镍基合金/NiCrAlY粘结层界面活性扩散障的研究

Study on an active diffusion barriers between Ni-based alloy and NiCrAlY bond coating interface

采用电子束物理气相沉积技术(EB-PVD)在Rene N5镍基高温合金表面分别制备出N5/NiCrAlY和N5/ZrO_2/NiCrAlY两种涂层体系试样,并对其进行1000℃/5 h和1000℃/350 h高温氧化处理。利用SEM、EDS、XRD等分析方法对比研究了高温环境中镍基合金基体与NiCrAlY粘结层界面的演变行为以及ZrO_2活性扩散障对界面演变的控制作用。结果表明,N5/NiCrAlY体系涂层在高温环境中由于各元素浓度的差异会发生元素互扩散行为,导致在基体/NiCrAlY涂层界面处形成柯肯达尔孔洞,二次反应区及TCP相;而对于N5/ZrO_2/NiCrAlY涂层体系而言,在高温环境中,其ZrO_2活性扩散障将演变为Al_2O_3/Zr-rich/Al_2O_3三层结构,该结构能够有效抑制基体与粘结层之间的元素互扩散行为,阻止二次反应区及TCP相的出现,并且该结构具有良好的高温稳定性能。

Two coating systems( NiCrAlYand ZrO_2/NiCrAlY) were coated on Rene N5 substrate by EB-PVD( electron beam-physical vapor deposition),and then both of them were treated by oxidation treatment at 1000 ℃. Finally,the evolution of N5/NiCrAlY interface and the effect of ZrO_2 diffusion barrier layer were analyzed by SEM,EDS and XRD et al. The results show that the elements,such as Ni,Cr,Al,et al,between Rene N5 substrate and NiCrAlY coating are inter-diffused because of the different concentration of the elements during the process of high-temperature oxidation. And this also made the Kendall holes,secondary reaction zone and the TCP phase format the interface of substrate/NiCrAlY. In the N5/ZrO_2/NiCrAlY coating system,however,the ZrO_2 diffusion barrier layer was developed into three-layer structure( Al_2O_3/Zr-rich/Al_2O_3) under the same condition,which can efficiently eliminate the second reaction zone and TCP phase. Moreover,the Al_2O_3/Zr-rich/Al_2O_3 layer presents good high-temperature stability.