纳米Ni-Si3N4-x复合镀层的超声电沉积机理及工艺研究

通过超声电沉积法制备纳米Ni-Si3N4-x复合层,研究超声电沉积纳米复合镀层的机理及工艺.在试验的基础上,主要研究了超声波的机械扰动效应、空化效应及脉冲电流对抑制纳米粒子团聚、控制晶粒成核及生长的作用.结果表明,适度功率超声波的引入,可以抑制镀液中纳米粒子的团聚,与高频、窄脉宽脉冲电流作用相结合,可以提高镀液扩散传质效率,加速纳米粒子与基质金属离子共沉积,使纳米陶瓷粒子均匀分散在镀层中,促进基质金属晶体形核并控制其生长,起到细晶强化的作用.获得了由纳米镍晶(20～60 nm)和纳米Si3N4-x粒子构成的纳米复合镀层.

Mechanism and Technology of Ultrasonic-Electrodepositing Nano Ni- Si3N4-x Composite Layer

Nano Ni-Si_3N_(4-x) composite layer was prepared by ultrasonic - electrodepositing method, and the mechanism and technology of ultrasonic - electrodepositing nano composite layer were studied. Main investigation concentrated on the mechanical disturbance effect and cavitation of ultrasonic wave, and the effects of pulse current on controlling reunion of nanoparticles, nucleation and growth of grains. Results show that the reunion of nanoparticles may be restrained by introducing moderate ultrason ic wave. The mass-transfer efficiency of electrolyte is raised, the co - deposition of nanoparticles and metal ions is accelerated, the nanoparticles are well distributed in composite layer as a strength ening phase, the nucleation multiplication of matrix metal is en hanced and the crystalline growth is hindered by combining ultra sonic wave with high frequency and narrow-width pulse current. The nano Ni - Si_3 N_(4-x) composite layer consisted of nanocrystalline nickel (20 -60 nm) and nano Si_3N_(4-x)particles is obtained.