Landolt-Börnstein - Group VIII Advanced Materials and Technologies

13.2 Raw materials used in the production of hard materials

Abstract

This chapter discusses on the raw materials used in the production of hard materials. Of the many forms of carbon required as the raw material for the conversion to diamond, graphite is the most commonly used. Chemical and physical properties of graphite used for conversion to diamond, Timrex SD 75, special graphite are tabulated. Chemical and physical properties of hexagonal boron nitride used for conversion to cubic boron nitride are also tabulated. There are two main ores of tungsten - woframite, (FeMn)WO4 and scheelite, CaWO4. Tungsten scrap is also a valuable source of tungsten for processing. Soft scrap is initially oxidized while hard scrap is processed via an alkaline fusion step. All these raw materials are processed to yield a very pure form of monoclinic white crystalline ammonium paratungstate. The production of tungsten carbide powder commences with the selection of a high purity form of carbon or graphite. Sedimentary hydro-thermal cobalt bearing copper ore, liquid magma-based nickel-copper seams, and oxide and silicate nickel laterite deposits are used for the extraction and recovery of cobalt. The production of other hard metals, namely, titanium carbide, tantalum (niobium) carbide, vanadium carbide, chromium carbide, and carbide mixed crystals (mixed carbides), and cermets, namely molybdenum carbide, titanium nitride, titanium carbonitride, and nickel, are also discussed. Physical and chemical properties of these hard metals and cermets are also tabulated. Special processes like menstruum process, direct reduction of ore, zinc process, combined reduction and carburizing, and production of nano grain size WC-Co alloy powder are also described.

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Title
13.2 Raw materials used in the production of hard materials
Book Title
Powder Metallurgy Data. Refractory, Hard and Intermetallic Materials
In
13 Hard materials
Book DOI
10.1007/b83029
Chapter DOI
10.1007/10858641_4
Part of
Landolt-Börnstein - Group VIII Advanced Materials and Technologies
Volume
2A2
Editors
  • P. Beiss
  • R. Ruthardt
  • H. Warlimont
  • Authors
  • G. E. Spriggs
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