 Several techniques are in use to protect equipment against wear.
Functional or structural parts can be made completely from cemented carbide, stellite or a superalloy. Alternatively, cemented carbide parts can be soldered onto selected surface areas.
Hardfacing by welding is frequently used to protect selected areas with a hard layer in the millimetre thickness range. For this purpose, sintered or tube-type welding electrodes are available to produce wear resistant surface layers. Cast tungsten carbide or tungsten monocarbide are the hard constituents, while most frequently iron or an iron-based alloy acts as a binder.
Thermal spraying is applied to make thinner wear resistant surfaces. Powders for hardfacing are, for example, made of pure tungsten or more frequently tungsten monocarbide and / or cast carbide combined with cobalt, nickel, or a Ni-Cr-B-Si alloy. A large variety of grades is available to meet almost every requirement.
Chemical vapour deposition starting from tungsten halogenides or alkoxides is a less common method to provide hard, acid-resistant tungsten coatings on bearings, dies, rolls, gauges, etc.
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