A method for evaluating composites in aerospace optics developed at Lobachevsky University
Lobachevsky University researchers, in partnership with their colleagues from the Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences, have developed a method to assess the fundamental optical properties of two-phase ceramic composites based on yttrium oxide (Y2O3) and magnesium oxide (MgO). These materials, distinguished by their exceptional strength and thermal resistance, hold promise for manufacturing infrared (IR) optics designed for operation in extreme conditions. Quality testing of these composite materials opens new avenues for their use in the aerospace industry.
One of the primary objectives of the Laboratory of Optical Ceramic Materials at the UNN Faculty of Chemistry is to develop and investigate the properties of the next generation of IR-transparent materials. Established in 2021 with support from the federal Priority 2030 programme, the laboratory aims to enhance the performance characteristics of components and products of IR optics through the implementation of these innovative optical composites.
"We have earlier developed a composite manufacturing method that can rival the best traditional optical materials. Its key advantage is the preservation of properties at high temperatures, which is crucial for aerospace applications. For instance, if onboard optics become cloudy due to the heating of the aircraft or spacecraft, the navigation system would essentially be blinded," explained Dmitry Permin, Head of the Research Laboratory of Optical Ceramic Materials at UNN.
Two-phase composites, such as those based on yttrium and magnesium oxides, achieve transparency in the IR range only when the grain size of these components is smaller than the wavelength of the transmitted radiation. To produce ceramics with a specific level of transparency, it is essential to understand the precise relationship between optical transmission and grain size, defects, and other features. The method developed by Nizhny Novgorod scientists allows for structural diagnosis and prediction of the composite's ultimate transparency.
"Due to their structure, optical losses in composites cannot be accurately assessed using approaches that treat scattering centres as isolated ones, for example, Mie scattering theory. By employing calculations based on a model that accounts for interference effects, we have found a way to correlate transparency with microstructure characteristics. This enables us to determine potential losses based on grain size and defects or, conversely, infer the composite's structure from IR transmission spectra. The developed method is also applicable for evaluating the quality of other optical materials with similar structures," noted Dmitry Permin.
"This research underscores Lobachevsky University's position as a leading centre for advanced materials development. The Laboratory of Optical Ceramic Materials, established thanks to the Priority 2030 programme, has quickly reached a level of achievement that meets the demands of the aerospace industry. This marks new opportunities for enhancing Russia's technological sovereignty in the field of specialised optics. Together with colleagues from the RAS Institute of Chemistry of High-Purity Substances, our scientists are laying the groundwork for the next generation of domestic aerospace systems," said Oleg Trofimov, Rector of Lobachevsky University.
The project was supported by a grant from the Russian Science Foundation. The research findings have been published in the Journal of the European Ceramic Society.
