National Repository of Grey Literature 12 records found  1 - 10next  jump to record: Search took 0.01 seconds. 
Impact resistence on nanocomposite Mo-B-C- and W-B-C coatings deposited using magnetron sputtering technique
Fořt, Tomáš ; Grossman, Jan ; Daniel, Josef ; Sobota, Jaroslav ; Dupák, Libor ; Buršíková, V. ; Zábranský, L. ; Souček, L. ; Mirzaei, S. ; Alishahi, M. ; Vašina, P. ; Buršík, Jiří
Recently, based on attractive mechanical properties of boride and carbide based X2BC ternary compounds (X = Mo, W and Ta) they became subjects of both theoretical calculations and experimental work. In the case of stoichiometric composition, X2BC with X = Mo, W and Ta are very promising candidates for protection of cutting and forming tools due to their unusually stiffness and moderate ductility.\nIn this work we focus on nanostructured Mo-B-C and W-B-C layers grown by magnetron sputtering on high speed steel (HSS) substrates. Mechanical properties of the layers were characterized by nanoindentation experiments in both static and dynamic loading regimes. Elastic modulus, indentation hardness and fracture resistance were evaluated and discussed. The fracture resistance of both Mo-B-C and W-B-C coatings was compared using both indentation and dynamic impact tests.\n
Study of fracture toughness and wear resistance of thin MoBC coating under dynamic conditions
Buršíková, V. ; Grossman, Jan ; Fořt, Tomáš ; Souček, P. ; Zábranský, L. ; Buršík, Jiří ; Vašina, P. ; Dupák, Libor ; Sobota, Jaroslav
The aim of the present work was to study the mechanical properties of thin amorphous MoBC coatings and MoBC coatings consisting of nanocrystalline Mo2BC embedded in amorphous MoBC matrix. The hardness of the amorphous MoBC coatings (20 GPa) is comparable with the common amorphous diamond-like carbon coatings, however their elastic modulus as well as fracture toughness and ductility are significantly higher. Magnetron sputtering of three targets, B4C, C and Mo, for MoBC was used for coatings preparation. The aim of this work was to study the mechanical and tribological properties of MoBC coatings deposited on high speed steel substrate. The classification of MoBC coatings was performed using an impact tester in a dynamic mode and enabled us to predict the limit load causing the coating destruction.
Dynamic impact tester of hard thin coatings
Grossman, Jan ; Dupák, Libor ; Fořt, Tomáš ; Sobota, Jaroslav
An impact test has been used to evaluate the impact wear resistance of nanostructured hard coatings using a system developed at the Institute of Scientific Instruments in collaboration with the Brno University of Technology. After the test, wear scars were evaluated by means of scanning electron microscope, spectral analyses and profilometer. The impact test offers an important new method for the determination of both the fracture toughness and wear behaviour of hard thin coatings.
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.
Studium mechanických vlastností gradovaných amorfních DLC povlaků deponovaných PECVD
Buršíková, V. ; Stoica, A. ; Sobota, Jaroslav ; Grossman, Jan ; Fořt, Tomáš ; Klapetek, P. ; Buršík, Jiří ; Peřina, Vratislav ; Bláhová, O.
For optimisation of performance of the coating there is necessary to optimise the following materials parameters: the elastic modulus, hardness, surface strength, film fracture toughness and film-substrate adhesion. We proposed to protect the substrate surface with graded coating, which has monotonically graded elastic modulus and Poisson's ratio.
Tribologické chovaní tvrdých uhlíkových kompozitních vrstev
Fořt, Tomáš ; Grossman, Jan ; Sobota, Jaroslav ; Vítů, T. ; Novák, R.
Carbon hard composite coatings were exposed to dynamical load and high temperature pin-on-disc CSM Tribometer. To evaluate the impact resistance of thin hard composite coating in dynamic loading wear applications an impact test was used. The sliding tests in air were carried out in the range from room temperature to 500 °C with controlled relative humidity. Hardness, elastic modulus and fracture toughness of deposited coatings were studied by indentation technique using Fisherscope H100 tester.
Funkčnost amorfních uhlíkových povlaků s obsahem křemíku deponovaných použitím nízkotlaké PECVD
Sobota, Jaroslav ; Buršíková, V. ; Fořt, T. ; Grossman, Jan ; Klapetek, P. ; Buršík, Jiří ; Franta, D. ; Peřina, Vratislav
Amorphous carbon films with silicon content were deposited using low pressure PECVD. The films were optimised for deposition on steel substrates. To evaluate the impact resistance of graded amorphous carbon films in dynamic loading wear applications an impact test has been used.
Mechanical Properties of TiCN Layers
Bláhová, O. ; Prušáková, L. ; Sobota, Jaroslav ; Fořt, Tomáš ; Grossman, Jan ; Fajkus, M.
The work deals with problems of evaluation mechanical properties of thin wear resistance layers deposited by PACVD method. Nanoindenter XP carried out the nanoindentation measurements with continuous stiffness measurement. The tribological properties were carrying out by high temperature pin-on-disk tribometer and by impact tester.
Testování a modelování napěťových polí v tenkých tvrdých nanokompozitních multivrstvých a monovrstvých povlacích
Fořt, Tomáš ; Grossman, Jan ; Sobota, Jaroslav
To optimize the design of a coating/substrate system before the deposition we apply modelling of the stress fields in the coating/substrate system. After the deposition of the designed system we use the dynamic impact tester to evaluate wear resistance of the system in dynamical load.
Testing of the impact load of hard wear resistant coatings
Sobota, Jaroslav ; Fořt, Tomáš ; Grossman, Jan
The dynamic impact wear tester developed in our laboratory has been used to evaluate hard wear resistant coatings. After each test, wear scars were evaluated by means of optical microscope and profilometer. Results of these tests show usability of various types of coatings in dynamic load and enable to optimize the design of the coating/substrate system.

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