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With increased awareness of environmental issues and regulations, developments for recent automotive engines are progressing towards engines with low fuel consumption. Due to these changes, automotive engine bearings are increasingly used in harsher environments, with higher loading and corresponding wear. From this background, resin overlays, where solid lubricant is dispersed in a resin binder, are being developed. Resin overlays show excellent sliding properties under boundary lubrication conditions, and are known to have superior wear and fatigue resistance compared with conventional aluminium based bearings. However, while conventional resin overlay bearings display excellent sliding properties, they tend to have inferior seizure resistance compared to Al-Sn-Si alloy bearings. In this study, by optimizing the strength of the resin overlay layer with addition of calcium carbonate particles, a resin overlay with equal wear resistance but improved seizure resistance was developed.

Resin-based overlays as lead-free bearing materials for automobile engines are experimentally studied using tribology testing apparatus and an engine bench test rig. A resin overlay newly proposed is composed of Polybenzimidazole (PBI) as the base resin and solid lubricant Molybdenum disulfide (MoS2) as an additive. PBI has high temperature performance and good adhesion and physical strength under higher temperatures. Consequently, a PBI-based overlay has good sliding properties in terms of wear resistance and fatigue resistance. The resin overlay shows applicability to automobile engine bearings which are used under high loads.