RESEARCH ON THE EFFECT OF PROTECTING COATING ON THE FIRE RESISTANCE OF ALUMINUM ALLOY STRUCTURES

Polyfunctional protective coatings based on filled polysiloxane compositions are technological and can be used to increase the fire resistance of metal structural materials due to high thermomechanical properties, which are determined by stable structural and phase composition. The influence of protective coatings on the basis of polysiloxane-filled oxide components on fire resistance of aluminum alloys is investigated in the work. The choice of the initial compositions for fire protection coatings was carried out with the aim of obtaining of expanded heat-insulating heatresistant layer on the surface of an aluminum alloy at temperatures of 473 K and higher. The methods of physico-chemical analysis have established that when heated more than 473 K as a result of thermo oxidative degradation of polysiloxane with the release of gaseous products, there is an expanding coating with the formation of a fire-proof porous heat-insulating layer on the surface of an aluminum alloy. The coefficient of expanding the coating is within the range of 9.8 ... 12.4. The reliability of the use of physicochemical criteria when choosing the component composition of the coating and the effectiveness of the fire protection function is estimated from the results of the test on the aluminum alloy AMG6 and on the model of its thermal conductivity. 20 Пожежна безпека, №34, 2019 A model of thermal conductivity of a protective coating is proposed, which consists of a layer that limits heat transfer through a two-layer wall. When exposed to the aluminum plate of the heat flow, it is heated to the depth of the coating, which leads to its expanding and the formation of a thermal barrier. The dynamics of temperature distribution during a fire on the protective coating of an aluminum alloy is predicted by simulating the heat transfer process in a homogeneous solid by a mathematical model. The theoretical and practical researches have established the dependence of the parameter of heating the protected aluminum alloy to the critical temperature, depending on the thickness of the coating. The presence on the surface of a protected alloy coating, based on the filled polysiloxane, changes the process of heat transfer to its surface, which increases the fire resistance of the structure by 3 ...4 times.