冷喷涂Cu402F涂层激光重熔表面改性后摩擦学行为

Tribological Behavior of Cold Sprayed Cu402F Coating after Laser Remelting

目的研究激光重熔后冷喷涂Cu402F涂层在腐蚀介质中的摩擦学行为。方法采用冷喷涂技术在镍铝青铜9442合金上制备了厚度约为882.11μm的Cu402F涂层,并使用激光重熔技术对冷喷涂涂层进行表面改性。使用OM、SEM观察涂层截面与表面的微观形貌;使用XRD、X射线残余应力测试仪、多功能表面性能测试仪、多频直线往复磨蚀实验机,重点表征测试了涂层的组织、表面残余应力、摩擦学性能与磨蚀行为。结果激光重熔后的涂层分为表面重熔层、多孔的重熔过渡层以及冷喷涂遗传层。激光重熔前后,涂层的物相、残余应力均未发生较大变化。在20、50、100 N条件下,激光重熔态涂层的平均摩擦系数呈递增趋势,磨损率分别为1.01×10^(-2)、1.17×10^(-2)、1.34×10^(-2) mm^3/(N·m);由磨蚀实验可知,磨蚀是涂层表面产生钝化膜与钝化膜被破坏的此消彼长的过程,反映着摩擦与腐蚀的协同作用,涂层在磨蚀过程中,开路电位与摩擦系数呈正相关,说明激光重熔态涂层表面钝化膜产生的速度快于钝化膜被坏的速度。结论激光重熔保留了冷喷涂技术制备的Cu402F涂层的优点,同时激光重熔涂层上产生钝化膜的速度更快,有利于提高涂层的耐磨蚀性能。

The work aims to study tribological behavior of cold sprayed Cu402F coating in corrosive medium after laser remelting. Laser remelting technology was applied to modify properties of a nearly 882.11 μm thick cold sprayed Cu402F coat- ing, which was prepared on nickel-aluminum bronze by adopting cold spraying technology. Microstrueture of coating section and surface was observed by using OM and SEM; structure, surface residual stress, tribological properties and corrosion beha- vior of the coating were mainly studied by using XRD, X-ray residual stress tester, multi-function surface property tester andmulti-frequency linear reciprocating abrasion tester. Laser remelted coating was divided into surface remelted layer, porous re- melted transition layer and cold spray inherited layer. Phases and residual stress of the coating did not change greatly after laser remelting. Average friction coefficient of the laser remelted coating increased progressively under the load of 20, 50 and 100 N, the wear rate was 1.01 × 10-2, 1.17 ×10^- 2 and 1.34 × 10-2 mm3/（N · m）, respectively. The abrasion test indicated that generation and breaking of passive film on surface of the coating appeared alternately, reflecting synergistic effect of wear and corrosion. OCP （open circuit potential） was positively correlated with friction coefficient, indicating that the generation of passive film was faster than destruction. Laser remelting reserve the advantages of cold spayed Cu402F coating. Meanwhile, quicker generation of passive film on laser remelted coating contributes to abrasion resistance improvement of coating.