超音速微粒轰击粘结层对热障涂层抗氧化性能的影响

Effect of Supersonic Fine Particle Bombarding Bonded Coating on Antioxidation Behavior of Thermal Barrier Coating

较长时间高温氧化,会使金属粘结层与热生长氧化物界面处贫铝,造成热喷涂陶瓷层失效。对金属粘结层进行超音速微粒轰击,可以增加铝扩散的浓度梯度,提高热障涂层的抗氧化能力。采用等离子喷涂(APS)在镍基高温合金GH99上制备了热障涂层,并对粘结层进行了超音速微粒轰击处理,研究了该处理工艺对粘结层显微结构及高温氧化行为的影响。结果表明:APS热障涂层经1050℃、96h氧化后,热生长氧化物层产生大量非保护性混合氧化物;超音速微粒轰击工艺使粘结层表层区域产生大量位错等缺陷,涂层经1050℃、3h氧化后进入稳态氧化期,同时出现Al在粘结层表层的富集,经1050℃、196h氧化后粘结层无加速氧化趋势,热障涂层的抗高温氧化性能得到提高。

Thermal barrier coating (TBC) was prepared on Ni-based high-temperature alloy GH99 by atmospheric plasma spraying (APS). The bonded coating was treated by supersonic fine particle bombarding, which was carried out in relation to the effect on the microstructure and oxidation behavior of the TBC. If was found that a thermally grown oxide (TGO) layer composed of detrimental oxides was formed in APS-TBC specimens after 96 h thermal exposure at 1 050 ℃. After treating the bonded coating by supersonic fine particle bombarding, large quantities of dislocations were generated in the thermal barrier coating. In this case the coating reached steady-state oxidation after thermal exposure at 1 050 ℃ for 3h, and Al was enriched atop the bonded coating. Subsequently, even after 196 h thermal exposure at 1050 ℃, the bonded coating still retained steadystate oxidation, implying that the high temperature antioxidation behavior of the thermal barrier coating was effectively increased.