304不锈钢激光熔覆搭接率对CoCrW涂层组织与耐磨及耐腐蚀性能的影响  

Effect of Laser Cladding Lap Ratio of 304 Stainless Steel on Microstructure,Wear Resistance and Corrosion Resistance of CoCrW Coating

作　　者：方振兴 祁文军[1] 李志勤 FANG Zhenxing;QI Wenjun;LI Zhiqin(School of Mechanical Engineering,Xinjiang University,Urumqi 830047,China;Xinjiang Uygur Autonomous Region Office of Defense Science,Technology and Industry,Urumqi 830000,China)

机构地区：[1]新疆大学机械工程学院,乌鲁木齐830047 [2]新疆维吾尔自治区国防科学技术工业办公室,乌鲁木齐830000

出　　处：《材料导报》2021年第12期12123-12129,共7页Materials Reports

基　　金：自治区高校科研计划自然科学重点项目(XJEDU20201007);国家大学生创新训练计划项目(201910755067)。

摘　　要：利用光纤激光器在304不锈钢表面制备CoCrW合金熔覆涂层,改善其表面耐磨损及耐蚀性能。使用OM、SEM、XRD、EDS、显微硬度计、MMG-500三体磨损试验机和CS310电化学工作站分析不同搭接率对涂层组织、硬度、耐磨及耐蚀性能的影响,并寻求合适的搭接率,以期获得性能较优的激光熔覆涂层。研究结果表明:30%搭接率下的涂层无明显缺陷,从顶部到底部依次是等轴晶、柱状晶、平面晶,这些晶体主要由fcc结构的γ-Co相形成的晶核以及部分Cr_(7)C_(3)、(Co,Cr)_(23)C_(6)等相形成的晶界组成。因此适宜搭接率为30%,该参数下涂层显微硬度达到450HV,约为基体显微硬度(210HV)的2.1倍;涂层磨损量为12.71 mg,约为基体(63.06 mg)的20%;涂层平均摩擦系数约为0.4,是基体平均摩擦系数(0.65)的60%;涂层自腐蚀电位为-889 mV,基体自腐蚀电位为-998 mV;涂层自腐蚀电流密度为5.7μA/cm^(2),约为基体自腐蚀电流密度(38.9μA/cm^(2))的14%。合适的涂层材料及激光熔覆工艺参数可使304不锈钢涂层腐蚀倾向更小,使显微硬度、耐磨损性能及耐蚀性显著提高。The CoCrW alloy coating was prepared on the surface of 304 stainless steel by fiber laser to improve the wear resistance and corrosion resistance of the surface of 304 stainless steel.The effects of different lap ratio on the structure,hardness,wear resistance and corrosion resistance of the coating were analyzed by OM,SEM,XRD,EDS,microhardness tester,MMG-500 wear tester and CS310 electrochemical workstation.The better lapping rate was found and obtain the best performance coating.Results of research indicated that:there were no obvious defects in the coating with 30%lap ratio.The top and bottom of the coating were cellular crystal,columnar crystal and plane crystal,respecticely.These crystals are mainly composed of the crystal nucleus formed by theγ-Co phase of fcc structure and the grain boundary formed by some Cr_(7)C_(3),(Co,Cr)_(23)C_(6) phases.The optimum lap ratio is 30%.Under this parameter,the microhardness of the coating reaches 450HV,about 2.1 times of the microhardness of the substrate(210HV);the wear amount of the coating is 12.71 mg,about 20%of the substrate(63.06 mg);the average friction coefficient of the coating is about 0.4,about 60%of the substrate(0.65);the self corrosion potential of the coating is-889 mV,the self corrosion potential of the substrate is-998 mV;the self corrosion current density of the coating is 5.7μA/cm^(2),about 14%of the substrate(38.9μA/cm^(2)).The corrosion tendency of 304 stainless steel coating is smaller and the microhardness,wear resistance and corrosion resistance are significantly improved by suitable coating materials and laser cladding process parameters.

关 键 词：激光熔覆 304不锈钢 多道搭接 显微组织 涂层性能 

分 类 号：TG174[金属学及工艺—金属表面处理]