日本金属学会誌

J. Japan Inst. Met. Mater, Vol. 79, No. 3 (2015),
pp. 146-150

Effect of Electroless Ni-P Plating on the Mechanical Properties of Al-4%Ge Alloy

Norihito Nagata1, Teruto Kanadani1, Keiyu Nakagawa1, Minoru Fukuhara1, Keitaro Horikawa2, Kouji Murakami3 and Makoto Hino4

1Department of Mechanical Systems Engineering, Faculty of Engineering, Okayama University of Science, Okayama 700-0005
2Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531
3Industrial Technology Research Institute of Okayama Prefecture, Okayama 701-1296
4Department of Mechanical Systems Engineering, Faculty of Engineering, Hiroshima Institute of Technology, Hiroshima 731-5193

Abstract:

In this study, the effect of electroless Ni-P plating on the mechanical properties of Al-4%Ge alloy was investigated. As the results, the following points were clarified. (1) Tensile strength of the specimen subjected to the Ni-P plating after aging treatment or furnace cooling treatment was improved by about 10% in comparison to one of the non-processed specimens. (2) Breaking elongation of the specimen subjected to the Ni-P plating after aging treatment showed no significant changes in comparison to one of the non-processed specimens. On the other hand, breaking elongation of the specimen subjected to Ni-P plating after a furnace cooling treatment was reduced to 70% in comparison to one of the non-processed specimens. (3) Fatigue strength of the specimen subjected to the Ni-P plating after a furnace cooling treatment was overall reduced rather than one of non-processed specimens. (4) Fatigue strength of the specimen subjected to the Ni-P plating after aging treatment was overall reduced, except for the low-stress region, rather than one of the non-processed specimens. (5) In the specimen subjected to Ni-P plating after a furnace cooling treatment or aging treatment, clear hydrogen desorption was recognized. On the other hand, there was only hydrogen desorption from a few of the non-processed specimens.
Especially, it is considered that the poor fatigue strength and ductility of the plating materials are mainly due to the interaction between the surface precipitates and hydrogen gas. [doi:10.2320/jinstmet.JC201413]


(Received 2014/11/12)

Keywords:

aluminum-germanium alloy, nickel-phosphorus plating, fatigue strength, tensile strength, breaking elongation, aging, surface precipitate, hydrogen gas


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