Coating Techniques

Plasma Coatings is the only company that combines the benefits of Thermal Spray (metal) coatings with polymer based coatings.

We use hardfacing techniques, dispersion spray and electrostatic methods to apply coatings. Each process deposits a coating onto a prepared base material forming a mechanical bond that enhances the properties of the surface.

Thermal Spray

This is the method of applying materials onto a prepared base material by heating particles in the stream of a heat source, creating a semi-molten state. Particles are then propelled by high velocity onto a prepared substrate where they adhere to the base surface via a mechanical bond.

Particles continue to build until a specified thickness is attained. This technique is considered the "cold method of welding", whereas high temperatures can be achieved in the heated pocket, while the temperature of the part itself usually remains under 200°F.

Typical physical specifications of coatings:

• Maximum hardness of 72 Rc hardness (Tungsten Carbides)
• Surface texture as sprayed is rough, from 150 to 1000+ Ra
• Thickness range from .002 to .150
• Bond strength range: 2500 -15000 PSI

Advantages

• No degrading of parts due to heat warping and distortion
• No degrading of part metallurgy or integrity
• Surfaces are enhanced to provide improved performance

We use five core coating application techniques:

1. Combustion Wire Metallizing: In this process, various metal wire is fed into an oxygen-acetylene gas mixture. It is then in a molten state and sprayed onto the part being processed. This most basic of coating techniques is limited by maximum temperature attainable and the universe of materials that can be set. 
   
   
2. Electric Arc: This process also uses materials in wire form, but in this case the heat source is the arcing of two electrically conductive wires. The material is melted and propelled onto the part at a greater velocity than seen in the metallizing process. Higher temperatures allow for an increased source of base materials, faster rates of deposition, and improved bond and coating density.
   
   
3. Thermal Spray: Like metallizing, our thermal spray is based on an oxygen-acetylene heat source. Unlike metallizing, however, the material begins in powder form. This process provides a larger selection of base materials and better bonding and density.
   
   
4. Plasma Spray: In this process we use various gasses that are ignited by an electric arc. Temperatures can rise up to 30,000° F while the part temperature remains at less than 200°F. Particle velocity is greater than in the other four systems. One of the benefits of using this system is the high heat, which can process materials with high melting points (including ceramics).
   
   
5. HVOF (High Velocity Oxygen Fuel): In this process particles actually travel faster than the speed of sound, generating the best bond strengths, density and hardness of all our processes. HVOF does not reach temperatures that are attainable with plasma processes so materials such as ceramics cannot be processed with this technique at this time.

Polymer Systems

A wide range of polymers is also available, typically in the .001-.003 thickness range. Methods of application will vary, as will the curing methods. Through dispersion or electrostatic systems we apply:

• Fluorocarbons
• Fluoropolymers
• Silicones
• Epoxies
• Teflon®