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Method for preparing neodymium hexaboride

A technology of hexaboride and powder is applied in the field of preparation of neodymium hexaboride, which can solve the problems of difficult to achieve synthesis conditions and increase the cost of neodymium hexaboride, and achieve the effects of easy sintering conditions, low price of production equipment and simple operation.

Inactive Publication Date: 2008-10-22
SHANGHAI JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the actual production process, high temperature and high pressure synthesis conditions are difficult to achieve, and using boron powder as a raw material will greatly increase the cost of neodymium hexaboride

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] The raw material Nd 2 o 3 Powder and B 4 C powder is placed in an oven and dried at 200°C for 4 hours without adding protective gas or vacuuming to the oven during the process. where Nd 2 o 3 Powder purity greater than 99%, B 4 The purity of C powder is greater than 97% (mass fraction).

[0016] Weigh the dried Nd 2 o 3 Powder and B 4 C powder (molar ratio 1:3). The above-mentioned powders were uniformly mixed by a V-shaped mixer, and then the mixed powders in the above steps were pressed into shape by a compression molding method to obtain a cylindrical blank (Φ38mm×30mm).

[0017] The blank was sintered in a vacuum sintering furnace, the sintering temperature was 1500°C, and the vacuum degree was 10 -1 Pa, the sintering time is 4 hours, and the neodymium hexaboride can be obtained by cooling in the furnace; the obtained neodymium hexaboride is ground and pulverized.

Embodiment 2

[0019] The raw material Nd 2 o 3 Powder and B 4 The C powder is placed in an oven and dried at 400°C for 2 hours. During the process, there is no need to add protective gas or vacuum to the oven. where Nd 2 o 3 Powder purity greater than 99%, B 4 The purity of C powder is greater than 97% (mass fraction).

[0020] Weigh the dried Nd 2 o 3 Powder and B 4 C powder (molar ratio 1:3). The above-mentioned powders were uniformly mixed by a ball mill, and then the mixed powders in the above-mentioned steps were pressed into shape by a compression molding method to obtain a cylindrical blank (Φ30mm×20mm).

[0021] The blank was sintered in a vacuum sintering furnace with a sintering temperature of 1400°C and a vacuum of 10 -2 Pa, the sintering time is 6 hours, and the neodymium hexaboride can be obtained with the furnace cooling; the obtained neodymium hexaboride is ground and pulverized.

Embodiment 3

[0023] The raw material Nd 2 o 3 Powder and B 4 C powder is placed in an oven and dried at 300°C for 3 hours without adding protective gas or vacuuming the oven during the process. where Nd 2 o 3 Powder purity greater than 99%, B 4 The purity of C powder is greater than 97% (mass fraction).

[0024] Weigh the dried Nd 2 o 3 Powder and B 4 C powder (molar ratio 1:3). The above powders were uniformly mixed by a ball mill, and then the mixed powders in the above steps were pressed into shape by cold isostatic pressing to obtain a cylindrical blank (Φ40mm×15mm).

[0025] The blank was sintered in a vacuum sintering furnace with a sintering temperature of 1800°C and a vacuum of 10 -1 Pa, the sintering time is 2 hours, and the neodymium hexaboride can be obtained by cooling in the furnace; the obtained neodymium hexaboride is ground and pulverized.

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Abstract

The invention discloses a method for preparing neodymium hexaboron, belonging to field of material preparation. The method comprises following steps: selecting neodymium oxide powder and boron carbide powder; drying said powder under temperature of 200-400 Deg.C for 2-4 hours; weighing said power according to molar ration 1: 3 between neodymium oxide and boron carbide; mixing powder evenly with V-arrangement mixing machine and ball grinder; preparing green compact with mixed powder by way of compression molding and cool isostatic compaction; sintering green compact in vacuum sintering furnace under conditions as that: temperature: 1400-1800 Deg.C, vacuun degree: 1*10-1 Pa-1*10-3 Pa; time: 2-8 hours; cooling in furnance and getting product. The invention is characterized by low cost, high efficiency, short cycle, and low price of used device, simple operation and suitness for industrial preparation.

Description

technical field [0001] The invention relates to a method in the technical field of material preparation, in particular to a method for preparing neodymium hexaboride. Background technique [0002] Neodymium hexaboride (NdB 6 ) has a special crystal structure, like CaB 6 The same simple cubic structure: Nd atoms occupy each corner of the cube, and B atoms arranged in a regular octahedron are located in the center of the cube. NdB 6 The preparation methods include: pure element synthesis method, compound reduction sintering method, B reduction sintering method, zone smelting method, solvent method, vapor deposition method, etc. The pure element synthesis method uses Nd element and B element as raw materials, and performs high-temperature sintering according to the molar ratio of 1:6 to directly obtain NdB 6 , the reaction and sintering time of this method is generally more than 10 hours, and the reaction temperature is high, so it is difficult to apply in industrial produc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F17/00
Inventor 吕维洁刘阳张荻覃继宁马凤仓
Owner SHANGHAI JIAOTONG UNIV
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