关键词: 聚甲醛, 静电喷涂, 聚四氟乙烯, 二硫化钼, 耐磨改性, 摩擦因数

Abstract: In this work， an orthogonal experiment of 4 factors and 3 levels was carried out to determine the optimal process conditions for powder electrostatic spraying process of polyoxymethylene （POM） powders as a spraying voltage of 60 kV， a powder supply air pressure of 0.2 MPa， a curing temperature of 170 oC， and a curing time of 20 min. The coatings were then modified using polytetrafluoroethylene （PTFE） and molybdenum disulfide （MoS2） to improve their wear resistance. The resultant composite coatings were characterized by testing their thickness， hardness， adhesion， impact strength， chemical solvent resistance， microstructure， and frictional wear. The results indicated that all of coating samples had good appearance and chemical solvent resistance， their thickness was distributed in the range of 100~140 μm， their Shore hardness was above 63， and their impact performance reached at least 36 kg·cm. However， the composite coatings could all reach an adhesion of grade 2 or above except for the coating containing 0.7 wt% MoS2 powers. The composite coatings looked dense and compact without any holes and defects， and the two types of wear?resistant fillers were evenly dispersed in the coatings. When 5 wt% PTFE and 0.7 wt% MoS2 were incorporated into the POM powders， the friction coefficient of the composite coating decreased to 0.223 and 0.245， respectively， and their wear amounts decreased to 1.4 mg and 1 mg， respectively. This suggests a significant improvement in the friction and wear performance of the POM?matrix composite coatings.

Key words: polyoxymethylene, electrostatic spraying, polytetrafluoroethylene, molybdenum disulfide, wear?resistant modification, friction coefficient