In January 2019, Dmitriy Serebrennikov, a researcher from the Immanuel Kant Baltic Federal University, received a patent for his invention of new composite materials. The new materials, which have both Invar and functional properties, are highly demanded in instrumentation engineering, radio-electronic equipment, aviation and aerospace industry.
The researcher explains that most metals expand when heated but there are alloys that hardly change at certain temperatures . Such alloys are called Invar. In 1920, Charles Edouard Guillaume, a Swiss-French scientist, got the Nobel Prize for the Invar invention. Later, it became widely used for the manufacturing of high-precision mechanical watches. Invar does not possess other unique physical properties though. Meanwhile, functional materials often have a very high thermal expansion, which is a significant problem for a number of technical devices. However, it is possible to make an alloy consists of both functional materials and particles of another material with a significantly lower coefficient of thermal expansion.
The new materials are designed to compensate for the thermal expansion of the functional material. They are valence-unstable compounds with a negative thermal expansion. Unlike simple metals, these compounds compress when heated. Therefore they are perfectly suitable for creating composite Invar materials.
It took four years for Dmitriy to complete his research in collaboration with Dr Evgeny Clementyev, Head of the Laboratory for Strongly Correlated Electron Systems at IKBFU, and Dr Pavel Alekseev, a researcher from National Research Nuclear University MEPhI.
Dmitriy Serebrennikov, junior research associate (IKBFU):
Today, the research group of the Immanuel Kant Baltic Federal University is setting new goals - to synthesize new composites and to produce new alloys. The next step is to study the thermodynamic properties of the obtained alloys.
The results of this research were published in the Journal of Magnetism and Magnetic Materials.