WC-6%Ni硬质合金中碳平衡状态对其耐腐蚀性能影响  

Effect of Carbon Balance on Corrosion Resistance of WC-6%Ni Cemented Carbides

作　　者：孙建春 邓雁琳 魏连春 何军浪 吴翔[2] 黄政豪 杨舜鑫 Sun Jianchun;Deng Yanlin;Wei Lianchun;He Junlang;Wu Xiang;Huang Zhenghao;Yang Shunxin(College of Metallurgy and Materials Engineering of Chongqing University of Science and Technology,Chongqing 401331,China;Zigong Cemented Carbide Co.Ltd,Zigong Sichuan 643011,China)

机构地区：[1]重庆科技大学冶金与材料工程学院,重庆401331 [2]自贡硬质合金有限责任公司,四川自贡643011

出　　处：《硬质合金》2023年第6期450-456,共7页Cemented Carbides

基　　金：重庆市自然科学基金项目(CSTB2022NSCQ-MSX1186);重庆科技学院研究生科技创新项目(YKJCX2220725)。

摘　　要：镍黏结相硬质合金因具有较好的耐腐蚀性、相对较低的价格,取得了一定的工业应用,但关于其耐蚀性与合金相结构,特别是碳析出状态之间的关系研究还缺乏系统性。本文利用不同烧结工艺获得了不同碳平衡状态的样品,运用金相、XRD、电化学工作站等对合金的组织结构及耐蚀性进行了系统表征研究。结果表明,镍黏结相硬质合金中都存在游离碳,但处于脱碳或碳平衡状态时,游离碳颗粒尺寸很小,分散分布;处于渗碳状态时,出现大颗粒聚集的游离碳;配碳量、烧结温度等均影响合金的碳析出状态。在不同碳平衡状态镍黏结相合金中,腐蚀电流密度最小为3.14×10^(-7)A/cm^(2),最大为1.04×10^(-6)A/cm^(2);腐蚀电位最大的为-0.114 V,最小的为-0.199 V。碳含量越高,镍黏结相硬质合金耐腐蚀性能越好;脱碳相会降低镍黏结相硬质合金耐腐蚀性能,游离碳相会增强镍黏结相硬质合金耐腐蚀性能;碳析出相的数量多、分布密集也会降低镍黏结相硬质合金耐腐蚀性能。Ni-bonded cemented carbides are widely used in industry due to their corrosion resistance and low price.However,the relationship between the corrosion resistance and the alloy phase structure,especially the carbon precipitation state,has not been systematically studied.In this paper,samples with different carbon balance states were obtained by different sintering processes,and the microstructure and corrosion resistance of the cemented carbides were systematically characterized by metallography,X-ray diffraction(XRD),etc.The results show that there is free carbon in the Ni-bonded cemented carbides,but when in the decarburization or carbon balance state,the size of free carbon particles is smaller and dispersed;when in the carburized state,larger free carbon accumulates.The carbon content and sintering temperature both affect the carbon precipitation state of the cemented carbides.For nickel-bonded cemented carbides with different carbon balance states,the minimum corrosion current density is 3.14×10^(−7)A/cm^(2),and the maximum corrosion current density is 1.04×10^(−6)A/cm^(2).The maximum corrosion potential is−0.114 V,and the minimum corrosion potential is−0.199 V.Higher carbon content indicates a better corrosion resistance of Ni-bonded cemented carbides.Decarbonized phase reduces the corrosion resistance of Ni-bonded cemented carbides,and the free carbon phase enhances the corrosion resistance of Nibonded cemented carbides.The large number and dense distribution of decarburized phases also reduce the corrosion resistance of Ni-bonded cemented carbides.

关 键 词：镍黏结相硬质合金 组织结构 脱碳 渗碳 耐蚀性 

分 类 号：TG135.5[一般工业技术—材料科学与工程]