| 摘要 |
PROBLEM TO BE SOLVED: To give a process to incorporate a grain growth inhibitor, in a cobalt/tungsten carbide composite, which minimizes grain growth, so as to form a finer grain structure, and further minimizes the oxygen sensitivity thereof. SOLUTION: A method of forming cobalt/tungsten carbide particles containing a grain growth inhibiting metal comprises: subjecting a precursor powder including cobalt, tungsten, and at least one kind of a grain growth inhibiting metal selected from the group consisting of vanadium, chromium, tantalum and niobium to an initial carburization with a carburizing gas comprising a mixture of carbon monoxide and carbon dioxide at a temperature effective to form tungsten carbide; and a second carburization step using a carburizing gas comprising a diluent and a hydrocarbon gas having a carbon activity greater than about 1.4 at a temperature of about 900°C to 1,000°C. COPYRIGHT: (C)2008,JPO&INPIT
|
