Thermal Spray Solutions offers a variety of coatings that can be applied to composite substrates.
Excellent strength to weight ratio and low inertia of rotating components are the primary reasons there is increased interest in the use of composite materials for a number of applications in a broad range of industries.
In addition, the application of thermal spray coatings to composite substrates to improve performance allows composites to be engineered into applications where previously they have not been feasible and allows lightweight composites to replace metallic components.
Thermal spray coatings can enhance the surface properties of composites to provide wear resistance, thermal barriers, EMI/RFI shielding, and corrosion.
The most commonly used composite materials for the application of thermal spray coatings are carbon or glass fibers reinforced with a number of polymer resins such as polyester, epoxy, phenolic, and vinyl ester. Thermal spray coatings have also been successfully applied to some plastic substrates however, these applications present some unique application challenges.
Depending on the particular application, there are a wide variety of thermal spray coatings that can be applied to composites using various thermal spray processes. Aluminum, zinc, tungsten carbide, chrome oxide, aluminum oxide, and yttria-stabilized zirconia are typical coating materials for this purpose.
The Unique Challenge
The successful application of thermal spray coatings on composite substrates provides unique challenges in every step of the thermal spray process. Surface preparation is critical as establishing a good bond between the coating is a bit more challenging that thermal spraying on metallic substrates. Careful monitoring of blasting parameters as well as proper blast media selection is important as composite materials can deteriorate or disintegrate if blasting is too aggressive.
Due to the low melting point of the polymer resins and the higher temperatures associated with thermal spray processes, attention must be paid to the spray parameters as well.
Careful selection of bond coat materials, surface prep, and controlling the spray process for the application of thermal spray coatings on composites have resulted in the development of some rather novel prep and spray techniques especially for the application of multi-layer coatings.
Many of these approaches to thermal spraying were developed using the tried and true method of “trial and error”, but once a successful process is established and meticulously documented it is readily repeatable.