机械搅拌对纳米复合镀层微观组织及性能的影响(英文)

Effects of Mechanical Stirring on Microstructures and Properties of Nan o-composite Coatings

通过Ni、W、P和CeO2、SiO2纳米颗粒的脉冲共沉积,在普通碳钢表面制备了Ni-W-P-CeO2-SiO2纳米复合镀层,研究了机械搅拌速度对纳米复合镀层微观组织及性能的影响,采用化学组成、元素分布、沉积速率、显微硬度和微观组织进行表征。结果表明:当机械搅拌速度控制在1000r/min时,纳米复合材料微观组织致密,基质金属轮廓清晰,晶粒较细,纳米颗粒以弥散态均匀分布在基质金属中。同时,元素线扫描和面扫描分析表明,W、P、Si和Ce的平均含量非常接近,说明元素在纳米复合镀层中的分布是均匀的。提高机械搅拌速度,纳米复合镀层晶粒得到细化,沉积速率和显微硬度增加,当机械搅拌速度提高到1000r/min时,沉积速率(32.68μm/h)和显微硬度(6820MPa)最高。继续提高机械搅拌速度,纳米复合镀层晶粒尺寸反而增加,沉积速率和显微硬度降低。

Ni-W-P-CeO2-SiO2 nano-composite coatings were prepared on the carbon steel surface by pulse co-deposition of Ni, W, P, nano-CeO2 and nano-SiO2 particles. The effects of mechanical stirring velocity on microstructures and properties of the nano-composite coatings were researched; the characteristics were assessed by chemical compositions, element distribution, deposition rate, microhardness and microstructure. The results indicate that when the mechanical stirring velocity is controlled at 1000 r/min, the nano-composite coatings possess compact microstructure, clear outline of spherical matrix metal crystallite, fine crystal size and uniform distribution of the nano particles in the dispersion state within matrix metal. Meanwhile, element line scanning and scanning analysis shows that the average contents of elements W, P, Si and Ce in the composite coatings are close, displaying that the distribution of every element within the composites is very uniform. Increasing mechanical stirring velocity leads to refinement in grain structure and the corresponding increase of the deposition rate and the microhardness. When it is increased to 1000 r/min, the deposition rate with 32.68 μm/h and the microhardness with 682Hv are highest respectively. After that, the deposition rate and the microhardness will decrease if it increases continually.