Al₂O₃-Ni composites: impact of cooling on composites in centrifugal gel casting

This study investigates the influence of polymerization kinetics and the processing sequence on the microstructure and mechanical performance of AlO-Ni composites fabricated via centrifugal gel casting.Two fabrication approaches were compared, differing in the sequence of component addition and the temperature of the casting mass.The optimized method, involving cooling the suspension to below 5C prior to the addition of nickel powder and the polymerization initiator, significantly extended the gelation idle time from 225 s to 475 s, allowing improved control over polymerization and particle dispersion.As a result, the microstructure exhibited enhanced phase homogeneity and reduced porosity.Compression tests demonstrated substantial enhancement in mechanical performance: the compressive strength increased from 22 MPa in the non-optimized series to 185 MPa in the optimized series, representing more than an eightfold improvement.These findings highlight a practical strategy for tuning the polymerization behavior to engineer high-performance ceramic-metal composites with potential applications in structural and functional components.