The influence of the addition of aluminum anodizing waste on the friction and emission behavior of different kinds of friction material formulations

Abstract

The study focuses on the characterization and one-of-a-kind utilization of aluminum anodizing waste (AAW) in different friction material formulations. Through TGA and FT-IR analysis, the AAW was observed to have a dominant presence of hydroxide, sulfate hydrate, and a fraction of alumina. After heat treatment at 400 ℃ for 4.5 h, the AAW also constituted of AlOx, obtained from the conversion of hydroxides. The AAW was included in two kinds of friction material compositions – a basic composition (BC) with few constituents, and a commercial composition (CFM), wherein, the AAW was added at 12, 24, and 32 wt% of variation, and subjected to friction, wear, and emission analysis. The tests were conducted on a pin on disc testing equipment at 1.51 m/s, 1 MPa, and room temperature testing conditions. The analysis with BC revealed the mild abrasive nature of the AAW, along with acceptable friction, wear, and emission characteristics. With the CFM, the steady state CoF trends, permissible CoF, pin and disc wear, and desirable emission characteristics were observed with 12 wt% addition of AAW. Higher AAW content led to the degradation of wear and emission characteristics of the CFM specimens. Through this preliminary investigation, the possibility of the recycling/utilization of AAW was explored comprehensively, paving the path for further exploration and feasibility analysis of the inclusion of AAW in braking applications.