真空热处理双粘结层热障涂层抗氧化性能

Oxidation Resistance of Thermal Barrier Coating with Vacuum Heat Treated Double-Layer Bond Coating

传统单层结构粘结层热障涂层抗氧化性能不足寿命短,采用超音速火焰喷涂(high velocity oxy-fuel,HVOF)和大气等离子喷涂(atmosphere plasma spray,APS)制备双层结构粘结层,对粘结层进行真空热处理,研究热障涂层的抗氧化性能。结果显示,经过1050℃×3 h真空热处理,粘结层组织中β-(Co,Ni)Al相含量从13.91%升高至27.78%,分布更加均匀;HVOF粘结层真空热处理后粗糙度降低,等离子层的引入,使真空热处理态粘结层粗糙度R_(a)由7.2μm提升至10.4μm,热障涂层结合强度达到39.4 MPa;热障涂层1050℃×200 h氧化速率低至0.1719 g/m^(2)·h,达到了航空工业标准的"抗氧化级";等离子粘结层优先发生氧化反应,起到牺牲作用,并提高了粘结层/面层界面的应力容忍度,延长了涂层的使用寿命。

The lifetime of traditional thermal barrier coating with one layer bond coating is limited by the insufficient oxidation resistance.A thermal barrier coating with a double-layer bond coating was prepared by HVOF and APS. Vacuum heat treatment was carried out prior to the top coating. Oxidation resistance of the thermal barrier coating was researched. The results show that the content of β-(Co, Ni)Al phase increases from 13.91% to 27.78% after 1050 ℃×3 h vacuum heat treatment, and the distribution is more homogeneous. The roughness of HVOF sprayed bond coating is decreased by vacuum heat treatment. The roughness of vacuum heat treated bond coati ng increases from 7.2 μm to 10.4 μm by the introduction of APS layer, and the bonding strength of thermal barrier coating is up to 39.4 MPa.The mass gain rate of thermal barrier coating is 0.1719 g/m^(2)·h after oxidizing at 1050 ℃ for 200 h, which is consistent with antioxidant level of aviation industry standard. The bond coating sprayed by APS is sacrificed to oxidize prior to HVOF layer. The stress tolerance of bond coating/top coating interface is improved, and the lifetime will be extended.