Protective coating to inhibit oxidation and/or carburization of metallic surfaces

Abstract

Abstract OXIDATION AND CARBURIZATION OF STEEL SURFACES HEATED TO ELEVATED TEMPERATURES ABOVE 600* C. ARE INHIBITED BY A PROTECTIVE COATING CONTAINING AT LEAST 10% FUSIBLE MATERIALS TO SHIELD, UPON SOFTENING, THE STEEL SURFACE FROM DETERIORATING AGENTS AND AT LEAST 20% SACRIFICIAL METAL PARTICLES TO REACT WITH CARBONACEOUS MATERIALS PENETRATING THE PROTECTIVE SHIELD FORMED BY THE SOFTENED FUSIBLE MATERIALS. THE PROTECTIVE COATING PREFERABLY IS APPLIED IN DUAL LAYERS WITH THE BASE COAT FOR A MACHINED STEEL SURFACE GENERALLY COMPRISING A SUSPENSION OF IRON PARTICLES AND A SOLUBLE SILICATE BINDER TO ADHERE A SPRAY APPLICATION OF THE BASE COAT TO THE MACHINED STEEL SURFACE. AFTER THE BASE COAT HAS PARTIALLY DRIED, A SEALER COAT CONTAINING SUSPENSIONS OF NEPHELINE SYENITE AND GLASS PARTICLES IN WATER AND A SODIUM SILICATE BINDER IS SPRAYED ATOP THE BASE COAT TO SERVE, UPON SOFTENING OF EITHER THE NEPHELINE SYENITE OR GLASS PARTICLES, AS A BARRIER LAYER TO SHIELD THE STEEL SURFACE FROM OXYGEN AND CARBON-BEARING MATERIALS. WHEN THE PROTECTED SURFACE IS TO BE WORKED IN A DAMP ENVIRONMENT, A WATERPROOFING COAT OF 25% SIO2 CONTENT HYDROLYZED ETHYL SILICATE SOLUTION IS APPLIED ATOP THE SEALER COAT. A MIXTURE OF THE BASE COAT AND THE SEALER COAT PROVIDES PROTECTION AGAINST PITTING OF A STEEL SURFACE LOCATED IN A DRY ENVIRONMENT WITH A SINGLE APPLICATION OF THE PROTECTIVE COATING WHILE THE INCORPORATION OR A SUITABLE CARBONATE, HYDROXIDE, OXIDE OR FLUORIDE INTO EITHER THE SEALER COAT OR THE MIXTURE OF THE BASE COAT AND THE SEALER COAT ELIMINATES THE NEED FOR A SEPARATE WATERPROOFING COAT WHEN THE ALLOY IS HEAT WORKED IN A DAMP ENVIRONMENT.

Inventors

• 👤 Roland T Girard
• 👤 George A Rice

Bibliographic Details