RESEARCH AND MODERNIZATION OF A GAS DYNAMIC SPRAYING DEVICE FOR THE CREATION OF POLYMER FUNCTIONAL COATINGS

Abstract

The article analyzes various methods of creating polymer coatings. The following methods of application of polymer powder materials, namely in a pseudo-liquid state, electrostatic, thermojet, gas flame, have become the most widespread in production. Each of the listed methods has its own features and advantages and disadvantages, which determine the scope of their use based on the parameters of the objects to be coated, their structures and features, conditions of future operation, as well as the required thickness of the polymer coating layer. The only factor that unites all methods is the thermal effect in the process of creating a polymer coating, which is necessary for the formation of a strong adhesive bond between the coating and the substrate. The article shows the results of research into the possibility of using a device for gas-dynamic application of metal coatings to create polymer coatings, and its modernization in order to eliminate the identified shortcomings and achieve optimal conditions for the formation of polymer functional coatings. The possibility of a high-speed coating application regime and its influence on the formation of the coating were analyzed. The structure of the researched gas-dynamic device for applying coatings is shown, which contains an electronic heater for the flow of compressed air, and a nozzle assembly for accelerating the heated compressed air in which, due to the ejection effect, the molten polymer material is sucked in and accelerated, which can be in the form of a finely dispersed powder or in the form of a solid dart in the hottest zone with a temperature of about 350 ºС, which contributes to its rapid melting to a liquid state, at the same time, reducing the length of the nozzle to 40 mm allows maintaining the temperature of the polymer material at the level of 230 ºС, which allows the formation of a high-quality coating, while the air pressure is reduced from 0.5 MPa to 0.02 MPa. The conducted studies showed that the use of gas-dynamic sputtering makes it possible to significantly simplify the control and regulation of the heating temperature of polymer materials compared to gas-flame sputtering, due to the possibility of adjusting the temperature of the air flow by changing the current strength on the heating element. Compared to the technology of creating polymer coatings using powder paints, there are also significant advantages associated with the fact that there is no need for long-term heating of these coatings in thermal polymerization chambers. In addition, it is possible to apply polymer coatings on the surface of large-sized products that are not limited by the size of thermal chambers.