石墨粉添加对WC增强Ni基复合涂层组织结构及性能的影响  

Effects of Graphite Powder on Microstructure and Properties of WC Reinforced Ni-based Composite Coatings

作　　者：夏俊佳 尹宇 周辰 张树玲 郭峰[1] 马兴华 XIA Jun-jia;YIN Yu;ZHOU Chen;ZHANG Shu-ling;GUO Feng;MA Xing-hua(Qingdao University of Technology,Shandong Qingdao 266520,China)

机构地区：[1]青岛理工大学,山东青岛266520

出　　处：《表面技术》2023年第7期139-148,287,共11页Surface Technology

基　　金：山东省自然科学基金(ZR2020QE039)。

摘　　要：目的改善WC/Ni60A涂层的耐蚀耐磨性能,通过激光熔覆技术制备不同石墨添加量的C/WC/Ni60A复合涂层。方法首先制备多含量的WC(质量分数分别为15%、25%、35%)增强Ni基涂层,利用SEM、EDS及XRD等表征手段,分析涂层的微观组织形貌、元素分布及物相组成。利用多功能摩擦磨损试验机、形貌显微镜及电化学工作站等,测试涂层的耐蚀耐磨性能,并选出WC的最佳添加量。其次,向最佳性能的WC/Ni60A中添加经过超声预处理的石墨粉(质量分数分别为0.25%、0.5%、0.75%、1.0%),并进一步通过混粉湿磨获得类石墨烯结构,分析测试相应涂层的微观结构及耐蚀耐磨性能。结果采用激光熔覆制备的复合涂层组织结构致密,且与基体发生了冶金结合。当WC的添加量为25%时,WC/Ni60A复合涂层的耐蚀耐磨性能最好。石墨的添加细化了显微组织,进一步提高了涂层的显微硬度,并显著改善了涂层的耐蚀耐磨性能。当石墨的添加量为1.0%时,复合涂层的摩擦系数稳定在0.25,磨损率约为0.0032 cm3/(N·m)。结论石墨粉体的加入可有效提高WC/Ni60A涂层的耐磨耐蚀性能,有望成为极端海洋环境的新型表面防护材料。Laser cladding ceramic reinforced metal matrix composite(MMC)is a new surface modification technology,which combines excellent mechanical properties of metal and excellent wear resistance of ceramic.In this work,with WC ceramics of high hardness and chemical stability as reinforcement phase and Ni60A as binder,crack-free WC reinforced Ni-based composite coating was prepared on H13 steel matrix.The effect of different contents of WC particles on the microstructure and properties of the coating was studied.Meanwhile,multilayer grapheme-like structure was generated from graphite powders by ultrasonic stripping and wet ball milling to further improve the wear and corrosion resistance of WC/Ni60A coating.The specimens with dimensions of 35 mm×15 mm×10 mm,cut from H13 steel,were used as matrixes,and the cladding coating was prepared by coaxial powder feeding method with FL020 fiber laser.During the cladding process,the laser power was 1400 W,the spot diameter was 2 mm,the scanning speed was 7 mm/s,the overlap rate was 40%,and the powder feeding rate was 15~20 g/min.Firstly,multi-content WC(15 wt.%,25 wt.%and 35 wt.%)reinforced Ni60A-based coatings were prepared.SEM,EDS and XRD were used to analyze the microstructures,element distribution and phase composition of the coatings.The wear and corrosion resistance of the coatings were tested by UMT,morphology microscope and electrochemical workstation,and the addition amount of WC with the best properties was selected.Next,varied amount of graphite powders(0.25 wt.%,0.5 wt.%,0.75 wt.%and 1.0 wt.%)pre-treated by ultrasonic were added into the specimen with the best properties,and during the ball milling process,the pre-treated graphited powders were further reduced into graphene-like structures,and the corresponding microstructures,corrosion and wear resistance were further evaluated.The microstructures of the composite coatings prepared by laser cladding were compacted,with metallurgical bonding with the matrix.The microstructure of cladding coating mainly consisted of pla

关 键 词：激光熔覆 WC/Ni60A涂层 石墨 组织结构 耐磨耐腐蚀 

分 类 号：TG178[金属学及工艺—金属表面处理]