Thermal Sprayed Parts

Thermal spray coatings are applied to a variety of industrial and consumer components with a large variety of shapes and sizes. Very small components to very large structures can be coated. In general, thermal spray processes are capable of coating objects if a clear line of site is available from the thermal spray device to the surface to be coated. In many cases, internal surfaces of a part can be coated including the internal diameters of tubes with diameters as small as 75mm, (3 inches). The following are some examples of coated components with different sizes and shapes.

Large Components

The processes of thermal spray are used to coat large components such as highway bridges, locks, and dams. Coatings of zinc or alloys of zinc and aluminum are deposited by electric-arc spray techniques to provide excellent corrosion protection for steel and concrete rebar. The technology has proven to provide much better corrosion protection than traditional painting methods.

In the paper industry, very large paper making rolls are coated for various reasons. An example is center press rolls that are coated with ceramic coatings to provide controlled wet-release properties as water is removed during the paper making process. Center press rolls can be over 3 meters in diameter and over 20 meters long. Below is a picture of a center press roll where the ceramic coating is being ground smooth before the roll is put into operation.

Small Components

Small common parts like the heads of bolts are coated to provide protection from erosive wear. Thin coatings of carbide containing materials provide excellent wear resistance to bolts used in severe wear conditions to make sure the component that the bolt is fastening remains in place during the machine’s operation. Parts such as this can be coated in large production volumes.

Brake poles are also coated; these are used in braking systems to stop riding lawn mower blades from rotating when the rider gets off the seat of the mower. This application sees severe high temperature adhesive wear while the brake is engaged. A thin thermal sprayed coating provides excellent resistance to the wear mechanisms in this application. The coating provides over twenty times the life compared to a heat-treated-only brake pole.

Thermal spray coated brake poles to prevent high temperature adhesive wear		Bolts with thermal spray coated heads to combat erosive wear

Rolls, Rods, Plungers and Shafts

Many rolls, rods, plungers and shafts are coated for a variety of reasons. Several different coatings are used in the printing industry on a variety of rollers. One example is Anilox rolls. Anilox roll bodies are made from steel, aluminum, or carbon fiber composites and are ceramic coated, ground and polished, and then laser engraved to produce wear resistant cells on the rolls surface. The cells are used to carry ink to imaging rolls that print a desired image on the media being printed.

Ceramic coated printing roll coated for wear resistance

Rods and shafts are commonly coated to provide specific properties such as wear resistance. Surfaces of these parts that are used for sealing or bearing surfaces are coated and the coatings are typically ground smooth. Many rod and shaft manufactures have realized that using a thermal spray coating eliminates the need for heat treating, where heat treating was used to provide wear resistance by hardening the surface. Thermal spray coatings commonly provide much better wear resistance than heat treatments. Plungers used to homogenize liquids are coated for wear resistance and from abrasion and cavitation. Many of these plungers are used for homogenizing food products in the food processing industry.

Thermal spray wear resistant coated seals, plungers and shafts

Every Day Components

Thermal sprayed coatings can be found on every day common items. The braking surfaces of bicycle rims are coated with ceramic coatings that are partially ground smooth. The coating provides benefits such as aggressive braking capability in both wet and dry conditions, it also provides excellent wear resistance. The wear resistance can be especially important in mountain biking where dirt and grit are common and can cause wear on aluminum rims.

Filters for household electronic furnaces have been thermal spray coated. An electrically conductive metal coating is deposited onto the paper filter media. The coating allows the filter to be electrically charged so finer dust particles can be filtered out of the air that would normally flow through the filter without the electrical field.