Study On Preparation And Properties Of Ceramic Cores By Al₂O₃ Combined With Organic Silicon Resin

The blades on an aero engine are the"heart"components of an aero engine.The performance of the blades plays a decisive role in the performance of the aero engine.The preparation of high-performance hollow blades puts forward higher requirements for the production of ceramic cores with high comprehensive performance.In this paper,liquid silicone resin is selected as the precursor and binder,and the porous alumina ceramic core is prepared by dry pressing sintering method,and reasonable process parameters are formulated.The effects of sintering atmosphere,sintering temperature,liquid silicone addition and Ti C addition on the bending strength,linear shrinkage,apparent porosity,bulk density,microstructure and phase composition of the ceramic core were systematically studied.The following main conclusions are obtained:The preparation process of ceramic core was studied,the effects of the mixing method,the type of dispersant used and the sintering temperature on the performance of the ceramic core were investigated in detail,and it is concluded that the selection of acetone as the dispersant is more suitable.The performance is much higher than the magnetic stirring method,the baking temperature is within 1500?1600?,and the ceramic core has the best performance.The effect of the particle size of alumina matrix powder on the properties of ceramic core was studied,and find that the particle size of the alumina powder should be moderate.Although the particle size is too small,the bending strength of the ceramic core will be improved,but it will also cause excessive linear shrinkage,and the final dimensional accuracy cannot be guaranteed.When the ball milling time is24h,the average particle size of the alumina powder is 15.01?m,and the particle size of the alumina powder is concentrated between 6?32?m.The ceramic cores prepared by this type of powder have better comprehensive performance.The effect of the liquid silicone resin content on the performance of the ceramic core was studied.It was found that adding an appropriate content of silicone resin can effectively improve the sintering performance of the ceramic core.Although the linear shrinkage of the ceramic core increases with the increase of the liquid silicone resin content,it is relatively stable overall,and its value is in the range of 0.5%-1.0%,so it can ensure the stability of the alumina ceramic core.When sintered at 1550?,when the content of liquid silicone resin increases from 0.3wt%to 1wt%,the apparent porosity of the ceramic core is between 28.14%and 31.11%,and the bulk density is between 2.31g/cm~3and 2.53g/cm~3.When the amount of liquid silicone resin added is0.8wt%,the maximum bending strength of the ceramic core is 50.76MPa,and the ceramic core has the best comprehensive performance.Ti C addition agent has a great influence on the apparent porosity of ceramic cores.The effect of the content of Ti C addition agent added on the performance of the ceramic core was studied.It was found that the addition of the Ti C addition agent is beneficial to improve the comprehensive performance of the ceramic core.Especially at low sintering temperature,the addition of Ti C is particularly significant.During high-temperature sintering,Ti C has less effect on the ceramic core.When sintered at1550?,the Ti C content is 3wt%,the bending strength of the ceramic core reaches 50.04MPa.