Useful Facts About Diffusion Coatings

By Marci Nielsen


The operation and application of metal components is done in diverse environments. The variance in the environments is of great importance because some of the environments have diverse impacts on components. Corrosive environments and high temperatures for instance can be very damaging. Adverse environments impact functionality, longevity, and beauty of components. As such, in an attempt to reduce or eliminate the effects, diffusion coatings were invented. The purpose of these coatings is protecting substrates from being ruined by adverse environments. The information below discusses the process and how it offers protection to substrates.

The process of applying a diffusion coating on a metal substrate is called diffusion coating too. This process is done inside a chamber at temperatures that are very high. Various metals such as nickel, iron, and cobalt are activated thermally during the procedure. Before the process can start, the substrate needs to be cleaned thoroughly first. Cleaning can be done through various methods, but abrasive blasting is commonly used. Cleaning is for removing dirt and other undesirable materials from the surface of substrates.

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.

At those temperatures, the diffusion of the metal occurs, which allows it to form an alloy with the substrate or component. This process lasts variable amounts of time depending on the metal used and the nature of the substrate. Typically, it lasts between two to four hours. During the entire time, the component is rotated slowly for a uniform coating to form.

The smoothness of the resultant coating is high while the thickness if uniform. Thicknesses can be varied to suit different functions. However, 15-80 micrometers is the normal range of thickness. The coating resembles the metal used in color. Iron, cobalt, chromium, aluminum, and silicon are some among the commonest metals in use. Various metals such as iron, steels, cobalt, and nickel can be coated.

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 use of this process is mostly confined in industrial settings. Very few household devices incorporate this process in their production. The invention of the process happened several years ago and it has been undergoing modification over time to achieve perfection. Currently, better methods and technology exist.

Modern day furnaces have a lot of improvements in the form of features aimed at increasing efficiency and functionality. Today it is possible to achieve very thin coatings that are very strong and effective at eliminating corrosion. The automotive industry is particularly known for using this technology.




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