压力对块状纳米镍热稳定性的影响

Effect of Pressure on the Thermal Stability of Bulk Nano-Ni

用氢、氩等离子体法制备了平均粒径在15 nm左右的镍纳米粉,研究了热压法制备块状纳米镍的压力对纳米镍晶粒热稳定性的影响,并对其进行了热力学分析。结果表明:在一定条件下,压力小于3 GPa时,随着压力升高,晶粒有长大的趋势,而压力大于3 GPa,晶粒尺寸却呈下降趋势;达到6 GPa时,晶粒尺寸在70 nm左右,镍纳米晶粒的热稳定性得到了提高。

The nanoscale powders of Ni with average diameter of about 15 nm prepared by the plasma of hydrogen and argon were applied to investigate effect of pressure on the nanocrystal stability in hot pressure sintering process. The effect was analyzed by thermodynamic theory. The nanoscale crystals could grow quickly with the pressure increasing below 3 GPa. The size of crystal would decrease with the pressure increasing above 3 GPa. The size of nanocrystal could be controlled to be smaller than 70 nm at 6 GPa. The stability of nanoscale Ni grains was increased.