powders

Powders are substances consisting of fine, discrete solid particles that can range from a few micrometers to several hundred micrometers in size. In bulk, powders exhibit properties that differ from bulk materials, including high surface area, porosity, cohesiveness, and a tendency to flow or cake depending on particle size distribution, shape, moisture, and electrostatic charging. They can be classified by composition (inorganic, organic, metallic, ceramic, or polymeric) and by application, such as pharmaceutical, cosmetic, food, or industrial powders.

Production and processing methods for powders include milling and grinding to reduce particle size, classification by sieving or air classification, and formation processes such as spray drying, atomization, crystallization, and agglomeration. Powder characteristics of interest include particle size distribution, shape, flowability, bulk density, porosity, moisture content, and surface chemistry, all of which influence handling and performance.

Common applications span medicine and health (drug powders and inhalable formulations), food and nutrition (instant mixes and flavorings), cosmetics (setting and finishing powders), paints and coatings, metallurgy and ceramics (metal and ceramic powders for sintering and additive manufacturing), and catalysts and materials science (powder catalysts and powders for 3D printing).

Safety and handling concerns center on dust hazards, inhalation risks, and flammability or explosion potential for certain powders in dust form. Proper storage in dry, sealed containers with humidity control, adequate ventilation, and appropriate personal protective equipment is recommended. Storage and transport standards vary by jurisdiction and material.

Powders have long played roles in food processing, pigments for art, and weaponry, with gunpowder representing a pivotal development in technology.