Estudo de revestimentos aplicados em um bocal de minifoguete a propelente sólido utilizando a técnica de ion plating

Abstract

The choice of materials for manufacturing nozzles used in rocket engines is a complex topic, as nozzles are subjected to high temperatures that cause plastic deformation, even disintegration of the nozzle. In this sense, this work aims to mitigate the dimensional variation in nozzles arising from plastic deformation, using coatings and substrate material that extend the useful life of the nozzles as a whole. In this sense, the solution presented in this work includes the use of the ion plating deposition process, which is an environmentally correct technique for carrying out the deposition of coatings. As coating materials, zirconia partially stabilized with 3 % mol yttria (3Y-PSZ) and boron carbide (B4C) were used, with the approximate thickness of both coatings being 500 nm. AISI 304 and Thermodur 2367 EFS were used as substrate materials. 18 nozzles were manufactured, 9 for each substrate, where 6 different configurations were made: 3 AISI 304 nozzles coated with B4C, 3 AISI 304 nozzles coated with 3Y-PSZ, 3 AISI 304 nozzles without coating, 3 Thermodur 2367 EFS nozzles coated with B4C, 3 Thermodur 2367 EFS nozzles coated with 3Y-PSZ and 3 uncoated Thermodur 2367 EFS nozzles. 54 static tests were carried out, 3 for each configuration. By carrying out the study, it was evident that the use of Thermodur 2367 EFS as a substrate material proved to be competent compared to AISI 304 since it imposed an 85.37% smaller dimensional variation, thus its use as a substrate material for manufacturing nozzles in experimental high power rocketry becomes promising. The use of coatings proved to be effective in reducing the dimensional variation on both substrates in the first test. From the second test onwards, boron carbide showed a loss in performance, on the other hand, the 3Y-PSZ coating demonstrated, from the second test onwards, superior performance to boron carbide. At the end of the third tests, on both substrates the performance is similar at a statistical level, however due to the loss of performance of boron carbide, this results in an indication that makes the use of 3Y-PSZ more promising on both substrates. In this sense, the best configuration observed in this study is Thermodur 2367 EFS as substrate and zirconia partially stabilized with 3 % mol yttria (3Y-PSZ) as coating. [resumo fornecido pelo autor]