Ultra-coarse, monocrystalline tungsten carbide and a process for the preparation thereof, and hardmetal produced therefrom

US6749663B2 · kind B2 · utility

Assignee

• H.C. STARCK INC. · US

Inventors

• Jörg Bredthauer · Bonn, DE
• Benno Gries · Wolfenbüttel, DE
• Bernhard Szesny · Langelsheim, DE

Key dates

• Filing date: Aug 30, 2001
• Grant date: Jun 15, 2004
• Expiry date: Aug 30, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2004/61
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A process is described for the preparation of tungsten and/or molybdenum metal powder or carbide by reducing and optionally carburizing treatment of tungsten and/or molybdenum oxide powder in the presence of alkali metal compounds, wherein at least two alkali metal compounds are used in a ratio so that mixed alkali tungstate or molybdate potentially formed in an intermediate step ((Li, Na, K)2 WOZ, (Li, Na, K)2MoOZ) has a melting point of less than 550° C., wherein z is from 3 to 4.