Thermal spray coatings refer to processes used across many industries. Fine metallic or nonmetallic materials (feedstock) are sprayed onto a prepared surface. These materials form a solid coating. The coating adds desired surface properties, like wear resistance, without changing the substrate’s core traits. For example, titanium wear rings can gain a hard tungsten carbide coating.
Applications for spray coatings
Thermal spray coatings are most often used to protect components and products from wear, temperature extremes and corrosion. However, Thermal spray coatings are very often used for dimensional restoration of old worn parts.
- Wear Resistance: Protect parts like rollers, blades, and pump components from abrasion and erosion.
- Corrosion Protection: Shield surfaces like pipes, valves, and structural steel from harsh chemicals and environments.
- Thermal Barrier: Insulate turbine blades and boiler tubes to withstand high temperatures.
- Electrical Insulation: Apply dielectric coatings to prevent conductivity in electronics and optics.
- Surface Restoration: Repair worn parts like shafts and bearings, extending service life.
- Friction Control: Provide low-friction or non-stick surfaces for rollers and molds.
- And many more
The Benefits
Improve Properties. Thermal spray coatings significantly enhance component durability. They provide superior wear resistance, extending the life of parts like rollers and valves. These coatings offer excellent corrosion protection, ideal for harsh environments. They also improve thermal resistance, ensuring performance in high-temperature applications. Additionally, coatings can reduce friction, boosting efficiency in moving parts.
Restoration of Failing Parts. Worn and corroded parts, which would otherwise be scrapped, can be reclaimed using thermal spray coatings. The part can be brought back to specification again and again, yielding considerable savings over time.
Industrial Chrome Plate Replacement. Hexavalent chromium, a toxic chemical used in traditional chrome plating, has faced strict government regulations due to health and environmental risks. Thermal spray coatings, such as those applied via HVOF, HVAF, or plasma, offer a safe, effective, and environmentally friendly alternative. These coatings provide comparable or superior wear and corrosion resistance without hazardous byproducts. The process generates recyclable powder overspray that is typically non-soluble, reducing environmental impact and ensuring compliance with regulations.
Reduced downtime and costs, improved productivity.
THE PROCESSES
To meet diverse service conditions and leverage the advanced properties of modern coating materials and substrates. Longevity Coatings utilizes a range of sophisticated thermal spray processes. Each process is distinguished by its heat source and feedstock material used for deposition. Below is a concise overview of our most commonly used processes. For detailed explanations, click the links provided.
- HVOF Process: A thermal spray process where fuel and oxygen combust to create a high-speed jet, propelling heated powder onto a surface. This forms dense, durable coatings with excellent wear and corrosion resistance, ideal for various industrial applications.
- HVAF Process: is a thermal spray process similar to HVOF, but it uses compressed air instead of pure oxygen as the combustion oxidizer. The process generates a high-velocity gas jet with slightly lower temperatures but higher velocities than HVOF, resulting in denser, harder coatings with excellent wear and corrosion resistance, ideal for demanding industrial applications.
- Plasma Coatings: A thermal spray process where a plasma arc, formed by ionizing gas (e.g., argon or nitrogen) with an electric current, creates an extremely high-temperature jet (up to 15,000°C). Powder materials (e.g., ceramics or metals) are injected into the jet, melted, and propelled onto a surface. This produces dense, high-quality coatings with excellent thermal, wear, and corrosion resistance, ideal for oxide ceramics and other high temperature coating materials.
- Twin wire arc: A thermal spray process where two electrically conductive wires are fed into a spray gun, creating an arc that melts the wire tips. Compressed air atomizes and propels the molten material onto a surface, forming a coating. Often used for bonding layers, or dimensional repair, and others.
- Fused coatings: (also known as flame-sprayed and fused coatings, or diffusion bonding) are a thermal spray process where a powder (typically self-fluxing alloys like nickel or cobalt-based materials) is flame-sprayed onto a surface using an oxy-fuel torch and then fused by heating the coated part (via torch, furnace, or induction) to 1,000–1,200°C. This creates a metallurgically bonded, dense coating with excellent wear and corrosion resistance, ideal for industrial applications like pump sleeves and rollers, or anything that takes high impact