Method for preparing boron nitride/sialon ceramic composite material by using boron-rich slag

A technology of ceramic composite materials and boron-rich slag, which is applied in the field of preparing BN/α′-Sialon ceramic composite materials, can solve the problems of unsuitability for industrial scale production, non-resource utilization method, poor reproducibility of sintered products, etc. Air oxidation resistance, fine particle size, improved thermal shock resistance

Inactive Publication Date: 2008-05-28
NORTHEASTERN UNIV
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  • Application Information

AI Technical Summary

Problems solved by technology

Although this method can prepare materials with high purity, the cost of raw materials is high and the process is complicated, so it is not suitable for industrial scale production.
In addition, there is a self-propagating sintering method (SHS) using natural minerals or industrial waste as raw materials to prepare α'-Sialon. Although this method has a short reaction time and fast speed, it is also not suitable for industrial-scale production, and the reproducibility of sintered products is poor.
Boron-rich slag is a kind of waste slag produced after the separation of boron ore by blast furnace or electric furnace. At present, there is no effective resource utilization method, and long-term accumulation will cause great pollution to the environment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0023] Example 1: Synthesis of BN / (Ca, Mg)α'-Sialon powder in the first step. First, the boron-rich slag is crushed, and then the crushed slag is processed with a sample maker to obtain slag powder, and then the slag powder is put into a polyurethane ball mill tank for fine grinding until the particle size of the slag powder reaches below 200 mesh. Finally, magnetic separation is used to remove elemental iron and ferromagnetic substances contained in the slag. The boron-rich slag after magnetic separation is mixed with silica fume, bauxite, and carbon black. The ratio is: boron-rich slag is 35.78g, silica fume is 21.97g, bauxite is 15.49g, and carbon black is 26.76g . The prepared mixture was placed in a polyurethane ball mill tank, wet-mixed with absolute ethanol as a medium for 24 hours, and then the slurry was dried in an oven at 60°C. After the mixture is fully dried, dry mix for 4 hours to ensure that the mixture is fully uniform. Put the dry-mixed billet into a steel ...

example 2

[0025] Example 2: Synthesis of BN / (Ca, Mg)α'-Sialon powder in the first step. The ratio of raw materials is: 29.06g of boron-rich slag, 25.48g of silica fume, 22.15g of bauxite, and 23.31g of carbon black. The sintering temperature is 1500°C, the temperature is kept constant for 6h, the heating rate is 3°C / min, and the nitrogen flow rate is 600ml / min. The second step prepares BN / (Ca, Mg) α'-Sialon ceramic composite material: the above-mentioned powder and the additive CaCO that accounts for 15% of powder mass 3Dry-mix in an agate mortar for 0.5h; sinter at 1650°C and keep warm for 1h. The heating system is: when the temperature is raised to 1150 °C at 30 °C / min, keep it warm for 0.5 h, then raise the temperature to 1400 °C at a speed of 25 °C / min, then raise it to the firing temperature at a speed of 10 °C / min, and keep it for 1 h. , began to cool down, and the cooling rate was 40° C. / min. The other process steps and process conditions of the above two steps were the same as...

example 3

[0026] Example 3: Synthesis of BN / (Ca, Mg)α'-Sialon powder in the first step. The ratio of raw materials is: 7.94g of boron-rich slag, 55.55g of silica fume, 3.62g of bauxite, and 32.89g of carbon black. The sintering temperature is 1450°C, the temperature is kept constant for 10 hours, and the nitrogen flow rate is 800ml / min. The second step is to prepare BN / (Ca, Mg)α'-Sialon ceramic composites. The sintering temperature is 1600°C and the temperature is kept for 1.5h. The heating system is: when the temperature rises to 1150°C at 28°C / min, keep it warm for 0.5h, then raise the temperature to 1400°C at a speed of 23°C / min, then raise it to the firing temperature at a speed of 7°C / min, and keep it warm for 1.5h After that, start to drop the temperature at a rate of 35°C / min. The other process steps and process conditions of the above two steps are the same as in Example 1. The test results show that the main phases in the synthesized powder are α'-Sialon and BN, and more Si...

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Abstract

The invention relates to a preparation method of boron nitride/sialon composite material by adopting boron-rich slag. The preparation method comprises two steps: the first step is that synthesis sialon powder BN/ (Ca, Mg) Alpha' : 1. crushing, 2. ball milling, 3. screening, 4. magnetic separating, 5. proportioning according to mass percent: 7.94 to 45.79 portions of boron-rich slag, 12.19 to 58.78 portions of silicon fume, 3.82 to 19.78 portions of bauxite, 21.70 to 35.41 portions of carbon black, 6. wet mixing with anhydrous ethanol as the medium, 7. drying with the temperature 60 DEG C; 8. dry mixing, 9. molding forming, 10. high-temperature sintering under one atmospheric pressure, temperature of 1450 to 1500 DEG C, insulation for 6 to 10 hours and protection of nitrogen; 11. eliminating carbon residual by burning; the second step is that mixing the powder obtained by the first step and additive CaCO3, and after the molding forming, the final product sialon ceramic composite material BN/(Ca, Mg) Alpha' is made by sintering through burying powder in furnace under temperature 1600 to 1700 DEG C; all properties of the product are good. The invention has simple process, low production cost, and starts a new way for boron-rich slag integrating utilization and decreases environment pollution.

Description

technical field [0001] The invention relates to a method for preparing a ceramic composite material, in particular to a method for preparing a BN / (Ca, Mg)α'-Sialon ceramic composite material by utilizing boron-rich slag. Background technique [0002] At present, there has not been any report on the preparation of BN / (Ca, Mg)α'-Sialon ceramic composites using boron-rich slag at home and abroad. Single-phase α'-Sialon and α'-Sialon-based ceramic composites are mostly prepared by reaction sintering (RS) using pure nitrides and oxides as raw materials. Although this method can prepare materials with higher purity, the cost of raw materials is high and the process is complicated, so it is not suitable for industrial scale production. In addition, there is a self-propagating sintering method (SHS) using natural minerals or industrial waste as raw materials to prepare α'-Sialon. Although this method has a short reaction time and fast speed, it is also not suitable for industrial-s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/583C04B35/599C04B35/622
Inventor 薛向欣姜涛巫俊斌段培宁杨合
Owner NORTHEASTERN UNIV
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