Microstructure, Mechanical Property, and Linear Expansion Coefficient of ZrO₂@Diamond/2024 Composite

This study investigates the preparation and properties of diamond/2024 composites with a diamond content of 15 vol% and ZrO 2 ‐coated diamond/2024 composites (ZrO 2 @diamond/2024). ZrO 2 is coated onto diamond particles using evaporation crystallization, and the effects of different thermal decomposition temperatures and durations on the coating are examined. The results show that a smooth and uniform ZrO 2 coating is achieved at a thermal decomposition temperature of 600 °C with a holding time of 2 h. In diamond/2024 composites, noticeable voids are observed at the interface, while the ZrO 2 @diamond/2024 composites exhibit a flat, well‐bonded interface without cracks, voids, or Al 4 C 3 formation. The ZrO 2 coating effectively prevents direct contact between diamond and aluminum melt, inhibiting Al 4 C 3 formation, which leads to a tensile strength increase of ZrO 2 @diamond/2024 composites to 200.1 MPa, 10.8% higher than the uncoated composites. Additionally, the linear expansion coefficient and dimensional change rate of ZrO 2 @diamond/2024 composites are lower than those of diamond/2024 composites, indicating better interface bonding and thermal expansion constraint.