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New generations of PVD coatings
Kantar, Filip ; Kolář, Ladislav (referee) ; Jaroš, Aleš (advisor)
Bachelor thesis deals with methods of coating, cutting tools and a new generation of coatings. In the first part are listed and described basic coating methods. The next part is aimed on coating of PVD methods. In the third part are listed basic tool materials and their characteristics. The last part is focused on new generation of coatings, their application, properties and structures.
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Structure and Properties of Coatings Produced by PVD Technology
Doubrava, Marek ; Horynová, Miroslava (referee) ; Čelko, Ladislav (advisor)
The submitted work is focused on study of 3rd generation DLC films produced by Platit a.s. company. Thin films are deposited utilizing filtered cathodic vacuum arc process (FCVA). The main goal of thesis was to find out the influence on film properties, caused by change of the substrate holders with different heat dissipation. The change of the substrate holders is motivated purely by economical effort to increase productivity of the deposition process. Teoretical part of the thesis is about the principles of PVD deposition process, characterization of the thin films, DLC thin films and materials used for cutting tools. Experimental part includes description of devices used for specimens analyses, including also the description of measuring process and used conditions. Acquiered results, not only the thin film thickness, adhesion or amount of sp^3 bonds, match with expected results.
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Modern cutting cemented carbide tools
Vopařil, Josef ; Humár, Anton (referee) ; Píška, Miroslav (advisor)
This thesis is focused on cutting tools made of cemented carbides. It contains analysis of cemented carbides for uncoated and coated cutting tools. It contains examples of modern tools for turning, milling and drilling. Practical part of this thesis evaluates and compares cutting properties of two types of spiral drills.
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Digital Image Steganography
Kolarčík, Tomáš ; Šimek, Václav (referee) ; Strnadel, Josef (advisor)
This bachelor thesis deals with digital image steganography and implements some of the available methods. This thesis describes steganography on a general level, it's history and it's current form. It also shows it's classification according to the type of carrier, the classification of the methods according to the style of hiding data and the influence of the hidden information. The primary subject of this thesis is image steganography, where facts that allow imperceptibly hide data inside image are described. A great part of this thesis is dedicated to the characteristics of the methods, which we observe and to the methods themselves. All of the methods described are implemented in a graphical and console application. The created application provides multiple image formats for hiding. In the last part, testing is performed in terms of capacity, imperceptibility and robustness.
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Reducing friction losses of piston rings
Csintalan, Radoslav ; Novotný, Pavel (referee) ; Svída, David (advisor)
This diploma thesis deals with the possibilities of reducing the friction losses of the first sealing piston rings of the VW Group 1.5 TSI, 110kW engine. The first part of the thesis theoretically deals with the issue of piston rings in terms of their classification. Reduction of friction losses is ensured by PVD and PECVD coating technology. The second part of the thesis describes the production of coated piston rings. Measurements are performed on the created coatings, which are compared and evaluated in the conclusion at the end of the thesis.
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HSS milling cutters deposited by nanocomposite coatings
Ludvík, Radek ; Kolář, Ladislav (referee) ; Jaroš, Aleš (advisor)
This bachelor thesis deals with nanocomposite coatings deposited on cutting tools of high speed steel. The paper describes the fundamentals of milling, tools for milling and their division and clamping. Gradually, there are analyzed problems of high speed steels (their classification, marking, properties and uses, chemical composition and heat treatment). Then there is described the main characteristics of coating methods (division of coatings into generations, surface preparation before the coating and PVD and CVD methods). The last part of the thesis focuses on the properties of nanocomposite materials and to companies dealing with their application to the high-speed steel.
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Digital Image Steganography
Mazánek, Antonín ; Šimek, Václav (referee) ; Strnadel, Josef (advisor)
This bachelor's thesis introduces the steganography scientific discipline. It presents its ancient and relative recent history, mentions its current use and outlines the possible directions for steganography future. It introduces steganography into context of hiding information superior domain and highlights differences between other methods in this domain. It describes steganography subdivisions and closer deals with digital image steganography. It presents some known methods and types of digital image data. The thesis also contains more detailed description of image data in PNG format. It describes the implementation of LSB and PVD steganography methods with images in PNG format as cover object and evaluates their key properties, namely: imperceptibility, capacity and robustness. At the end of the thesis, the author's reflection on the results and possibilities of further modifications of the mentioned methods is given.
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Enhancement of HSS tools cutting performance with PVD coatings
Medek, Martin ; Sliwková, Petra (referee) ; Píška, Miroslav (advisor)
Diploma work describes speed drill steels and its qualities before and after coating by methods PVD (Physical Vapour Deposition). The theoretic part is concerned with thermic processing of speed drill steels and their qualities with regard to individual alloying elements contained and its mechanical features. Second part of the theoretic part is concerned with particular methods of coating by the help of PVD technologies, kinds of coating with regard to additional elements and their qualities and surface treatments of coated material before and after its coating. The goal of the experimental part was the confrontation of cutting power features of cylindrical four-fluted face mills with straight shank, from speed drill steels non-coated and coated in two basic modes of milling – down-feed method and upfeed method. The results of measurements were interpreted by the help of four basic pictures (source values, power analysis, specific values). The result of all the experiment is that the application of PVD coatings enabled the increasing of cutting speed (with preservation of other cutting requirements) and led to decreasing of cutting force and cutting enforcements and extended durability of cutters.
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