THERMAL SPRAYED TO PROTECT AGAINST CORROSION

SUMMARY: Coatings of System #43, a plasma overlay of nickel-chromium followed by a high temperature sealer, are applied to heat treating equipment in order to prevent loss from corrosion. Components exposed to high temperatures, corrosive environments,and salt bath fumes can be protected with this low cost overlay. Carbon steel weldments and foundry iron castings are most often treated. The purpose of this coating is long term protection and lower maintenance costs.

BCKGRND: Foundry, steelmaking, and heat treating equipment is often made from carbon steel or low grade cast iron in order to reduce costs. Sales of replacement parts are guaranteed. Internal components are exposed to conditions varying from extreme heat to water quenches. Stainless steel systems have to be custom made and are very expensive. High temperature paints have limited strength and poor bonding. Chrome Plating is expensive and environmentally unfriendly.

TECHNICAL: Corrosion is the deterioration of a substance because of a reaction with its environment. Corrosion of carbon steel is caused by the migration of ions from the iron at elevated temperatures and the formation of iron oxide (rust) at lower and humid conditions. All of the processes mentioned above do nothing to prevent this except to exclude the environment. If the paint gets a scratch, then the part rusts.

COATING: System #43 is the only process that bonds elemental ni-chrome directly to the substrate using a Plasma Coating System that was developed by NASA to test re-entry heat shields on spacecraft. This is metallurgical protection. The electromotive process is reversed. The corrosion is stopped. The coating is stable at temperatures up to 1800 deg. F. and will not migrate or dissolve.
It is used extensively for the protection of steelmaking equipment, oil refining equipment, chemical processing equipment, and marine vessels.

Common applications in the heat treatment industry include:

Furnace Piers Gate Valves Baffle Grids

Exhaust Ducts Exhaust Fans Furnace Walls

Annealing Covers Annealing Pans Ingot Car Axles

Hot Bed Rolls Thermowells Positioners

CERTIFICATIONS: Pratt and Whitney Aircraft PWA 1315
Boeing Aircraft BMS 10-67
U.S. Military MIL-P-85856/20
General Electric Company B50TF40, Class B
Rolls Royce Specification 9507/27