arXiv subjects

Ilya B. Afanasyev

Publications and source records attributed to Ilya B. Afanasyev.

4 recordsLinked to original sources

arXiv2023

Thermal-fluctuation mechanism of long-term corrosion of glass caused by internal stress: processes of depolymerization, impurity migration and fracturing on an atomic scale

Long-term corrosion of glass is studied using polarising light microscopy, FTIR and SEM including EDX and elemental mapping. Early 19th century beads made of lead-potassium glass are the object of the study. Non-uniformly distributed internal stresses were introduced into the studied glass during bead manufacturing. Corrosion of 19th century bead glass has been shown to comprise several mutually connected processes developing in parallel and intensifying one another. These processes are the depolymerization of glass, the directed migration of alkali-metal impurities and local glass leaching, and the nucleation of micro discontinuities followed by the formation of micro cracks and their gradual growth. In course of time, their cumulative and apparently synergistic effect results in glass fracturing terminated with bead crumbling into tiny discoloured particles. All these phenomena are controlled by the internal stress originated from the bead production process. Thus, the phenomenon of stressed bead glass corrosion is the process of the internal stress relaxation in glass through the nucleation and growth of cracks, which lasts for many decades at room temperature. It is dramatically accelerated when beads are heat treated. Annealing at 300°C for 15 min. is sufficient for artificial ageing of initially intact beads. The corrosion has been observed to occur in glass even if beads are kept in well-controlled museum environment. The local thermal-fluctuation mechanism is proposed to account for the corrosion phenomenon on an atomic scale. The approach based on the thermal-fluctuation mechanism is applicable to describe degradation and destruction processes in various solid substances and composite materials under stress; this approach enables understanding the phenomena of formation and degradation of nanostructures, e. g., heterostructures with quantum wells or quantum dots.

cond-mat.mtrl-sci↗

arXiv2021

Identification of CaCuSi$_4$O$_{10}$ (Egyptian blue) in the "Birch. Spring" painting by Robert Falk (1907) using photoluminescence

We have detected Egyptian blue pigment in the paint layer of the "Birch. Spring" painting by Robert Falk (1907); we have also found this pigment in the paints of the sketch drawn on the canvas back side. This is probably the first discovery of Egyptian blue in a 20th century work of art. We have analyzed a modern commercial Egyptian blue pigment (Kremer) and found it to be suitable as a standard for photoluminescence spectral analysis. The characteristic photoluminescence band of CaCuSi$_4$O$_{10}$ reaches maximum at the wavelength of about 910 nm. The luminescence is efficiently excited by incoherent green or blue light. The study demonstrates that the photoluminescence spectral micro analysis using excitation by incoherent light can be efficiently used for the identification of luminescent pigments in paint layers of artworks.

physics.app-ph↗

arXiv2021

Crystals in the 19th century glass beads

Glass seed beads probably are the most numerous group of art historical glass. From the ancient times to the modern era, glass beads played an essential role in culture, as they were used, e.g., to decorate clothing, religious objects and functional tools, and served as an important good for global trade. The conservation state of items made of glass beads is an actual issue for curators and conservators. Glass, as well known, is often unstable material, so a number of internal and external factors are responsible for chemical and physical processes in glass and on the glass surface. It was noticed that some types of historical 19th century glass beads are subjected to more intense destruction than others. The samples of glass beads of different colours and conservation states were examined by means of SEM-EDX, EBSD, Raman and FTIR microspectroscopy. Research showed that some types of beads are characterized by the presence of nano- and microcrystals in glass, which could be one of the causes of glass destruction. The elemental composition of crystals is different in each case and depends on raw materials and technical components used for glass manufacturing. The structure of crystals was identified by means of EBSD analysis.

physics.app-ph↗

arXiv2019

Cathodoluminescence of CdZnSSe crystals synthesized in 19th century bead glass

The article presents an experimental investigation of band-edge cathodoluminescence of CdZnSSe crystals that nucleated and grew in silicate glass melt during its production. We have studied Zn-rich red glass made for manufacture of seed beads in the 19th century and found it to contain CdZnSSe crystals. Due to colloidal staining using the CdZnSSe crystallites embedded in glass, glass makers were enabled to produce lustrous red glass that, as we presently know, manifests bright luminescence. The CdZnSSe crystallites exhibit intense band-edge cathodoluminescence both at room temperature and at liquid nitrogen temperature. We have found the band-edge cathodoluminescence of these crystals to peak in the range from 2.00 to 2.03 eV at 300 K and from 2.02 to 2.06 eV at 80 K. We have also estimated the value of the band gap derivative d$E_g$/d$T$ in the interval from 80 to 300 K and found it to lie in the range from $-2.5 \times 10^{-4}$ to 0 eV/K. CdZnSSe crystals in glass demonstrate high temperature and temporal stability. The glass-crystal composite on their basis is resistant to the electron-beam irradiation and long-term weathering. Possible applications of this composite in modern technologies, and processes and components that might be used for making glass stained with CdZnSSe in the past are also discussed.

cond-mat.mtrl-sci↗