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In-situ formed Al-AlN sintered composite materials have been developed by the direct nitriding process based on the reaction of the aluminum matrix to nitrogen gas during sintering. A traditional press-sinter(P/S) method, hot extrusion(H/E) and powder forging (P/F) processes are available to consolidate the composite aluminum alloys. Fine AlN particles less than 1 μm in diameter dispersed as hard particles in the material have a significantly strong bonding to the matrix. They have an important role to improve wear resistance equivalent to the hard anodizing or Ni-P plating. The aluminum alloy also shows a low friction coefficient (less than 0.01) under oil lubricating conditions because fine AlN particles make it possible to form oil film at the interface between the counterpart material.

A new sintered composite friction material consisting of mechanically-alloyed copper-based composite powders has been developed. It has a unique microstructure of fine hard particles that are embedded in the matrix of the copper-based primary particles. This friction material reduces abrasive wear and/or seizures that are often caused by hard particles which become detached from the matrix, because the hard particles in this material are bonded tightly to the matrix even under harsh service conditions. The fine hard particles are also very useful for improving high friction force when contacting a surface material. Therefore, this new friction material provides a higher friction coefficient than the conventional material containing coarse hard particles. Furthermore, this friction material is less abrasive to the surface material than the conventional one.

An internal gear-type pump has advantages compared with an external involute gear-type pump, for example, higher mechanical or volumetric efficiency, considerable reduction of weight and dimension in the oil-pump system[1]. This paper presents characteristics of the internal gear type rotors with a modified trochoidal profile in the oil-pump system, and new P/M(Powder Metallurgy) aluminum alloys which satisfy required wear properties as the lubrication oil-pump rotors. Also, the advantage of high volumetric efficiency and discharge performance and excellent properties of the oil-pump rotor with a modified trochoid profile were combined with a R/S (Rapidly Solidified) aluminum alloy in the scavenging pump for racing car engine. Good results without wear or damage after an actual race are also reported.