Preparation and Bond Properties of Thermal Barrier Coatings on Mg Alloy with Sprayed Al or Diffused Mg-Al Intermetallic
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JTTEE5 23:304–316 DOI: 10.1007/s11666-013-9985-9 1059-9630/$19.00 Ó ASM International
Preparation and Bond Properties of Thermal Barrier Coatings on Mg Alloy with Sprayed Al or Diffused Mg-Al Intermetallic Interlayer Xizhi Fan, Ying Wang, Binglin Zou, Lijian Gu, Wenzhi Huang, and Xueqiang Cao (Submitted April 8, 2013; in revised form July 16, 2013) Sprayed Al or diffused Mg-Al layer was designed as interlayer between the thermal barrier coatings (TBCs) and Mg alloy substrate. The effects of the interlayer on the bond properties of the coats were investigated. Al layers were prepared by arc spraying and atmospheric plasma spraying (APS), respectively. Mg-Al diffused layer was obtained after the heat treatment of the sprayed sample (Mg alloy with APS Al coat) at 400 °C. The results show that sprayed Al interlayer does not improve the bond stability of TBCs. The failure of the TBCs on Mg alloy with Al interlayer occurs mainly due to the low strength of Al layer. Mg-Al diffused layer improves corrosion resistance of substrate and the bond interface. The TBCs on Mg alloy with Mg-Al diffused interlayer shows better bond stability than the sample of which the TBCs is directly sprayed on Mg alloy substrate by APS.
Keywords
bond stability, interlayer, magnesium alloy, TBCs
1. Introduction Mg alloys are the lightest materials among those metals used for structural or mechanical applications (Ref 1). They also have many excellent properties such as high specific tensile strength, good stiffness, and vibration absorption (Ref 2, 3). Therefore, Mg alloys have potential applications in automobiles, electronic products, aerospace, etc. (Ref 4, 5). Unfortunately, Mg alloys have low melting point, poor wear resistance, and high chemical activity that have limited their widespread applications. Several surface coating technologies have been developed to improve the corrosion resistance, wear resistance, and thermal resistance of Mg alloys, such as electroless plating, conversion coatings, anodizing, gas-phase deposition, and thermal spraying (Ref 6). Among various surface coating treatments, thermal spraying is considered to be a relatively effective choice, as it can provide Mg alloy substrates with various coatings that have the desired properties of good corrosion, wear resistance, and thermal resistance. Thermal barrier coatings (TBCs), typically comprising MCrAlY (M = Ni, Co) bond coat and yttria-stabilized Xizhi Fan, Lijian Gu, and Wenzhi Huang, State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin China and Graduate School of Chinese Academy of Sciences, Beijing 100049, China; Ying Wang, Binglin Zou, and Xueqiang Cao, State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin China Contact e-mail: [email protected].
304—Volume 23(3) February 2014
zirconia (YSZ) top coat, have low thermal conductivity and excellent surface properties
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