Morphology Characteristics and Mechanical Properties of Micron Calcium Hexaboride Sintered Body

Nano/Micron Calcium Hexaboride (CaB6) composite ceramics with different CaB6 nano powder additions were prepared under 1750℃, 32MPa for 5min in a vacuum. Influences of CaB6 nanopowders on morphology and mechanical properties of sintered bodies were investigated. Composite ceramic with 10wt% CaB6 nanopowder addition has the highest compactness degree and mechanical properties, whose hardness, bending strength, and fractural toughness are 92.6 HRA, 331.7MPa and 3.06MPa·m1/2, respectively, better than those of CaB6 ceramics without nanopowder adding or those of reinforced by Ni as sintering additive. The proper amount of nano-particles filled in the micron grain boundaries and the formation of “inner crystal” result in improved compactness and mechanical properties for the CaB6 sintered body. To minimize boron loss, due to the high hydrophilicity and ability to form cross-linked PVA-borate gels, PVA was used as a carbon source, and the carbon coating process was carried out via pyrolysis of the PVA - CaB6O10.5H2O mixed gels. In this study, PVA-CaB6O10.5H2O precursor mixtures were prepared by coating the ceramic powders with PVA to synthesize CaB6 via carbothermal reduction. Boron loss, the main problem in the synthesis of borides, was reduced by using metastable CaB6O10 as a transitional phase which is stable until the critical temperature ranges where the boron sub-oxides have higher volatilities. The optimum synthesis conditions were determined for forming CaB6 at 1450 degrees C for 12 h under an Argon flow using the CaB6O10.5H2O-PVA60 mixed precursor. If you are looking for high quality, high purity, and cost-effective Calcium hexaboride, or if you require the latest price of Calcium hexaboride, please feel free to email contact mis-asia.

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