Carbide coatings, applications

ECAKEsters for Coating Applications, Brochure F-48S89A, Union Carbide Corp., Conn., 1988. 

UCAR Alcohols for Coatings Applications, Brochure F-48588, Solvents and Coatings Materials Division, Union Carbide Chemicals and Plastics Corp., Danbury, Conn., Sept. 1984. 

Tobiason furnishes us with two examples of EP formulations for electronic encapsulation and primer coating applications as shown in Tables II and 12, respectively [213]. The coating formula was obtained from a Union Carbide Technical Bulletin. 

The Dilex Process utilises a molten lead bath as transfer medium and is applicable to diflfusion coatings of Cr, Al, Ti, Mo, Ni and Co. Finally, a Japanese fused borate bath process produces carbide coatings (Cr, V, Nb or Ta) on carbon and tool steels. The coatings are wear and corrosion resistant. The TD Process uses this technique. 

Fluidized-bed CVD was developed in the late 1950s for a specific application the coating of nuclear-fuel particles for high temperature gas-cooled reactors. PI The particles are uranium-thorium carbide coated with pyrolytic carbon and silicon carbide for the purpose of containing the products of nuclear fission. The carbon is obtained from the decomposition of propane (C3H8) or propylene... 

Other potential applications are ceramic powders coated with their sintering aids, zirconia coated withyttria stabilizer, tungsten carbide coated with cobalt, or nickel, alumina abrasive powders coated with a relatively brittle second phase such as MgAl204 and plasma spray powders without the segregation of alloying elements. 

The carbides and nitrides of vanadium and titanium crystallize in the same face centered cubic (fee) system, and because of the closeness of their cell parameters (Table 15.1) form solid solutions. These ceramic materials exhibit interesting mechanical, thermal, chemical and conductive properties.1,2 Their high melting point, hardness and wide range of composition have therefore attracted considerable attention in the last decade. Moreover, their good abrasion resistance and low friction also make these ceramics attractive for protective coating applications.3-5 Chemical vapor deposition (CVD) is a commonly used technique for the production of such materials. In the conventional thermally activated process, a mixture of gases is used.6-9 In the case of TiC, TiN, VC and VN, this mixture is... 

The MOCVD technique has also been used to deposit a number of refractory compounds for a wide range of applications. One of the advantages of this technique is the lower deposition temperature, which makes it very suitable for deposition on substrates, which are thermally sensitive, such as steels. Wear - resistant tungsten carbide coatings have been deposited on steel, using WF6 and suitable hydrocarbon gases at temperatures below 873 K.4,5... 

Silicon carbide Coatings for ceramic heat exchangers, radiation resistant semiconductor applications, susceptor coatings, heteroepitaxial film on silicon, coatings for nuclear waste containers. 

The industrially available ketones offer a wide range of evaporation rates for the various coating applications. A solvent with excellent solvency and a fast, intermediate or slow evaporation rate for a particular coating application is available in the commercially produced ketones. Major producers of the ketones include Eastman Chemical Company, Exxon Chemical Company, Hoechst Celanese Company, Shell Chemical Company, and Union Carbide Corporation. BASF Corporation produces the cyclic ketone cyclohexanone. Acetone the lowest boiling-point ketone is produced by The Dow Chemical Company, Exxon Chemical Company, and Texaco Chemical Company. 

T. Arai and N. Komatsu, Carbide Coating Process by Use of Salt Bath and its Application to Metal Forming Dies, Proc. 18th Intematioruil Machine Tool Design and Research Conference, 14-16 Sept 1977, p225-231... 

This can only be used for a narrow range of materials, both for the choice of coating materials and as substrates. Oxides and carbides are commonly deposited. The high-velocity impact of materials such as tungsten carbide and chromiiun carbide restricts application to metal surfaces. 

A wide range of applications for hard, wear-resistant coatings of electroless nickel containing silicon carbide particles have been discussed by Weissenberger . The solution is basically for nickel-phosphorus coatings, but contains an addition of 5-15 g/1 silicon carbide. Hiibner and Ostermann have published a comparison between electroless nickel-silicon carbide, electrodeposited nickel-silicon carbide, and hard chromium engineering coatings. 

Chemical vapor deposition (C VD) is a versatile process suitable for the manufacturing of coatings, powders, fibers, and monolithic components. With CVD, it is possible to produce most metals, many nonmetallic elements such as carbon and silicon as well as a large number of compounds including carbides, nitrides, oxides, intermetallics, and many others. This technology is now an essential factor in the manufacture of semiconductors and other electronic components, in the coating of tools, bearings, and other wear-resistant parts and in many optical, optoelectronic and corrosion applications. The market for CVD products in the U.S. and abroad is expected to reach several billions dollars by the end of the century. 

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