Method for preparing silicon carbide woodceramics

Abstract

The invention discloses a method for preparing silicon carbide woodceramics. The method comprises the steps of carbonizing billets prepared by wood powder with fineness of 100 meshes to 800 meshes to obtain carbon billets; and using a liquid phase siliconizing method or a gas phase siliconizing method for leading the carbon billets and the carbon to prepare the silicon carbide woodceramics. The billet body is prepared by hot-press forming or roll forming of the wooden powder. The water content of the wooden power is 0-80g100g. The temperature of the hot-press forming or roll forming is 120 DEG C to 220 DEG C and the temperature of carbonization is 600 DEG C to 1600 DEG C. The method for preparing the silicon carbide woodceramics has easy-available raw materials, simple and easy technique and controllable ceramic structure, and can prepare the silicon carbide woodceramics with high mechanical property and high reliability.

Description

technical field [0001] The invention relates to a method for preparing silicon carbide wood ceramics. Background technique [0002] Silicon carbide ceramics is an important material system in engineering ceramics. It can be prepared by a variety of sintering processes, including pressureless sintering, hot pressing sintering, isostatic pressing sintering and reaction sintering. Among them, the reaction sintering process has a low sintering temperature. , short reaction time, low requirements for raw material purity, and the ability to prepare products with complex shapes, etc., so it is a low-cost and widely applicable silicon carbide ceramic preparation process. [0003] In the past ten years, wood materials have also been used in the reaction sintering process to prepare silicon carbide ceramics (called SiC wood ceramics). The method is to use wood, MDF and wood powder / resin-based composite materials as wood bodies Porous carbon blanks were obtained by pyrolysis under the...

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Problems solved by technology

However, research results and reaction sintering theory show that the technology of preparing SiC wood-based ceramics from the above-mentioned wood materials does not have practical application value: wood is a natural porous material, and its pore size has a wide distribution due to the complexity of its microstructure. ; and due to the differences in the growth environment of the tree, the trunk of the wood, etc., the pore size distribution has great variability, and the existence of some structural defects also leads to changes in the pore size distribution and pore characteristics.

When wood is directly used to prepare SiC wood ceramics, due to the low density of wood and large structural fluctuations, the prepared ceramics have low density, unsatisfactory mechanical properties and poor reliability; when fiberboard is used as raw material, the structural uniformity is improved, but the density It is still low, and the density of the prepared ceramics is still low; when using wood powder / resin-based composite materials as raw materials, high-density SiC wood ceramics can be obtained, but the resin powder introduced in the raw material system makes the amount of residual carbon in the ceramics too high , limiting the further improvement of its mechanical properties

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