Thermal Plasma Spray Cost Factors

Thermal Plasma Spray Cost Factors

The main factors affecting the price of thermal plasma spray can seem unclear, but they are actually fairly straightforward.

Feedstock Material

Powder or wire is fed into the plasma torch. The cost of a powder or wire can vary greatly. In general the price of a tungsten carbide or zirconia-based ceramic material will be much greater than that of a standard aluminium oxide or stainless steel powder. It is easy to add too much cost to a part by specifying an exotic material to meet a performance requirement that can be met by a less expensive material.

Part Size and Batch Volume

The cost per unit also reduces dramatically as you coat more than one part at a time (as the time spent setting up and masking the part up is spread over the whole batch).

Surface Preparation Requirements

Many customers assume that the cost of preparing the parts for Thermal Plasma Spray is low, but this is not the case. If parts are corroded, contaminated or of complex geometry then the cost of preparing the parts for coating can be high. This can be kept to a minimum by supplying clean parts that are well specified for thermal spraying. Detailed process guidance on thermal spraying operations notes that substrate condition affects adhesion and process time.

Coating Thickness

This also applies to the coating thickness. If you require a thick build-up, whereas a thinner coating would be sufficient, you are overpaying. We therefore recommend checking the required thickness against the expected wear or corrosion attack.

Post-Spray Machining

Sprayed coatings may require subsequent machining. Coatings made with harder materials such as tungsten carbide are very difficult to grind or machine. This time can be added to the spraying process but a generous and realistic tolerance can be allowed in the drawing to minimise rework.

A little preparation in the specification phase can save more than it costs.