Senju Metal Industry Co., Ltd.

Sinzo Nakamura

Naoki Sato

Toshio Hakuto

Ryoichi Kurata

Issaku Sato

Hiroshi Takahashi

A sliding material has a sintered layer formed atop a backing plate. The sintered layer contains 5-15 mass % of Bi nonuniformly distributed in a Cu&#x2014;Sn alloy matrix consisting essentially of 8-12 mass % of Sn and a remainder of Cu. The sliding material can be manufactured by nonuniformly mixing Cu&#x2014;Sn alloy powder and Bi powder, dispersing the mixed powder on a backing plate, and sintering the mixed powder to form a sintered layer on the backing plate. The sliding material does not undergo seizing and does not have separation of the sintered layer from the backing plate even when used in severe conditions such as in hydraulic equipment or construction equipment.

Sliding material and a method for its manufacture

A conventional Bi-containing sliding material sometimes underwent seizing in a sliding part operating at a high rotational speed. The present invention provides a sliding material which does not undergo seizing in a sliding part operating at a high rotational speed and a method for its manufacture. A low melting point alloy containing at least 20 mass % of Bi and having a liquidus temperature of at most 200&#xb0; C. is made to penetrate into a porous portion comprising a Cu&#x2014;Sn based alloy. A Bi&#x2014;Sn based alloy or a Bi&#x2014;In based alloy is suitable as the low melting point alloy. After a low melting point alloy paste is applied to a porous portion, the low melting point alloy is melted and made to penetrate into the porous portion.

A solder paste comprises a lead-free solder alloy powder and a flux and is suitable for use in reflow soldering of electronic parts at a soldering temperature of 230&deg; C. or below with minimized damage to the electronic parts to form soldered joints of good bond strength. The solder alloy powder is a mixture of from 10 to 30 vol % of a first powder of an Sn&mdash;Bi alloy consisting essentially of 10-45 wt % of Bi and a balance of Sn and from 70 to 90 vol % of a second powder of an Sn&mdash;Zn alloy consisting essentially of 9-15 wt % of Zn and a balance of Sn. The mixture gives an alloy having a composition upon melting which consists essentially of 7-11 wt % of Zn, 1-5 wt % of Bi, and a balance of Sn.

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Mooka, Japan

Sinzo Nakamura