DETERMINATION OF THE SPECIFIC SURFACE OF POWDERS USED IN THE PRODUCTION OF HARD ALLOYS
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
Pagination or Media Count:
Adsorption and gas permeability methods adsorption of nitrogen by B. V. Deryagin and Carman methods, and the adsorption of methyl alcohol were compared for use in determining the specific surface of powders. The method using the adsorption of MeOH was not considered sufficiently accurate in the evaluation of powder dispersion. The N adsorption method, although sufficiently accurate was considered too time consuming and complicated. The Koseni-Carman method was considered valid for determining the specific surfaces of coarsely dispersed powders only. Deryagins method resistance to filtration of rarefied air makes it possible to determine quickly and accurately the external specific surface of highlydispersed powders of hard alloys, and to calculate the average particle size. Particle sizes of 100 microns and less of any degree of dispersion can be determined by this method.