29 research outputs found
Evaluation of electrochemical properties of steel sheets for automotive applications
Galvanizing as a process of zinc coating of base material is still the most widely used technology
applied in surface treatment of materials which are supposed to meet the requirement of high
corrosion resistance in various environments. This article presents the results of research aimed at
determining the corrosive properties of galvanized sheets in selected environments – distilled water,
NaCl and SARS solution, using electrochemical potentiodynamic test
Mogućnosti rabljenja visoko brzinskih kisikovih (VBK) prevlaka u uvjetima toplinskog cikličkog opterećenja
The item deals with the possibilities of utilization HVOF coatings in thermal cyclic loading conditions. There were evaluated three types of coatings based on WC-Co, WC-Co-Cr and Cr3C2-25NiCr. The quality of coatings was evaluated in terms of their adhesion as sprayed and also during the cyclic thermal loading, EDX analysis and evaluation of microhardness. Construction and structure of coatings were studied using optical and electron microscopy. There was also evaluated resistance of the coatings against erosive wear.Članak objašnjava mogućnosti rabljenja VBK-a prevlake u uvjetima toplinsko cikličnog opterećenja. Vrijednosti su za tri prevlake na temelju WC-Co, WC-Co-Cr i Cr3C2-25 NiCr. Kakvoća analize je provedena na temelju prijanjanja u početnom stanju i tijekom cikličkog toplinskog opterećenja sa EDX elektronskim mikroskopom. Vrijednovane su također otpornost prevlake na erozivno trošenje
Mogućnosti rabljenja visoko brzinskih kisikovih (VBK) prevlaka u uvjetima toplinskog cikličkog opterećenja
The item deals with the possibilities of utilization HVOF coatings in thermal cyclic loading conditions. There were evaluated three types of coatings based on WC-Co, WC-Co-Cr and Cr3C2-25NiCr. The quality of coatings was evaluated in terms of their adhesion as sprayed and also during the cyclic thermal loading, EDX analysis and evaluation of microhardness. Construction and structure of coatings were studied using optical and electron microscopy. There was also evaluated resistance of the coatings against erosive wear.Članak objašnjava mogućnosti rabljenja VBK-a prevlake u uvjetima toplinsko cikličnog opterećenja. Vrijednosti su za tri prevlake na temelju WC-Co, WC-Co-Cr i Cr3C2-25 NiCr. Kakvoća analize je provedena na temelju prijanjanja u početnom stanju i tijekom cikličkog toplinskog opterećenja sa EDX elektronskim mikroskopom. Vrijednovane su također otpornost prevlake na erozivno trošenje
Diagnostics of degradation of surfaces treated by thermal spraying
The paper deals with possibilities of utilization HVOF coatings in thermal cyclic loading
and wear conditions. There were evaluated three types of coatings based on WC-Co, WC-Co-Cr
and Cr3C2-25NiCr. The quality of coatings was evaluated in terms of their adhesion during the
cyclic thermal loading (pull-off test), microhardness and wear resistance (pin-on-disc test).
Structure of coatings was studied using optical and electron microscopy. The coating Cr3C2-25NiCr
showed the highest resistance to thermal cycles and wear resistance at 900°C and can be
recommended for renovation components stressed by high and cyclic temperatures and wear
Assessment of properties thermal sprayed coatings realised using cermet blend powder
The article deals with the assessment of selected properties of plasma sprayed coatings based on ZrSiO<sub>4</sub> doped with different volume fractions of metal dopant (Ni). Mixed powders are cermet blends. Aim of the work consists of verificating the possibility to replace the application of Ni interlayer by adding Ni directly to the ceramic powder and apply them together in a single technological operation. The coatings were studied from point of view of their structure, porosity, adhesion of the coatings in relation to the volume of dopant added and wear resistance. The best properties reached composite coating doped with 12 % Ni
Resistance of surface layers to selected tribodegradation factors
Contribution presents the results of research focused on resistance of surface layers to selected tribodegradation factors. Research is focused on the renovation of dies for hot work. Newly created renovation layers made with new types of filler materials are compared with conventionally used renovation materials. X37CrMoV5-1 was chosen as the die base material, which was hardened and tempered to a working hardness of 500 ± 15HV. The experiments are carried out practical measurements of mechanical properties of cladding. The quality of cladding was evaluated in tribological conditions of adhesion wear (ČSN EN 1071-13) and abrasive wear (STN 01 5084)
Orbital Josephson effect and interactions in driven atom condensates on a ring
In a system of ac-driven condensed bosons we study a new type of Josephson
effect occurring between states sharing the same region of space and the same
internal atom structure. We first develop a technique to calculate the long
time dynamics of a driven interacting many-body system. For resonant
frequencies, this dynamics can be shown to derive from an effective
time-independent Hamiltonian which is expressed in terms of standard creation
and annihilation operators. Within the subspace of resonant states, and if the
undriven states are plane waves, a locally repulsive interaction between bosons
translates into an effective attraction. We apply the method to study the
effect of interactions on the coherent ratchet current of an asymmetrically
driven boson system. We find a wealth of dynamical regimes which includes Rabi
oscillations, self-trapping, and chaotic behavior. In the latter case, a full
many-body calculation deviates from the mean-field results by predicting large
quantum fluctuations of the relative particle number.Comment: Published versio
The change in the morphology of the blasted surface after phosphating and cataphoretic coating
The paper focuses on the quality of coatings applied by cataphoretic deposition and cataphoretic deposition technology with a phosphate layer. The quality of the coatings was evaluated by determining the roughness of the coatings, the morphology of the coatings, spectral analyses were performed detecting the presence of individual elements in the coatings. There was analysed also defect – uncoated spot