Thermal decomposition, densification and mechanical properties of AlN–SiC(–TiB2) systems with and without B, B4C and C additives

✍ Scribed by Sea-Hoon Lee; Shuqi Guo; Hidehiko Tanaka; Kenji Kurashima; Toshiyuki Nishimura; Yutaka Kagawa

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 759 KB
• Volume: 28
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2007.11.012

✦ Synopsis

Thermal decomposition of AlN-SiC(-TiB 2 ) systems during densification was analyzed, and effects of B, B 4 C and C on the densification behavior of the systems were studied. SiO 2 impurity in the powder mixture was nearly completely removed by carbothermal reaction at 1500 • C in vacuum, while Al 2 O 3 remained and affected the densification behavior of the system. The onset temperature of densification of a AlN-SiC-TiB 2 system decreased from 2050 to 1850 • C by the addition of carbon, which decreased further (1680 • C) by adding both B 4 C and carbon. Dense AlN-SiC-TiB 2 specimens were obtained after the hot pressing at 2000 • C by the application of carbon and boron or B 4 C. Young's modulus, hardness, fracture toughness and thermal conductivity of a AlN-SiC-TiB 2 system sintered with B 4 C and C were 313 GPa, 18.2 GPa, 3.7 MPa m 1/2 and 22.9 W/(m • C), respectively.