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. Tile P 10%(weight percentage ratio) Ni-P coati ng 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 an d 0.28 nm. The P 10% NI-P coating after heat treatment at 400 C is a m ixture of Ni3P and non-crystal Ni-P, The formation of nickel phosphonu s likely structure is established by EXAFS and confirmed by experiment s 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 v ery suitable for the studies of non-crystal alloy. The coordination en vironment 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 tre atment. 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 structu re may be useful for interpretation of the properties Ni-P non-crystal alloy coating from the view of molecular level.