利用超音速火焰喷涂方法制备出NiCr/ Cr3C2 和NiCr/ Cr3C2-BaF2 ·CaF2 两种涂层,?炝肆街滞坎愕淖橹?测定了两种涂层在650 ℃和800 ℃下的摩擦磨损性能,进而分析了BaF2 ·CaF2 共晶相对涂层的润滑减摩作用,讨论了两种涂层的适用范围。结果表明,NiCr/ Cr3C2-BaF2 ·CaF2 涂层在800 ℃展现出优异的耐磨自润滑效果,摩擦系数最低,仅为0. 2644,磨损率也较小,为5. 88×10-6 mm3 / (N·m);而NiCr/ Cr3C2 涂层在650℃的磨损率更小,仅为3. 66×10-6 mm3 / ( N·m)。两种涂层在不同温度下表现出不同的摩擦磨损机制:NiCr/Cr3C2 涂层在650 ℃和800 ℃均表现为典型的粘着磨损,但在650 ℃时有疲劳迹象,在800 ℃时则发生严重塑性变形;NiCr/ Cr3C2-BaF2·CaF2 涂层在650 ℃以磨粒磨损为主,在800 ℃时,由于氟化物润滑膜的作用,仅发生轻微的粘着剥落。

Two coatings, NiCr/ Cr3 C2 and NiCr/ Cr3 C2 -BaF2·CaF2 , were prepared by means of high velocity oxy-fuel spraying (HVOF). After that, by observing the microstructure and detecting the friction wear performances of the two coatings, the lubricating and friction-lessen role which BaF2·CaF2 eutectic played in the coating were analyzed. In addition, the applicable range of two coatings was discussed as well based on the experimental result. It is found that NiCr/ Cr3 C2 -BaF2·CaF2 coating which got the lowest friction coefficient (0. 2644) and lower wear rate (5. 88×10-6 mm3·N-1·m-1 ), possessed excellent wear-resistant and self-lubricating performances at 800 ℃; The most antiwear coating is NiCr/ Cr3 C2 , which had the even lower wear rate, only 3. 66×10-6 mm3 / N·m. The coatings behaved differently under two temperatures on friction and wear mechanisms. Typical adhesive wear dominated in NiCr/ Cr3 C2 coating under both temperatures. Besides, the coating was found some signs of fatigue at 650 ℃, while severe plastic flow at 800 ℃. In contrast, the main abrasion mode of NiCr/ Cr3 C2 -BaF2·CaF2 coating was the micro-cutting wear at 650 and only some minor adhesive spalling occurred on the surface at 800 ℃ due to the function of the fluoride film.