The introduction of sintering aids into silicon carbide powder system is a critical step in the development of SiC-based materials. In this contribution two different powder processing are used for the addition of a fixed amount of sintering aids (Al2O3 + Y2O3) in a SiC powder batch: traditional ball milling and coprecipitation. The powders obtained are pressure-less sintered at 1900°C for 1-2 hours in argon atmosphere. The microstructural characteristics are related to the powders processing and sintering parameters. Mechanical properties are investigated from room temperature to 1300°C. The ball milling process produces a microstructure with large and elongated grains. The coprecipitation process allows a high final density to be obtained in a short sintering time (1h at 1900°C) with very fine microstructure and uniform distribution of sintering aids. All the sintered materials exhibit high values of hardness and toughness. At high temperature the coprecipitated material shows the highest value of flexural strength.
Processing and characterization of liquid phase sintered silicon carbide
BALBO, Andrea;
2005
Abstract
The introduction of sintering aids into silicon carbide powder system is a critical step in the development of SiC-based materials. In this contribution two different powder processing are used for the addition of a fixed amount of sintering aids (Al2O3 + Y2O3) in a SiC powder batch: traditional ball milling and coprecipitation. The powders obtained are pressure-less sintered at 1900°C for 1-2 hours in argon atmosphere. The microstructural characteristics are related to the powders processing and sintering parameters. Mechanical properties are investigated from room temperature to 1300°C. The ball milling process produces a microstructure with large and elongated grains. The coprecipitation process allows a high final density to be obtained in a short sintering time (1h at 1900°C) with very fine microstructure and uniform distribution of sintering aids. All the sintered materials exhibit high values of hardness and toughness. At high temperature the coprecipitated material shows the highest value of flexural strength.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
