NEW POWDERS FOR ELECTRICAL BRUSHES AND MICROBEARINGS

A copper powder, has been developed for the manufacture of electrical brushes. The higher surface area and lower apparent density of the pow der give improved green and sintered strength, maintain a copper matri x in the brush at higher graphite content, and result in higher electr ical conductivity. Low-noise microbearings made from a new prealloyed bronze premix, exhibit a uniform alpha bronze grain structure, fine po re size, and close dimensional tolerances.