激光复合等离子喷涂NiCr-Cr_3C_2涂层的微观组织与沉积机理研究(英文)

Microstructure and Deposition Mechanism of Laser-Hybrid Plasma Spraying NiCr-Cr_3C_2 Coating

利用激光复合等离子喷涂工艺在38CrMoAl基体表面沉积了NiCr-Cr3C2涂层,采用光学显微镜、扫描电镜、高速摄像等研究了涂层的微观组织和沉积机理,同时,对涂层的结合强度与显微硬度也进行了测试分析。结果表明,激光热源在复合喷涂过程中发挥了两个重要作用。一方面,它使得NiCr-Cr3C2粉末熔融更加充分,有良好的流动性和均匀性;另一方面,它加热基体表面,形成微熔池。因此,与等离子喷涂涂层机械结合方式相比,由于激光热源的加入,复合喷涂涂层实现了冶金结合,获得了更高的结合强度和显微硬度。由于复合热源喷涂的沉积机理非常有利于提高涂层的性能和延长涂层的服役寿命,因此该工艺方法具备广阔的发展前景。

The NiCr-Cr3C2 coatings were deposited on 38CrMoAl substrate by laser-hybrid plasma spraying(LHPS) technique.The microstructures and the deposition mechanism of LHPS coatings were studied using an optical microscope,a scanning electron microscope and a high speed camera system.Meanwhile the bonding strength and microhardness of the coatings were tested and analyzed.The results indicate that the laser power plays two important roles in the LHPS processing.On the one hand,it makes the NiCr-Cr3C2 powder melt more sufficiently and has good fluidity and uniformity; on the other hand,it heats the substrate surface to be the micro molten pool.Therefore the LHPS NiCr-Cr3C2 coating achieves metallurgy bonding rather than mechanical bonding and has higher bonding strength and microhardness than the air plasma spraying coating for the addition of the laser power.The LHPS technique has a broad prospect for its deposition mechanism to improve the coatings' performances and to prolong the coatings' service life greatly.