Author, institution: Nerita Žmuidzinavičienė, Kaunas University of Technology
Science area, field: Physical Sciences, Chemistry – 03P
The Doctoral Dissertation is available at the library of Kaunas University of Technology (K. Donelaičio St. 20, Kaunas).
Scientific Supervisor: Prof. Dr. Algirdas ŠULCIUS (Kaunas University of Technology, Physical Sciences, Chemistry – 03P).
Dissertation defence board of Chemistry Science Field:
Prof. Dr. Habil.Algirdas ŠACKUS (Kaunas University of Technology, Physical Sciences, Chemistry – 03P) – chairman;
Doc. Dr. Nijol DUKŠTIEN (KaunasUniversity of Technology, Physical Sciences, Chemistry – 03P);
Prof. Dr. Habil. Aivaras KAREIVA (Vilnius University, Physical Sciences, Chemistry – 03P);
Prof. Dr. Habil. Rimantas RAMANAUSKAS (Center for Physical Sciences and Technology, Institute of Chemistry,Physical Sciences, Chemistry – 03P);
Prof. Dr. Eugenijus VALATKA (KaunasUniversity of Technology, Physical Sciences, Chemistry – 03P).
Annotation:
Literature data on the influence of Te compounds as additives in the electrolytic bath on electrodeposition, microhardness and internal stresses of Mn coatings are rather spare. Therefore, from theoretical and practical points of view, it is relevant to determine the influence of Te compounds as additives on the physical and mechanical properties of electrolytic Mn deposition coatings, and which condition the corrosion properties of these coatings. Aim of the work-to determine the influence of a Te(VI) additive in an acidic manganese ammonium sulphate bath on electrodeposition of electrolytic Mn coatings and the physical-mechanical properties of electrodeposited coatings. In addition to investigating the possibility of application of electrodeposited Mn coatings with Te intermixtures for the protection of steel against corrosion.
Optimal electrolysis conditions, enabling electrodeposition of high quality, nanocrystal size and resistant towards corrosion electrolytic Mn coatings containing Te from an acidic manganese ammonium sulphate bath have been determined. It has been shown that phosphatic coatings increase significantly the resistance against corrosion of electrolytic Mn coatings with Te additive. The influence of the bath temperature and current density on morphology, size of crystalites, internal stesses and microhardness of electrolytic Mn coatings electrodeposited from electrolyte with Te(VI) additive has been determined. It has been determined, that electrolytic Mn coatings electrodeposited from a manganese ammonium sulphate bath are nanocrystal, and an average size of crystalites and variation of Te concentration in the pits and bumps on the coating surface depend on the current density and electrolyte temperature.
