Surface Microstructure and High Temperature Oxidation Resistance of Thermal Sprayed NiCoCrAlY Bond-Coat Modified by Cathode Plasma Electrolysis

doi:10.1016/j.jmst.2016.09.005

Abstract

Abstract:

The surface properties of the air-plasma sprayed bond-coat have been modified by cathode plasma electrolysis (CPE). After modification, a re-melted layer without obvious pores and oxide stringers is formed, the gain size of re-melted layer is approximately 80-120 nm. It is shown, from cyclic oxidation at 1100 °C, that a thin oxide scale mainly composed of α-Al₂O₃ has been formed on the modified bond-coat and the oxidation resistance of the modified bond-coat has been significantly improved. Such beneficial result can be attributed to following effects: during CPE process, the plasma discharges with high temperature take place on the bond-coat surface. With plasma discharge treatment, the surface is melted and quickly re-solidified, the grain size decreases, and the pores and oxide stringers disappear. During cyclic oxidation, owing to the above modification of surface properties, the critical content of Al for selective oxidation is significantly decreased. Therefore, a continuous Al₂O₃ scale is formed.

Key words: Cathode plasma electrolysis, NiCoCrAlY bond-coat, Surface modification, Microstructure, High-temperature oxidation

Deng Shunjie, Wang Peng, He Yedong, Zhang Jin. Surface Microstructure and High Temperature Oxidation Resistance of Thermal Sprayed NiCoCrAlY Bond-Coat Modified by Cathode Plasma Electrolysis[J]. J. Mater. Sci. Technol., 2017, 33(9): 1055-1060.

Figures/Tables 9

Table 1 Air plasma spray parameters

Parameter	Value
Spray gun	SG-100
Voltage (V)	39
Current (A)	800
Powder feed rate (rpm)	2.5
Spray distance (mm)	85
Primary gas Ar pressure (psi)	50
Secondary gas He pressure (psi)	110

Fig. 1. Surface and cross-section morphologies of the different samples: (a and b) the APS bond-coat; (c and d) the modified bond-coat.

Fig. 2. TEM morphologies of the APS and the modified bond-coats: (a) the APS bond-coat; (b) the modified bond-coat.

Fig. 3. Oxidation kinetic curves of the APS bond-coat and the modified bond-coat: (a) mass gain versus time and (b) spallation mass versus time.

Fig. 4. XRD patterns of the APS bond-coat and the modified bond-coat after cyclic oxidation.

Fig. 5. Cross-section morphologies of the different samples after the cyclic oxidation: (a) the APS bond-coat; (b) the modified bond-coat.

Fig. 6. EDS elemental maps of the cross-section of the APS bond-coat after the cyclic oxidation.

Fig. 7. EDS elemental maps of the cross-section of the modified bond-coat after the cyclic oxidation.

Fig. 8. Schematic illustration for mechanism of CPE surface modification.

References

[1]	N.P. Padture, M. Gell, E.H. Jordan, Scienc. 296 (2002) 280-284.
[2]	G. Marginean, D. Utu, Appl. Surf. Sc. 258 (2012) 8307-8311.
[3]	T. Patterson, A. Leon, B. Jayaraj, J. Liu, Y.H. Sohn, Surf. Coat. Techno. 203 (2008) 437-441.
[4]	P. Richer, M. Yandouzi, L. Beauvais, B. Jodoin, Surf. Coat. Techno. 204 (2010) 3962-3974.
[5]	L.Y. Ni, C. Liu, H. Huang, C.G. Zhou, J. Therm. Spray Techno. 20 (2011) 1133-1138.
[6]	G.Y. Liang, C. Zhu, X.Y. Wu, Y.Wu, Appl. Surf. Sc. 257 (2011) 6468-6473.
[7]	K. Vaidyanathan, E.H. Jordan, M. Gell, Acta Mate. 52 (2004) 1107-1115.
[8]	R.G. Wellman, A. Scrivani, G. Rizzi, A. Weisenburger, F.H. Tenailleau, J.R. Nicholls, Surf. Coat. Techno. 202 (2007) 709-713.
[9]	D. Strauss, G. Müller, G. Schumacher, V. Engelko, W. Stamm, D. Clemens, W.J. Quaddakers, Surf. Coat. Techno. 135 (2001) 196-201.
[10]	Z. Zhou, S. Gong, H. Li, H. Xu, C. Zhang, L. Wang, Chin. J. Aeronau. 20 (2007) 145-147.
[11]	A.C. Karaoglanli, Sci. Adv. Mate. 7 (2015) 173-177.
[12]	A.C. Karaoglanli, K.M. Doleker, B. Demirel, A. Turk, R. Varol, Appl. Surf. Sc. 354 (Pt B) (2015) 314-322.
[13]	L. Ni, C. Zhou, Prog. Nat. Sci. Mater. In. 22 (2012) 237-243.
[14]	M. Li, M. Chao, E. Liang, J. Yu, J. Zhang, D. Li, Appl. Surf. Sc. 258 (2011) 1599-1604.
[15]	J. Cai, S.Z. Yang, L. Ji, Q.F. Guan, Z.P. Wang, Z.Y. Han, Surf. Coat. Techno. 251 (2014) 217-225.
[16]	J. Cai, Q. Guan, X. Hou, Z. Wang, J. Su, Z. Han, Appl. Surf. Sc. 317 (2014) 360-369.
[17]	E.V. Parfenov, A. Yerokhin, R.R. Nevyantseva, M.V. Gorbatkov, C.J. Liang, A. Matthews, Surf. Coat. Techno. 269 (2015) 2-22.
[18]	E.I. Meletis, X. Nie, F.L. Wang, J.C. Jiang, Surf. Coat. Techno. 150 (2002) 246-256.
[19]	P. Gupta, G. Tenhundfeld, E.O. Daigle, D. Ryabkov, Surf. Coat. Techno. 201 (2007) 8746-8760.
[20]	C. Quan, Y. He, Appl. Surf. Sc. 353 (2015) 1320-1325.
[21]	S. Deng, P. Wang, Y. He, Surf. Coat. Techno. 279 (2015) 92-100.
[22]	A.L. Yerokhin, X. Nie, A. Leyland, A. Matthews, S.J. Dowey, Surf. Coat. Techno. 122 (1999) 73-93.
[23]	P. Wang, Y. He, J. Zhang, Surf. Coat. Techno. 283 (2015) 37-43.
[24]	H. Yamano, K. Tani, Y. Harada, T. Teratani, J. Therm. Spray Techno. 17 (2008) 275-283.
[25]	F. Tang, L. Ajdelsztajn, J.M. Schoenung, Oxid. Me. 61 (2004) 219-238.
[26]	C. Zhou, J. Yu, S. Gong, H. Xu, Mater. Sci. En. A 348 (2003) 327-332.
[27]	A.L.Y.L.O. Snizhko, A. Pilkington, N.L. Gurevina, D.O. Misnyankin, A. Leyland, A. Matthews, Electrochi. Acta 49 (2004) 2085-2095.
[28]	T. Paulmier, J.M. Bell, P.M. Fredericks, Surf. Coat. Techno. 201 (2007) 8771-8781.
[29]	C. Wagner, J. Electrochem. So. 103 (1956) 627-633.
[30]	C. Wagner, J. Electrochem. So. 99 (1952) 369-380.