无电解镀镍磷非晶态合金的近边结构研究

Studies on Structure of Electroless Ni-P Alloy

用ＤＴＡ、ＸＲＤ和ＥＸＡＦＳ方法研究无电解镀镍磷合金层结构。其中含Ｐ１０％（重量百分比）左右的Ｎｉ－Ｐ合金层是非晶态合金固溶体，Ｎｉ、Ｐ之间存在共价键作用，Ｎｉ—Ｎｉ键长０．２５ｎｍ；Ｎｉ—Ｐ键长０．２８ｎｍ；经４００℃热处理１ｈ后的含Ｐ１０％的Ｎｉ－Ｐ镀层是Ｎｉ３Ｐ晶态与Ｎｉ－Ｐ非晶态的混合物。ＥＸＡＦＳ方法给出了镍磷合金层的结构、键长和配位原子情况，体现出ＥＸＡＦＳ方法在研究金属结构尤其是非晶态金属结构方面的优越性。

The structure of Electroless Ni-P alloy has been studied by using DTA,XRD and EXAFS methods,The P 10%(weight percentage ratio) Ni-P coating is a non-crystal alloy.The action between Ni and P is a convalent bond applied force,The lengths of Ni Ni and Ni P bonds are 0.25 nm and 0.28 nm.The P 10%Ni-P coating after heat treatment at 400℃ is a mixture of Ni_3P and non-crystal Ni-P.The formation of nickel phosphonus likely structure is established by EXAFS and confirmed by experiments in contrast to DTA and XRD which does not provide more information.The extended X-ray absorption fine structure(EXAFS) spectrophotometry developed with the development of synchronous radiation light.It is very suitable for the studies of non-crystal alloy.The coordination environment of Ni and P in Ni-P alloy coating has been measured by means of EXAFS.The degree of order in Ni-P alloy increases by the heat treatment.The loss of long-range order is even more pronounced with the increasing P content in Ni-P coating.The local order around Ni in Ni-P alloy coating resembles that in Ni metal.The discription of structure may be useful for interpretation of the properties Ni-P non-crystal alloy coating from the view of molecular level.