Ni-P-纳米金刚石黑粉化学复合镀层的摩擦磨损性能

Friction and Wear Properties of Ni-P Electroless Composite Coatings with Core-Shell Nanodiamond

通过非均匀形核法,在纳米金刚石黑粉颗粒表面包覆一层Al2O3,采用包覆后颗粒制备了Ni-P-纳米金刚石黑粉化学复合镀层.通过沉降法分析了包覆前后纳米颗粒悬浮液的分散稳定性;研究了金刚石质量浓度、搅拌转速及粉体热处理工艺对复合镀层显微硬度和耐磨性能的影响;利用SEM和EDS分析了镀层微观形貌和组分.结果表明:颗粒表面包覆氧化铝可以显著提高其在分散介质中的悬浮稳定性;综合考虑摩擦磨损特性,其最优工艺参数为金刚石质量浓度4 g/L,搅拌转速500 r/min,复合粉体经100℃下热处理4 h;与Ni-P镀层相比,复合镀层摩擦系数降低58%,耐磨性能提高59%.

Ni -P -nanodiamond （ND） composite coatings were prepared by adding core -shell ND particles to electroless plating bath. Core- shell ND particles were coated with A1203 layer by using heterogeneous nucleation. The stability of colloidal particles in nickle solution was evaluated by sedimentation test. The effect of core - shell ND concentration in electrolyte, rotation speed of stirrer and heat treatment of coated powders on microhardness and wear of the coating were investigated. The friction and wear were evaluated on a pin - on - disk tribo - meter under unlubricated condition, while micro- morphology and composition of coatings were analyzed by scanning electron microscopy. The results demonstrate stable dispersions of coated core - shell ND particles in solution. The significant improvement in tribologieal properties of Ni -P -ND composite coatings was obtained under the condition of core -shell ND concentration of 4g/L, rotation speed of 500 r/rain and heat treatment at 100 ℃ for lh. The friction coefficient decreased by 60% and wear-resistance increased by 50% in contrast with pure Ni - P coating.