摘要
目的研究不同前驱体配比下,激光熔覆复合溶胶凝胶在3Cr13不锈钢表面制备的陶瓷涂层的性能,并对强化机理进行分析。方法通过溶胶凝胶法制备均匀的前驱体,即Ti O2和C(微米石墨和碳纳米管),利用激光熔覆技术,在3Cr13不锈钢基体表面制备出高性能的涂层。采用光学显微镜、X射线衍射仪、扫描电镜和能谱仪对涂层组织和相成分进行分析,采用维氏硬度计对涂层的硬度进行测试,采用HT-600型高温摩擦磨损试验机测试基体和熔覆层在常温下的磨损性能。结果通过溶胶凝胶法,制备出均匀的Ti O2和C混合粉末。激光熔覆后,在覆层中均匀分布着Ti C和Cr7C3强化相。改变前驱体配比,当C和Ti O2的摩尔比增大时,涂层组织明显细化,且涂层中无气孔,显微硬度也有较大提高。当n(TiO2)∶n(C)=1∶8时,次表面显微硬度达到810HV0.2,涂层硬度从上到下呈现递减的趋势,且涂层的耐磨性最好,为基体的4.5倍。结论增大C和Ti O2两者摩尔比,可以提高熔覆层的显微硬度和耐磨性。在熔池中,Ti C密度较小,涂层中硬质颗粒从上到下依次减少,与之对应,硬度也依次递减。同时,碳纳米管的加入将对涂层起到细晶强化的效果。Ti与碳纳米管和微米石墨结合生成微米级和亚微米级Ti C,提高了形核率,Cr7C3以亚微米级Ti C为非均质核心,形核长大,生成均匀分布的Cr7C3强化相。
The work aims to study the properties of the ceramic coating of 3Cr13 stainless steel prepared by laser cladding composite sol gel under the different ratios of precursor,and analyze the strengthening mechanism.A homogeneous precursor of TiO2 and C(micro-graphite and carbon nanotubes(CNTs))was prepared by sol-gel method,and a high-performance coating was prepared on the surface of the 3Cr13 stainless steel substrate by laser cladding.The microstructure and phase composition of the coating were analyzed by optical microscopy(OM),X-ray diffractometry(XRD),scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).The hardness of the coating was tested by Vickers hardness tester and the wear resistance of substrate and cladding layer was tested by HT-600 high temperature friction machine.A homogeneous mixed powder of TiO2 and C could be prepared by the sol-gel method.The TiC and Cr7C3 strengthening phases were uniformly distributed in the cladding layer.If the precursor ratio was changed,when the moral ratio of C and TiO2 increased,the coating structure was remarkably refined,there was no pore in the coating,and the microhardness was also greatly improved.When n(TiO2)∶n(C)was 1∶8,the microhardness of subsurface reached 810HV0.2 and the coating tended to decrease and had the best wear resistance which was 4.5 times that of the substrate.When the mole ratio of C and TiO2 is increased,the microhardness and wear resistance of cladding layer can be improved.The hard particles in the coating gradually decreases from top to bottom when the TiC density is lower in the molten pool.Correspondingly,the hardness of the coating has a tendency of decrease.At the same time,the addition of CNTs has a fine grain strengthening effect on the coating.The Ti element combines with CNTs and micron graphite to form micro-scale TiC,and then Cr7C3 will use micro-scale TiC as a nucleus to grow and form a wrap-like Cr7C3 strengthening phase.
作者
张群莉
姚中志
周塘
姚建华
Volodymyr S.Kovalenko
ZHANG Qun-li;YAO Zhong-zhi;ZHOU Tang;YAO Jian-hua;Volodymyr S.Kovalenko(Institute of Laser Advanced Manufacturing,Zhejiang University of Technology,Hangzhou 310014,China;School of Mechanical Engineering,Zhejiang University of Technology,Hangzhou 310014,China;Laser Technology Research Institute,National Technical University of Ukraine“Kiev Polytechnic Institute”,Kiev 03056,Ukraine)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2019年第2期1-9,共9页
Surface Technology
基金
国家自然科学基金(51605441)
浙江省公益技术应用研究项目(2017C31048)~~
