電析Ni-P合金めっき膜の微細構造と熱平衡状態図との関係

Abstract

The electrodeposited Ni-P alloy films were obtained from Watts baths containing H3PO3. The crystallographic structure and morphology of electrodeposited Ni-P films were studied by using XRD, HRTEM, SEM and heat-treatment technique. The crystallographic structures of electrodeposited Ni-P alloy films was also compared with the Ni-P thermal equilibrium diagram. The X-ray diffraction patterns of Ni-P electrodeposited films with various P contents gradually changed from sharp peaks to broad peaks with increasing P contents in electrodeposited films. HRTEM observation revealed that the crystallographic structure of electrodeposited Ni-P film with 18.5 at%P content was crystalline and its crystal size was about 10 nm. Moreover, the crystalline structure was observed and the crystal size was about 3 nm in the electrodeposited Ni-P alloy film with 21.5 at%P content. However, when the film with 21.5 at%P content was heat treated, the crystalline phase did not grow and Ni3P existed alone under 300°C heat-treatment. From this result, it was clear that the crystallographic structure of Ni-P film with 21.5 at%P content was amorphous. Therefore, it can be concluded that the microcrystalline phase existed up to 19 at%P in electrodeposited Ni-P alloy film and the amorphous phase existed from 19 at% to 32 at%P.