Studies on reduced scale tribometer to investigate the effects of metal additives on friction coefficient – Temperature sensitivity in brake materials

Abstract

▶ New approach defined in this study on RSP proved to have potential to study temperature sensitivity of μ (fade and recovery behavior). ▶ This method has significant advantages such as very limited infrastructure, substantially less testing time and manpower along with extremely low cost as compared to the standard method on full scale dynamometer. ▶ Use of metallic ingredients in NAO friction composites affected all performance properties in a beneficial way. Cu was most effective in boosting TC significantly followed by brass and iron). ▶ Inclusion of metallic fillers enhanced all performance parameters related to friction and wear. Copper which is most expensive filler proved best followed by brass (moderately expensive) while iron powder (cheapest) was least effective in boosting performance of reference composite. ▶ Increased TC of the composites due to metallic fillers was the main reasons for improved friction performance. Standard methods practiced by the industry to evaluate performance of friction materials need huge infrastructure, manpower and time. It is necessary for researchers working in this applied field to develop a different approach to screen the potential of friction materials on reduced scale prototype (RSP) which would rank the materials based on performance. In this paper a new test methodology is reported to study the influence of metallic contents on temperature sensitivity of friction composites on RSP. Three friction composites were developed with identical parent composition (90% by wt.) except metallic filler viz. brass, copper and iron powder (10% by wt.). One more was developed without metallic powder by adjusting 10% amount with barite (space filler). All composites were characterized for physical, chemical and mechanical properties. These were tribo-tested on RSP for friction, wear, fade and recovery behavior as per new test methodology. It was concluded that with use of metal contents, friction and wear performance of composites improved in general. Copper containing composite showed best friction and wear behavior followed brass, while iron powder based composite showed moderate behavior. Thus new test methodology proved very effective to rank the performance of friction composites.