Effect of sintering temperature on the structure and properties of polycrystalline cubic boron nitride prepared by SPS

✍ Scribed by Yucheng Zhao; Mingzhi Wang

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 987 KB
• Volume: 209
• Category: Article
• ISSN: 0924-0136
• DOI: 10.1016/j.jmatprotec.2008.02.005

✦ Synopsis

were heated to a sintering temperature between 1250 • C and 1450 • C at a heating rate of 300 • C/min, with a holding time of 5 min in nitrogen atmosphere. The microstructure, phase constitution, microhardness and fracture toughness of the prepared PcBN were then studied. It was shown that the Si 3 N 4 -AlN-Al 2 O 3 -Y 2 O 3 -cBN polycrystalline materials were densified in a very short sintering time resulting in materials with relative densities of more than 95%. When the sintering temperature increased, the microhardness and fracture toughness of prepared PcBN were also increased. The microhardness of PcBN prepared at 1250-1450 • C was between 28.0 ± 0.5 GPa and 48.0 ± 0.9 GPa, and its fracture toughness K IC was from 7.5 ± 0.2 MPa m 1/2 to 11.5 ± 0.3 MPa m 1/2 . Microstructure study showed that the ceramic-binding agents bonded with cubic boron nitride particles firmly. Our work demonstrated that spark plasma sintering technology could become a novel method for the preparation of PcBN cutting materials.