DEVELOPMENT OF AN ELECTROCHEMICAL INFILTRATION METHOD FOR CARBON-CARBON COMPOSITE SURFACE PREPARATION

THE USE OF CARBON-CARBON (C-C) COMPOSITES IN MANY INDUSTRIAL APPLICATIONS HAS BEEN LIMITED DUE TO DIFFICULTIES IN JOINING TO OTHER STRUCTURAL MATERIALS. APPROACHES USING ACTIVE BRAZE ALLOYS HAVE MET WITH LIMITED SUCCESS BECAUSE OF INHOMOGENEITY OF THE BRAZE ALLOY, WETTABILITY PROBLEMS, AND EMBRITTLEMENT OF THE JOINT. TO OVERCOME THESE PROBLEMS A NOVEL METHOD FOR BRAZING C-C COMPOSITES HAS BEEN DEVISED. THE C-C SURFACE IS FIRST SPECIALLY PREPARED AND THEN INFILTRATED TO A DEPTH OF 15040 MICRONS WITH A NON-CARBIDE FORMING METAL. THE RESULTING SURFACE ZONE, FIRMLY BOUND TO THE C-C SUBSTRATE, IS A CARBON FIBER REINFORCED METAL MATRIX COMPOSITE SUITABLE FOR BRAZING WITH CONVENTIONAL BRAZE ALLOYS. IN PHASE I, THE FEASIBILITY OF ACHIEVING FULLY-BONDED C-C COMPOSITE TO A METAL ALLOY IN TEST COUPONS WITH THE SURFACE INFILTRATION METHOD WILL BE DEMONSTRATED. BRAZED JOINTS WILL BE EVALUATED USING MECHANICAL TESTING AND NON DESTRUCTIVE TECHNIQUES. PHASE II EFFORTS WILL CONSIST OF DEVELOPMENT OF TECHNIQUES FOR JOINING LARGER PANELS WITH APPROPRIATE TESTING IN TARGET FUSION REACTOR APPLICATIONS.