In-situ synthesized mullite whisker toughened 90 alumina ceramic and preparation method thereof

Abstract

The invention discloses a preparation method of an in-situ synthesized mullite whisker toughened 90 alumina ceramic. The method consists of: taking 85-95wt% of highly dispersed alpha-alumina powder and 5-15wt% of highly dispersed silicon dioxide powder as the raw materials, adopting aluminum fluoride trihydrate powder accounting for 4-18% of the weight of the raw materials and dry basis titanium dioxide accounting for 0.5-3% of the weight of the raw materials as the catalysts, mixing the raw materials with the catalysts, then using water as the medium to perform ball-milling so as to form an Al2O3-SiO2 precursor containing AlF3 and TiO2, then adding polyvinyl alcohol accounting for 1-3% of the weight of the raw materials to serve as the adhesive, conducting mixing, then employing spray drying process to perform granulation and ageing, then conducting isostatic pressing dry process forming, and performing high temperature firing so as to obtain the mullite whisker toughened 90 alumina ceramic. According to the invention, adding of expensive whiskers is unnecessary, a complicated dispersion process of additional adding of whiskers is omitted, also the preparation process is simple, the obtained whiskers have large length, high length-diameter ratio and uniform dispersion, and the method is suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of inorganic non-metallic ceramics. Specifically relates to an in-situ synthesis of mullite whisker toughened 90 alumina ceramics and a preparation method thereof. Background technique [0002] Alumina ceramics and refractory materials have the characteristics of high mechanical strength, high hardness, wear resistance, high temperature resistance, corrosion resistance, high electrical insulation and low dielectric loss, and are widely used in aerospace, aviation, engine wear parts, cutting tools, etc. , has very broad application prospects. However, due to its fatal weaknesses such as high brittleness and poor uniformity, it affects the reliability and safety of ceramic parts. Therefore, improving the toughness of alumina ceramics is an important issue that needs to be solved urgently. At present, the commonly used methods of toughening alumina ceramics include phase transformation toughening, particle di...

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Problems solved by technology

[0004] In terms of in-situ toughening alumina ceramics with mullite whiskers, the current literature and patents are limited to laboratory results, which cannot meet the needs of actual industrial production, and in many cases are based on the theoretical composition of mullite ——75% Al 2 o 3 , 25% SiO 2 Because the synthesis reaction of mullite is expansive, the volume increases by about 10%, which leads to the deterioration of the compactness of the material, which greatly limits the adaptability of the product; especially, the original technology generally uses kaolin as the raw material As a source of silica! Kaolin is relatively scarce in the world, but SiO such as quartz 2 It is extremely rich in minerals and industrial waste

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