Taiho Kogyo Co., Ltd.

Denso Corporation

Daisuke Yoshitome

Hiromi Yokota

Takashi Tomikawa

Hitoshi Wada

Masashi Suzuki

Youichi Murakami

Takahiro Nozu

Hiroaki Hayakawa

Naruhiko Inayoshi

Hiroaki Kobayashi

Hiroyuki Kawaguti

Yasuhisa Tanaka

When a Cu&#x2014;Sn&#x2014;Bi had&#x2014;particle based sliding material is used for sliding, Cu of Cu matrix flows and covers up Bi phase. Seizure resistance lowers as time passes. A Pb-free sliding material preventing the reduction of seizure resistance is provided. (1) Composition: from 1 to 15% of Sn, from 1 to 15% of Bi, from 0.02 to 0.2% of P, and from 1 to 10% of hard particles having an average diameter of from 50 to 70 &#x3bc;m, with the balance being Cu and unavoidable impurities. (2) Structure: Bi phase and the hard particles are dispersed in the copper matrix, and all of said hard particles are bonded to the copper matrix.

Pb-free copper alloy sliding material

Seizure resistance and wear resistance of Cu&#x2014;Bi&#x2014;In copper-alloy sliding material are enhanced by forming a soft phase of as pure as possible Bi. Mixed powder of Cu&#x2014;In cuprous alloy powder and Cu&#x2014;Bi containing Cu-based alloy powder is used. A sintering condition is set such that Bi moves outside particles of said Cu&#x2014;Bi containing Cu-based powder and forms a Bi grain-boundary phase free of In, and In diffuses from said Cu&#x2014;In containing Cu-based powder to said Cu&#x2014;Bi containing Cu-based powder.

Process for production of sintered copper alloy sliding material and sintered copper alloy sliding material

In a Cu&#x2014;Bi based sintered alloy, to which hard particles, such as FeP, are added, the main constituent components of the microstructure are a Cu matrix, Bi phase and the hard particles. In the sintering method of the present invention, the flow of the Bi phase is suppressed to as low level as possible. The novel structure is that the contact between the Bi phase and hard particles is kept to a low ratio. A lead-free bearing used for a fuel injection pump according to the present invention contains from 1 to 30 mass % of Bi and from 0.1 to 10 mass % of hard particles having from 10 to 50 &#x3bc;m of the average particle diameter, the balance being Cu and unavoidable impurities. The properties of the main component phases are utilized at a high level such that the sliding properties are equivalent to those of a Pb containing Cu-based sintered alloy.

Pb-free bearing used for fuel-injection pump

In a Pb-free copper-based sintered alloy containing from 1 to 30% of Bi and from 0.1 to 10% of hard matter particles having from 10 to 50 &#x3bc;m of average particle diameter, the Bi phase has a smaller average particle diameter than that of the hard matter particles and is dispersed in the Cu matrix, or the hard matter particles having 50% or less of a contact length ratio with the Bi phase based on the total circumferential length of the hard particle, which are in contact with said Bi phase, are present in a ratio of 70% or more based on the entire number of the hard matter particles.

Pb-free copper-alloy sliding material

A lead-free solder, which contains from 1.0 to 3.5% of Ag, from 0.1 to 0.7% of Cu, and from 0.1 to 2.0% of In, the balance consisting of unavoidable impurities and Sn, is appropriate for ball-grid array (BGA). The solute Cu suppresses growth of intermetallic compound formed at the interface between the bulk of solder and a Ni or Cu conductor.

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Aichi, Japan

Daisuke Yoshitome