Simultaneous Synthesis and Sintering of Nano structured MgAl₂O₄-Mg₃Al₂Si₃O₁2 Composite and its Mechanical Properties

Nano powders of MgO, Al₂O₃ and SiO₂ were made by high energy ball milling. The simultaneous synthesis and consolidation of non-conductor's MgAl₂O₄-Mg₃Al₂Si₃O₁2 composites from milled 4MgO, ₂Al₂O₃ and 3SiO₂ powders was investigated by a high-frequency induction heating process. The advantage of this process is that it allows very quick densification to near theoretical density and inhibition of grain growth. Highly dense nano structured MgAl₂O₄-Mg₃Al₂Si₃O₁2 composites were produced with a simultaneous application of 80 MPa pressure and an induced current within 1 min. The relative density and fracture toughness of the composite were 98% and 3.2 MPam1/2, respectively. The fracture toughness of the MgAl₂O₄-Mg₃Al₂Si₃O₁2 composite was higher than that of monolithic MgAl₂O₄.