中文摘要：

采用低压等离子喷涂（LPPS）、常规超音速火焰喷涂（HVOF）和低温超音速火焰喷涂（LT-HVOF）三种工艺在铸造镍基高温合金K438基体上制备了Ni-Cr-Al-Y涂层,并对三种工艺制备涂层的显微结构、元素分布、相组成和基本性能进行对比研究。结果表明：LPPS涂层致密无层状结构,含氧量微小,具有较高的显微硬度和好的抗氧化性;HVOF涂层为典型的层状结构,含氧量高,显微硬度低,抗氧化性差;LT-HVOF涂层含氧量大大降低,具有优良的抗氧化性;三种涂层都发生了元素扩散。

英文摘要：

Ni-Cr-Al-Y coatings were prepared on cast Ni-based superalloy K438 using low pressure plasma spraying （LPPS）, high velocity oxygen fuel （HVOF） and low temperature high velocity oxygen fuel （LT-HVOF）. A comparative study of microstructure, elemental distribution, phase and fundamental properties was conductded. The results show that LPPS coating has no layered structure, low level of oxygen, higher micro hardness and good oxidation resistance. HVOF coating owns typical layered structure, high level of oxygen, low microhardness, bad oxidation resistance. LT-HVOF coating has much lower level of oxygen and better oxidationg resistance compared with the HVOF coating. Element diffuse is found in all three coatings.