STANDARD REFERENCE MATERIALS FOR PARTICLE-SIZE ANALYSIS OF CERAMIC POWDERS BY GRAVITY SEDIMENTATION

Two standard reference materials (SRM), one a nitride powder and the o ther of an oxide powder, of mean size in the range of 1.0 mu m, were d eveloped to assist in the measurement and analysis of fine size powder s. SRM 659, a silicon nitride powder and SRM 1978, a zirconium oxide p owder, are intended for calibration and evaluation of instruments used to measure particle size distribution using Sedigraph(R), a gravitati onal sedimentation method. In the development of these SRMs, the param eters of the powder deagglomeration procedures were studied to determi ne their effects on the measured particle size distribution of powders . The parameters studied included power output and time of sonication, initial pH of the suspension, and dispersant concentration. The morph ology, density, surface area, and surface chemistry of these powders w ere also measured.