| 摘要 |
PURPOSE:To improve consumption resistance, low contact characteristic, deposition resistance, and arc extinction characteristic, by specifying a graphite grain size and also by uniformly dispersing the graphite grains in a contact material composed of a copper-silicide-graphite alloy with a specific composition. CONSTITUTION:A copper powder, a powder of silicide of the group IVa, Va, and VIa metals of the periodic table, and a graphite powder are mixed in the ratio of copper to the above silicide to graphite of 50-97pts.wt. to 3-50pts.wt. to 0.1-10pts.wt. by mechanical alloying. In this way, the silicide powder and the graphite powder can be inlayed in the copper powder, so that a powder mixture in which grain size of graphite is regulated to <=3mu and the graphite grains are uniformly dispersed can be obtained. When the above graphite grain size exceeds 3mu, gasificating reaction in which graphite is reacted with O2 in the air by arc heat at the time of making and breaking a contact into CO is liable to occur to a further extent than is required and, as a result, arc extinction is deteriorated. Moreover, deposition due to segregation is eliminated because silicides and graphite are uniformly dispersed. |
