摘要
目的研究等离子喷涂与超音速火焰喷涂NiCr-Cr3C2涂层的组织、力学性能和摩擦磨损性能。方法采用等离子喷涂与超音速火焰喷涂工艺制备NiCr-Cr3C2涂层,并采用X射线衍射仪(XRD)、扫描电镜(SEM)、万能试验机、显微硬度计和高速往复摩擦磨损试验机,系统地分析了两种工艺所得涂层的物相、组织、结合强度、硬度及摩擦磨损性能。结果两种工艺制备的NiCr-Cr3C2涂层与基体界面结合效果良好。等离子喷涂NiCr-Cr3C2涂层为层片状组织,层间可见微裂纹,孔隙率较高;超音速火焰喷涂NiCr-Cr3C2涂层组织均匀,无明显微裂纹,可见少量微小孔隙。物相分析表明,等离子喷涂涂层由NiCr、Cr3C2和Cr7C3相组成,而超音速火焰喷涂涂层由NiCr和Cr3C2相组成。超音速火焰喷涂NiCr-Cr3C2涂层的耐磨性优于等离子喷涂涂层,等离子喷涂涂层和超音速火焰喷涂涂层的稳态摩擦系数分别为0.4和0.6。随载荷升高,两种工艺制备的NiCr-Cr3C2涂层摩擦系数均显著下降。磨损后,等离子喷涂NiCr-Cr3C2涂层表面具有明显的凹痕和剥落,而超音速火焰喷涂NiCr-Cr3C2涂层磨痕表面较光滑,未见明显剥落。两种工艺制备的涂层磨损机制均为磨粒磨损和疲劳磨损。结论超音速火焰喷涂NiCr-Cr3C2涂层较等离子喷涂涂层组织更为致密,具有更为优良的综合力学性能和耐磨性,等离子喷涂制备的NiCr-Cr3C2涂层的减摩性较好。
The work aims to investigate microstructrure, mechanical behavior and friction and wear properties of NiCr-Cr3C2 coating prepared by APS and HVOF. NiCr-Cr3C2 coatings were fabricated by APS and HVOF, respectively. Phase compostion, microstructure, bonding strength, hardness and friction wear performance of the coatings prepared by two different processes were investigated systematically with X-ray diffractometer (XRD), scanning electron microscope (SEM), universal test machine, microhardness tester and high speed reciprocating friction testing machine. The prepared coatings had good bonding effects with substrate interface. The coating prepared by APS had a lamellar microstructure with some microcracks between the lamellars and higher porosity. However, the coating prepared by HVOF had a uniformal microstructure with no apparent microcrack and lower porosity. The XRD results showed that the phases of coating prepared by APS were NiCr, Cr3C2 and Cr7C3, while the phases of coating prepared by HVOF were NiCr and Cr3C2. The coating prepared by HVOF presented a better wear resistance than that prepared by APS. The steady friction coefficients of coating fabricated by APS and HVOF were 0.4 and 0.6, respectively. The friction coefficients of coating prepared by the two processes decreased significantly with the increase of load. The worn surface of NiCr-Cr3C2 coating prepared by APS showed apparent indentation and spalling, while that of NiCr-Cr3C2 coating prepared by HVOF showed a smooth grinding crack with no apparent spalling. Main wear mechanisms of the coatings prepared by the two processes were abrasive wear and fatigue wear. The NiCr-Cr3C2 coating prepared by HVOF has more compact structure and better comprehensive mechanical properties and wear resistan than that by APS.
作者
赵子鹏
司洪利
李忠盛
何庆兵
易同斌
宋凯强
丛大龙
ZHAO Zi-peng;SI Hong-li;LI Zhong-sheng;HE Qing-bing;YI Tong-bin;SONG Kai-qiang;CONG Da-long(Southwest Technology and Engineering Research Institute, Chongqing 400039, China;Chongqing Military Missile Equipment Representative Office of Navy, Chongqing 402760, China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2019年第8期225-230,共6页
Surface Technology
基金
国防技术基础项目(JSCG2016209B005)~~
