CrON扩散阻挡层对NbCrAl涂层与Nb基高温合金元素互扩散的影响

利用磁控溅射技术在C103型Nb基高温合金上制备了含和不含CrON扩散阻挡层的NbCrAl涂层,对比研究了2种涂层分别经900℃和1000℃真空热处理后的元素扩散行为。结果表明:NbCrAl涂层以Cr₂Nb和AlNb₂相为主,含非晶态组织;真空热处理后生成了NbAl₃和(Nb,Cr)沉淀相。热处理温度由900℃升至1000℃时,NbCrAl涂层中元素扩散速度加快。不含扩散阻挡层样品中Cr和Al元素扩散至基体的含量分别为2.76wt%和1.21wt%,而含扩散阻挡层样品中Cr和Al元素扩散到基体的含量分别仅为2.52wt%和0.84wt%。扩散阻挡层保持连续,且与涂层及基体的界面结合良好,经高温处理后主要以密排六方结构的Cr₂O₃和Al₂O₃相为主,有效地抑制了元素互扩散。

Influence of CrON diffusion barrier on elements inter-diffusion between NbCrAl coating and Nb-based superalloy

NbCrAl coatings with and without CrON diffusion barrier (DB) are prepared on C103 Nb-based superalloy by magnetron sputtering technique. The element diffusion behavior of two kinds of the coatings during vacuum heat treatment at 900℃ and 1000℃ is investigated. The results indicate that the as-deposited NbCrAl coating is composed of Cr₂Nb and AlNb₂ with amorphous phases. After vacuum heat treatment, NbAl₃ and (Nb,Cr) precipitated phases are formed. When the heat treatment temperature is increased to 1000℃ from 900℃, the rate of diffusion of elements in the NbCrAl coating becomes accelerated. Cr and Al elements in the samples without a DB diffuse to C103 substrate are 2.76wt% and 1.21wt%, while in the samples with a DB are only 2.52wt% and 0.84wt%. CrON diffusion barrier maintains continuous and has good adhesion to the coating and substrate as well. During high-temperature treatment, the CrON diffusion barrier, which is mainly composed of Cr₂O₃ and Al₂O₃ phases with close-packed hexagonal structure phases, effectively suppresses the elements inter-diffusion between the coating and substrate.