摘要
为提高45钢的耐磨性,采用激光熔覆工艺在其表面制备以镀Ni金刚石为耐磨相、Ti与WC等材料为结构增强相的新型合金耐磨涂层,研究激光功率对金刚石石墨化及涂层冶金结合的影响,并通过金相显微镜、扫描电镜和维氏硬度计分析合金涂层的显微组织和显微硬度。结果表明:在45钢表面激光熔覆镀Ni金刚石合金涂层后,合金涂层中含有完整的金刚石颗粒且其与黏结相之间形成良好的冶金结合,合金涂层与基体间无明显分层现象;使用镀Ni金刚石以及添加WC、TiC粉末等可在高能激光束下保护金刚石,减少金刚石的烧蚀和石墨化现象;进一步添加Co、Ti等元素可改善合金涂层的流动性,增强其与金刚石的结合力,提高涂层硬度,使其平均显微硬度达到HV 257.85,为基材显微硬度HV 170.40的1.51倍。通过添加镀Ni金刚石和增强相,可有效提高合金涂层的硬度和耐磨性能,同时提高45钢表面耐磨性和使用寿命。
Objectives:To significantly enhance the surface wear resistance of 45 steel under high friction and highload conditions,a new type of wear-resistant alloy coating with high hardness and strong adhesion is constructed on its surface using laser cladding technology.The coating is mainly composed of nickel-plated diamond as the wear-resistant phase,and high-melting-point ceramics such as WC and TiC as the reinforcing phases.Meanwhile,the microstructure and fluidity of the coating are improved by adding metal elements such as Ti and Co.The focus is on studying the influence of laser power on the graphitization of diamond and the metallurgical bonding quality with the substrate during the laser cladding process,thereby optimizing the process parameters and improving the comprehensive performances of the coating.Methods:A multi-component alloy wear-resistant coating is prepared on the surface of 45 steel by the laser cladding process.The coating formula contains a certain proportion of nickel-plated diamond,WC,TiC,Ti and Co powders.The influence of adjusting the laser power on the structural stability of diamond particles,the interface bonding state and the overall microstructure morphology is investigated.After cladding,the microstructure of the coating is observed by metallographic microscope(OM)and scanning electron microscope(SEM)respectively,and the elemental distribution is analyzed by energy dispersive spectroscopy(EDS).Moreover,the microhardness of the coating is tested using a Vickers hardness tester,thereby comprehensively evaluating the performance of the coating.Results:The laser power has a significant impact on the stability of the diamond structure during the coating formation process.Under appropriate laser power,the nickel-plated diamond particles do not exhibit significant graphitization during the melting process,and the particles remain intact and form a good metallurgical bond with the metal substrate.On the contrary,excessive laser power can cause some diamond particles to undergo graphitization,thereby affecting the performance of the coating.The introduction of WC and TiC reinforcing phases can effectively absorb some of the laser energy,reduce the thermal shock on the diamond surfaces,suppress their ablation and graphitization,while promoting the formation of fine-grained microstructures,improving the structural stability and wear resistance of the coating.In addition,the addition of Co and Ti elements significantly improves the wettability of the molten pool metal and the fluidity of the coating,enhances the bonding strength between the alloy coating and the ceramic particles,and effectively improves the uniformity and density of the coating.The internal structure of the alloy coating is uniform,without obvious cracks or delamination.The diamond particles are densely distributed and the interfaces are tightly bonded.The average hardness of the coating reaches HV 257.85,which is approximately 51%higher than HV 170.40 of the base 45 steel.Therefore,the hardness enhancement effect is remarkable.Conclusions:By optimizing the laser cladding parameters and reasonably designing the alloy powder system,the nickel-plated diamond and the reinforcing phases such as WC and TiC can synergistically work under high-temperature laser cladding conditions,effectively improving the density of the coating structure,the stability of the diamond structure,and its adhesion with the substrate.The prepared alloy wear-resistant coating significantly improves the microhardness and the wear resistance of the 45 steel surface,and has good interfacial bonding and thermal stability,making it an ideal material for improving the wear resistance and service life of 45 steel.
作者
芦甜
王传留
马少明
朱颖
LU Tian;WANG Chuanliu;MA Shaoming;ZHU Ying(CCTEG Xi′an Research Institute(Group)Co.,Ltd.,Xi′an 710077,China)
出处
《金刚石与磨料磨具工程》
北大核心
2025年第4期470-478,共9页
Diamond & Abrasives Engineering
基金
中煤科工西安研究院(集团)有限公司科技创新基金(2024XAQN02)
国家自然科学基金资助项目(42302355)。
关键词
镀Ni金刚石
合金涂层
激光熔覆
显微组织
显微硬度
nickel-plated diamond
alloy coating
laser cladding
microstructure
microhardness
