Investigations of the disturbed layer of ground quartz

It is shown electron microscopically that in 3 μm diameter wet ground quartz powders less than 1% of the mass consists of sub-microscopical 'adhering' particles. The observed decrease in the peak intensities of the X-ray diffraction lines of these 3 μm powders must be attributed to disturbed outer layers of the powder particles. It is shown that the outer layers recover to a considerable extent by a heat treatment at 1200°C and the X-ray and electron diffraction diagrams reveal that the disturbance is rather slight. From the profiles of the X-ray powder lines it can be derived that the thickness of the disturbed layer in these powders is greater than or equal to 0.4 μm.