Method for preparing anti-ablation hafnium boride (HfB2) powder

An anti-ablation, hafnium boride technology, applied in boron/boride, metal boride and other directions, can solve the problems of many powder impurities, long process cycle, expensive raw materials, etc., to increase the reaction activity, simple operation and cost. low cost effect

Inactive Publication Date: 2012-09-12
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to avoid the deficiencies of the prior art, the present invention proposes a hafnium boride HfB 2 The preparation method of anti-ablation powder overco

Method used

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  • Method for preparing anti-ablation hafnium boride (HfB2) powder
  • Method for preparing anti-ablation hafnium boride (HfB2) powder
  • Method for preparing anti-ablation hafnium boride (HfB2) powder

Examples

Experimental program
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Example Embodiment

[0018] Example 1:

[0019] Step 1: Add hafnium chloride (HfCl 4 ), boric acid (H 3 BO 3 ), phenolic resin (residual carbon rate is 60%) respectively dissolved in alcohol solution, among them, HfCl 4 , H 3 BO 3 The molar ratio of phenolic resin to phenolic resin is 1:2:4, and the solution is stirred uniformly with a magnetic stirrer for use;

[0020] Step 2: Mix the three solutions uniformly under the stirring of a magnetic stirrer, and use concentrated ammonia (NH 3 ·H 2 O) Adjust the pH of the solution to 4-4.5, and make a wet gel after thorough stirring;

[0021] Step 3: Dry the prepared three kinds of wet gels in an oven at 80°C for 24 hours, and then ball mill them with a planetary ball mill for 24 hours, set the speed to 250r / min, and set the forward and reverse commutation cycle to 20min;

[0022] Step 4: Under the protection of 400~600ml / min Ar gas, the powder is heated in a graphitization furnace at a heating rate of 5~10℃ / min to 1800℃ for 1h, then the power is cut off and the ...

Example Embodiment

[0023] Example 2:

[0024] Step 1: Add hafnium chloride (HfCl 4 ), boric acid (H 3 BO 3 ), phenolic resin (residual carbon rate is 60%) respectively dissolved in alcohol solution, among them, HfCl 4 , H 3 BO 3 The molar ratio of phenolic resin to phenolic resin is 1:4:8, and the solution is stirred uniformly with a magnetic stirrer for use;

[0025] Step 2: Mix the three solutions uniformly under the stirring of a magnetic stirrer, and use concentrated ammonia (NH 3 ·H 2 O) Adjust the pH of the solution to 4-4.5, and make a wet gel after thorough stirring;

[0026] Step 3: Dry the prepared three kinds of wet gels in an oven at 80℃ for 24 hours, and then ball mill them with a planetary ball mill for 24 hours, set the speed to 250r / min, and set the positive and negative commutation cycle to 20min

[0027] Step 4: Under the protection of 400~600ml / min Ar gas, the powder is heated in a graphitization furnace at a heating rate of 5~10℃ / min to 1800℃ for 1h, then the power is cut off and the ...

Example Embodiment

[0028] Example 3:

[0029] Step 1: Add hafnium chloride (HfCl 4 ), boric acid (H 3 BO 3 ), phenolic resin (residual carbon rate is 60%) respectively dissolved in alcohol solution, among them, HfCl 4 , H 3 BO 3 The molar ratio of phenolic resin to phenolic resin is 1:6:12, and the solution is stirred uniformly with a magnetic stirrer for use;

[0030] Step 2: Mix the three solutions uniformly under the stirring of a magnetic stirrer, and use concentrated ammonia (NH 3 ·H 2 O) Adjust the pH of the solution to 4-4.5, and make a wet gel after fully stirring;

[0031] Step 3: Dry the prepared three kinds of wet gels in an oven at 80°C for 24 hours, and then ball mill them with a planetary ball mill for 24 hours, set the speed to 250r / min, and set the forward and reverse commutation cycle to 20min;

[0032] Step 4: Under the protection of 400~600ml / min Ar gas, the powder is heated in a graphitization furnace at a heating rate of 5~10℃ / min to 1800℃ for 1h, then the power is cut off and the te...

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Abstract

The invention relates to a method for preparing an anti-ablation hafnium boride (HfB2) powder, and to a method for preparing HfB2 powder with low cost and short period. The method comprises steps of dissolving HfC14, H3BO3, and phenolic resin in absolute ethyl alcohol respectively to obtain alcoholic solutions, mixing the alcoholic solutions and dropping a concentrated ammonia liquor to adjust the PH of the alcoholic solution mixture to 4-4.5 in order to turn the solution to be a sol and finally to be a gel. A xerogel is formed after drying the gel in a baking oven at a temperature of 60-100 DEG C for 20-30 hours, and the HfB2 powder with high purity is obtained after ball milling of the xerogel as well as a high-temperature heat treatment at 1400-1800 DEG C. The high-purity HfB2 with low cost and short period is prepared by employing a precursor conversion of the alcoholic solutions of inorganic salts and combining a sol-gel method and a carbon thermal reduction reaction.

Description

technical field [0001] The invention relates to a hafnium boride HfB 2 A method for preparing an anti-ablation powder. Background technique [0002] HfB 2 It has the characteristics of high melting point, high hardness, good heat transfer and electrical conductivity, and is an ultra-high temperature ceramic material with excellent performance. In addition to being applied to the nose cone and leading edge of aerospace vehicles, it can also be used for engines, molten metal crucibles, cutting tools and wear-resistant coatings. HfB 2 It is expensive and difficult to compact, and it is easy to mix in difficult-to-remove impurities during the process. In terms of preparation technology, traditional methods include: melting synthesis of metal hafnium and boron in inert gas or vacuum, carbon reduction method, self-propagating high-temperature synthesis method, and chemical vapor infiltration method. The raw materials of the direct synthesis method are relatively expensive, th...

Claims

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Application Information

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IPC IPC(8): C01B35/04C04B35/58
Inventor 李贺军姚栋嘉李克智付前刚王永杰张东生
Owner NORTHWESTERN POLYTECHNICAL UNIV
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