New ceramic sintering furnace
The scientists of the Tomsk Scientific Center of the SB RAS manufactured a prototype of an energy-saving sintering furnace that uses the filtration combustion of natural gas and is designed to synthesize and sinter a wide range of refractory ceramics used in energetics, metallurgy, and aerospace engineering.
The main advantage of the new furnace is the ability to quickly reach high temperatures of up to 2000 0C while reducing the fuel consumption by up to two times. The results of fundamental research in the filtration combustion field, obtained by the scientific team (Alexander Kirdyashkin, Ramil Gabbasov, Vladimir Kitler and Anatoly Maznoy), became the basis for the high-performance production of ceramics based on aluminum and magnesium oxides. These results were reported in one of the high-ranking journals in the energy and combustion field (Fuel).
(Alexander Kirdyashkin, Ramil Gabbasov, Vladimir Kitler, Anatoly Maznoy. Ceramic sintering furnace based on combustion of premixed natural gas in porous inert media // Fuel, Volume 309, 1 February 2022, 122098 https://doi.org/10.1016/j.fuel.2021.122098).
Both electric and gas furnaces are now widely used for industrial sintering of ceramics. The gas furnaces are more efficient since heat production requires much less energy. In traditional gas furnaces, the ceramic samples are placed inside the furnace chamber and heated to the desired temperature using the flame of a gas burner. Even a filled furnace has a lot of free space, which limits the heating rate and the sintering temperature of materials, not higher than 1750 degrees.
In the ceramic sintering furnace, the combustion chamber is filled with refractory granules (periclase, zirconium oxide), and the combustion of natural gas occurs in the pores of packed granules. Ceramic samples placed inside the packed granules are heated faster and to a higher temperature. The high efficiency of the ceramic sintering furnace is explained by the accelerated transfer of fuel energy to the sample, as well as by additional heat accumulation in the packed granules. This opens qualitatively new prospects for high-performance sintering of ceramic materials with unique properties.
“A significant obstacle to the development of ceramic sintering furnaces was the poor theoretical base describing the mechanisms of filtration combustion and the low level of automation of this process," says Alexander Kirdyashkin, a Lead Researcher at the Laboratory of Physical Activation. At present, these problems have been solved. The combustion process has become controllable and predictable, making these furnaces attractive, convenient, and efficient.
As Alexander Ivanovich noted, they can produce transparent ceramics for the defense industry and high-strength nanoceramics for the tooling industry. In turn, ceramic sintering furnaces are a low-cost alternative to production of hard-to-melt materials, such as pure titanium and silicon carbides and aluminum oxynitride, which are quite costly to produce using other methods.
