Synthesis of high-purity hafnium boride powder

A high-purity, powder technology, applied in the field of ceramic materials, can solve the problems of low powder purity, narrow distribution range, low cost, etc., and achieve the effect of simple preparation process, less equipment, and easy realization.

Inactive Publication Date: 2009-05-13
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem of HfB produced by the original carbothermal/borothermic reduction method by adjusting the ratio of raw materials. 2 To solve the p...

Method used

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  • Synthesis of high-purity hafnium boride powder
  • Synthesis of high-purity hafnium boride powder
  • Synthesis of high-purity hafnium boride powder

Examples

Experimental program
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Embodiment 1

[0019] Using hafnium dioxide (2μm, 99%), boron carbide (1.5μm, 96%), graphite (1.5μm, 99%) as raw materials, based on carbothermal reduction reaction, weigh HfO 2 : 4.214g, B 4 C: 0.691g, C: 0.225g, using absolute ethanol as the ball milling medium, Si 3 N 4 The ball is a grinding ball, the ratio of ball to material is 2.5:1, and the ball mill is mixed for 10 hours. After the obtained slurry is dried by rotary evaporation, the 2 The compact is compacted under a pressure of 1000°C, and then heat-treated in a vacuum furnace with a vacuum degree of 2 , the oxygen content is 0.2wt%, and the average particle size is 1.15μm. The XRD pattern of the powder is as follows figure 1 shown. Sample labeled: HBC.

Embodiment 2

[0021] Based on the carbothermal reduction reaction, weigh HfO 2 : 4.214g, B 4 C: 0.921 g, batching was performed. Prepare HfB according to the method of embodiment 1 2 Powder. The main component of the obtained powder is HfB 2 , the oxygen content is 0.16wt%, and the average particle size is 0.92μm. The XRD pattern of the powder is as follows figure 1 shown. Sample labeled: HB1.

Embodiment 3

[0023] Based on the carbothermal reduction reaction, weigh HfO 2 : 4.214g, B4 C: 0.873g, C: 0.05g were compounded. Prepare HfB according to the method of embodiment 1 2 Powder. The main component of the obtained powder is HfB 2 , the oxygen content is 0.18wt%, and the average particle size is 0.66μm. The XRD pattern and microscopic appearance of the powder are as follows: figure 1 and figure 2 As shown in (a), the particle size distribution is as follows image 3 shown. Sample labeled: HB2.

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Abstract

The invention relates to hafnium boride powder with advantages of high purity, good dispersibility, small grain size and narrow distribution range, and a process for synthesizing the powder. The invention is characterized in that the process adopts hafnium oxide, boron carbide, graphite and amorphous boron as raw materials and is based on carbothermic/borothermic reduction reaction, wherein, in the carbothermic reduction, the mass ratio of HfO 2, B4C and C ranges from (1-5/4):(5/7-6/7):(0-3/2); and in the borothermic reduction, the mass ratio of HfO2 and B is 1:(10/3-4). Through adjusting the proportion of the raw materials, controlling the synthesizing process, adopting relatively cheap HfO2 raw material, the invention can synthesize the HfB2 powder with oxygen content less than 0.2wt% under the conditions that the temperature is 1500-1600 DEG C, an Ar atmosphere is adopted, or the vacuum degree is smaller than 1 Pa. SEM and laser grading analysis show that the distribution range of powder grain diameter is narrow (the polydispersity coefficient is 0.005), and the average grain diameter is around 1Mum. All of the parameters are superior to the ordinary commercial HfB2 powder, the preparation process and the required equipment are simple, the cost is low and the yield is high.

Description

technical field [0001] The invention relates to a method for synthesizing hafnium diboride powder with high purity, good dispersibility, small particle size and narrow distribution range, and belongs to the field of ceramic materials. Background technique [0002] Hafnium diboride (HfB 2 ) has a high melting point (3380°C), high hardness (28GPa), high chemical stability (△G f =-332.2KJ / mol), excellent electrical and thermal conductivity and thermal shock resistance, etc., can be used in thin film resistors and diffusion barriers in the microelectronics industry. in HfB 2 After adding SiC, it can greatly improve its oxidation resistance and ablation resistance, HfB 2 -SiC-based ceramics are considered to be one of the most promising candidate materials for ultra-high temperature structural components of aerospace vehicles. But since HfB 2 It is expensive, which limits its research and application in this field to a certain extent. Therefore, the development of high-purit...

Claims

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Application Information

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IPC IPC(8): C01B35/04
Inventor 张国军倪德伟阚艳梅王佩玲
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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