USE OF NANOINDENTATION TO ASSESS POTENTIAL ATTRITION OF PARTICULATE SOLIDS

A nanoindentation technique has been used to investigate the influence of processing conditions and equipment on the surface hardness of par ticulate solids. The sensitivity of this technique is such that it can be used to detect differences in the surface properties of the same m aterial which has undergone different types of handling in the process equipment. Changes in the near-surface hardness of crystals that resu lt, for example, from work hardening by inelastic impacts can be ident ified and characterized by monitoring the hardness as a function of de pth. This enables the attrition propensity of the particles with a sem i-brittle failure mode to be assessed. Results of ongoing work on pure dried vacuum (PDV) salt are described in this paper.