Thermal stability of composite materials based on boron oxide modified basalt fibers

DOI: 10.62564/M4-SI1303

Stanislav Ivanitskii, Yurii Chuvashov

Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Composite materials (CM) based on fibers containing B2O3 are used for neutron radiation shielding in nuclear reactors. Thermal stability of CM is related to the ability to maintain high strength of reinforcing fibers under thermal loads. The main reason for the decrease in strength is crystallization. This is due to the development of microcrystalline nuclei that formed in the fibers at the stage of drawing in the crystallization zone. The aim of this work is to analyze the influence of the rheological properties of the melt containing B2O3 on the conditions of fiber drawing, which affect the appearance of the microcrystalline phase in them. Modified glass was obtained by adding B2O3 to andesite basalt. The viscosity of the glass melt was determined on a rotary viscometer. The study of the conditions for the drawing of modified fibers was carried out on a laboratory bench and through theoretical analysis. The temperature of the upper limit of crystallization of the melt Tulc was determined by the quenching method. A mathematical model of the continuous fiber drawing process was used to estimate the crystallization zone. The viscosity of the glass melt with a content of 6 wt.% B2O3 is lower than viscosity of the andesite-basalt melt. The temperature Tulc of modified glass and andesite basalt is the same. Calculations of the speed of movement and the cooling rate of the melt jet during fiber drawing were carried out, which made it possible to determine the glass transition temperature Tgl, the temperature zone of crystallization from Tulc to Tgl and the residence time of the melt in this zone (the time of crystallization). The research results showed that the addition of B2O3 to the composition of glass changed the rheological properties of the glass melt and the conditions for drawing fibers from it. This led to a change in the fibers production interval and the concentration of microcrystalline nuclei in them and affected the thermal stability of fibers.

Keywords
Modified glass, fiber drawing, crystallization zone

Acknowledgments
Not provided

References
1. Ivanitskii S.G., Chuvashov Y.M., Materials Science Forum, 2024. V. 1113, P. 95-100