纳米晶体Ni－P合金晶粒微观结构的研究

采用非晶晶化法制备出晶粒尺寸不同的Ｎｉ－Ｐ合金复相纳米晶体样品。利用Ｘ射线衍射技术分别对样品中Ｎｉ固溶体和Ｎｉ_３Ｐ的晶格参数随晶粒尺寸的变化进行了测试，发现在Ｎｉ固溶体纳米相中Ｐ的固溶浓度增大，约为平衡固溶度的１０－１５倍，形成超过饱和固溶晶格结构；在Ｎｉ_３Ｐ化合物纳米相中空位浓度增加导致晶格畸变发生，而且随晶粒尺寸减小晶格畸变程度增大。

MICROSTRUCTURES OF CRYSTALLITES IN NANOCRYSTALLINE Ni-P ALLOYS

Different grain-sized nanocrystalline Ni-P alloy samples with two crystalline phases of a Ni solid solution and a Ni_3P compound have been synthesized by the crystallization method. By means of the X-ray diffraction technique, variations of the lattice parameters of these two nanophases with the grain size were determined. It was found that the values of the lattice parameters for the two nanophases obviously deviated from the equilibrium data for the corresponding perfect crystals. Analysis of the experimental results indicated that the P concentration in the Ni(P) solution nanophase was much enhanced, being about 10-1 5 times as much as the equilibrium solubility, and a highly supersaturated Ni(P)solid solution formed in the nanophase samples. For the Ni_3P nanophase, an evident lattice distortion was detected, and the lattice distortion of the Ni_3P nanophase increases with a reduction in grain size, which might be oringinated from an enhancement of the vacancies in the nanometer-sized crystallites.