Thermal Spray Coatings
Thermal spray coating is a coating process that utilizes heated materials to coat the surface of many different surfaces. In general, thermal spray coatings are created by shooting super heated particles at high velocities toward the surface of an object, and these particles quickly accumulate on the substrate forming a coating on the surface. There are a variety of thermal spraying techniques used in industrial applications, and they can be used to create all kinds of coatings on a broad range of materials.
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Advantages to Thermal Spraying
Many industrial companies utilize thermal spray coating techniques due to their distinct benefits and advantages. Coatings created through thermal spraying processes can vary in thickness from 20 micrometers to several millimeters, making it a very versatile coating option. In addition, thermal spraying provides high deposition rates when compared with other coating techniques like electroplating and vapor deposition. This means that a thick and strong coating can be applied to large areas quickly. For high volume applications and applications requiring quick turnarounds, thermal spraying is a precise and efficient solution. Thermal spray coating also allows for a diverse range of coating materials, including metals, metal alloys, plastics, and more. Therefore, many different coating properties can be achieved. Thermal spraying is an excellent option for corrosion resistance, wear resistance, altering conductivity, thermal barrier creation, and many other applications.
Process of the Thermal Spraying
All thermal spraying processes require the coating material to be heated and sprayed; however, depending on the process and the application, this can be achieved in many different ways. The flame spraying technique is one of the first and most widely used thermal spraying techniques. In this process, the coating material is fed into a spray gun in a powder or wire form.
A gaseous fuel, commonly acetylene, and oxygen mixture is ignited within the spray gun, melting the coating material which is projected from the gun onto a substrate. These high energy particles collide with the substrate and accumulate on its surface. To improve the coating process, the coated material can then be heated to fuse the coating to the substrate, reducing porosity and improving bond strength. Plasma spraying is another thermal spray coating method.
Instead of using a flame, plasma spraying uses a plasma jet created by arc discharge, which generates higher temperatures. This process allows for the use of different kinds of coating materials, and it creates high density, strong coatings. Other thermal spray coating variations include: detonation spraying, cold spraying, wire arc spraying, and HVOF spraying.