Microstructure and Corrosion Properties of the (Mn-N-O-P) Type Layers Created on Aluminium Alloys

The microstructure, chemical and phase composition as well as corrosion investigations of the (Mn-N-O-P) type surface layers in comparison to uncoated an aluminium alloy have been performed. An elaborated multiplex surface treatment of aluminium alloys enables forming of phase composition in the several zones of the (Mn-N-O-P) type layers. The zone microstructure with phases consisted of nitrogen, oxygen and phosphorus has fundamental influence on the hardnes and corrosion resistance of aluminium alloys.