HVOF热喷WC-Co-Cr涂层在不同攻角下的料浆冲蚀行为  

Slurry Erosion Behavior of HVOF Sprayed WC-Co-Cr Coatings at Different Impingement Angle

作　　者：李阳[1] 刘阳[1] 段德莉[1] 李曙[1] 

机构地区：[1]中国科学院金属研究所专用材料与器件研究部,沈阳110016

出　　处：《中国表面工程》2011年第6期11-18,共8页China Surface Engineering

基　　金：国家自然科学基金(50475159)

摘　　要：用3种高速火焰热喷涂(HVOF)设备将成分相同的6种商品粉末喷涂在0Cr13Ni5Mo不锈钢基材上,制成9种WC-Co-Cr涂层。用自制射流冲蚀试验机对各涂层在15°、45°、75°和90°攻角下的料浆冲蚀行为进行研究,重点分析涂层孔隙和层状结构等缺陷在不同攻角下所起的作用。结果表明:低攻角时涂层冲蚀机制以微切削去除为主,高孔率涂层更易发生切削导致冲蚀率较高;高攻角时涂层冲蚀机制以冲击作用下裂纹萌生扩展导致涂层剥落为主,高孔率涂层有利于对冲击能量的吸收耗散,孔隙抑制裂纹扩展,而层状结构明显的涂层其裂纹更易在层间萌生和扩展,导致涂层呈片状剥落,冲蚀率更高。在试验的基础上提出了考虑缺陷的硬质涂层射流冲蚀模型,并讨论了涂层冲蚀率随攻角变化的双峰值现象。Three different HVOF/HVAF thermal spray devices and six kinds of commercial powders with various particle sizes were used to prepare specimens of WC-Co-Cr coatings with different microstructure on 0Crl3Ni5Mo stainless steel substrate. The erosion behavior of them at 15°, 45°, 75° and 90°impingement angle was investigated by slurry jet e- rosion tester. The effect of porosity and laminar structure on erosion resistance of WC-Co- Cr coatings at different im- pingement angle was researched. The results show that the dominant erosion mechanism is micro-cutting at shallow im- pingement angle. The high porosity coatings are easy to cut, which make the erosion resistance worse. The dominant e- rosion mechanism is detachment of coatings at high impingement angle. The high porosity coatings could absorb and dis- sipate the impact energy. Pores could prevent the cracks from prolonging. The cracks in the coatings with obvious lami- nar structure are easy to initiate and prolong, which make the erosion resistance of coatings with obvious laminar structure worse. The model of hard coatings with defects is proposed and the dual-peak phenomenon of erosion rate at different impingement angle is discussed.

关 键 词：高速火焰热喷涂 WC-Co-Cr涂层 攻角 孔隙 层状结构 

分 类 号：TG174.442[金属学及工艺—金属表面处理]