电泳共沉积NiCoCrAlY粘结层制备及抗高温氧化研究

目的 分析研究Ni基合金与粘结层之间的扩散和界面反应规律,以及其对热障涂层的抗高温氧化性能和工作寿命的影响.方法 采用电泳共沉积、真空致密化处理,在K17镍基高温合金表面制备NiCoCrAlY粘结涂层,并进行1000℃×100 h抗高温氧化实验,采用XRD、SEM、EDS分析NiCoCrAlY粘结涂层在高温氧化过程中合金元素的扩散规律.结果 高温氧化动力学曲线表明,氧化100 h制备的NiCoCrAlY粘结涂层的氧化速率为17.2134 mg/cm2,远低于K17镍基高温合金的.Ni由涂层向基体内扩散,Cr和Co向外扩散,Al向界面处扩散.电泳沉积制备的NiCoCrAlY粘结层经真空致密化处理后,涂层均匀、致密,粘结层主要由Ni3 Al、Al3 Y5 O12、Cr23 C6以及α-Al2 O3等组成.结论 NiCoCrAlY粘结涂层的抗高温氧化性高于K17镍基高温合金,在高温氧化过程中,α-Al2 O3氧化膜提高了NiCoCrAlY粘结涂层的高温抗氧化性.Ti主要来自基体的缺陷中,随着高温氧化作用,获得了由基体向外扩散所需要的能量,并且同时与氧反应生成TiO,TiO容易在粘结层表面形成泡状物质,Ti的扩散对粘结层的致密度与均匀度造成一定的影响.

Preparation of Electrophoresis Co-deposition NiCoCrAlY Adhesive Layer and Its Resistance to High Temperature Oxidation

Objective To analyze and study the law of diffusion and interface reaction between Ni-base alloy and the adhesive layer, and its impact on high temperature oxidation resistance and working life of the thermal barrier coating. Methods NiCoCrAlY bonding coating was prepared on the surface of K17 Nickel-based heat-resistant alloy by electrophoretic co-deposition and vacuum densifying treatment. The high temperature oxidation resistance experiment was carried out at 1000 ℃ for 100 h, and the diffusion law of alloying elements in the NiCoCrAlY bonding coating during oxidation at high temperature was analyzed by XRD, SEM and EDS. Results The high temperature oxidation kinetic curves showed that the oxidation rate of NiCoCrAlY bonded coating prepared by 100 h oxidation was 17. 2134 mg/cm2 , which was much lower than that of K17 Nickel-based heat-resistant alloy. SEM and EDS analysis of the diffusion of NiCoCrAlY bonding coating in the process of high temperature oxidation of alloy elements showed that Ni was diffused from the coating to the substrate, Co and Cr spread out, while Al diffused at the interface. The adhesive layer was uni-form and dense after vacuum densifying process, and the adhesive layer was mainly composed of Ni3 Al, Al3 Y5 O12 , Cr23 C6 andα-Al2 O3 . Conclusion The high temperature oxidation resistance of NiCoCrAlY bonding coating was higher than that of K17 Nickel-based heat-resistant alloy. In the process of high temperature oxidation, the oxidation resistance of NiCoCrAlY bonding layer was increased by α-Al2 O3 oxidation film. Ti mainly came from defects of the substrate, with the high temperature oxidation, the out-ward diffusion of energy needed by the matrix was gained and TiO was simultaneously generated by reacting with oxygen, leading to easy generation of foam-like substance on the surface of the adhesive layer. The diffusion of Ti had certain impact on the density and uniformity of the adhesive layer.