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本文考察了不同镍基高温合金与两种化学成分的MCrAlY粘结涂层的互扩散行为。为明确涂层沉积过程对其影响,本文采用超音速火焰喷涂(HVOF)和低压等离子喷涂(LPPS)两种不同的喷涂工艺制备了MCrAlY粘结涂层。本文重点考察Kirkendall孔隙度的演变过程,其主要形成于基材与粘结层界面,并主要受涂层及基材化学成分的影响。实验研究表明:涂层沉积过程对Kirkendall孔隙度的演变过程具有较大影响。孔隙的形成可导致基材与涂层间粘结强度的降低,甚至引起涂层系统的功能性破坏。本文在涂层沉积后,将样品置于1050℃条件下进行最长可达2000小时的退火。为评估Kirkendall孔隙度,对样品进行微观组织和化学成分分析。结果表明:Kirkendall孔隙度的形成量以及形成位置很大程度上受涂层沉积过程的影响。一般而言,通过HVOF工艺制备粘结涂层的样品提高了元素扩散速率。由于在涂层沉积之前进行了表面处理,故造成上述现象的主要原因为基材材料的再结晶。
In this paper, we investigate the interdiffusion behavior of MCrAlY bond coatings with different Ni-based superalloys and two chemical compositions. In order to clarify the influence of coating deposition process, MCrAlY bond coating was prepared by two different spraying processes: HVOF and LPPS. This paper focuses on the evolution of Kirkendall porosity, which is mainly formed at the interface between the substrate and the adhesive layer and is mainly affected by the chemical composition of the coating and the substrate. Experimental results show that the deposition process has a great influence on the Kirkendall porosity evolution. The formation of voids can lead to a decrease in the bond strength between the substrate and the coating and can even cause functional damage to the coating system. In this paper, the coating deposition, the sample is placed at 1050 ℃ for up to 2000 hours of annealing. To assess Kirkendall porosity, samples were analyzed for microstructure and chemical composition. The results show that the formation and formation of Kirkendall porosity are largely affected by the deposition of the coating. In general, samples prepared by the HVOF process to increase the elemental diffusion rate increase the diffusion rate of the element. Since the surface treatment is performed before the deposition of the coating, the main reason for the above phenomenon is the recrystallization of the base material.