Details

Autor(en) / Beteiligte

• GALUSEK, Dusan
• SEDLACEK, Jaroslav
• SVANCAREK, Peter
• RIEDEL, Ralf
• SATET, Raphaelle
• HOFFMANN, Michael

Titel

The influence of post-sintering HIP on the microstructure, hardness, and indentation fracture toughness of polymer-derived Al2O3-SiC nanocomposites

Ist Teil von

• Journal of the European Ceramic Society, 2007, Vol.27 (2-3), p.1237-1245

Ort / Verlag

Oxford: Elsevier

Erscheinungsjahr

2007

Quelle

ScienceDirect

Beschreibungen/Notizen

• Al2O3-SiC nanocomposites containing 3-8 vol% SiC were prepared from fine alumina powder and a poly(allyl)carbosilane precursor of SiC by polymer infiltration of porous alumina matrix (composites IP), or by warm pressing of polymer-coated alumina powder (composites CW). The polymer was converted to SiC by careful heating of green specimens in an inert atmosphere (Ar). The residual porosity was eliminated to < 10% by pressureless sintering (PS) at temperatures between 1700 and 1850 C. The post-sintering hot isostatic pressing (HIP) at 1700 C eliminated the residual porosity to < 1%, but also resulted in coarsening of the alumina matrix grains, and the inter- and intragranular SiC inclusions. The Vickers hardness of IP specimens sintered at T < 1850 C increased by 1-10%, which is attributed to the elimination of residual porosity. The hardness and indentation fracture toughness of IP specimens sintered at 1850 C decreased after HIP by 6 and 15%, respectively. The HIP of CW composites increased their hardness and fracture toughness by approximately 10%. The maximum fracture toughness of 5.2 plus or minus 0.2 MPa.m1/2 was measured for the materials containing 8 vol% of SiC. A correlation was found between the fracture toughness, and the mean size and volume fraction of the intergranular SiC inclusions in the CW composites. 22 refs.