Fabrication of Al₂O₃/(ZrB₂ + TiB₂) Composite Using MACS and Microwaves

Abstract

Because of the excellent thermal and mechanical properties of engineering ceramics, they have been used as structural materials or composite matrixes and reinforcements in recent years. Alumina, titanium diboride, and zirconium diboride have found important uses in the past two decades. In this study, Al₂O₃/(ZrB₂ + TiB₂) ceramic composite powders were fabricated in situ and mechanical activation by milling was used to assist combustion synthesis (CS). A mixture of Al, ZrO₂, TiO₂, and B₂O₃ powders were used as raw materials. Mechanical activation was done using ball milling of different durations. Afterward, combustion was initiated using microwaves on the activated mixtures. X-ray diffraction (XRD) and scanning electron microscopy were used to investigate the purity and microstructure of the products. XRD analysis of the samples in the final stages of the process revealed that Al₂O₃/(ZrB₂ + TiB₂) composite powder was successfully fabricated using mechanical activation and CS, but that the CS reaction did not occur in unmilled samples. It was shown that increasing milling time from 3 to 10 hours increased purity and homogeneity of the products to the point that no noticeable impurity existed in the samples milled for 10 hours.