Improving oxidation resistance of diamond by adding silicon into diamond-borosilicate glass composites

Diamond-borosilicate glass composites have been used for vitrified diamond tools. The major challenge in the development of these composites is to avoid oxidation of diamond during sintering. In this study, silicon powder was added into the diamond-borosilicate glass composites to enhance oxidation resistance of diamond. The results showed that silicon powder was oxidized prior to diamond and its oxide products could enter into the glass network. Consequently, the oxidation resistance of the diamonds was improved, and the bending strength and volume expansion ratio of the composites with silicon additive were evidently changed compared to that of composites without silicon powder. A maximum bending strength of 60.94 MPa, and a minimum volume expansion ratio of -11.3% were obtained in the composite containing 8 wt.% silicon powder. (C) 2011 Elsevier Ltd. All rights reserved.