Friday, 16 March 2018

An Overview Of Tungsten Carbide Coatings

By Richard Patterson


Tungsten is a wolframite metallic chemical element that is believed to have a very high adhesive power. On the other hand, carbide is a carbon alloy consisting of a semiconductor with a cohesive ability. A blend of the two chemical components forms a highly adhesive and cohesive, wear resistance coating to vexing, erosion and fretting. The tungsten carbide coatings are majorly applied by thermal sprays to achieve the densest and most well-bounded coatings.

The coating can as well be applied by other modest ways of application to attain a higher texture coating which normally depends on the application procedures. When plasma sprays are used, it triggers the use of flame spray for secondary fusing purposes and to provide a metallic bonded coating. The essential aspect of the use of tungsten carbide as the coating powder is to ensure consistency in application and a presentable metallic surface output.

The process of application is usually initiated by a jet of combusted high-pressure fuel gas together with oxygen gas. It is then pressurized more in pressure chambers where it jets out via a small diameter-nozzle at an accelerating velocity in a long gas barrel. It is thus mixed with carbide powder at nozzle point where the two attains a supersonic speed.

The speeding gas-powder mixture is then imparted on the metal surface where its speed yields to zero, but the particles normally absorb it by cohesively clinging together and adhesive attaching permanently to the metal surface. This leads to the formation of a very turgid, rigid coating. The coating shiny and smooth due to its low porosity characteristics. Also, the resulting coating is strongly bonded by giant ionic bonds which contribute to its durability.

Some critical instances demand a specified coating texture. It is thus achieved through mixing the carbide powder with the selected binder material containing the desired characteristics. The resulting compound manifest increased hardness due to its higher boiling point. It is thus sprayed by a high-velocity oxygen thermal spray resulting in the formation of a hard and resistant to corrosion coating.

Similarly, the chemical procedure employed instills a greater influence on the coating characteristics and its ability to withstand abrasive processes like erosion, corrosion and wear. Owing to the above features, the coating technique is widely applicable in industrial production. For instance, in paper production where the rolling surface is coated to attain the desired paper output regarding quality and texture specifically.

Similarly, the coating is applicable in power generation mostly where coal is the chief fuel source. This is because the component surfaces must be keenly protected from extreme cases of gouging like an abrasion. Also, the coating is also widely used in steel and metal products throughout the entire process. It thus accrues a benefit in that it dramatically manifests reduced maintenance costs and advanced production quality.

Lastly, the adoption of the tungsten carbide coating technology has revealed endless benefits. This is because it is the most durable and efficient mode of coating in that it serves the metal substrate extremely longer time duration. Still, it overpowers the former conventional chrome plating due to its faster deposition rate and does not undergo lengthy processes of embrittlement-treatment.




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