基于冷喷涂制备ZrC掺杂NiAl热障涂层粘结层

Preparation of Cold Spraying-based NiAl/ZrC Bond Course of Thermal Barrier Coating

目的开发NiAl金属间化合物热障涂层粘结层。方法通过机械合金化技术制备了Ni/Al、Ni/Al+0.5%ZrC与Ni/Al+0.07%三种复合结构粉末。采用冷喷涂在镍基高温合金(IN738)基体上制备Ni/Al、Ni/Al+0.5%ZrC与Ni/Al+0.07%三种复合涂层,然后在保护气氛Ar气中进行热扩散制备这三种金属间化合物涂层。结果低温球磨8 h后可以获得具有亚微米层状结构的Ni/Al+ZrC复合结构粉末。喷涂态Ni/Al合金复合涂层保留了粉末的结构,经1080℃保温10 h后,形成了致密的NiAl金属间化合物涂层。结论掺杂ZrC(0.07%和0.5%)的Ni/Al粉末在球磨后比未掺杂ZrC的粉末更均匀。掺杂ZrC的粉末形成了部分NiAl金属间化合物,而没有掺杂ZrC的粉末则无NiAl金属间化合物形成。冷喷涂可以制备几乎无氧化Ni/Al粉末粘结层。热处理后原喷涂态涂层中的亚微米的层状结构已基本消失,变成了较为均匀的组织。

The work aims to prepare bond course of thermal barrier coating of NiAl intermetallic compound. The composite structure powder of Ni/Al, Ni/Al＋0.5 at%ZrC and Ni/Al＋0.07 at% was prepared by utilizing mechanical alloying technology. Firstly composite coatings of Ni/Al, Ni/Al＋0.5 at%ZrC and Ni/Al＋0.07 at% were prepared on nickel base superalloy（IN738） sustrate by cold spraying of ball-milled Ni/Al alloy powders. Then the intermetallic compounds were annealed in protective atmosphere Ar. The results showed that a submicron lamellar structure of Ni/Al＋ZrC composite structure powder could be obtained after ball milling for 8 h at low temperture. Composite coating of as-sprayed Ni/Al alloy maintained structure of the powder and formed compact NiAl intermetallic compound after 10 h of heat preservation at 1080 ℃. Ni/Al powder doped with ZrC（0.07 at% and 0.5 at%） is more uniform than that not doped with ZrC. Part of NiAl intermetallic compound is formed in powder doped with ZrC while none formed in powder not doped with ZrC. Nearly non-oxidized bond course of Ni/Al powder can be prepared by cold spraying. Submicron lamellar structure in original as-sprayed coating almost disappears and becomes uniform structure after heat treatment.