INVESTIGATION INTO THE STRUCTURE OF ELECTRODEPOSITED NICKEL-PHOSPHORUS ALLOY DEPOSITS

This paper presents a study into the structure of Ni-P deposits contai ning 1.15-15.43 mass% P using X-ray diffraction. The coatings were dep osited from electrolytes containing both phosphorous and phosphoric ac ids using conventional direct current. Samples obtained by electroless deposition were also examined for comparative purposes. The effects o f composition on crystallite/grain size have been determined quantitat ively using an X-ray diffraction line broadening technique and the for mation of X-ray amorphous structures have also been followed using X-r ay diffraction. The development of the amorphous phase, however, was f ound to be sensitive to crystallographic orientation. At amorphous con tents above 70%, the crystalline nickel phase was associated only with (111)/(222) orientations parallel to the surface of the deposits. Thi s appeared to result from a decrease in the growth rate of other orien tations, e.g. (200), relative to the (111) orientation.