Controllable synthesis of Al2OC-AlN solid solution by two-step sintering in resin-bonded Al-Al2O3 composites

A method of synthesizing Al2OC-AlN solid solution with cost-effective materials at lower temperature to achieve industrial production was proposed in this paper. Aluminum, tabular alumina and binder phenolic resin were used to prepare the resin-bonded Al-Al2O3 composites. The sintered samples were obtained by one-step sintering and two-step sintering, respectively. Then, the basic physical properties were tested. XRD, SEM and EDS were employed to investigative the sintered samples. The results indicated the controllable synthesis of Al2OC-AlN solid solution was successfully achieved in resin-bonded Al-Al2O3 composites containing 12 wt% Al by two-step sintering at 580 °C for 8 h and then 1600 °C for 3 h under N2. After sintering at 580 °C, the Al@AlN structure with AlN coating the surface of Al was formed. Active AlN and dispersed Al droplets were introduced after the disappearance of Al@AlN structure, thereby solving difficulties such as the introduction of active AlN and the agglomeration of liquid Al during direct sintering. The active AlN transient phase and liquid Al promoted the formation of Al2OC-AlN solid solution. Meanwhile, the binding agent resin provided active carbon resources for the formation of Al2OC-AlNss. The formation mechanism of Al2OC-AlN solid solution during two-step sintering was investigated.