What Is a Refractory Coating?

It is possible to think the refractory coating as a protective paint, specially developed for the metal casting industry. The refractory coating can withstand the high temperatures of molten metal and act as a barrier between the heat and the surface of the furnace. The refractory coating is also known as foundry coating, protective paint, blackings, and washes. The refractory coating is in liquid form, consisting of minerals. After being applied to a surface the liquid vaporizes and only a layer of refractory is left. This layer will protect the inner walls of the furnace, increase its lifetime and prevent burn-on. In general, the quality of the casting surfaces will greatly improve because of the refractory coatings.

When to Use Refractory Coating?

The cleaning, repair and reduction costs will also decrease because of the refractory coatings. It is not a standard procedure for every industrial furnace, and the decision to use a refractory coating should be based on the economic outcome. If the cost of the coating is higher than the cleaning, repairing, and maintenance fees; there is no need to use it. The components of a refractory coating are refractory mineral, carrier, binder, suspending agent and special additives, such as biocides and wetting agents.

Components of a Refractory Coating

The refractory mineral is the most important ingredient. The coating consists of %90 refractory mineral and %10 other materials. The refractory mineral determines the strength of the coating and the application properties. The carrier part is in liquid form and also known as “solvent”. The only function of the carrier is to transform the mineral to the surface. It completely dries up during the process. The binder bonds the refractory minerals together. Acrylics, starches, and wood derived resins are examples of binders. The suspending agent is used to keeping all materials in suspension and prevent hardening during the installation. Clays, polymers, and gums are amongst the suspending agents.