Synthesis and Properties of MoAlB Composites Reinforced with SiC Particles

To develop MoAlB advanced ceramic with improved mechanical properties and oxidation resistance, the use of SiC particles to reinforce MoAlB composites has been adopted. 5–15 vol.% SiC/MoAlB have been prepared and characterized. A flexural strength of 380 MPa and a Vickers hardness of 12.7 GPa were achieved in the 5 vol. %SiC/MoAlB composite, increased by 24% and 51%, respectively, as compared with those for MoAlB. Oxidation at 1200°C and 1300°C for 10 h in air showed that the 5 vol. %SiC/MoAlB composite has good oxidation resistance than MoAlB due to the formation of a dense and continuous scale composed of Al2O3 and SiO2, which prevents oxygen inward diffusion and the evaporation of oxides. We expect that the general strategy of second phase reinforcing for materials will help to widen the applications of MoAlB.

A study on fabrication of silicon nitride-based advanced ceramic composite materials via spark plasma sintering

The present study provides an overview of the fabrication of silicon nitride (Si3N4)-based advanced ceramic materials using spark plasma sintering. Being an excellent engineering ceramic material, silicon nitride is extensively being used in tribological components, aerospace, and automotive industries due to its unique blend of thermo-mechanical, tribological, and chemical properties. The selection of the sintering process, as well as sintering aids, strongly affects the properties of silicon nitride ceramics. Several conventional sintering techniques have been utilized in the past to optimize the structure and properties of silicon nitride ceramics such as hot pressing. However, spark plasma sintering, a relatively new, non-conventional, powder consolidating technique has recently gained significant attention to fabricate silicon nitride ceramic due to high heating rates, extremely short sintering time, and relatively low sintering temperatures which renders it an ideal technique for mass production. Both the composition and concentration of sintering additives during processing play a vital part in achieving the final desired properties of the bulk silicon nitride ceramic materials. In this review, the critical aspects like the effects of additive composition, additive concentration, and sintering parameters on microstructure and bulk properties of silicon nitride ceramics fabricated via spark plasma sintering are presented. The review may come in handy for scientists and engineers concerned with fabricating future silicon nitride composites with desired properties and performance for different engineering applications.

Super strong, shear resistant, and highly elastic lamellar structured ceramic nanofibrous aerogels for thermal insulation

Advanced ceramic aerogels with ultra-strong mechanical properties and excellent fire resistance are critically required as heat insulators under extreme conditions. Nevertheless, the current use of ceramic aerogels is usually restricted...