Glass surfaces including those of automotive glazing show insufficient scratch resistance. In order to improve this, a sol-gel process has been developed by means of which scratch-resistant and transparent corundum coatings may be deposited on glass surfaces. Coatings which were produced by using commerical boehmite (A1OOH) dispersions could also be completely transformed into a-Al203, but they were not dense enough at about 500nm thickness. Coatings produced by an alkoxide-gel process from aluminium butoxide were dense at a thickness of maximal 100nm and adhered very well to the glass surface which had been slightly roughened by HF etching. A scratch test with a quartz grain showed that the damage of the glass surfaces coated in this way was less than 2% compared to that of uncoated surfaces. Transmission was about 90% in the visible wavelength range.
