What is Tungsten Carbide Coating?
Tungsten carbide is typically found as a fine powder that is gray in color in its basic form. However, it is formed and pressed via sintering to create jewelry, cutting tools, and industrial machinery. When combined with a small portion of metallic powder (typically Co, Cr, or Ni) it can be turned into carbide coatings known for strong resistance to abrasion, erosion, and wear.
Are Tungsten Carbide Coatings Metallic?
While tungsten carbide is a hard, brittle ceramic it is typically combined with Nickel, Cobalt and/or Chrome when used as a coating. This Cermet composite coating combines the ductility of the metallic material with the high hardness of the ceramic tungsten carbide which results in the excellent properties associated with this coating.
Benefits of Tungsten Carbide Coatings
Tungsten carbide can be applied using various processes including the detonation gun (d-gun) and high-velocity oxygen fuel (HVOF). There are benefits for each process.
D-Gun
Tungsten carbide coatings applied with the detonation gun (d-gun) involve a controlled spark to ignite acetylene gas with the tungsten carbide powder shooting down a barrel and landing on the workpiece. As more particles in the d-gun coating arrive, the coating builds up at a rapid pace.
The use of d-gun thermal spray for carbide coatings leads to a strong bong strength with options for thickness and roughness to provide the proper corrosion, wear, and erosion protection.
HVOF
Tungsten carbide coatings applied with high-velocity Oxygen Fuel (HVOF) involve a high kinetic energy being sent into the powder particles as a thermal spray. These particles are highly energetic but when they hit the substrate, the velocity goes to zero and the kinetic energy is absorbed. This results in the particles flattening and instantly bonding with the workpiece. As more particles in the HVOF coating arrive, the coating builds up at a rapid pace.
The use of HVOF thermal spray for carbide coatings leads to a strong bond strength, low porosity, good corrosion resistance, great wear resistance, resistance to erosion, and low residual stress.
Additionally, the HVOF thermal spray process results in relatively customizable coatings because the wear resistance, strength, and hardness depend on the volume fraction and grain size of the particles and on the types and ratios of the metallic binder used. This allows you to adapt the hardness and other properties of the carbide coatings to meet specific needs for a given item.
PST offers several options for Tungsten Carbide coating chemistries. These can be optimized for protection against erosion, abrasion, or corrosion of the coated part and can be used in many applications such as aviation parts, deep sea oil/gas wells, zinc galvanizing rolls, and many, many others.
What is Tungsten Carbide Used for?
There are multiple potential applications of tungsten carbide, including thermal spray carbide coatings. These carbide coatings are common on brake discs for performance cars. In this application, the coating improves performance and service intervals while reducing brake dust.
One of the most important applications of tungsten carbide is to create tools for machining. These tools take advantage of the abrasion-resistance and heat-resistance of the material. They are commonly used in situations where steel would wear down too quickly, such as high-precision or quantity production.
It is also common to use this material or variations of it such as tungsten carbide cobalt composite in ammunition designed to pierce armor. The strength of tungsten carbide is also common in mining as well as foundation drilling. In sports, it is commonly used as a material for trekking poles or ski pole tips.
The metal is commonly used for jewelry to wear as well as surgical instruments. In the latter application, it offers better performance than stainless steel, but it is more expensive and requires handling that is more delicate.