系统研究Ni-TiO2复合纳米晶的晶粒生长及热稳定性.通过电沉积法制备Ni-TiO2复合纳米晶,并在电沉积过程中改变纳米TiO2纳米颗粒含量,制得不同TiO2含量的Ni-TiO2复合纳米晶.详细讨论TiO2含量对晶粒尺寸、相结构和显微硬度的影响;并考察不同TiO2含量Ni-TiO2复合纳米晶在加热过程中对应晶粒的生长和扩散机制.400℃退火处理保温90 min之后,掺入20 g/L TiO2的复合纳米晶具有最佳的显微硬度,达到HV50270.激活能的计算结果表明,高温时晶格扩散为复合纳米晶生长的主导机制;高温时增加TiO2纳米颗粒含量能提高晶粒生长的激活能,从而抑制晶粒生长.%The grain growth and thermal stability of nanocrystalline Ni-TiO2 composites were systematically investigated. The nanocrystalline Ni-TiO2 composites with different contents of TiO2 were prepared via electroplating method with the variation of TiO2 nano-particles concentration. The effect of TiO2 content on the grain size, phase structure and microhardness was investigated in detail. The corresponding grain growth and diffusion mechanisms during the heating process were also discussed. The optimal microhardness of HV50270 was achieved for the composite with addition of 20 g/LTiO2 nano-particles after annealing at 400 ℃ for 90 min. The calculation of the activation energy indicated that lattice diffusion dominated at high temperatures for the nanocrystalline Ni-TiO2composites. It was indicated that the increase of TiO2nano-particles content took effect on restricting the grain growth at high temperatures by increasing the grain growth activation energy.
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