Effect of additives introduced by ball milling on sintering behavior and mechanical properties of hot-pressed B_4C ceramics

摘要

The ball-milling process is a usual route employed to break up agglomerates in the powder or mix the powder with additives when preparing ceramics. Although it is well known that a powder can be "contaminated" by the wear particles from the milling balls, the study dealing with how the preparation and properties of a hard material would be affected by additives just introduced by scrape of milling balls has been scarce. In the present work, sintering behavior and mechanical properties of hot-pressed B_4C with additives derived from milling balls were investigated. Polyoxymethylene, ZrO_2, Al_2O_3 and Si_3N_4 were selected as different ball materials. The results show that the sinterability of B_4C could be significantly enhanced because of the incorporation of one of these additives, i.e. ZrO_2, Al_2O_3 and Si_3N_4 (approximately 3-6 vol%). As a result of improvement in density, excellent mechanical properties of B_4C ceramics were obtained. Among them a flexural strength of B_4C added by ZrO_2 reached 630 MPa.