PROTECTED GRAPHITE MATERIALS FOR HIGH TEMPERATURE INDUSTRIALAPPLICATIONS

THE UNIQUE PHYSICAL AND MECHANICAL PROPERTIES EXHIBITED BY GRAPHITE MAKES IT AN ATTRACTIVE ENGINEERING MATERIAL FOR HIGH TEMPERATURE INDUSTRIAL APPLICATIONS. HOWEVER, THE STRONG CHEMICAL REACTIVITY OF GRAPHITE IN OXIDIZING ENVIRONMENTS AT ELEVATED TEMPERATURES REQUIRES THAT GRAPHITESURFACES BE PROTECTED IN SUCH APPLICATIONS. A NEED EXISTS: FOR MODIFYING THE SURFACE CHEMISTRY OF GRAPHITE, FOR DEVELOPING NEW APPROACHES FOR THE IMPREGNATION OF GRAPHITE, AND FOR COATING GRAPHITE PARTS WITH PROTECTIVE CERAMIC COATING LAYERS. NEW ELECTROCHEMICALLY-BASED PROCESSES WHICH TAKE ADVANTAGE OF THE HIGH ELECTRICAL CONDUCTIVITY OF GRAPHITE HAVE BEEN PROPOSED TO ADDRESS THESE NEEDS. MODIFICATION OF THE SURFACE CHEMISTRY OF GRAPHITE BY THE SURFACE SYNTHESIS OF VARIOUS OXYGEN- AND NITROGEN- CONTAINING FUNCTIONALITIES WILL BE ACHIEVED BY ANODIC OXIDATION OF GRAPHITE IN "FLOWING" AQUEOUS SOLUTIONS. SIMILARLY, THE ELECTROCHEMICALLY INDUCED IMPREGNATION OF GRAPHITE WILL BE ACCOMPLISHED FROM PRESSURIZED ELECTROLYTE "FLOW" THROUGH THEPOROUS MATRIX. IMPREGNANTS CONSIDERED INCLUDE: ELECTROACTIVE POLYMERS, METAL OXIDES, SOLID LUBRICANTS AND VARIOUS METALS. ELECTROCHEMICALLY DEPOSITED HEAT-RESISTANT COATING MATERIALS INCLUDE: OXIDATION RESISTANT ALLOY COATINGS (COCRA1Y), METAL OXIDES (A1203), CERAMIC COATINGS (TIB2), AND METAL-CERAMIC COMPOSITE COATINGS. THE ELECTROCHEMICALLY-BASED TECHNICAL APPROACH WILL BE COUPLED WITH AN INTENSIVE SURFACE AND BULK ANALYSIS OF THE VARIOUS MODIFICATIONS USING HIGH VACUUM ANALYTICAL TECHNIQUES. STRUCTURE-PROPERTY-PERFORMANCE RELATIONSHIPS WILL BE USED TO EVALUATE THE TECHNICAL APPROACHES.