Facts One Should Know About Diffusion Coatings

By Marci Nielsen


Metal components are meant to be used or operated in different environments. Some of those environments are very harsh in that they have very high temperatures, are very corrosive, or are very reactive among other conditions. Such environments are able to cause very severe effects when they come in contact with metal components, which may lead to a significant reduction in durability, aesthetic value, and functionality among others. To curb the effects of such environments, diffusion coatings were invented.

Diffusion coating is the process through which metal substrates are coated with diffusion coating. The process requires a special piece of equipment called a chamber and optimal temperatures are usually very high. Thorough cleaning of substrate must be done first before the process is started. Abrasive blasting is the most commonly used method although other methods can be used. Unwanted materials must be removed because they prevent complete bonding between the metal and substrate.

After proper cleaning has been done, the component is placed inside the container and the coating material added. The container is then completely sealed and placed into a furnace, which may be in the form of a chamber. The temperature of the furnace is then raised to very high levels in the range of 380 to 425 degrees Celsius.

Diffusion of the metal occurs when temperatures rise high enough within the range specified. An alloy between the substrate and metal is formed in turn. The duration of the whole processes varies relying on the kind of metal and substrate used. However, 2-4 hours is the normal range. Continuous turning of substrates must be done for uniformed thickness to be attained.

When the process is finished, the coating that results is usually smooth and has a uniform thickness. The thickness can be varied depending on the purpose the components is meant to do. However, typical thicknesses are between 15 to 80 micrometers. The coating takes the color of the metal used and common ones include chromium, silicon, aluminum, and iron. Various materials can also be coated including nickel, steels, cobalt, and iron among many others.

The coating that results is capable of resisting erosion, oxidation, and reaction with substances like air and water. Metal components that are used for critical functions are made stronger, more durable, and more reliable. Gave valves, pump impellers, power generation components, and gas turbines engine constituents including vanes, blades, and cases are among the components that are coated this way.

The process is used mostly in industrial settings and few household equipment have components that are coated this way. The technology was invented several years ago and has been undergoing a lot of modifications aimed at perfecting it. Currently, there are better methods and technology for doing it.

Modern furnaces incorporate several important features that make them more effective and functional. The improved functionality and efficiency allows for the attainment of thin coats that last longer and are stronger, while offering good protection at the same time. The employment of this technology seems to be higher in automobile industry.




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