The performance of modern materials is not only related to high-tech bulk materials, but also to the properties of their surface. The aim of this thesis was to investigate the influence of various doping elements on the structure and modification of wear-protective Al2O3 coatings, deposited by high temperature chemical vapor deposition. For this purpose Cr, Sr, Sn and Nb have been selected as promising candidates. Metallic and chloride precursors were used for co-vaporization parallel to Al. The depositions were carried out in a horizontal hot wall reactor within a temperature range between 450 °C and 1000 °C, using an HCl/Ar/N2/H2/CO2 atmosphere. Cemented carbide and Mo were used as substrate material. Gravimetric analysis, XRD measurements, GDOES and SEM investigations were conducted for the evaluation of the experiments. Cr, Sn and Sr could be incorporated in contents up to 10 at.-%, 0.1 at.-% and 0.01 at.-%, respectively. The doping resulted in modification of surface appearance and structure.