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.
出处
《材料保护》
CAS
CSCD
北大核心
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
