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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。
Ni-Cr-Al-Y coatings were prepared on cast nickel-base superalloy K438 by low pressure plasma spraying (LPPS), conventional supersonic flame spraying (HVOF) and low temperature supersonic flame spraying (LT-HVOF) The microstructures, elemental distributions, phase compositions and basic properties of the three coatings were compared. The results show that the LPPS coating has a dense and non-layered structure with low oxygen content, high microhardness and good oxidation resistance. HVOF coating is a typical layered structure with high oxygen content and low microhardness , Poor oxidation resistance; LT-HVOF coating oxygen content is greatly reduced, with excellent oxidation resistance; elemental diffusion have occurred in all three coatings.