Mechanical properties of Mn coatings, electrodeposited from sulphate electrolyte with Te(VI) additive at different temperatures
Keywords:Mn electrodeposition, Te(VI) additive, microhardness, tensile stress
The influence of electrolyte temperature and cathode current density on the microhardness and tensile stress of electrodeposited Mn coatings have been investigated. It has been determined that mostly hard coatings were electrodeposited from the acid manganese electrolyte with the Te(VI) additive at 20 °C using a low current density (2 A×dm–2). Mn coatings of the same high hardness were electrodeposited using a higher current density (15 A×dm–2) and at a higher electrolyte temperature (70 °C). Supposedly, the hardness is related to the structure and composition of coatings very closely.
It has been assumed that Te incorporates in the Mn coatings during the initial stage of electrolysis and changes their structure and morphology. This leads to the maximum tensile stress values of the relatively thick coatings (1–2 mm).