Cr12MoV模具钢化学镀Ni-W-P/PTFE复合镀层及耐磨性能研究

Electroless plating of Ni-W-P/PTFE composite coatings on Cr12MoV die steel and their wear resistance

以Cr12MoV模具钢作为基体化学镀Ni-W-P/PTFE复合镀层,以期提高模具的耐磨性能。通过改变PTFE颗粒添加量获得不同Ni-W-P/PTFE复合镀层,并对复合镀层的表面形貌、化学成分、晶相结构、硬度及耐磨性能进行表征。结果表明:不同复合镀层表面都存在尺寸不同、分布不均匀的胞状物,还附着白色PTFE颗粒,但是晶相结构无显著性差异。随着PTFE颗粒添加量从2 g/L增至14 g/L,复合镀层中PTFE颗粒含量呈现先升高,后降低趋势,并且颗粒分散状况不同,硬度呈现减小趋势,而耐磨性能逐步提高,然后变差。当PTFE颗粒添加量为8 g/L获得的Ni-WP/PTFE复合镀层中PTFE颗粒含量达到3.63%,并且颗粒分布趋于均匀,具有优良的耐磨性能,其摩擦系数仅为0.41,表面磨痕宽度和深度分别为500μm和14.7μm,作为表面改性层能有效减轻Cr12MoV模具钢的磨损程度。

Cr12MoV die steel was used as the substrate for electroless plating of Ni-W-P/PTFE composite coating to improve the wear resistance of the die.Different Ni-W-P/PTFE composite coatings were obtained by changing the additive amount of PTFE particles,and the surface morphology,chemical composition,crystal structure,hardness and wear resistance of the composite coating were characterized and tested.The results show that there are cellulars with different size and uneven distribution on the surface of different composite coatings,and white PTFE particles are adhered,but the crystal phase structure of different composite coatings has no significant difference.With the increase of additive amount of PTFE particles from 2 g/L to 14 g/L,the content of PTFE particles in the composite coating increases first and then decreased,the distribution status of PTFE particles is different,the hardness shows a decreasing trend,and the wear resistance gradually improved and then deteriorated.The content of PTFE particles in the Ni-W-P/PTFE composite coating obtained when the additive amount of PTFE particles is 8 g/L reaches 3.63%,and the particles is evenly distributed.The composite coating has excellent wear resistance,its friction coefficient is only 0.41,and the surface wear width and depth are 500μm and 14.7μm,respectively,which can effectively reduce the wear degree of Cr12MoV die steel as surface modification coating.