無電解Ｎｉ‐Ｃｕ‐Ｐ合金めっき皮膜の電気抵抗特性

Abstract

The electric resistance behavior and the structure of electroless nickel-copper-phosphorus alloy films obtained from various kinds of plating baths containing sodium hypophosphite as a reducing agent were investigated by means of an X-ray diffraction method, a film resistance measurement, and a differential scanning carolimetry. It was found that resistivity of films as-plated became constant value more than 1-2μm thickness, and it became smaller when the contained the larger content of copper. For change of resistivity of films by the heat treatment, the ratio of its decrease became larger when the films contained the larger content of phosphorus and its relation corresponded well to the structural variation of films. For the films deposited from caustic alkaline citrate bath, the returning of films became worse, when content of copper incresed. The heat treatment at 300°C 1hr. in vacuum, however, developed its returning. In case of ammonia alkaline citrate bath, the returning of films were better than that deposited from caustic alkaline citrate bath. In all films asplated, the resulting temperature coefficient of resistance (TCR) were lower with decreasing the grain size of film and TCR were larger by the heat treatment.