Powder Materials. A Technology of Producing Spherical Fine Powders by Water Atomization and the Characteristics of the Fine Powders.

Production of fine calcium powders by centrifugal atomization with rotating quench bath

Microstructure Characteristics of Ultra-fine ZrO2-Y203 Ceramic Powders*

Yttria-doped zirconia powders" with an extremely small crystallite size (8 nm) and a narrow size distribution have been prepared by gel precipitation methods. Precipitation of an alkoxide solution in water ("alkoxide" synthesis) results in weaker agglomerates when compared with a precipitation of a metal chloride solution in ammonia ("chloride" synthesis). Both types of agglomerate are fracture...

Dustiness of Fine and Nanoscale Powders

Dustiness may be defined as the propensity of a powder to form airborne dust by a prescribed mechanical stimulus; dustiness testing is typically intended to replicate mechanisms of dust generation encountered in workplaces. A novel dustiness testing device, developed for pharmaceutical application, was evaluated in the dustiness investigation of 27 fine and nanoscale powders. The device efficie...

Jamming threshold of dry fine powders.

We report a novel experimental study on the jamming transition of dry fine powders with controlled attractive energy and particle size. Like in attractive colloids dry fine particles experience diffusion-limited clustering in the fluidlike regime. At the jamming threshold fractal clusters crowd in a metastable state at volume fractions depending on attractive energy and close to the volume frac...

Aerated bunker discharge of fine dilating powders

The discharge rate of coarse powders (mean particle size >500 pm) from bunkers without aeration can be described by both empirical relations and theoretical models. In the case of small particles the discharge rate is largely overestimated. As the powder dilates during flow a negative pressure gradient develops near the hopper outlet, inducing an air flow into the hopper. This extra drag force ...