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Alena Michalcova

Publications and source records attributed to Alena Michalcova.

2 recordsLinked to original sources

Hybrid films of Co - C60 preparation and changes induced by external stimuli

In this work, we report on the study on organic-metal hybrid systems, in particular Co-C60 fullerene thin films. This study mainly focused on the investigation of the morphological and structural evolution of the film surface after various external stimuli designed to provide energy to the system. For film growth, we adopted an innovative approach, combining ion-beam sputtering of a pure metal target with thermal evaporation of C60 in a co-deposition setup. The films underwent a series of treatments to induce modifications. Laser and ion irradiations were performed using a pulsed laser, a continuous Ar beam, and a pulsed C beam. In addition, thermal annealing in vacuum was performed to examine the long-term effects of temperature. The composition of deposited film was investigated using Ion Beam Analysis, the morphology and the structure, and the effects of treatments on the films were studied using SEM and TEM microscopies and Raman spectroscopy. Changes in electrical resistance were also measured to explore potential applications of these films after treatment.

cond-mat.mtrl-sci

Harmonizing Microstructures and Enhancing Mechanical Resilience: Novel Powder Metallurgy Approach for Zn-Mg Alloys

Zinc alloys are recognised for their excellent biocompatibility and favourable corrosion rates, making them suitable for bioabsorbable implants. However, their mechanical properties necessitate improvement to fulfil the rigorous requirements of biomedical applications. This research focuses on engineering pseudo-harmonic structures within zinc alloys through a comprehensive method combining mechanical alloying, spark plasma sintering, and hot extrusion techniques. This fabrication process results in a composite material characterised by a soft core surrounded by a continuous, three-dimensional, ultrafine-grained hard shell. The experiment involved blending pure zinc with Zn-1Mg alloy powder, leading to the formation of both ductile zinc and fine-grained Zn-1Mg regions. While the Mg2Zn11 intermetallic phase was found to enhance the alloy's mechanical strength, the presence of oxide shells adversely affected the material's properties. The elimination of these shells via hot extrusion markedly improved the alloy's tensile strength, reaching an average value of tensile strength of 333 MPa. This study provides significant insights into the material engineering of zinc-based alloys for biodegradable implant applications, demonstrating a viable approach to optimising their mechanical performance.

cond-mat.mtrl-sci