Effect of Copper Infiltration on Fretting Wear Properties of Powder Metallurgy Iron Based Valve Seat Material

Abstract

A high quality iron-based P/M valve seat material was prepared by pressing, sintering, and copper infiltration. Fretting wear experiments were carried out by SRV Ⅳ tester to investigate the effect of the amount of infiltration on fretting wear properties of valve seat material. The results indicate that within certain range, with the increase of the amount of infiltration, higher density, hardness and crushing strength of the material are obtained, the friction coefficient and wear volume are reduced as well, and the wear mechanism changes in different degrees. The wear mechanisms of the specimens infiltrated with low amount of copper or without infiltration are mainly abrasive wear and fatigue spalling. When infiltrated with 10%Cu(mass fraction, the same below), the specimens are worn in the form of slight abrasive and fatigue spalling. The specimens infiltrated with 15%Cu show the best fretting wear resistance with very slight adhesive wear. As the infiltration amount reaches 20%, the mechanical properties of the specimens decline, the wear volume increases simultaneously, and adhesive wear is the main wear mechanism. The copper infiltrated specimens show better wear resistance than the substrate.

Keywords

• powder metallurgy
• valve seat
• copper infiltration
• fretting wear
• wear mechanism