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Evaluation of electrochemical characteristics of AZ31 wrought magnesium alloy
Hána, Tomáš ; Tkacz, Jakub (referee) ; Drábiková, Juliána (advisor)
This thesis deals with the issue of electrochemical characterization of AZ31 wrought magnesium alloy, which was exposed to corrosive environment of 0.1 moldm3 solution of sodium chloride. Electrochemical impedance spectroscopy and potentiodynamic tests were used for evaluation of electrochemical characteristics such as corrosion rate, corrosion current density, corrosion potential and polarization resistance. There is a summary of ways of a production of magnesium alloys, influence of alloying element on properties of material and types of corrosion, which leads to degradation of material in the theoretical part. In the experimental part there is characterization of used methods, summary of results and a discussion of obtained data and its comparison.
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Evaluation of electrochemical characteristics of AZ61 magnesium alloy processed by squeeze casting
Pikner, Jan ; Hadzima, Branislav (referee) ; Fintová, Stanislava (advisor)
Bachelor thesis deals with the characterization of electrochemical corrosion properties of AZ61 magnesium alloy prepared by squeeze casting method. The theoretical part of the work focuses on properties of AZ61 alloy, influence of alloying elements on magnesium alloys and corrosion. The practical part of the work deals with electrochemical characteristics of AZ61 alloy with different surface condition in of 0.1 M NaCl solution. Corrosion potential (Ekor) and corrosion current density (ikor) were determined by potentiodynamic test. Polarisation resistance was determined by electrochemical impedance spectroscopy. Based on the measured results was discussed the influence of production, chemical composition, structure and surface treatment (grinding and polishing) on corrosion characteristics of the alloy.
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Evaluation of electrochemical properties of wrought Mg-Al-Zn type magnesium alloys
Slouková, Karolína ; Hadzima, Branislav (referee) ; Tkacz, Jakub (advisor)
The aim of this master’s thesis is electrochemical characteristics evaluation of magnesium alloys. The theoretical part describes the properties of magnesium and its alloys and their corrosion characteristics. In the experimental part are presented results of corrosion resistance measurement of two types of wrought magnesium alloys. It was AZ31 and AZ61 magnesium alloys, which were measured in Hank’s solutions with addition of ions Ca2+ and Mg2+ (SBF+) and without addition of the ions (SBF). The solution temperature during the measurement was 37 ± 1 °C. The experiments were used electrochemical impedance spectroscopy (EIS) and potentiodynamic tests using linear polarization (LP). EIS measurements were done in times of 5 minutes, 1, 2, 4, 8, 12, 24, 48, 72, 96 and 168 hours. Potentiodynamic tests were only short-term and they started after 5 minutes of stabilization. Both methods were used for measuring the electrochemical characteristics of polished and ground surface of the samples. The most important measurement results were polarization resistance, corrosion potential and corrosion current density. The electrochemical measurements are used to estimate the chemical composition influence and alloy’s structure of the corrosion resistance.
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Hydrothermal synthesis and characterization of calcium phosphate-based coatings on AZ31 magnesium alloy
Knoflíčková, Lenka ; Doskočil, Leoš (referee) ; Buchtík, Martin (advisor)
The aim of this diploma thesis was to summarize all necessary knowledge needed for preparation of a quality CaP coating on AZ31 wrought magnesium alloys, and to implement its optimization for use in simulated body fluids. The theoretical part discusses biomaterials and their classification. Subsequently, the potential of magnesium alloys, their corrosion, and the possibility of surface treatment for in vivo applications are described in detail. The theoretical part concludes with the mechanism of deposition of CaP coatings on magnesium alloys and methods to evaluate their corrosion resistance. The experimental part includes the process of optimization of Mg alloy pretreatment and optimization of CaP coatings preparation, where the quality evaluation criteria were the appearance of the coating and its electrochemical and corrosion properties. These were evaluated by potentiodynamic tests. The microstructure and the chemical composition of deposited coating were observed and measured by optical and scanning electron microscopy. Long-term corrosion tests using electrochemical impedance spectroscopy (EIS) were performed on the optimized CaP coatings and these results were then compared with the corrosion properties of the uncoated AZ31 alloy.
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Hydrothermal synthesis and characterization of calcium phosphate-based coatings on AZ31 magnesium alloy
Knoflíčková, Lenka ; Doskočil, Leoš (referee) ; Buchtík, Martin (advisor)
The aim of this diploma thesis was to summarize all necessary knowledge needed for preparation of a quality CaP coating on AZ31 wrought magnesium alloys, and to implement its optimization for use in simulated body fluids. The theoretical part discusses biomaterials and their classification. Subsequently, the potential of magnesium alloys, their corrosion, and the possibility of surface treatment for in vivo applications are described in detail. The theoretical part concludes with the mechanism of deposition of CaP coatings on magnesium alloys and methods to evaluate their corrosion resistance. The experimental part includes the process of optimization of Mg alloy pretreatment and optimization of CaP coatings preparation, where the quality evaluation criteria were the appearance of the coating and its electrochemical and corrosion properties. These were evaluated by potentiodynamic tests. The microstructure and the chemical composition of deposited coating were observed and measured by optical and scanning electron microscopy. Long-term corrosion tests using electrochemical impedance spectroscopy (EIS) were performed on the optimized CaP coatings and these results were then compared with the corrosion properties of the uncoated AZ31 alloy.
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Evaluation of electrochemical characteristics of AZ31 wrought magnesium alloy
Hána, Tomáš ; Tkacz, Jakub (referee) ; Drábiková, Juliána (advisor)
This thesis deals with the issue of electrochemical characterization of AZ31 wrought magnesium alloy, which was exposed to corrosive environment of 0.1 moldm3 solution of sodium chloride. Electrochemical impedance spectroscopy and potentiodynamic tests were used for evaluation of electrochemical characteristics such as corrosion rate, corrosion current density, corrosion potential and polarization resistance. There is a summary of ways of a production of magnesium alloys, influence of alloying element on properties of material and types of corrosion, which leads to degradation of material in the theoretical part. In the experimental part there is characterization of used methods, summary of results and a discussion of obtained data and its comparison.
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Evaluation of electrochemical characteristics of AZ61 magnesium alloy processed by squeeze casting
Pikner, Jan ; Hadzima, Branislav (referee) ; Fintová, Stanislava (advisor)
Bachelor thesis deals with the characterization of electrochemical corrosion properties of AZ61 magnesium alloy prepared by squeeze casting method. The theoretical part of the work focuses on properties of AZ61 alloy, influence of alloying elements on magnesium alloys and corrosion. The practical part of the work deals with electrochemical characteristics of AZ61 alloy with different surface condition in of 0.1 M NaCl solution. Corrosion potential (Ekor) and corrosion current density (ikor) were determined by potentiodynamic test. Polarisation resistance was determined by electrochemical impedance spectroscopy. Based on the measured results was discussed the influence of production, chemical composition, structure and surface treatment (grinding and polishing) on corrosion characteristics of the alloy.
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Evaluation of electrochemical properties of AZ31 magnesium alloy prepared by sqeeze casting
Mikulášová, Kristýna ; Drábiková, Juliána (referee) ; Tkacz, Jakub (advisor)
The bachelor thesis deals with electrochemical characterization of corrosion properties of magnesium alloy AZ31. This alloy produced by squeeze casting method was exposed to a corrosive environment of 0,1 M solution of NaCl. Scanning electron microscopy (SEM) with elemental analysis measured by energy dispersive spectroscopy (EDS) was used for the evaluation of the AZ31 magnesium alloy’s surface. Consequently, short term corrosion tests (5 min) were undertaken by potentiodynamic tests. Long term tests (168 h) were measured by electrochemical impedance spectroscopy (EIS). The effects of different alloy surface treatment (grinding and polishing) on the corrosion rate of the AZ31 magnesium alloy produced by squeeze casting method were evaluated by measured results.
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Evaluation of electrochemical properties of wrought Mg-Al-Zn type magnesium alloys
Slouková, Karolína ; Hadzima, Branislav (referee) ; Tkacz, Jakub (advisor)
The aim of this master’s thesis is electrochemical characteristics evaluation of magnesium alloys. The theoretical part describes the properties of magnesium and its alloys and their corrosion characteristics. In the experimental part are presented results of corrosion resistance measurement of two types of wrought magnesium alloys. It was AZ31 and AZ61 magnesium alloys, which were measured in Hank’s solutions with addition of ions Ca2+ and Mg2+ (SBF+) and without addition of the ions (SBF). The solution temperature during the measurement was 37 ± 1 °C. The experiments were used electrochemical impedance spectroscopy (EIS) and potentiodynamic tests using linear polarization (LP). EIS measurements were done in times of 5 minutes, 1, 2, 4, 8, 12, 24, 48, 72, 96 and 168 hours. Potentiodynamic tests were only short-term and they started after 5 minutes of stabilization. Both methods were used for measuring the electrochemical characteristics of polished and ground surface of the samples. The most important measurement results were polarization resistance, corrosion potential and corrosion current density. The electrochemical measurements are used to estimate the chemical composition influence and alloy’s structure of the corrosion resistance.
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