SUSU scientists continue to develop new materials, combining sometimes unexpected components. This time, they have succeeded in combining glass and aluminium alloy. This alloy could serve as a thermal barrier coating for pistons of internal combustion engines, which operate under extreme conditions.
This innovative coating was studied by scientists of the SUSU Institute of Engineering and Technology Vitaly Khizhniak, Anastasiia Dmitrieva, Dmitry Zherebtsov, Andrey Riazanov, Denis Vinnik, Kirill Pashkeev, and Mariia Samodurova. The results were published in the "Chemistry" series of the SUSU Bulletin.
Thermal barrier coatings are heat-resistant layers applied to engine parts to protect them from overheating. They act as thermal insulators, reducing the flow of heat from combustion products to the metal parts. This allows the engine to operate at higher temperatures, increasing its efficiency and reducing the fuel consumption. Traditionally, such coatings are made of ceramics.
To create a new material from glass and aluminium, scientists used a detonation spraying method, in which powder particles are accelerated to the speeds of 500-1000 meters per second using a controlled explosion of a gas mixture. This method allows for the creation of dense and durable coatings with minimal pores.
AK4 aluminium alloy (containing 91-94% of aluminium) and regular silicate glass were used in the experiments. AK6 aluminium alloy was also used, but the coating's performance was inferior.
“Glass itself is quite brittle, and its coating develops cracks and roughness. Pure aluminium tends to form skulls (“frozen icicles”) when melted, which is also undesirable for a coating. Aluminium and glass act synergistically together: glass, by expanding the emission spectrum in the gas jet, helps melt the aluminium particles, and aluminium, by binding the glass particles, ensures strength,” says Doctor of Sciences (Chemistry) Dmitry Zherebtsov, senior research fellow at the SUSU Institute of Engineering and Technology.
The scientists succeeded in producing and applying a 1.34-millimeter-thick coating to the sample. The coating turned out to be smooth, even, and low-porous (1-2% porosity).
The technology will help increase the efficiency of engines, reduce fuel consumption, and make them resistant to thermal loads. The scientists plan to continue working on optimizing the coating composition. There is a hypothesis that a coating consisting of 60-80% of glass and 40-20% of metal will result in an optimal combination of ductility and heat resistance.