What is "powder"? How does powder come?
Powder is everywhere, the noodles on the bowl in the morning, the raw material flour is powder, the ceramic bowl, step on the foot of the ceramic brick, the preparation of raw material is also powder;After breakfast, make up, with eyebrow powder, foundation of its raw materials and powder;Walking on the clean cement road, the main raw material or powder, even if it is a mud road, the main soil is the largest powder in nature.Cold to take a pill, its raw material is powder.Cold weather stick a warm baby, its working active ingredient is metal iron powder.In addition to the "identity" clear powder, there are also some powder to hide (compound) to other materials, such as car tyres will add carbon black have enhanced or shading effect, coating of powder materials have the effect of filling or paint, mixed with the powder in the plastic can enhance, hard, incremental, etc.In short, the powder is everywhere.
At present, we pay attention to the basic properties of powders: particle size and particle size distribution, particle morphology, specific surface area, voidage and density, fluidity and filling, hygroscopicity, etc., different characteristics will bring different effects to the application of materials.For example, in the pharmaceutical industry application even if it is a single substance, if the shape, size and adhesion of the various unit particles of the powder are different, the nature of the powder as a whole will have a great difference.Therefore, it is difficult to describe or define the properties of powder such as gas and liquid by mathematical model.But powder technology can also provide important theoretical basis and test method for formulation design, production process and quality control of solid preparations.And as an example, inorganic non-metallic materials microstructure formed by sintering process, to a great extent, determined by the characteristics of the raw materials adopted by the powder, according to the requirements of the material application, used for powder materials preparation process control and performance control, suitable post-treatment is the precondition of material with excellent performance.
