Sialon/TiB2 ceramic composites: synthesis, properties, and tribology
UNSPECIFIED. (1999) Sialon/TiB2 ceramic composites: synthesis, properties, and tribology. BRITISH CERAMIC TRANSACTIONS, 98 (6). pp. 274-281. ISSN 0967-9782Full text not available from this repository.
The addition of titanium diboride particulates to a sialon matrix offers the possibility of ultrahard ceramic materials suitable for tribological applications (e.g. ball bearings, cutting tools, etc.). Sialon matrix composites have been fabricated by hot pressing and pressureless sintering with TiB2 added by both direct addition and in situ reaction sintering. Both processes require a dual atmosphere sintering cycle of argon followed by nitrogen at the sintering temperature. Hot pressing has been used to produce materials which approach full density independent of the amount of TiB2 present. However, the densification of pressureless sintered materials is inhibited by the presence of TiB2. Measurements of hardness, indentation fracture toughness, microstructural examination, and tribological behaviour showed significant improvements as a result of the TiB2 addition. At >40 vol.-%TiB2 the low resistivity of these materials also allows the possibility of electrodischarge matching (EDM). A mini pin-on-disc apparatus was constructed to measure the coefficient of friction mu and the wear rate k of the composites. Worn surfaces were studied by electron microscopy. The wear behaviour is dominated by tribochemical reactions, forming oxygen rich tribofilms adhered to the disc surface. Wear then occurs by degradation of the tribofilm and the polishing action of wear debris. Inherent problems with this type of wear test are discussed.
|Item Type:||Journal Article|
|Subjects:||T Technology > TP Chemical technology|
|Journal or Publication Title:||BRITISH CERAMIC TRANSACTIONS|
|Number of Pages:||8|
|Page Range:||pp. 274-281|
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