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On the modern surface treatment of pressure casting dies
Černý, Štěpán ; Sliwková, Petra (referee) ; Píška, Miroslav (advisor)
Bachelor thesis is focused on the influence of surface treatments due to prolonging life and decreasing an amount of service hours on the die casting molds of aluminium alloys. Theoretical analysis of the problem deals with the requirements for tools materials used for making these moulds. Furthermore it deals with the materials which are most commonly used in their production and the species of aluminium alloys which are most commonly casted. The second part of this thesis, which is discussed in detail, deals with design solution regarding to usage of surface finishes on the moulds for die casting and their specific properties. Another part of this thesis contains experimental tests where was measured selected coating in order to determine its behaviour during the casting cycles with a focus on increasing lifetime of the mould insert, also reducing the amount of glued metal on the walls and finally improving the surface of casted part. It was found, according the analysis results, that the TiAlN coating helped to reduce the amount of glued metal on the mould walls. This also helped to reduce the amount of service intervals. On the other side for achieving much better results is better to use TiB2 coating. It has been experimentally confirmed that the TiAlN coating is not suitable for using in die casting moulds of aluminium alloys.
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Structure and properties of DLC layers for industrial applications
Mates, Tomáš ; Ledinský, Martin ; Vetushka, Aliaksi ; Pikna, Peter ; Fejfar, Antonín ; Marek, A. ; Vyskočil, J. ; Erichsen, J. ; Dawah, P.
Diamond-like carbon (DLC) layers based on amorphous carbon are used for wide range of applications, mostly for mechanical protection of various industrial components. We examined DLC layers at micro- and nanoscale by two independent microscopic techniques: Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) with a good agreement. We compared DLC layers grown on steel substrate and Si wafer and found similarly structured clusters and a certain difference in the density of nucleation centres. The measurements of local mechanical properties by the AFM tip revealed that the Si wafer behaves as softer material compared to the growing DLC nanoclusters that also exhibit lower values in the map of the relative local friction coefficient. Finally, we observed changes in the Raman spectra of the DLC exposed to annealing at ambient conditions and found a gradual shift from the diamond phase to the graphite phase as a function of increasing temperature.
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On the modern surface treatment of pressure casting dies
Černý, Štěpán ; Sliwková, Petra (referee) ; Píška, Miroslav (advisor)
Bachelor thesis is focused on the influence of surface treatments due to prolonging life and decreasing an amount of service hours on the die casting molds of aluminium alloys. Theoretical analysis of the problem deals with the requirements for tools materials used for making these moulds. Furthermore it deals with the materials which are most commonly used in their production and the species of aluminium alloys which are most commonly casted. The second part of this thesis, which is discussed in detail, deals with design solution regarding to usage of surface finishes on the moulds for die casting and their specific properties. Another part of this thesis contains experimental tests where was measured selected coating in order to determine its behaviour during the casting cycles with a focus on increasing lifetime of the mould insert, also reducing the amount of glued metal on the walls and finally improving the surface of casted part. It was found, according the analysis results, that the TiAlN coating helped to reduce the amount of glued metal on the mould walls. This also helped to reduce the amount of service intervals. On the other side for achieving much better results is better to use TiB2 coating. It has been experimentally confirmed that the TiAlN coating is not suitable for using in die casting moulds of aluminium alloys.
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Studium mechanických vlastností DLC tenkých vrstev deponovaných v jedno a dvoufrekvenčním kapacitním výboji
Buršíková, V. ; Stoica, A. ; Sobota, Jaroslav ; Grossman, Jan ; Fořt, Tomáš ; Klapetek, P. ; Buršík, Jiří ; Bláhová, O.
Nanostructured diamond-like carbon coatings were deposited on several different substrate materials (silicon, glass, polycarbonate and steel) in single (13.56 MHz) and dual capacitive r.f. discharges (LF=100-300kHz, HF =13.56 MHz). The objective of our study was to find the optimum combination of the high and low frequency (continuous or pulsed) excitation enabling to cover uneven substrate surfaces and significant lowering of the internal stress in films.
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