0000000000387855
AUTHOR
E. Tamanis
Influence of mechanoactivation on the adhesion and mechanical properties of metal/oxide interfaces
Properties of interfaces in solid state metal/oxide joints (Al/SiO2, Al/MgO, Al/glass, Mg/MgO, In/glass, Mg/SiO2 etc.) are reported. Interfaces were formed at plastic deformation of metal on the oxide surface at room temperature. Structure, composition, and micromechanical properties of the interfaces are studied by AFM, X-ray diffraction, SIMS, electron, optical microscopy, and precision microindentation. A noticeable adhesion is observed in the regions of maximum shear strain in case of metals with low oxide formation energy. Formation of a reaction zone with oxygen concentration gradient is detected in which the metal near the interface hardens. The effect of mechanoactivation is conside…
Thermo-Optical Investigation of Sodium-Bismuth Titanate Single Crystal and PLZT Ceramics
Thermal lensing in relaxor type ferroelectrics as a function of temperature has been investigated by using pulse/probe method. Enhanced thermo-optical (TO) properties had been observed in 3d elements (Cu, Co) doped PLZT ceramics and in sodium-bismuth titanate single crystals near phase transitions (PT). Comparison of TO signals for several doped PLZT materials reveals that 0.5 wt.% Cu doping is responsible for improved thermal lensing parameters interpreted by optimal light absorption, heat transfer and possible PT adjustment. TO experiments in sodium-bismuth titanate single crystals ([001] cut) show enhancement of TO properties in the region of PT and coexisting phases (rhombohedral and te…
Nanoindentation and photoluminescence characterization of ZnO thin films and single crystals
In this work an optical and micromechanical properties of ZnO films deposited on glass by simple method based on the mechanoactivated oxidation have been investigated and compared with those of bulk ZnO single crystal and commercial ZnO films. Results showed that investigated ZnO films have stable high adhesion with glass and can form grained structure with hardness 8–10 GPa or whiskers nanostructure with high hardness 18–20 GPa. Young’s modulus is in range from 80 to 120 GPa. Optical properties of obtained ZnO films with whiskers structure are typical for transparent high quality ZnO single crystal. These coatings also exhibit a photo-electric response which reflects on the change in resis…
Morphology Influence on Wettability and Wetting Dynamics of ZnO Nanostructure Arrays
This study has been supported by internal research grant No. 14-95/2021/10 of Daugavpils University “Development of the Nanostructured Metal Oxide Coatings and Their Application in Optical Sensing for Heavy Metal Detection”.
Object size effect on the contact potential difference measured by scanning Kelvin probe method
International audience; Contact potential difference (CPD) was measured by macroscopic Kelvin probe instrument and scanning Kelvin probe microscope on Al, Ni and Pt on ITO substrates at ambient conditions. CPD values measured by scanning Kelvin probe microscope and macroscopic Kelvin probe are close within the error of about 10-30% for large studied objects, whereas scanning Kelvin probe microscope signal decreases, when the object size becomes smaller than 1.4 m. CPD and electric field signals measured using many-pass technique allowed us to estimate the influence of electrostatic field disturbance, especially, in the case of small objects.
MeV-energy Xe ion-induced damage in LiF: The contribution of electronic and nuclear stopping mechanisms
The contribution of electronic and nuclear damage mechanisms in the modification of structure and micromechanical properties of LiF crystals irradiated with 52, 224, and 450 MeV Xe ions at fluences 1010–1014 ions cm−2 has been studied. The ion-induced formation of dislocations and hardening in LiF at fluences above 1010 ions cm−2 has been observed. The depth profiles of nanoindentation show a joint contribution of electronic excitation and nuclear (impact) mechanisms to the ion-induced hardening. The electronic excitation mechanism dominates in the major part of the ion range while the impact mechanism prevails in a narrow zone at the end of the ion range. The efficiency of hardening produc…
<title>Second harmonic generation in selenium-metal structures</title>
The article examines the processes of second harmonic generation (SHG) when selenium-metal (Cu) film structures are illuminated by femtosecond radiation (180 fs, 80 MHz) at wavelength 800 - 1000 nm. Selenium-copper structures were obtained by successive thermal evaporation of selenium and copper onto the glass substrate in vacuum. Microanalysis of the film composition was performed to determine amount of copper in thin films. The as-evaporated selenium-copper structures were crystallised by annealing in inert atmosphere at temperature 85°C. Just evaporated as well as annealed thin films were explored. The experiment was performed by confocal microscope [1] where the femtosecond radiation fr…
Obtaining of nanostructured ZnO coatings using mechanoactivated oxidation
The concept to use nanostructured state of metal at the instant of destruction in air environment was used to obtain nanostructured Zn-ZnO coatings on glass and quartz by mechanical method. Subsequent annealing in the ambient atmosphere, annealing in vacuum and irradiation with 532-nm YAG:Nd laser were used to obtain completely oxidized, transparent ZnO coatings. The saturated with oxygen nanostructured coatings were transformed into nanostructured ZnO coatings after annealing above 773K or irradiation with laser (allowing to reach 673K) in ambient atmosphere. AFM and SEM images show that after annealing ZnO coatings have multi-shaped structure. The formation of ZnO need-like whiskers (d = …
Nanostructuring and strengthening of LiF crystals by swift heavy ions: AFM, XRD and nanoindentation study
Abstract Modifications of the structure and micromechanical properties of LiF crystals under high-fluence irradiation (10 11 –10 13 ions cm −2 ) with swift C, Ti, Au and U ions of the specific energy of 11.1 MeV/u have been studied. In the case of heavy ions (U, Au), the AFM and SEM results reveal the bulk nanostructure consisting of columnar grains with nano-scale dimensions (50–100 nm). For lighter C ions the structure enriched with prismatic dislocation loops has been observed. High-resolution XRD reciprocal space maps for nano-structured LiF expose a mosaic-type structure with low-angle boundaries between grains.
Adhesion and interfacial reactions on metal/oxide interface during plastic deformation at room temperature
Properties of interfaces in solid state metal/oxide joints (Al/SiO2, Al/MgO, Al/glass, Mg/MgO, Mg/SiO2, In/glass etc.) are reported. The interfaces were formed at plastic deformation of metal on the oxide surface at room temperature. Their structure, chemical composition, and micromechanical properties were studied by the AFM, XRD, SIMS, optical microscopy, and precision microindentation techniques. A noticeable adhesion was observed for metals with high affinity for oxygen and only in the regions of the maximum shear stress. Formation of an interfacial reaction zone with an oxygen concentration gradient is detected. In this zone metals are nanostructured and noticeably hardened. The effect…
Comparative Study on Micromechanical Properties of ZnO:Ga and ZnO:In Luminiscent Ceramics
The research has been supported by the Project ERANET RUS_ST#2017-051(Latvia) and #18-52-76002 (Russia). The Institute of Solid State Physics, University of Latvia as the Centre of Excellence has received funding from the European Union’s Horizon 2020 Framework, Program H2020-WIDESPREAD-01-2016-2017-Teaming Phase 2 under grant agreement No. 739508, project CAMART2.
Properties of ZnO coatings obtained by mechanoactivated oxidation
In this work a new method based on the mechanoactivated oxidation has been applied for obtaining thin nanostructured transparent ZnO coatings on glass. Zn has been transferred onto a glass substrate at room temperature using a quickly rotating steel wire brush. Afterwards by subsequent annealing it is modified into a transparent ZnO coating. The temperature range in which formation of the needle-like (whiskers) structure and transition to the fine-grained structure occurs has been determined. The interrelation between physical properties and the change of microstructure of the ZnO coatings has been shown.