Brake pad is the combination of lining and metallic components, e.g. steel backing plate (disc brake) and aluminum brake shoe (drum brake). Shear bond strength plays a major role to provide the safety and/or drive performances. This work aimed to study the processing factors affected the bonding strength. The molding temperature couple with post-curing temperature was simultaneously analyzed in order to optimize the processing temperature. The shear bond strengths of metallic plates were continually investigated with regard to the effect of different surface treatments. The obtained results indicated that the mechanical strength was increased as the molding temperature raised in ranges of 160°C to 180°C. Conversely, the deterioration of adhesive strength was progressively presented with rising post curing temperature. In comparing different backing plate, aluminum showed the higher shear bond strength than that of steel plate. In fact, the weakened property of aluminum in nature would be easily destroyed by mechanical treatments. From the shear tested results, an increase of surface roughness was inversely changed the shear bond strength. On the other hand, the contact angle of water droplet affected directly to adhesive strength. It was suggested that an adding surface roughness, commonly used in automotive industry, was inappropriate criteria, whist geometrical surface should be taken into account for improving the shear bond strength. Moreover, the contact angle and mechanical interlocking were recommended to use as a criteria of brake pad shear strength.
Effect of sandblasting on surface roughness of zirconia-based ceramics and shear bond strength of veneering porcelain