Effect of Nanometer Lanthanum Fluoride as Filler on the Tribological Behavior and Corrosion Resistance of Polyimide Boned Solid Lubricating Coating
纳米LaF3微粒对聚酰亚胺粘结固体润滑涂层摩擦学性能及抗腐蚀性能的影响

The tribological behavior of polyimide (PI) boned solid lubricating coatings filled with nanometer lanthanum fluoride (LaF_3) sliding against SAE2100 steel was examined on an MHK-500 friction and wear tester, using the PI-based coating without nano-LaF_3 as a control. The corrosion resistance of the coatings was evaluated according to GB 10125-88. Thus the effect of nano-LaF_3 as the filler on the antiwear ability and corrosion resistance of the coatings was highlighted. It was found that the coating with l%~2% nano-LaF_3 showed the best antiwear ability, but it recorded a friction coefficient almost the same as that of the coating without the nano-LaF_3 filler. Moreover, the incorporation of 2% nano-LaF_3 filler led to a significant increase in the corrosion resistance of the coating, and the corrosion resistance of the PI-based bonded solid lubricating coatings were related to the water contact angles. Namely, the PI-based coating containing 4% nano-LaF_3 had a smaller water contact angle, which corresponded to the poorer corrosion resistance of the coating. The improvement in the wear resistance and corrosion resistance of the PI-based bonded solid lubricating coatings by the incorporation of the nano-LaF_3 filler was attributed to the strengthened interfacial bonding among the nano filler and the polymeric matrix and various other fillers. However, the PI-based coating of a too high mass fraction of the nano filler had increased surface and interface defects, which led to the worsening of the wear resistance and corrosion resistance of the coating.