Tribological investigations of diamond-metal grinding pads

New grinding pads have been developed as composite materials consisting of synthetic diamonds embedded in a metallic matrix of bronze. The wear resistance of the pad material and its abrasive action was determined in reciprocating sliding tests with a corundum ball acting on the polishing sheets with water in the contact. Tests with 5000 and 50,000 cycles have been carried out. The material removal is not the same on the pad and the corundum ball. High abrasion was found on the corundum ball for big size diamond crystals and a sufficient amount of diamonds in the pad, whereas a fine diamond grain size shows higher wear of the pad. These fine-grained pads are suitable for fine polishing of sapphire plane surfaces down to a roughness Ra of less than 40 nm.