Pressureless sinterability study of ZrB2–SiC composites containing hexagonal BN and phenolic resin additives

This research is dedicated to the role of different amounts hexagonal BN (hBN: 0, 1.5, 3, and 4.5 wt%) on pressureless sinterability ZrB2–25 vol% SiC ceramics. Phenolic resin (5 with a carbon yield ~40 % was incorporated as binder powder mixtures after initial cold pressing, final sintering process performed at 1900 °C for 100 min in vacuum furnace. The as-sintered specimens were characterized by X-ray diffractometry, field emission scanning electron microscopy, energy-dispersive spectroscopy. results disclosed that incorporation 1.5 wt% hBN could increase relative density ~92%, while sample zero content just reached ~81% full densification. Appropriate not only facilitated particle rearrangement during but also removed harmful oxide impurities sintering. Nevertheless, addition higher remarkably lessened densification because more delamination non-reacted flakes release entrapment gaseous by-products induced reacted phases.