纳米TiO<sub>2</sub>/Ni复合刷镀层的接触疲劳性能

纳米TiO₂/Ni复合刷镀层的接触疲劳性能

摘要: 采用电刷镀技术制备了纳米TiO2/Ni复合镀层,研究了镀层的接触疲劳性能,采用扫描电镜观察了镀层疲劳断口.结果表明：含有纳米颗粒的复合镀层表面形貌均匀细小,镀层内应力较大:载荷为60 N时,复合镀层的接触疲劳性能显著高于纯镍镀层,接触疲劳寿命达到140万次:载荷为140 N时,其接触疲劳性能低于纯镍镀层.低载荷时,复合镀层接触疲劳断口呈明显的塑性特征:而高载荷时疲劳断口呈完全的脆性,疲劳裂纹呈近似直线扩展.

Abstract: The nano-TiO2/Ni composite coating was prepared by electro-brush plating and its contact fatigue property was examined and the fracture morphology of nano-TiO2/Ni was analyzed by scanning electron microscope.The results show the surface topography of nano-TiO2/Ni is smooth and fine and large internal stress existe in the coating.Under a load of 60 N,contact fatigue life of nano-TiO2/Ni could reach to 1 400 000 cycles,obviously higher than that of the nickel coating.Under a load of 140 N,contact fatigue life of nano-TiO2/Ni is lower than that of the nickel coating.It is showed by failure analysis that under 60 N and 140 N plastic deformation and brittlement respectively are the main characteristics in the fracture morphology of nano-TiO2/Ni,and the fatigue cracks linearly propagated under the load of 140 N.