Ni、Cr基WC-Co粉末加入La_2O_3后钎焊层的抗氧化性能与机理  

Effect of Lanthanum Oxide on Antioxidant Performance of(Nickel-Chromium)-Based Tungsten Carbide-Cobalt Infiltration Brazed Coating

作　　者：刘德辉[1] 卢全国[1] 晏建武[1] 刘国亮[1] 姜丽红[2] 李卿鹏[3] 

机构地区：[1]南昌工程学院微纳驱动与控制研究所,江西南昌330099 [2]江西现代职业技术学院机械学院,江西南昌330099 [3]江西省电力公司办公室,江西南昌330000

出　　处：《材料保护》2013年第12期34-37,7-8,共4页Materials Protection

基　　金：国家自然科学基金(NO 51161019);江西省教育厅科技项目(GJJ12638);(NO GJJ12630);(NOGJJ13751)资助

摘　　要：采用粉末冶金技术制备了Ni、Cr基WC—Co复合粉末，并钎焊成涂层。通过差重法测定并分析了WC-Co粉末及钎焊层的抗氧化性能；测定了不同成分涂层在不同温度下的质量对比；运用氧化动力学曲线分析了涂层的抗氧化性能。结果表明：（1）WC—Co粉末在较低温度（≤400℃）时氧化不明显，基本保持不变，具有较好的抗氧化性能；400—600℃抗氧化性能比较差，粉末变绿且有结块现象；600℃以上抗氧化性能很差，随着氧化温度升高，粉末颗粒逐渐变大；在温度不变时，随着时间的延长，增重量与时间成正比关系；（2）Ni、Cr基WC．Co钎焊层随着温度升高，氧化加重，550℃以下氧化较轻，550℃以上氧化较为严重；加入h203改善了WC．Co复合涂层的组织，使组织更加均匀致密，降低了氧化速度，使涂层具有更好的抗氧化性能。(Ni-Cr)-based WC-Co composite powder was prepared by powder metallurgy technology.As-obtained(NiCr)-based WC-Co composite powder was then made into infiltration brazed coating on the surface of Q235 steel by infiltration brazing in a vacuum furnace.The antioxidant properties of WC powder and the brazed coating were investigated by thermogravimetric analysis;and the anti-oxidation behavior of the brazed coating was analyzed based on oxidation kinetics curve.Results showed that WC-Co powder underwent slight oxidation at relatively low temperature(≤ 400 ℃) and exhibited good antioxidant performance thereat.In the range of 400 ~ 600 ℃,the antioxidant performance of WC-Co powder was worsened,accompanied by green-turning of color and agglomeration.Above 600 ℃,WC-Co powder had very poor antioxidant performance,and the size of the powder tended to gradually rise with elevating temperature.As to(Ni-Cr)-based WC-Co brazed coating,oxidation weight gain emerged during heating process,and the oxidation of the coating was slight below 550 ℃ but severe above 550 ℃.Moreover,the introduction of La 2 O 3 helped to improve the microstructure of WC-Co composite coating,resulting in more uniform and compact microstructure thereby reducing the oxidation rate and increasing the antioxidant performance of the brazed coating.

关 键 词：抗氧化性能 WC-CO涂层 氧化机理 LA2O3 渗透钎焊 组织 

分 类 号：TG454[金属学及工艺—焊接]