Binders tungsten carbides

Kentanium has better corrosion resistance than the cobalt binder tungsten carbides in salt solutions. 

Cobalt and compounds SPA Cobalt oxide Catalysts Eibres Paint Paper and pulp processing Tungsten carbide binder... 

Thermal spray is a well-established, relatively low-cost, industrial processes which is used widely for the deposition of metals and compounds, including the refractory carbides and nitrides. Examples are coatings of tungsten carbide with a cobalt binder which are of major industrial importance. PI... 

Type 1 tungsten carbide—as required for service conditions, with cobalt binder (solid part, not overlay) ... 

Type 1 tungsten carbide- as required for service conditions, with cobalt binder (solid part, not overlay). Type 2 tungsten carbide-as required for service conditions, with nickel binder (solid part, not overlay) Type 3 tungsten carbide-sprayed overlay as required for service conditions. 

Cemented carbides were first developed in Germany in the eady 1920s. The first cemented carbide to be produced was tungsten carbide [12070-12-1], WC, having a cobalt [7440484], Co, binder (1). A number of scientific and technological advances provided impetus to development (2) (/) discovery of the bigb hardness of cast WC (2) production of fine particles of WC, by reaction of the elements or by carburizing with hydrocarbons (qv) ... 

Figure 2.4 Representative microstructures of steel-cutting grades of cemented tungsten carbide (a) 94%WC-6%Co alloy, submicron grain size, (b) 94%WC-6%Co alloy, medium grain size, (c) 86%WC-8% (Ti, Ta, Nb)C-6%Co alloy, medium grain size. The gray angular particles are WC, and the dark gray, rounded particles are solid-solution carbides. The white areas are cobalt binder. (Ref. 14).

A second technique involves heating the cemented tungsten carbide to the solidus—liquidus temperature region of the binder phase in a decarburizing atmosphere, such as C02 gas (93). Decarburization occurs at the surface whereby the carbon concentration at the surface is reduced to reach the solidus line of the binder phase, and the liquid phase solidifies. As a result, the liquid phase is supplied to the inner portion, and this also reaches near the surface where it is decarburized to reach the solidus line and this again solidifies. This procedure is repeated until Co is enriched in the zone near the rake face. 

The most important property of tungsten carbide in its utilization in cemented carbides is its ability to dissolve partially in compressed powder mixtures of WC and ferrous metals, particularly cobalt, at 1300 to 1500°C. In the case of sintering with a liquid phase, WC partly crystallizes out of the binder phase of the WC-Co-alloy upon cooling. It becomes embedded in the tough but hard (not brittle) binder phase. 

Cemented carbide parts are used for demanding wear applications. They are primarily made of tungsten carbide and contain a small percentage of binder such as nickel or cobalt to provide structural homogeneity. Cemented carbides products include knives, blades, nozzles, jets guides, valve seats, seal parts, etc. The properties and design of cemented carbides strongly influence part life and overall equipment reliability. 

One such spherical agglomeration process uses an immiscible binder liquid to form spheroidal products from particles that are suspended in a second liquid. These highly specialized materials are required in small amounts and, therefore are carried-out in small, high energy, batch shaking devices as shown in Fig. 7.90. In this apparatus tungsten carbide spheres are manufactured which, after sintering, yield ball pen... 

Cobalt is the best binder for tungsten carbides and similar excessively hard materials welded on to steel for cutting purposes. 

The most widely used transition metal carbide is tungsten carbide, hexagonal WC, which is employed as the hard constituent in WC-Co hardmetals. Such hardmetals are sintered composite materials with 80-90% of hard particles such as WC embedded in a ductile binder phase such as Co. For these apphcations WC combines a number of... 

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