Process for preparing yttrium aluminum garnet-based continuous fibers through sol-gel method

Abstract

The invention discloses a process for preparing yttrium aluminum garnet-based continuous fibers through a sol-gel method. Yttrium aluminum garnet is taken as a main component, and a second component is added to serve as a grain inhibitor. The process comprises the following steps of: adding inorganic aluminum salt, yttrium oxide, the grain inhibitor, acetic acid and metal aluminum into distilled water, and reacting the mixture solution under the conditions of certain temperature, continuously stirring and condensing reflux so as to prepare grain inhibitor-containing yttrium aluminum garnet sol; adding a certain amount of spinning aid into the sol, and concentrating the solution so as to prepare spinnable fiber precursor sol; spinning to prepare precursors of organic matter-containing yttrium aluminum garnet-based continuous fibers by adopting a dry method or a wet method; and drying and sintering the precursors to prepare the yttrium aluminum garnet-based fibers. The prepared yttrium aluminum garnet-based continuous fibers can be used as reinforcement in a composite material to improve the strength, toughness and heat resistance of the material, and is widely applied in the fields of aerospace, automobiles and the like.

Description

technical field [0001] The invention relates to a preparation process for continuous yttrium aluminum garnet-based fibers that can be used as winding, lamination or other two-dimensional and three-dimensional weaving. Background technique [0002] The chemical formula of yttrium aluminum garnet (Yttrium aluminum garnet, YAG) is Y 3 Al 5 o 12 , is Y 2 o 3 -Al 2 o 3 A crystalline compound in the system. YAG is a cubic crystal system with a garnet structure. The melting point of YAG crystals is 1942°C and the density is 4.55g / cm 3 , high temperature strength, high thermal conductivity, stable physical and chemical properties, and good light transmittance to visible light and infrared light. [0003] YAG fiber is a new type of inorganic ceramic fiber developed in the 1970s. It is different from general alumina-based fibers, such as mullite fiber, high-purity alumina fiber (95wt% Al 2 o 3 ), not only has excellent properties such as high strength, high modulus, and high...

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Problems solved by technology

[0007] Pullar et al [Journal of the European Ceramic Society, 1998, 18:1759-1764] adjusted the pH value of the aluminum nitrate solution to 5.0 with ammonia water to obtain a cake-like precipitate, washed with distilled water, added a small amount of nitric acid to dissolve the precipitate, and obtained aluminum sol, the pH value of the sol is 3.0; adjust the pH value of the yttrium salt to 9.5 with ammonia water to obtain a precipitate, wash it with distilled water, add a small amount of nitric acid to dissolve the precipitate, and obtain the yttrium sol, the pH value of the sol is 7.0; use aluminum nitrate After the prepared aluminum sol was mixed with yttrium sol, YAG precursor fibers were prepared, but there was no YAG phase formation after the fibers were calcined at 1200 °C, and the quality of the fibers was poor, mainly due to poor gel mixing; they used The aluminum sol containing chloride ions purchased in the market is the original aluminum, and the YAG precursor fiber is prepared. The YAG crystal phase starts to form at 700-750°C, and the garnet crystal phase crystallization is completed at 750-800°C.

[0008] The length of the yttrium aluminum garnet fiber obtained by the above process is relatively short, and the crystal grains of the fiber are easy to grow when calcined at high temperature, which reduces the performance of the fiber

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