Due to their physical properties magnesium alloys are interesting materials for automotive and medical applications. Unfortunately, magnesium alloys are prone to corrosion, which limits their use. This issue can be overcome by application of coatings. In this work, corrosion inhibiting inorganic coatings were successfully applied on magnesium alloy AZ31 by sonochemistry. For automotive applications, cerium oxide and cerium phosphate coatings were developed as a replacement of carcinogenic Cr(VI)coatings. The coatings are primers, which should enhance corrosion resistance and at the same time promote adhesion of subsequently applied organic top-coats. The coatings for orthopaedic use consist of calcium phosphate species, i. e. nanocrystalline apatite and octacalcium phosphate, which are main inorganic components or precursors of bone, respectively. The coatings are supposed to enhance corrosion resistance and biocompatibility. Chemical composition of the coatings was investigated by means of vibrational spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The characterisation of morphology was performed by means of scanning electron microscopy. Corrosion inhibition was monitored by electrochemical impedance spectroscopy. Additionally, application-specific properties were tested as well: bonding of cerium oxide and phosphate coatings to organic adhesive and cytocompatibility of calcium phosphate coatings.