Development of electrical discharge machinable SiC-ZrN composites: Unveiling high temperature sliding wear resistance

Abstract

Dense SiC-(10-30 vol%) ZrN composites were developed using spark plasma sintering with AlN-Y₂O₃ additives at 1800 °C for 5 min in nitrogen atmosphere. The nascent oxide present on ZrN surface reduces liquid phase formation temperature, facilitating improved densification of SiC ceramics. Mechanical properties were retained, and electrical conductivity increased with ZrN addition. To demonstrate a rapid and low-cost machining alternative for SiC ceramics, SiC-ZrN composites were successfully cut using wire-EDM. The tribological potential of novel electrical discharge machinable SiC-ZrN composite disk against SiC ball at various conditions of reciprocating sliding contacts was investigated. Friction is less affected by reinforcement content at room temperature (25 ℃) but significant change is observed at high temperature (600 ℃). Minimum one order of lower wear rate is reported with an increase in temperature from 25 ℃ to 600 ℃. The major wear mechanism changed from abrasion to tribo oxidation with increase in temperature.