Preparation method of high-purity hexagonal boron nitride powder

A technology of boron nitride powder and purity, which is applied in the field of preparation of relatively high-purity hexagonal boron nitride powder, and can solve the problems of limited effect, difficult implementation, and high cost

Active Publication Date: 2019-03-22
山东博奥新材料技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In the known technology, the impurity content in the boron nitride powder is generally reduced by using high-purity raw materials, relatively reasonable roasting conditions, and a high degree of product pickling, which can reduce the content of most metal impurities, but there is a cost Higher, difficult to implement or limited effect, etc., the control effect on non-metallic impurity elements, especially oxygen and carbon, is relatively limited

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] (l) Mix 6.2kg of boric acid, 3.78kg of melamine, and 0.82kg of anhydrous borax in a 30L ball mill tank and grind for 6 hours; the ball mill tank is lined with polyurethane, Pack 12kg of Φ10mm alumina ceramic ball material; the material after grinding can be sampled and tested to pass through a 140-mesh sieve; pressed into a medium Φ100x80mm block by a hydraulic press to obtain a molding material;

[0022] (2) React 8 pieces of molding materials in step (1) in a silicon nitride tube atmosphere furnace at 1100°C for 4hrs; the flow rate of ammonia gas is 50L / min, and the heating rate is 250°C / hr; after the reaction at 1100°C, the furnace cools down for 2hrs to After 820°C, switch ammonia to nitrogen with a flow rate of 50L / min (purity: 99.9%). After 0.5 hours, when the temperature drops to 800°C, switch nitrogen to air with a flow rate of 80L / min. Keep warm for 20 minutes, then cut off the power supply, and take out the block. Disperse and cool in air at room temperature, ...

Embodiment 2-8、 comparative example 1-18

[0026] Basically the same method as in Example 1, boron nitride was prepared respectively, and the different conditions were listed in Table 1-3.

[0027] In each preparation process, a proportion and the pressed molding material in step (1) can be used in multiple atmosphere furnace roasting reactions and air treatment conditions. For example, the pressed molding material in Example 1 was used in Comparative Examples 3 and 7 respectively. The proportioning molding material of Example 2 was used in Examples 5, 7, 9 and Comparative Examples 4, 8 respectively, and if the mixing was not enough once, it was mixed again and formed.

[0028] In comparative examples 15-18, only one of alkali treatment or acid treatment was carried out when the samples of roasted materials in Examples 2 and 3 were washed with water.

[0029] In Table 3, the contents of O and C elements in boron nitride products were measured by X-ray fluorescence spectrometer (XRF), and the contents of metal element i...

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PUM

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Abstract

The invention provides a preparation method of high-purity hexagonal boron nitride powder, which is low in cost, easy to implement and good in effect. The preparation method has good control effect onmetallic element impurities and non-metallic element impurities, especially an oxygen impurity element and a carbon impurity element which are in a large quantity. The prepared boron nitride powder has a low oxygen content and carbon content, has very low contents of the metallic element impurities and other non-metallic element impurities, is good in hot press performance, can be used to preparepure hexagonal boron nitride ceramic products or parts for high-temperature electric insulation in a non-oxidizing atmosphere, and can be also mixed with high-stability resin such as polytetrafluoroethylene to prepare high-voltage insulation plastic products or parts in a hot press or extrusion way.

Description

technical field [0001] The invention belongs to the field of inorganic non-metallic materials, and in particular relates to a preparation method of relatively high-purity hexagonal boron nitride powder. Background technique [0002] Hexagonal boron nitride has a layered structure similar to graphite. It has a relatively stable structure in the layer, and the bonding between the layers is weak, and it is easy to peel off into a sheet. It has excellent properties in the direction of the layer and the direction perpendicular to the layer. Excellent insulation and dielectric properties; the oxidation resistance temperature is 200°C higher than that of graphite in the air, and it can remain stable at about 2000°C in a non-oxidizing atmosphere; it can be used as a temperature-resistant lubricant and electrical insulating material. The sintered body of hexagonal boron nitride has a Mohs hardness of about 2 and is easy to machine. Ceramic materials containing more than 15% hexagonal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/064
CPCC01B21/0646C01P2006/80
Inventor 张春先颜继鹏王军令晓阳姜能明姜兴全
Owner 山东博奥新材料技术有限公司
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