Crack-healing behavior and bending strength of Si3N4/SiC composite ceramics by SiO2 colloidal

✍ Scribed by Ki Woo Nam; Mi Kyung Kim; Sung Won Park; Seok Hwan Ahn; Jong Soon Kim

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 621 KB
• Volume: 471
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2007.03.005

✦ Synopsis

Si 3 N 4 /SiC composite ceramics were sintered in order to investigate their bending strength behavior after crack-healing. Y 2 O 3 and TiO 2 powder was added as sintering additives to enhance it's sintering property. A three-point bending specimen was cut out from sintered plates. About 100 m semi-circular surface cracks were made on the center of the tension surface of the three-point bending specimen using Vickers indenter. After the cracked specimen with SiO 2 colloidal coating healed from 500 to 1300 • C for 1 h in air, the bending strength behavior was carried out systematically at room temperature. Si 3 N 4 /SiC ceramics using additive powder (Y 2 O 3 + TiO 2 ) were superior to that of additive powder Y 2 O 3 . The additive powder TiO 2 exerted influence at growth of Si 3 N 4 . The optimum crack-healing conditions coated SiO 2 colloidal were 1000 and 1300 • C at Si 3 N 4 /SiC using additive powder (Y 2 O 3 + TiO 2 ) and Y 2 O 3 , respectively.