Materials with grain sizes down to the nanometer range have recently attracted a lot of scientific interest, as an increase in hardness, mechanical strength, Weibull modulus and wear resistance is expected. In this work, SiC-based materials having mean grain size ranging from 500 down to 70 nm are produced starting from diverse SiC powders, commercial and laboratory synthesized. Different processing routes are carried out in order to optimise the final microstructure. Dense specimens are obtained through hot pressing with the aid of Al2O3 and Y2O3 as sintering agents. Microstructural characteristics are analysed by XRD, SEM, EDX, TEM techniques. The following mechanical properties are measured: four-point bending strength (from room temperature up to 1300°C), fracture toughness, hardness and Young modulus. Microstructural parameters and mechanical properties are discussed to point out if the decrease of mean grain size down to 100 nm or less results in a actual improvement of the performance of this specific system
Sub-micro and nano-sized SiC ceramics: comparison and mechanical properties
BALBO, Andrea;
2004
Abstract
Materials with grain sizes down to the nanometer range have recently attracted a lot of scientific interest, as an increase in hardness, mechanical strength, Weibull modulus and wear resistance is expected. In this work, SiC-based materials having mean grain size ranging from 500 down to 70 nm are produced starting from diverse SiC powders, commercial and laboratory synthesized. Different processing routes are carried out in order to optimise the final microstructure. Dense specimens are obtained through hot pressing with the aid of Al2O3 and Y2O3 as sintering agents. Microstructural characteristics are analysed by XRD, SEM, EDX, TEM techniques. The following mechanical properties are measured: four-point bending strength (from room temperature up to 1300°C), fracture toughness, hardness and Young modulus. Microstructural parameters and mechanical properties are discussed to point out if the decrease of mean grain size down to 100 nm or less results in a actual improvement of the performance of this specific systemI documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
