(7):945–55. [4] Contreras A, Leon CA, Drew RAL, Bedolla E. Wettability and spreading kinetics of Al and Mg on TiC. Scr Mater 2003;48:1625–30. [5] Laurent V, Chatain D, Eustathopoulos. Wettability of SiC by aluminium and Al–Si alloys. J Mater Sci 1987;22:244–50. [6] Zhou XB, Hosson JTD. Reactive wetting of liquid metals on ceramics substrates. [J] Acta Mater 1996;44(2):421–6. [7] Shinozaki N, Sonoda M, Mukai K. Wettability, surface, tension, and reactivity of the molten manganese/zirconia–yttria ceramic system. Metall Mater Trans 1998;29A:1121–5. [8] Shen P, Hidetoshi F, Taihei M, Kiyoshi N. Reactive wetting of SiO2 substrates by molten Al. Metall Mater Trans 2004;35A:583–8. [9] Kun-fung Lin, Chien-cheng Lin. Interfacial reactions between zirconia and titanium. Scr Mater 1998;39(10):1333–8. [10] Jun Zhu, Kamiya A. Surface tension, wettability and reactivity of molten titanium in Ti/yttria-stabilized zirconia system [J]. Mater Sci Eng 2002;A237: 117–27. [11] Ueki M, Naka M, Okamoto I. Wettability of some metals against zirconia ceramics [J]. J Mater Sci Lett 1986;5(12):1261–2. [12] Laurent V, Chatain D, Eustathopoulos. Wettability of SiO2 and oxidized SiC by aluminium [J]. Mater Sci Eng 1991;135A:89–94.
ZrO2(CaO stabilized)
a
b O
Al Zr
Ca
100µm
Ti
Fig. 4. SEM image and Ti, Al, Zr, Ca and O line analyses on the longitudinal-section perpendicular to the Ti6Al4V–ZrO2(CaO stabilized) interface.
Contents lists available at SciVerse ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Wettability of Ti6Al4V on calcia-stabilized zirconia Aihui Liu a, b,⁎, Bangsheng Li b, Dinggen Yan a, Jingjie Guo b a b
Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai'an 223003, China School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001
a r t i c l e
i n f o
Article history: Received 22 December 2011 Accepted 2 January 2012 Available online 8 January 2012 Keywords: Interfaces Ceramics Metals and alloys
a b s t r a c t The wettability between liquid Ti6Al4V alloy and calcia-stabilized zirconia was studied by the self-designed measuring apparatus in argon atmosphere. By means of the testing device, a kinetic and interfacial study on the wettability and spreading behavior of Ti6Al4V alloy melt on calcia-stabilized zirconia is presented. The micrographic observation made on cross sections perpendicular to the interface using map analyses shows that the interfacial reaction occurred at high temperature. However, the contact angles are relative stable and larger than 90° within experimental duration, and the equilibrium contact angle is 110°. The influence of interfacial reaction on the wettability can be explained by the total free energy at the liquid/solid interface. © 2012 Elsevier B.V. All rights reserved.
1. Introduction
2. Experimental procedure
Titanium alloys have been widely used in the aerospace, automobile applications, and relative industries for their excellent properties, such as high specific strength, good corrosion resistance, and appropriate high temperature properties [1–3]. Thanks to the efforts of different researchers, various methods have been applied in titanium alloys processing such as forging, forming, casting, powder metallurgy, welding etc. On the other hand, the investing casting is the optimal processing method for titanium alloy complex components. Wettability is crucial factor for making titanium alloy castings. The wetting of ceramic surface by molten metal is one of the most important phenomena to consider when a titanium alloy casting is produced. The sessile drop [4,5] is the most extensive method used to measure the contact angle. But it is usually applied in the measurement of low-activity alloys, such as Al, Cu, Ni, Zn and Fe [6–8]. Titanium alloy is metal with high melting point and high reactivity. The conventional sessile drop method is not suitable to measure the contact angle of molten titanium alloy/ceramic molds; it is because liquid metal reacts with ceramics resulting in a new ceramic surface before titanium alloy melts into droplet. The contact angle measured after titanium alloy melting is not that between molten titanium alloys and initial ceramic substrates [9,10]. In this work, a testing device to measure the contact angle of high-activity metal melt on ceramics is developed. By means of the testing device, a kinetic and interfacial study on the wettability and spreading behavior of Ti6Al4V alloy melt on calcia-stabilized zirconia (ZrO2 (CaO stabilized)) is presented. On the basis of thermodynamics, the wetting mechanism is analyzed.
In this study, ZrO2 (CaO stabilized) was used as the substrate, which was plate with 20 mm in diameter and 10 mm in thickness. The ceramic substrate was put on the resistance heating element, and then put into the testing device to measure the contact angle of high-activity metal melt on ceramic. Fig. 1 shows the apparatus for wetting experiments. Ti6Al4V alloy bar (5 mm in diameter) was employed in this study. It was ultrasound cleaned by acetone and ethanol and then dried in an air blast. Ti6Al4V alloy sample was held in the clamp of lift placed directly above the ceramic substrate. Before the heating cycle, the furnace chamber was evacuated down to 0.001 Pa and back-filled with argon gas three times, in order to reduce the oxygen content to a minimum level. After that, when the ceramic substrate was heated up to the Ti6Al4V alloy melting point by the resistance heating element, the end of Ti6Al4V alloy sample was put into the coil by lift. The high frequency induction coil in 50 kHz was used to heat Ti6Al4V alloy sample. As soon as the melting metal liquid dropped onto the ceramic substrate, the Ti6Al4V alloy sample was lift from the coil to avoid the liquid metal dropping again. At the same time, the metal drop was held in the liquid state by the resistance heating element, and images were obtained using the CCD camera and recorded on videotape at a speed of 6.3 frame/s. The contact angle was measured directly from the image of drop sections with an accuracy of ±5°. 3. Results and discussion 3.1. Contact angle
⁎ Corresponding author at: Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai'an 223003, China. Tel.: + 86 51783559150; fax: + 86 51783559150. E-mail address: [email protected] (A. Liu). 0167-577X/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2012.01.002
Fig. 2 shows the video images of Ti6Al4V alloy droplet on the ZrO2 (CaO stabilized) substrate at various time. From Fig. 2, it can be seen that the shape of the droplet is relatively smooth at initial contact
A. Liu et al. / Materials Letters 73 (2012) 40–42
41
1:Furnace
5: CCD video camera
9: Metal drop
13: Lift
2: Vacuum pump
6: Resistance heater
10: Quartz glass window
3: Spotlight
7: Ceramic insulating sleeve
11: Induction coil
4: Image processing system
8: Substrate
12: Metal sample
Fig. 1. Schematic diagram of experimental apparatus.
stage, and the contact angle changes as time goes on. Fig. 3 presents the change of contact angle with time. The curve exhibits two characteristic regions of the contact angle with respect to time: the first region presents a rapid slope (chemical reaction), and another where the value of θ is nearly constant and reaches a “steady state”. The examined system revealed unwetted states, θ > 90° at all time.
oxide compound is not clear yet, it may play an important role in inhibiting wetting of Ti on ZrO2 substrate. Furthermore, the stability of the CaO controls the rate of chemical reaction, which blocks the spreading of the droplet.
3.2. Interface
The dispersion force and Van der Waals force are the main driving forces during wetting, when the liquid metal/solid ceramic interface is nonreactive. In this case, the wettability for the system is poor. The contact angel depends mainly on the surface energy of liquid metal/ceramic substrate, liquid metal/vapor, and ceramic substrate/ vapor, which can be expressed as the Young equation for the conventional non-reactive wetting system:
In reactive systems, wetting frequently occurs with extensive chemical reaction and the forms of a new solid compound at the metal/substrate. After the experiment, it is found that the solidified droplet adheres well to ZrO2 (CaO stabilized) substrate. The micrographic observation made on the cross section perpendicular to the interface of sample using EPMA shows that there are two distinct layers between Ti6Al4Vand ZrO2 (CaO stabilized), as illustrated in Fig. 4a. The observed area is situated near the drop center. The unaffected ZrO2 (CaO stabilized) is located at the right end, while the unaffected Ti6Al4V is at the left end of the micrograph. To the left side of the unaffected ZrO2 (CaO stabilized) is a layer of the oxygen deficient zirconia (indicated as Zone A). At high temperature, the liquid metal infiltrated into ZrO2 (CaO stabilized) forming a thick chemical reaction zone (indicated as B) at the interface. Zone C (dark gray phase around zone B) is to the right of the unaffected Ti6Al4V [9]. The map analyses of Ti, Al, Zr, Ca, and O elements on cross section [Fig. 4a] are given in Fig. 4b. It can be seen that the reactive products formed near the interface and Ca displays a high concentration along the interface contrary to Zr. Although the composition of the reactive
1s
7s
3.3. Influence of the interfacial reaction on the wetting properties
cosθ ¼
σ sl −σ sg σ lg
ð1Þ
where θ is the contact angle; σlg, σsg and σsl are the surface tensions of liquid metal-vapor, ceramic-vapor and liquid metal-ceramic substrate, respectively. However, besides physical action, there is chemical action between high-activity Ti6Al4V alloy melt and ceramic materials. On the basis of physical chemistry fundamentals, for the reactive system, the free energy change is induced because the nature of matter is changed through the chemical reaction, and the interaction between reactive product and liquid metal occurs. At a high temperature, highly chemical active Ti ions in molten Ti6Al4V alloy attract intensively O
13s
32s
Fig. 2. Images of Ti6Al4V alloy droplet on ZrO2 (CaO stabilized) substrate at different holding times.
42
A. Liu et al. / Materials Letters 73 (2012) 40–42
the main driving force for improving the system wettability is the interfacial reaction free energy change of the molten Ti6Al4V alloy/ oxide ceramic system. The stability of the CaO controls the rate of chemical reaction, which blocks the spreading of the droplet.
132
Contact angle, deg
128 124
4. Conclusions
120
The study of high temperature wetting properties of molten Ti6Al4V on the ZrO2 (CaO stabilized) substrate, carried out by the self-designed measuring apparatus. Although the interfacial reaction between Ti6Al4V and ZrO2 (CaO stabilized) occurs at high temperature, the contact angle of molten Ti6Al4V on ZrO2 (CaO stabilized) substrate is larger than 90° and reaches stable in 10 s. The CaO exhibits a higher stability in contact with molten Ti6Al4V than ZrO2 and slows down the rate of Ti6Al4V/ZrO2 reaction.
116 112 108 0
5
10
15
20
25
30
35
Time, s Fig. 3. Variation of contact angle with time for the Ti6Al4V/ZrO2 (CaO stabilized) system.
ion in ceramic materials. The greater the affinity of liquid metal and O, the greater the adhesive work, the smaller the contact angle, based on the reference [11]. When liquid metal reacts with ceramic materials resulting in the formation of a continuous reactive product layer, the total free energy change at the liquid/solid interface, caused by interfacial reaction, is equal to the sum of free energy change produced by liquid metal reacting with ceramic materials and the interfacial energy of liquid metal/reactive product. Laurent et al. [12] introduced the chemical reaction free energy into Young equation and established the new contact angle formula in the reactive-wetting system: ′
cosθ ¼ cosθ−ΔGr =σ lg −Δσ r =σ lg
ð2Þ
where θ ' is the contact angle of the high-activity liquid metal and ceramic mold after interfacial reaction, Δσr is interfacial energy change caused by interfacial composition change, and ΔGr is the Gibbs free energy change of interfacial reaction in the gravitational field. According to Eq. (2), though the interfacial reaction free energy change and the interfacial energy change caused by ceramic matrix composition are key factors affecting the system wettability, the interfacial reactive product is the covalent compound with stability close to ceramic matrix for the molten Ti6Al4V alloy/oxide ceramics system. Thus, at the interface the change of surface component of ceramic matrix is small, that is to say, the effect of Δσr on the system wettability is weak, but the interfacial reaction free energy is large. Consequently,
Ti6Al4V
C
B
A
Acknowledgments The authors gratefully acknowledge financial support from the National Natural Science Foundation of China (51004051, 51175212), and the Natural Science Foundation of Jiangsu Province (BE2011726). References [1] Boyer RR. An overview on the use of titanium in aerospace industry. [J]Mater Sci Eng 1996;A213:103–14. [2] Schutz RW, Watkins HB. Recent developments in titanium alloy application in the energy industry. [J]Mater Sci Eng 1998;A243:305–15. [3] Joaquim Barbosaa, Ribeirob C Silva, Monteiro A Caetano. Influence of superheating on casting of γ-TiAl. Intermetallics 2007;15(7):945–55. [4] Contreras A, Leon CA, Drew RAL, Bedolla E. Wettability and spreading kinetics of Al and Mg on TiC. Scr Mater 2003;48:1625–30. [5] Laurent V, Chatain D, Eustathopoulos. Wettability of SiC by aluminium and Al–Si alloys. J Mater Sci 1987;22:244–50. [6] Zhou XB, Hosson JTD. Reactive wetting of liquid metals on ceramics substrates. [J] Acta Mater 1996;44(2):421–6. [7] Shinozaki N, Sonoda M, Mukai K. Wettability, surface, tension, and reactivity of the molten manganese/zirconia–yttria ceramic system. Metall Mater Trans 1998;29A:1121–5. [8] Shen P, Hidetoshi F, Taihei M, Kiyoshi N. Reactive wetting of SiO2 substrates by molten Al. Metall Mater Trans 2004;35A:583–8. [9] Kun-fung Lin, Chien-cheng Lin. Interfacial reactions between zirconia and titanium. Scr Mater 1998;39(10):1333–8. [10] Jun Zhu, Kamiya A. Surface tension, wettability and reactivity of molten titanium in Ti/yttria-stabilized zirconia system [J]. Mater Sci Eng 2002;A237: 117–27. [11] Ueki M, Naka M, Okamoto I. Wettability of some metals against zirconia ceramics [J]. J Mater Sci Lett 1986;5(12):1261–2. [12] Laurent V, Chatain D, Eustathopoulos. Wettability of SiO2 and oxidized SiC by aluminium [J]. Mater Sci Eng 1991;135A:89–94.
ZrO2(CaO stabilized)
a
b O
Al Zr
Ca
100µm
Ti
Fig. 4. SEM image and Ti, Al, Zr, Ca and O line analyses on the longitudinal-section perpendicular to the Ti6Al4V–ZrO2(CaO stabilized) interface.