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Optimization of surface pretreatment of steel and aluminum alloy for subsequent application of powder paint
Běloch, Martin ; Březina, Matěj (referee) ; Wasserbauer, Jaromír (advisor)
This diploma thesis deals with various procedures of surface pretreatment of steel and aluminum alloy for subsequent application of powder coating substance. The work begins with an overview of the general characteristics of the materials used. The core part of the work is then a summary of the individual methods of pretreatment that can be used to modify the material surface. A special chapter is devoted to methodologies for the application of powder substances. Before separate application, the sample must first be carefully pretreated to ensure removal of organic compounds (e.g. oils from primary processing - grinding, cutting), or dust impurities to ensure the correct barrier effect. After dividing the individual methods of surface preparation, a powder paint system with a total thickness of approximately 50 µm is applied to the test material. Samples with different surface pretreatments will be compared both in terms of mechanical properties and in terms of electrochemical properties.
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Corrosion Resistance of Structural Magnesium Alloys
Tkacz, Jakub ; Pacal, Bohumil (referee) ; Hadzima, Branislav (referee) ; Havlica, Jaromír (advisor)
This thesis describes magnesium alloys, their properties and methods of their production. However, experimental part is focused on AZ91 magnesium alloy. Conversion coatings were prepared on the AZ91 surface – chromate coating, phosphate permanganate coating and fluoride coating. Corrosion resistance of the prepared coatings were compared by immersion tests and by potentiodynamic methods. Evaluation of corrosion resistance by immersion tests was successful only for phosphate permanganate coating. Only this coating was removed during cleaning of the samples. For comparison of corrosion resistance was important to find the correct procedures and optimize the measurements methods. For these purposes have been chosen galvanic zinc coating on steel sheets. Thickness of the zinc coating were 8 and 30 microns. This coatings provide uniform zinc surface without heterogenities which was important for the potentiodynamic measurements. After optimization methods for potentiodynamic measurements by galvanic zinc coatings have been measured magnesium alloy AZ91 uncoated and coated by conversion coatings. For uncoated AZ91 magnesium alloy was determined suitable method so called virgin cathodic curve. On the other hand, for the coated AZ91 magnesium alloys was determined suitable method so called combined curve, within which we measured cyclic voltammetry curve (± 5 mV) and then virgin anodic curve.
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Galvanic plating of magnesium alloy with Ni-P bond coat
Zahálka, Martin ; Kosár, Petr (referee) ; Wasserbauer, Jaromír (advisor)
Cílem této diplomové práce jse najít nejnižší možnou tloušťku nikl-fosforového povlaku, který může být galvanicky pokoven mědí bez defektů na horčíkové slitině, nikl-fosforového nebo měděného povlaku. V teoretické části jsou shrnuty poznatky o hořčíkových slitinách a jejich korozi. Navíc se teoreticá část zaměřuje na popis procesu bezproudého niklování a elektrochemického pokovování mědí a jejich porovnání. Na konci teoretické části je shrnut současný výzkum o elektrochemickém pokovování hořčíkových slitin. V experimentální části byl popsán proces přípravy povlaků Ni-P a Cu na horčíkové slitině AZ91. Na jedné vrstvě a dvojité vrstvě Ni-P povlaku byla provedena elektrodepozice mědi. Navíc byl diskutován vliv předůpravy před samotnou elektrodepozicí mědi. Za účelem zjištění korozních vlastností vzorků byl vykonán potenciodynamický test. Následně byly připraveny metalografické výbrusy jednotlivých vzorků a pomocí světelného a rastrovacího elektronového mikroskopu byla provedena charakterizace. Na konec bylo zjištěno prvkové složení jednotlivých povlaků pomocí EDX analýzy.
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Optimization of surface pretreatment of steel and aluminum alloy for subsequent application of powder paint
Běloch, Martin ; Březina, Matěj (referee) ; Wasserbauer, Jaromír (advisor)
This diploma thesis deals with various procedures of surface pretreatment of steel and aluminum alloy for subsequent application of powder coating substance. The work begins with an overview of the general characteristics of the materials used. The core part of the work is then a summary of the individual methods of pretreatment that can be used to modify the material surface. A special chapter is devoted to methodologies for the application of powder substances. Before separate application, the sample must first be carefully pretreated to ensure removal of organic compounds (e.g. oils from primary processing - grinding, cutting), or dust impurities to ensure the correct barrier effect. After dividing the individual methods of surface preparation, a powder paint system with a total thickness of approximately 50 µm is applied to the test material. Samples with different surface pretreatments will be compared both in terms of mechanical properties and in terms of electrochemical properties.
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Galvanic plating of magnesium alloy with Ni-P bond coat
Zahálka, Martin ; Kosár, Petr (referee) ; Wasserbauer, Jaromír (advisor)
Cílem této diplomové práce jse najít nejnižší možnou tloušťku nikl-fosforového povlaku, který může být galvanicky pokoven mědí bez defektů na horčíkové slitině, nikl-fosforového nebo měděného povlaku. V teoretické části jsou shrnuty poznatky o hořčíkových slitinách a jejich korozi. Navíc se teoreticá část zaměřuje na popis procesu bezproudého niklování a elektrochemického pokovování mědí a jejich porovnání. Na konci teoretické části je shrnut současný výzkum o elektrochemickém pokovování hořčíkových slitin. V experimentální části byl popsán proces přípravy povlaků Ni-P a Cu na horčíkové slitině AZ91. Na jedné vrstvě a dvojité vrstvě Ni-P povlaku byla provedena elektrodepozice mědi. Navíc byl diskutován vliv předůpravy před samotnou elektrodepozicí mědi. Za účelem zjištění korozních vlastností vzorků byl vykonán potenciodynamický test. Následně byly připraveny metalografické výbrusy jednotlivých vzorků a pomocí světelného a rastrovacího elektronového mikroskopu byla provedena charakterizace. Na konec bylo zjištěno prvkové složení jednotlivých povlaků pomocí EDX analýzy.
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Corrosion Resistance of Structural Magnesium Alloys
Tkacz, Jakub ; Pacal, Bohumil (referee) ; Hadzima, Branislav (referee) ; Havlica, Jaromír (advisor)
This thesis describes magnesium alloys, their properties and methods of their production. However, experimental part is focused on AZ91 magnesium alloy. Conversion coatings were prepared on the AZ91 surface – chromate coating, phosphate permanganate coating and fluoride coating. Corrosion resistance of the prepared coatings were compared by immersion tests and by potentiodynamic methods. Evaluation of corrosion resistance by immersion tests was successful only for phosphate permanganate coating. Only this coating was removed during cleaning of the samples. For comparison of corrosion resistance was important to find the correct procedures and optimize the measurements methods. For these purposes have been chosen galvanic zinc coating on steel sheets. Thickness of the zinc coating were 8 and 30 microns. This coatings provide uniform zinc surface without heterogenities which was important for the potentiodynamic measurements. After optimization methods for potentiodynamic measurements by galvanic zinc coatings have been measured magnesium alloy AZ91 uncoated and coated by conversion coatings. For uncoated AZ91 magnesium alloy was determined suitable method so called virgin cathodic curve. On the other hand, for the coated AZ91 magnesium alloys was determined suitable method so called combined curve, within which we measured cyclic voltammetry curve (± 5 mV) and then virgin anodic curve.
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