A comparative study on the crystallization behavior of electroless NiP and NiCuP deposits

School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, PR China
Surface and Coatings Technology (Impact Factor: 2.2). 12/2001; 148(s 2–3):143–148. DOI: 10.1016/S0257-8972(01)01345-7

ABSTRACT The crystallization behavior of electroless NiP and NiCuP was studied comparatively by using differential scanning calorimetry and X-ray diffractometry. It is apparent that low-P NiP deposits transform to the stable phase Ni3P directly, but low-P (high-Cu) NiCuP deposits transform to the metastable phase Ni5P2 first, and then to the stable Ni3P. Both the hypereutectic amorphous NiP deposits and amorphous NiCuP deposits with high phosphorus content transform to the metastable phases Ni5P2 and Ni12P5 first, then to the stable phase Ni3P. For the amorphous NiP and NiCuP deposits with P content of approximately 10 wt.%, the crystallization temperature of the latter is markedly higher than that of the former. In addition, the crystallization temperature of the hypereutectic NiP deposit is nearly the same as that of the amorphous NiCuP deposit with a similar P content. For the crystalline NiP and NiCuP deposits with low P content, the temperature at which the stable Ni3P forms in the latter is obviously higher than that of the former.

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