ABSTRACT
The determination of powder blend homogeneity is generally more complex than homogeneity determinations for other blend types due to the many factors that complicate powder blending, such as particle size, shape, density, resilience, and surface roughness. Also, the humidity of the local environment and electrostatic charge on the surface of materials to be blended is important. Mixing and segregation processes compete as powders are blended. Optimal blend times depend on the actual materials involved and the efficiency of the particular blender that is used. A thorough discussion of ordered and random powder mixtures and the various approaches to identifying process endpoints could easily fill a tome and is not appropriate for this chapter. The reader should keep in mind that a NIR spectrum provides chemical and physical information about all components of a sample. Such chemical and physical data should be valuable for homogeneity determination of all blend types.
