The frictional strength of the powder of two ballistic materials (SiC and Al2O3) under low confining pressures has been studied statically and dynamically. In the static tests, the influence of the ceramic fragment size upon the internal friction coefficient value was investigated. In the dynamic tests, the effect of the ceramic fragment size, the relative sliding velocity and the confinement load were studied. It was found in the experimental conditions, that the influence of the fragment size and of the relative sliding velocity upon the internal friction coefficient value of comminuted SiC and Al2O3 is important.