Optimization of a Semimetallic Friction Material Formulation

Abstract

A semimetallic friction material formulation consisting of Al2O3,B2O3, brass chips, graphite, NBR (nitrile rubber), steel wool, and benzoxazine (a ring-opening polymerized phenolic) with high friction coefficient ( μ) and low wear was developed using the Golden Section approach to search the optimal volume fraction of each ingredient in the formulations. All raw materials used were divided into three groups: fibers, fillers, and binder. The volume fraction of each ingredient in the formulations was calculated by means of V i = 0.618 n in phase 1, V j = V i ± V i × r m/ V F and V j = V i ± V i × r m/ V f in phase 2 and V j = V i ± V i × r m/( V F + V f) in phase 3. Two exponent equations, w = k0 V1 k1 V2 k2 … V p kp and μ = m0 V1 m1 V2 m2 … V p mp, were proposed to correlate the compositional dependence of wear and μ. The least-squares error method was utilized to calculate the effect of each ingredient on and wear. Experimental and calculated results proved that both brass chips and B2O3 play important roles in enhancing. After doing 18 formulation experiments that preformed using Friction Assessment and Screening Test (FAST), an optimized formulation (BB-17) with high μ (average μ = 0.701) and low wear ( w = 4.74%) was obtained.