论文部分内容阅读
利用多靶非平衡磁控溅射离子镀技术制备不同Y含量的CrxAlyY1-x-yN(x=0.88,0.89,0.86,0.83,0.703;y=0.12,0.083,0.077,0.071,0.057,下同)镀层,通过镀层的氧化动力学曲线,结合镀层形貌及相结构的变化,研究Y含量对CrxAlyY1-x-yN镀层热氧化行为的影响。结果表明:适量的Y可提高镀层的热稳定性,相对无Y的Cr0.88Al0.12N镀层,Y含量为3.28at%的Cr0.86Al0.077Y0.063N镀层氧化过程缓慢,动力学曲线变化平缓,900℃时镀层氧化增重量仅为无Y镀层的14%,且表面出现大量氧化物堆积,但没有出现氧化孔洞,断口形貌没有明显分层现象;但Y含量过多时,仅能维持镀层低温阶段的平稳,当温度超过900℃,Y含量为12.88at%的Cr0.703Al0.057Y0.24N镀层则加速氧化,出现线性上升的趋势,镀层严重氧化开裂;适量Y元素的添加,在镀层加热过程中可钉扎晶界,减小氧化过程中内应力的释放,提高了镀层的热氧化性能。而Y含量增多,镀层由固溶态转变为YN相,氧化过程中会阻止亚稳态(γ-,θ-)Al2O3向稳态(α-)Al2O3的转变,从而形成多孔氧化膜,且大尺寸Y2O3在晶界的偏聚,增加O原子扩散通道,加速了镀层的氧化。
CrxAlyY1-x-yN with different content of Y (x = 0.88,0.89,0.86,0.83,0.703; y = 0.12,0.083,0.077,0.071,0.057, the same in the following) was prepared by multi-target unbalanced magnetron sputtering ion plating technology. The effects of Y on the thermal oxidation behavior of CrxAlyY1-x-yN coatings were investigated by the oxidation kinetics of the coatings and the changes of the morphology and phase structure of the coatings. The results show that: the proper amount of Y can improve the thermal stability of the coating, the oxidation process of Cr0.86Al0.077Y0.063N coating with the Y content of 3.28at% is slow, the kinetic curve changes slowly compared with the Cr0.88Al0.12N coating without Y, At 900 ℃, the weight gain of the coating is only 14% of that of the non-Y coating, and a large amount of oxide deposits on the surface, but no oxidation pores appear and the morphology of the fracture is not obviously stratified. However, when the content of Y is too high, Stable phase, when the temperature exceeds 900 ℃, Y content of 12.88at% Cr0.703Al0.057Y0.24N coating is accelerated oxidation, a linear upward trend, coating serious oxidative cracking; the amount of Y element addition, in the coating heating process In the grain boundary can be pinned to reduce the release of internal stress during oxidation and improve the thermal oxidation properties of the coating. While the content of Y increases, the coating changes from solid solution state to YN phase, and the oxidation process can prevent the metastable (α -) θAl 2 O 3 transformation from metastable (γ-, θ-) Al 2 O 3 to form a porous oxide film The segregation of size Y2O3 at the grain boundaries increases the diffusion path of O atoms and accelerates the oxidation of the coating.