Studies on structure of electroless Ni-P alloy

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 C is a mixture of Ni₃P 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.