POWDERS & COATINGS

THIS STUDY IS FOR THE SYNTHESIS OF HIGH PERFORMANCE ULTRAFINE SI(3)N(4) CERAMIC MATERIAL (1 MICRON OR LESS SPERICAL PARTICLES) BY REACTING NITROGEN GAS WITH A BEAM OF MOLTEN SILICON MICRO-DROPLETS. THIS SINGLE-STEP PROCESS IS EXPECTED TO PROVIDE REACTION BONDED MATERIAL WITH EXCELLENT OXIDATION AND HOT CORROSION RESISTANCE AT ELEVATEDTEMPERATURES. ELECTROHYDRODYNAMIC METHODS, DEVELOPED PREVIOUSLY FOR SILICON COATING TECHNOLOGY, ARE APPLIED FOR THE GENERATION OF MICRODROPLETS. A MOLTEN SILICON DROPLET BEAM PASSES THROUGH A NITRIDATION CHAMBER (EXPOSURE TIME ON THE ORDER OF MILLISECONDS) AND IS SUBSEQUENTLY COLLECTED. CHARACTERIZATION OF THE PARTICLES IS PERFORMED TO DETERMINE THE CHEMICAL, PHYSICAL AND MICROSTRUCTURAL PROPERTIES OF THESI(3)N(4) ULTRAFINE POWDER. IN ADDITION TO SI(3)N(4) CERAMICMATERIALS ARE AMENABLE FOR PROCESSING BY THE PROPOSED METHODINCLUDING A1N.