1. The investigation into the comminution kinetics of zirconium diboride powder has demonstrated that comminution is more effective in a vibratory mill than in a ball mill. The optimum comminution time is 2–3 h. 2. Tsyurupa's analytical method of calculation can be employed for determining the particle-size distribution of powders. 3. Of the dispersing media investigated, ethyl alcohol gives the most agglomeration-resistant zirconium diboride suspensions. 4. Of the analysis methods examined, sedimentation analysis provides the fullest information on powder dispersion characteristics, but the most reliable values of mean particle size are obtained by the gas-stream ratio method.