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Mesoporous bioactive glass (MBG) is an extensively studied biomaterial used for the healing of bone defects. Its biological applications can be tailored by introducing metallic ions, such as strontium (Sr) and copper (Cu), which can enhance its functionalities, including osteogenetic, angiogenetic and antibacterial functionalities. In this study, Cu and Sr ions were co-doped (ratio 1:1) with x = 0.5, 1 and 2 mol% each in glass with an intended nominal composition of 80SiO2 -(15-2x)CaO5P2O5 -xCuO-xSrO and synthesized with an evaporation-induced self-assembly (EISA)-based sol-gel technique. XRD confirmed the amorphous nature of the glass, while compositional analysis using ICP-OES confirmed the presence of dopant ions with the required amounts. A TEM study of the MBG powders showed fringes that corresponded to the formation of a highly ordered mesoporous structure. The Cu-Sr-doped MBG showed a positive effect on apatite formation when immersed in SBF, although the release of Cu and Sr ions was relatively slow for 1 mol% of each co-dopant, which signified a stable network structure in the glass. The impact of the Cu and Sr ions on the osteoblast-like cell line MG-63 was assessed. At the particle concentrations of 1 wt./vol.% or lower, the cell viability was above 50%. An antibacterial test was conducted against Gram-negative E. coli and Gram-positive S. aureus bacteria. With a sequential increase in the co-doped ion content in the glass, the zone of inhibition for bacteria increased. The results suggest that the doping of MBG with Cu and Sr ions at up to 2 mol% can result in tailored sustained release of ions to enhance the applicability of the studied glass as a functional biomaterial for bone regeneration applications.

The influence of 4% acetic acid (pH~2.4) and an alkaline solution of NaOH (pH~10) on the corrosion resistance and micromechanical properties of disilicate crystals containing glass-ceramics (LS2-GC’s) is studied. Partially crystallized lithium metasilicate crystal containing glass-ceramics (LS-GC’s) are annealed to fully LS2-GC’s using a one stage and a two-stage heating to induce nucleation. Materials with various chemical and wear resistance are prepared. The content of the crystalline phase in the material annealed in the two-stage process A is 60.0% and increases to 72.2% for the material heated in the one-stage process B. The main elements leached in the acidic medium are lithium and phosphorus, while lithium, silicon, and phosphorus leached into the alkaline environment. Material B exhibits better chemical resistance to the corrosive influence of 4% acetic acid under quasi-dynamic conditions. In the alkaline corrosion medium, silicon is leached from material A faster compared to the material B. After prolonged exposure to acidic or basic environments, both materials show evidence of surface structural changes. A decrease of the sliding wear resistance is observed after corrosion in the acidic environment under dynamic conditions. In both materials, the wear rate increases after corrosion.&nbsp

journal article

The authors research and publish the results from a glass melting experiments conducted in a reconstruction of a historic wood-fired furnace from the 9th c. during the 2017–2019 period. The experiments focused on soda-lime glass and were implemented as pilot for the planned, long-term and annual experimentations in the Archeopark in Hanušovce nad Topľou. Experi-mental glass batches were weighed according to the composition of glass from archaeological samples from the 9th c., as well as according to the model soda ash glass. The aim was to obtain experimental data to verify archaeometric research of historical glass. The study focused on the possible use of a wood-fired furnace in the melting glass from glass batches, the effects of ash on the composition of glass, remelting of glass cullet, penetration of elements from crucible and flue gases into molten glass, causes of different quality of glass remelting or colouring with added CuO and MnO. Another aim of the study was to compare the results of the glass analyses from the SEM/EDS and XRF method, which we later interpret in historical contexts.

Polymer derived ceramic (PDC) polysilazane-based double layer composite coatings on steel substrates consisting of a PDC bond-coat, and a PDC-based top-coat containing ceramic passive (ZrO₂) and active (ZrSi₂) fillers, as well as a specially tailored passive glass filler with high melting temperature were developed. The corrosion and oxidation behaviour of the ferritic stainless steel AISI 441 with and without the PDC coating system was evaluated. SEM examination revealed the composite coatings were not dense but contained small closed pores with a diameter up to 100 nm. Cracks and occasionally also delamination were detected. The static corrosion tests under hydrothermal conditions at the temperature of 200 °C resulted in partial oxidation of the uncoated steel substrate, whereas the coated sample was protected by the PDC coating. No oxidation of the top coat was detected after the static corrosion test. The high temperature oxidation behaviour in a flow-through oxygen atmosphere was investigated at the temperatures of 900 °C, 1000 °C and 1100 °C. X-ray diffraction confirmed extensive corrosion of the uncoated AISI441 stainless steel accompanied by formation of a Cr₂O₃, TiO₂ and a (Mn, Cr)₃O₄ spinel containing layer of corrosion products. Beneficial effect of the PDC coating was observed at the temperature of 900 °C, demonstrated by marked reduction of the weight gain of coated steel after 196 h of exposure to flowing oxygen. At higher temperatures the protective action of the PDC coat was not observed, and a thick layer of corrosion products was formed at the steel/coating interface.

The study focuses on an assemblage of glass finds from the citadel of Kafir Kala, Uzbekistan, located along one of the major Eurasian branches of the “Silk Roads” with a consistent occupation between the 8th and 12th century CE. Glass fragments for this study were selected based on marked surface alterations they showed, with stratified deposits of different thickness and colours. Starting from a preliminary observation under Optical Microscope, fragments were clustered into four main groups based on the surface appearance of the alterations; Scanning Electron Microscopy investigations of the stratigraphy of the alteration products were then carried out, to evaluate micro‐textural, morphological and compositional features. Data from the analyses allowed identifying preferential patterns of development of the various degradation morphologies, linkable to compositional alterations of the glass due to burial environment and the alkali leaching action of the water. Iridescence, opaque weathering (at times associated with black stains), and blackening were identified as recurring degradation morphologies; as all but one sample were made of plant ash‐based glass, results show no specific correlation between glass composition and the occurrence of one or the other degradation pattern, often found together. Framed in a broad scenario, the paper aims to set the basis for the development of a study approach dedicated to the degradation morphologies affecting archaeological glasses, a topic still lacking systematisation and in‐depth dedicated literature