Atmospheric Pressure Microwave Plasma P/M Sintering of Cam Lobes

A new proprietary Atmospheric Pressure Microwave Plasma Technology, developed for various materials processing applications, has been applied to P/M sintering of cam lobes. The aims were a) to compare the new processing route with conventional process for the same alloy composition and b) to check the possibility of successful sintering at higher temperatures so that different higher temperature P/M alloys may be used. P/M green cam lobes were used, and sintering runs were carried out initially at temperatures comparable to that currently used in the conventional processes; this was followed by runs at higher temperatures that are not very practical in the conventional processing route due to equipment component constraints. Properties such as density and hardness were measured for the sintered samples, together with corresponding microstructural analysis. For atmospheric pressure microwave plasma processing at conventional process temperature, it was found that properties comparable to that for conventional processing could be obtained in the sintered samples for lesser overall processing time. At higher temperatures for the same processing period different properties were observed in the sintered samples, and these were correlated with microstructural observations.