Sintering preparation method of boron carbide ceramic

A technology of boron carbide ceramics and boron carbide powder, which is applied in the field of preparation of boron carbide ceramics, which can solve the problems of coarse raw material particle size, shortened kiln life, and low firing temperature, and achieves less metal residue, high density, and extended use. The effect of longevity

Active Publication Date: 2014-03-05
NINGBO VULCAN TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The reaction sintering method has low firing temperature, low energy consumption, coarse raw material particle size, low cost, high production capacity, no shrinkage or even slight expansion of the product, and excess metal remaining on the surface of the product needs special treatment. Liquid or gaseous metal is destructive to the kiln. Influence, shorten the life of the kiln

Method used

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Examples

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preparation example Construction

[0024] The boron carbide ceramic sintering preparation method of the present invention is prepared by two-step sintering in situ under normal pressure, comprising the following steps:

[0025] (1) Put various raw materials into the mixing and pulping equipment according to the proportion of the formula (conventional mixing equipment in the industry such as sand mill, ball mill, planetary mill, emulsifying machine, etc. can be used), and the various raw materials described include the following weight percentages Each component: boron carbide powder 60~90wt%, carbon powder 1.8~18wt%, metal powder 8~36wt%; dispersant 0.1~2wt%, binder 0.1~5wt%; then ball milling, ball milling pulping process In addition, deionized water is added so that the solid content of the resulting slurry is 30% to 60% by weight;

[0026] (2) Using the slurry obtained in step (1) to produce granulated material by spray drying and granulating process;

[0027] (3) The pellets produced in step (2) are formed...

Embodiment 1

[0039] Add 500 grams of boron carbide micropowder, 100 grams of metal aluminum powder, 30 grams of coke, and 800 ml of deionized water into a ball mill, add 1 gram of tetramethylammonium hydroxide and 5 grams of dextrin for ball milling, and then spray granulate to obtain Granulated material, the obtained granulated material is dry-pressed to obtain a biscuit, and the biscuit is placed in a vacuum sintering furnace at 800°C for 1 hour, pre-fired and debonded; Keep warm for 1.5 hours; continue to increase the temperature to 2100°C, keep warm for 1 hour, and obtain boron carbide ceramics after cooling.

[0040] The boron carbide ceramic density is 2.56g / cm 3 , the flexural strength is 380MPa, and the fracture toughness is 4.1MPa m 1 / 2 , Vickers hardness is 30GPa.

Embodiment 2

[0042] Put 500 grams of boron carbide micropowder, 150 grams of silicon aluminum alloy powder, 20 grams of graphite powder, and 800 grams of deionized water into the ball mill, add 3ml of ammonia water and 1 gram of polyvinyl alcohol for ball milling, and then spray granulation to obtain granulation The obtained granulated material is dry-pressed to obtain a biscuit, which is placed in a vacuum sintering furnace at 650°C for 1 hour, pre-fired and debonded; the pre-fired biscuit is placed in a vacuum furnace, and kept at a temperature of 1550°C 1h; continue to increase the temperature to 2050°C, keep warm for 1h, and obtain boron carbide ceramics after cooling.

[0043] The boron carbide ceramic density is 2.58g / cm 3 , the flexural strength is 340MPa, and the fracture toughness is 4.5MPa m 1 / 2 , Vickers hardness is 29GPa.

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Abstract

The invention discloses a sintering preparation method of boron carbide ceramic, which comprises the following steps: 1. sintering: carrying out mixing and ball milling on boron carbide powder, carbon powder, metal powder, a dispersant, an adhesive and deionized water to make a slurry, carrying out spray granulation, pressing into a biscuit, presintering for debonding, and carrying out thermal-insulation sintering at lower sintering temperature (slightly higher than the melting point of metal), thereby implementing primary shrinkage sintering of the product by utilizing the surface tension of the molten metal in the system; and 2. sintering: continuing enhancing the sintering temperature, carrying out in-situ reaction to generate metal carbide, metal boride or metal boro-carbide and nano B4C which have higher sintering activity, and forming a solid solution with boron carbide granules by using the metal carbide, metal boride or metal boro-carbide and nano B4C as sintering assistants to promote the further shrinkage sintering of the system, thereby obtaining the high-performance boron carbide ceramic. The method has the advantages of both the normal-pressure sintering technique and the reactive sintering technique.

Description

technical field [0001] The invention relates to a new preparation method of boron carbide ceramics, in particular to a sintering preparation method of boron carbide ceramics which adopts a normal pressure in-situ reaction two-step method. Background technique [0002] Boron carbide is an important superhard material whose hardness is second only to diamond and cubic boron nitride in nature. It has the characteristics of high hardness, high modulus, small specific gravity, good self-lubrication, wear resistance, radiation resistance, and neutron absorption. It is a new type of high-performance engineering ceramic material with outstanding comprehensive performance. It is used in high-end liquid and gas sealing materials, aerospace engine nozzles, high-end ceramic bearings, high-end bulletproof armor materials, nuclear radiation protection, polishing and fine grinding materials for hard materials, etc. has important applications. [0003] The covalent bond in the boron carbid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/563C04B35/65
Inventor 焦永峰谢方民戚明杰邬国平杨勇辉
Owner NINGBO VULCAN TECH CO LTD
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