Kovbasiuk T. Development of glass-ceramic material for insulating coating of flat heating with enchanced efficiency

The thesis is devoted to the solution of the scientific and technical problem, which consists in the development of a glass ceramic material for the improvement of the technology for manufacturing coatings for flat heating elements of heaters with enhanced functional properties. The technological processes of synthesizing dielectric coatings based on the PbO-B2O3-ZnO glass-ceramic system doped with Al2O3, SiO2 and BaO oxides, have been developed and optimized. An optimal method for preliminary preparation of the surface of 40X13 steel substrates is proposed to provide high adhesion strength and micromechanical properties of synthesized coatings. The features of microstructure formation, microtopography of the surface, phase composition and electrophysical properties of dielectric layers of flat heating elements based on the PbO-B2O3-ZnO glass-crystalline system are determined. The optimum chemical composition of the initial glass-crystalline mixtures of the PbO-B2O3-ZnO system and the optimal structure of the insulating coatings of flat heating elements is established by a comparative evaluation of their thermal and electrophysical properties. In view of thefact that synthesized coatings have high values of dielectric strength, resistivity and small dielectric losses in the temperature range of 20...300 °С, they can be recommended for use as a dielectric layers of flat heating elements for long-term operation at temperatures of 160...190 ° С. On the basis of the conducted researches were made prototypes were made that were installed in the design of the KEP 2-10-4-220 / 380 calorimeter and successfully passed bench and industrial tests at the KPPV "Creed" LLC.