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A copper based bushing alloy is used under boundary lubrication for the sliding part of a fuel injection pump etc. for automotive diesel engines. Lead is added to a copper based alloy bushing, because seizure resistant property is an important factor under boundary lubrication. However reducing the use of lead, an environmental pollutant, is required from environmental concerns. Therefore, a lead free bushing alloy was studied in this paper. Concept of material design is to prevent adhesion between a bushing alloy and a mating shaft leading to less wear under the boundary lubrication. The tested material is basically copper-based alloy to which low melting metal instead of lead, hard particles and solid lubricant are added. Tribological and mechanical properties of the material were evaluated in terms of seizure resistance, fatigue strength, conformability and cavitation resistance.

As the recent engines are designed for higher performance and better efficiency, three layers bearings must endure under heavy dynamic load and higher speed conditions. And it is also expected to develop the bearing without lead due to environmental concerns. In this report, a lead free copper based bearing alloy was studied. At first, in order to keep the anti-seizure property without lead, we studied the effects of bismuth and molybdenum carbide particles addition into the copper based bearing alloy. Secondly, we studied the influence of axial bearing relief to keep a conformability under high load condition.

As the recent engines are designed for higher performance, piston pin bushing used for small end of connecting rod must endure higher dynamic load and oil temperature conditions. Therefore, the bushing is required higher wear resistance and anti-corrosion. And it is also expected to develop the bushing without lead due to environmental concerns. In this report, lead free copper based bushing alloy was studied. At first, in order to keep the anti-seizure property without lead, we studied the effects of hard particles added into copper based alloy. Second, we evaluated the effect of addition of hard particles on wear resistance and anti-corrosion.