Authors: Jumpei Kita Hiroshi Suemasu Ian J Davies Seiichiro Koda Kiyoshi Itatani
Publish Date: 2010/06/17
Volume: 45, Issue: 22, Pages: 6052-6058
Abstract
The authors have examined the fabrication conditions of SiC composites containing carbon nanofiber ie vaporgrown carbon nanofiber VGCF to enhance the fracture toughness Commercially available ultrafine SiC powder specific surface area 475 m2 g−1 was mixed with VGCF and sintering aid in the Al4C3–B4C system Approximately 15 g of the mixture was uniaxially pressed at 50 MPa to obtain a compact with a diameter of 20 mm and a thickness of approximately 15 mm The resulting compact was hotpressed at 1800 °C for 1 h in Ar atmosphere under a pressure of 62 MPa The relative density of hotpressed SiC composite decreased from 980 to 963 whereas the fracture toughness was enhanced from 38 to 52 MPa m1/2 as the amount of VGCF increased from 0 to 6 mass Furthermore an acid treatment of VGCF was conducted to enhance its dispersibility within the SiC matrix owing to the formation of COO− groups on the VGCF surface As a result of this treatment the relative density and fracture toughness of hotpressed SiC composite with 6 mass acidtreated VGCF addition increased to 990 and 57 MPa m1/2 respectively
Keywords: