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Streszczenie:
The sustainable transformation of bio-waste into usable, material has gained great scientific interest. In this paper, we have presented preparation of an activated carbon material from a natural mushroom (Suillus boletus) and explor its properties for supercapacitor and dye adsorption applications. The produced cell exhibited a single electrode capacitance of ∼247 F g−1 with the energy and power density of ∼35 Wh kg−1 and 1.3 kW kg−1, respectively. The cell worked well for ∼20,000 cycles with ∼30% initial declination in capacitance. Three cells connected in series glowed a 2.0 V LED for ∼1.5 min. Moreover, ultrafast adsorption of methylene blue dye onto the prepared carbon as an adsorbent was recorded with ∼100% removal efficiency in an equilibrium time of three minutes. The performed tests indicate that the mushroom-derived activated carbon has the potential to become a high-performance electrode material for supercapacitors and an adsorbent for real-time wastewater treatment applications.

Słowa kluczowe:
Activated carbon, Amorphous material, Biomass, Polymer gel electrolyte, Supercapacitor, Dye adsorption

Streszczenie:
In the present study we report the changes in the modified near-surface layer on NiTi shape memory alloy, caused by ion implantation as well as their influence on the structure and mechanical properties of this material. Experimental results of an inhomogeneous structure and tribological properties of implanted NiTi are discussed in this paper.

Słowa kluczowe:
shape memory NiTi alloy, Ion implantation, DSC, X-ray diffractometry, TEM

Streszczenie:
This paper reports the application of nitrogen ion implantation for modification of a shape memory alloy. It is known that the problem of creating a protective surface coating for the shape memory alloy is the most acute for potential applications of this material. Thus, the problem of increasing surface protective properties and, at the same time, simultaneous preservation of functional properties of shape memory materials is a subject of research and development [Pelletier H, Muller D, Mille P, Grob J. Surf Coat Technol 2002;158:309.]. The surface characterization of nitrogen implanted (fluence 1018 cm−2 and energy 50 keV) equiatomic commercial NiTi alloy samples was performed with the assistance of high resolution transmission electron microscopy (HTEM) techniques and modifications of phase composition before and after irradiation are studied at room and martensitic transformation temperatures by X-ray diffraction methods. Differential scanning calorimetry (DSC, TA Instruments) was used to characterize the transformation sequence and transformation temperatures for the initial and surface-modified materials. Experimental results of an inhomogeneous structure of near-surface layers in the ion-implanted NiTi alloy are discussed in this paper

Słowa kluczowe:
Shape memory NiTi alloy, Ion implantation, DSC, X-ray diffractometry, TEM

Streszczenie:
Powder metallurgy technology was elaborated for consolidation of shape memory NiTi powders. The shape memory alloy was compacted from the prealloyed powder delivered by Memry SA. The powder shows Ms = 10°C and As = -34°C as results from DSC measurements. The samples were hot pressed in the as delivered spherical particle's state. The hot compaction was performed in a specially constructed vacuum press, at temperature of 680°C and pressure of 400 MPa. The alloy powder was encapsulated in copper capsules prior to hot pressing to avoid oxidation or carbides formation. The alloy after hot vacuum compaction at 680°C (i.e. within the B2 NiTi stability range) has shown similar transformation range as the powder. The porosity of samples compacted in the as delivered state was only 1%. The samples tested in compression up to ε = 0.06 have shown partial superelastic effect due to martensitic reversible transformation which started at the stress above 300 MPa and returned back to ε = 0.015 after unloading. They have shown also a high ultimate compression strength of 1600 MPa. Measurements of the samples temperature changes during the process allowed to detect the temperature increase above 12°C for the strain rate 10-2 s-1 accompanied the exothermic martensite transformation during loading and the temperature decrease related to the reverse endothermic transformation during unloading.

Słowa kluczowe:
Powder metallurgy technology, shape memory alloys, DSC measurements, compression test, exothermic martensite transformation, endothermic reverse transformation