Study On Preparation Techniques And Strengthen Behavior Of Al₂O₃ Fiber Reinforced Silica Based Ceramic Cores

The ceramic core is mainly used to form the complicated inner cavity structure, has always been one of the most key technology for producing hollow blade. However the silica-based ceramic cores manufactured at home is always tend to some problems such as low flexural strength, poor creep resistance characteristics and dimensional stability, which resulted in the great influence of core use. Therefore, there is a very important theoretical and practical significance to explore new preparation techniques and strengthen behavior research of ceramic core. In this paper, the Al₂O₃ fiber was mixed into ceramic core slurry as the enhancement material. The Al₂O₃ fiber of different content and length were added by using solvent as the carrier. Besides, the dispersion of fibers in ceramic core slurry and the effect laws of fiber content and length on the combination property of ceramic core were studied. Meanwhile, the strengthen behavior of fiber on ceramic core was analyzed. The experiment results can be summarized as follows:1. The HPMC dispersant are efficient to improve the dispersion of fibers in ceramic core slurry, fibers can be dispersion very uniformity by means of the new style of fiber added. When HPMC content is between 0.3%⁰.4%, the dispersion of fiber is more uniformity and the ratio of forming is very well.2. When fiber content increasing from 0.25% to 1.25%, the flexure strength and sintering shrinkage of ceramic core all increase and then decrease gradually. When fiber content is 1%, the flexure strength reached maximum, which is 20.48 MPa, and the sintering shrinkage is reduced 62%?0.335%?. The porosity of core achieved 36.16% when fiber content is 0.75%, which increased by 6.17% compared to the core which have no fibers.3. With the increasing of fiber length between 2mm to 7mm, the flexure strength, high temperature deformation, sintering shrinkage of ceramic core all increase and then decrease. Especially when fiber content is 4mm, the strength increased almost 34.8%. When fiber content is 7mm, the high temperature deformation and sintering shrinkage of core decreased 9%?1.73mm? and 75%?0.222%? respectively, and the porosity of core raised significantly.4. As the reinforce material, Al₂O₃ fiber mainly through the bridge role to limit the development of micro cracks and enhance the strength of ceramic cores. Due the limited of fiber types, there has a significant effect on crystallization of quartz glass which results in the increase of the ceramic cores deflection at the same time, the retardant effect of Al₂O₃ fiber to ceramic cores matrix also reduce the shrinkage.The influence law of the content and length of fiber on the combination property was studied, which adopt the method of solvent as the carrier to add the fiber into ceramic core slurry. It can provide the new research ideas and theoretical basis for performance reinforced of ceramic core, and laying a good foundation for the ever-accelerated of fiber reinforced ceramic core preparation technology.