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Zn and Mg based bulk materials for biomedical applications
Ryšťák, Jaroslav ; Fintová, Stanislava (referee) ; Doležal, Pavel (advisor)
Topic of the diploma thesis is Zn-Mg bulk material preparation by powder mixtures sintering at hot pressing. Structure, porosity and physically mechanical properties of prepared bulk materials were evaluated. Obtained results and their interpretation were served as feedback for following optimization of individual processing parameters of bulk materials preparation. Solution of diploma thesis is focused on study and control of processes during bulk material preparation and processes description from physical-chemical point of view with respect to structure creation and final material properties.
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Heat treatment of hand tightening tools
Gregor, Martin ; Kouřil, Miloslav (referee) ; Doležal, Pavel (advisor)
Bachelor´s thesis deals with problems of heat treatment of hand tightening tools. Literary analysis is focused on the principles of heat treatment such as annealing, austenitizing, quenching and tempering. Attention is also focused on unconventional heat treatment technology using vacuum and furnace atmospheres based on nitrogen. Analysis of dividing and heat treatment of tool steels is another subject of literary research. In the experimental part are machinery and technological progress of the stock in the company Wera Werk s.r.o., which has more than 50 years engaged in the manufacture, sales and innovation of hand tightening tools. Following processing of the experimental material with a focus on heat treatment and mechanical properties indicate in laboratory tests. Based on the measured and statistically processed values of mechanical quantities is developed design optimization process of heat treatment of hand tightening tools of Wera Werk.
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In-System Programmer for ICSP Interface of Pic Microcontrollers
Doležal, Pavel ; Strnadel, Josef (referee) ; Šimek, Václav (advisor)
This thesis is dealing with a design of programming device with the expected use for Microchip PIC 16F and 18F microcontrollers. Individual chapters are dedicated to aspects of circuitry, printed circuit board design and user software tools. The proposed device is based on PIC18F67J50 microcontroller, graphic LCD diplay, and memory card interface. Design can be easily adjusted in order to support wide range of devices. Microchip's In-Circuit Serial Programming protocol is described with focus on previously mentioned family of devices. Working prototype of the programmer is attached to this thesis as a demonstration of a practical outcome.
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Structure and properties of magnesium alloys Mg-Ca-Zn
Hlavnička, Jiří ; Pacal, Bohumil (referee) ; Doležal, Pavel (advisor)
This master’s thesis deals with design and preparation of a new biodegradable magnesium alloy based on Mg-Ca-Zn. Based on information from literature, the Mg-3Zn-2Ca alloy was designed. The base material was produced by gravity casting and the evaluation in the as-cast and heat treated state was performed. For preparation of the experimental material, following methods were designed: squeeze casting, hot rolling and the ECAP. During preparation by hot rolling, no optimal conditions were found and significant cracks occurred in both as-cast and heat treated material. In the case of experimental material, prepared by the ECAP method with back-pressure, better combination of stress-strain properties was observed. Also the squeeze casting method showed improvement; especially the amount of casting defects was eliminated. The evaluation of microstructure and mechanical properties was performed by the light and scanning electron microscopy, RTG phase analysis and the tensile and compression tests.
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Conversion coatings and their characterisation
Březina, Matěj ; Doležal, Pavel (referee) ; Zmrzlý, Martin (advisor)
Aim of this study is to improve corrosion resistance of magnesium alloy AZ91 by conversion coatings. Influence of alloy microstructure on conversion coating growth and corrosion resistance was evaluated. Properties of pure magnesium and magnesium alloy AZ91 as well as the influence of alloying elements on properties of this alloy are described in theoretical part. Recent results of corrosion protection by conversion coatings on AZ type magnesium alloys are summarised in recherché part. Practical part focuses on preparation of hexavalent chromium based conversion coating and phosphate-permanganate based conversion coating on as cast AZ91 magnesium alloy, these coatings were subsequently applied on annealed AZ91 magnesium alloy. Corrosion protection of the coatings prepared on as cast and annealed alloy was evaluated by potentiodynamic measurements and testing in neutral salt spray. Furthermore the influence of plasma activation on phosphate-permanganate coating surface was studied.
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Preparation and properties of porous zinc material
Ryšťák, Jaroslav ; Fintová, Stanislava (referee) ; Doležal, Pavel (advisor)
Bachelor thesis is focused on preparation of bulk material prepared from zinc powder by cold pressing followed by sintering. Topic of the work includes characterization of prepared material depending on the choice of the compaction process conditions. Bulk material is characterized by physical-mechanical tests, structure and porosity. Thesis solving and focuses on study and control of processes during bulk material preparation and description of the processes from physically-chemical point of view of the structure creation and final material properties.
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Powder metalurgically prepared materials based on Zn and Ca
Morcinek, Tomáš ; Hasoňová, Michaela (referee) ; Doležal, Pavel (advisor)
The topic of this bachelor thesis is a process of preparation and characterization of bulk material from zinc and calcium powder mixture by hot pressing. Materials thus prepared were evaluated in terms of their microstructure and physical-mechanical properties. The influence of calcium content in the material on physical-mechanical properties of the resulting structure was observed. The solution is focused on exploration of the influence of material composition in the process of preparation of bulk material, and description of these processes from the physical-chemical point of view on the structure formation and the resulting properties of the material.
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Corrosion of biodegradable magnesium alloys in Hank's solutions
Faltejsek, Petr ; Fintová, Stanislava (referee) ; Doležal, Pavel (advisor)
The aim of the thesis was to design a methodology for in-situ evaluation of degradation of selected magnesium alloys using AFM in SBF solutions. Study of the degradation of magnesium alloys in a chemically different corrosive environments of simulated body fluid (SBF - Hank's solution). For the pilot study were used magnesium alloys AZ31 and AZ61, manufactured by advanced method of squeeze casting. Part of the thesis was to evaluate the influence of the chemical composition and structure on the degradation properties of these alloys.
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