POLISHING OF POLY-CRYSTALLINE DIAMOND FILMS

POLYCRYSTALLINE DIAMOND FILMS IN AN AS-DEPOSITED CONDITION DO NOT PROVIDE THE REQUIRED OPTICAL QUALITY TO REDUCE SCATTER SUFFICIENTLY FOR MANY APPLICATIONS. A RESEARCH INVESTIGATION WILL BE CONDUCTED TO DETERMINE THE FEASIBILITY OF ACHIEVING AN OPTICAL-QUALITY SURFACE FINISH BY USING ABRASIVE-LIQUIDJETS (ALJE) TO PERFORM THE POLISHING OPERATION ON POLYCRYSTALLINE DIAMOND FILMS. WATER, POLYMERIZED WATER, OILS AND SOME SYNTHETIC FLUIDS WILL BE EXAMINED FOR USE IN ALJS. A WIDE RANGE OF ABRASIVE MATERIALS, COVERING A WIDE RANGE OF HARDNESSEA AND SIZES, WILL BE EXPLORED. EXAMPLES ARE SILICON CARBIDE, CERIUM OXIDE, CBN, GARNET AND SILICA SAND. A PARAMETRIC STUDY WILL BE CONDUCTEDTO DETERMINE SUITABLE ABRASIVES, LIQUIDJET PRESSURES AND FLOW RATES. SEVERAL METHODS OF PRODUCING ALJS WILL BE TESTED, INCLUDING ENTRAINMENT OF DRY ABRASIVE POWDER, ENTRAINMENT OF PREMIXED ABRASIVE SLURRIES AND DIRECT PUMPING OF ABRASIVE SUSPENSIONS JETS (ASJ). THE EFFECTS OF VARIATIONS IN THE DIFFERENT PARAMETERS ON APPLYING THE ALJ TO THE SURFACE AND ON THE REAULTANT SURFACE FINISH WILL BE DETERMINED. THE PARAMETERS TO BE VARIED INCLUDE THE TRAVERSE SPEED, NUMBER OF PASSES, STANDOFF DISTANCE AND ANGLE OF IMPACT. POLISHED SURFACES WILL BE INSPECTED FOR CORRELATIONS WITH THE POLISHING PARAMETERS. THE OVERALLTECHNICAL FEASIBILITY OF ALJ POLISHING WILL BE DETERMINED, AND DIRECTIONS FOR FURTHER DEVELOPMENT WILL BE IDENTIFIED.