等离子喷涂制备WC-Co-Cu-BaF2/CaF2自润滑耐磨涂层及其高温摩擦性能

通过大气等离子喷涂方法,使用自制的含有WC-Co、Cu和BaF2/CaF2共晶体的复合喷涂粉末,制备出WC-Co-Cu-BaF2/CaF2自润滑耐磨涂层。在200℃、400℃和600℃下进行WC-Co-Cu-BaF2/CaF2涂层和WC-Co涂层的高温摩擦试验,用扫描电镜观察涂层磨损表面微观形貌。结果表明:200℃时,由于WC-Co-Cu-BaF2/CaF2涂层摩擦产物层中含有的WC硬质颗粒引起磨粒磨损,该涂层摩擦因数和磨损率相对较高。而400℃和600℃时,WC-Co-Cu-BaF2/CaF2涂层的摩擦产物层中均无WC颗粒存在,且由于涂层中Cu和BaF2/CaF2等固体润滑剂的作用,生成的摩擦产物层光滑且致密,涂层的摩擦因数和磨损率均较低,在400～600℃下表现出比WC-Co涂层优异的耐磨性能。

Fabrication and High Temperature Tribological Properties of Plasma Sprayed WC-Co-Cu-BaF2/CaF2 Selflubricating Wear Resistant Coatings

WC-Co-Cu-BaF2/CaF2 self-lubricating wear resistant coating was deposited by atmospheric plasma spraying(APS) process using homemade feedstock powders composed of WC-Co,Cu and BaF2/CaF2 eutectic.The high temperature tribological properties of the WC-Co-Cu-BaF2/CaF2 and WC-Co coatings were investigated at 200 ℃,400 ℃ and 600 ℃.Microscopic observation of the coatings after wear was performed using SEM.It is found that the hard WC particles in the triboreaction layers of WC-Co-Cu-BaF2/CaF2 coating induce abrasive wear and result in higher friction coefficient and wear rate at 200 ℃.The triboreaction layers without any hard WC particles were formed in 400 ℃ and 600 ℃ wear tests.With the help of Cu and BaF2/CaF2 eutectic which acted as solid lubricants in the coating,the triboreaction layers became smooth and compact.Lower friction coefficient and wear rate of WC-Co-Cu-BaF2/CaF2 coating were achieved at these temperatures.The wear resistant behavior of WC-Co-Cu-BaF2/CaF2 coating was superior to that of WC-Co coating at relatively high temperature(400～600 ℃).