Durability of HVOF Sprayed MoB/CoCr Coating on the 316L Stainless Substrate in Molten 55％Al-Zn-1.5％Si Bath
In order to develop protective coatings for sink rolls in continuous hot-dip galvanizing, a sprayed MoB/CoCr cermet coating was formed on a 316L stainless steel by the HVOF spraying process and its durability in the molten 55％Al-Zn- 1.5％Si bath (923 k) has been investigated by SEM and EDS. The immersion test revealed that the MoB/CoCr coating has much higher durability (640 hours) in 55％Al-Zn-1.5％Si bath than the conventional sprayed coatings (120 hours), such as WC-Co, WC/Co/Cr and ceramics. It was found that the failure of MoB/CoCr coating is mainly caused by the mismatch of coefficient of thermal expansion (CTE) between the top coating and the substrate. The failure procedure is that first crack is generated because of heat stress, then the crack proceeds and causes scaled delamination, at the same time molten Al-Zn will enter into cracks and/or Al-Zn reaches the undercoat and/or substrate, finally molten Al-Zn dissolves the substrate.
H.P. Lv J. Wang C.S. Zhai F. Li B.D. Sun
State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, PR China
国际会议
北京
英文
2007-05-14（万方平台首次上网日期，不代表论文的发表时间）