纳米金属铜靶材的微结构与性能

Microstructure and properties of nanocrystalline copper target material prepared by flow-levitation-molding method

采用自悬浮定向流方法制备金属Cu纳米粉体，在25℃和1．0～1．75GPa的高压下，单向模压成型，制备含量高于95％的高密度纳米金属Cu晶体材料。用透射电镜、X射线衍射谱和场发射扫描电子显微镜对样品的结构进行表征。结果表明：X射线衍射分析的平均晶粒尺寸未退火时为19．9nm，退火后为30．5nm（TEM观察约为60nm），颗粒基本为球形；样品中除了纳米晶粒外，还出现孪晶结构；孪晶是纳米Cu粉在超高压作用下形变的重要特征之一；纳米晶体Cu样品的电阻率在室温下约为1．56×10^-7Ω·m，是粗晶Cu在室温下电阻率（0．167×10^-7Ω·m）的9．3倍。

The metallic Cu nanoparticles prepared by flow-levitation method were compacted by molding under uniaxial pressure of 1.0 - 1.75 GPa at 25 ℃, the bulk nanocrystalline Cu with high relative density of larger than 95 % was obtained. The microstructure was investigated by TEM, XRD and FESEM analysis. The results show that the spheric particles in bulk nanocrystalline metallic Cu have average grain size of 19.9 and 30.5 nm （which is about 60 nm by TEM）hy XRD before and after annealing respectively. Besides nanoscale grains twins also exist in samples. Twins are one of the important deformation characteristics of Cu nanapowders under high pressure. The electricl resistivity of nanocrystalline Cu is about 1.56×10^-7Ω·m, which is 9.3 times larger than that of the coarse-grained Cu sample （0.167×10^-7Ω·m） at 20℃.