Microstructure and properties of HfC and TaC-based ceramics obtained by ultrafine powder

• Published in: Journal of the European Ceramic Society Vol. 31; no. 4; pp. 619 - 627
• Main Authors: Silvestroni, L., Bellosi, A., Melandri, C., Sciti, D., Liu, J.X., Zhang, G.J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2011
• Subjects: Added value; Ceramics; Densification; Flexural strength; Hafnium carbide; HFC; Hot pressing; Mathematical analysis; Mechanical properties; Microstructure; Modulus of rupture in bending; Optimization; Tantalum carbide; Mechanical properties; Tantalum carbide; Hot pressing; Microstructure; Hafnium carbide
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2010.10.036

HfC and TaC-based ceramics were hot pressed at 1900 °C for 5–20 min starting from synthesized ultrafine powders. The addition of 5 vol.% of MoSi 2 improved the densification, which increased from around 85–90% for the pure matrices to 95% for the composites. The flexural strength was measured at room temperature and at 1500 °C under protective atmosphere. The added value of this work consists in the utilization of cheap synthesized powders for the realization of the composites with properties comparable to those obtained using more expensive commercial powders. The effect of the nanometric size of the starting powder showed to have the potential to improve the densification behavior and the mechanical properties, however it is necessary a further optimization of the synthesis condition in order to avoid the formation of agglomerates of unreacted powder.