The work presents the results of the investigations of the effect of inhibitors coated on the internal walls of a ceramic mould on the quality

of the obtained casts made of the AM60 alloy containing additions of chromium and vanadium. In order to reduce the reactivity of

magnesium alloy cast by the technology of investment casting with the material of the mould and the ambient atmosphere, solid inhibitors

were applied in the form of a mixture of KBF4 and H3BO3 after the stage of mould baking and before the mould’s being filled with the

liquid alloy. For the purpose of examining the effect of the inhibitors on the surface quality of the obtained casts, profilometric tests were

performed and the basic parameters describing the surface roughness, Ra, Rz and Rm, were determined.