Multi-layer sintering mold and sintering method for boron carbide absorbers for nuclear reactor

A nuclear reactor and boron carbide technology, applied in the direction of molds, manufacturing tools, ceramic molding machines, etc., can solve the problems of low density in the middle of sintered parts, low output and yield, poor density consistency, etc., to achieve density and size deviation Small, production The effect of shortening the cycle time and improving the yield

Active Publication Date: 2016-08-31
BEIJING TSINGNENG CHUANGXIN SCI & TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the high firing temperature of the hot pressing sintering method, the product has good mechanical properties and thermal stability, but the output and yield are relatively low, the grinding allowance is large, the cycle is long, and the cost is relatively high; at the same time, when sintered parts When the size is large, due to the uneven distribution of pressure in the axial direction of the pressure head, the density in the middle of the sintered part is low and the density consistency is poor

Method used

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  • Multi-layer sintering mold and sintering method for boron carbide absorbers for nuclear reactor
  • Multi-layer sintering mold and sintering method for boron carbide absorbers for nuclear reactor

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Assemble the mold, each layer of mold is composed of a lower support plate, a porous mold plate and an upper cover plate, the parallelism of the mold is less than 0.05mm; the porous mold plate contains 100 holes, each hole is equipped with a combined mold, the volume of the inner hole of the combined mold The deviation is less than 0.5%; a gap of 0.1mm should be reserved between the components of the composite mold. Select nuclear-grade boron carbide powder with a particle size D50 of 10 μm, weigh the powder with a mass deviation of less than 0.5%, and add it to the holes of the combined mold; combine the five-layer molds together and hang them into the hot-press sintering furnace.

[0025] Vacuumize the sintering furnace to below 100pa, heat up to 1000°C at a heating rate of 3°C / min, fill it with high-purity argon to gauge pressure -0.1Mpa, continue to heat up to 1400°C, evacuate, and heat up to 1800°C for 0.5 hours , natural cooling, out of the oven. The mechanical p...

Embodiment 2

[0027] Assemble the mold, each layer of mold is composed of a lower support plate, a porous mold plate and an upper cover plate, the parallelism of the mold is less than 0.05mm; the porous mold plate contains 10 holes, each hole is equipped with a combined mold, the volume of the inner hole of the combined mold The deviation is less than 0.5%; a gap of 4 mm should be reserved between the components of the composite mold. Select nuclear-grade boron carbide powder with a particle size D50 of 30 μm, weigh the powder with a mass deviation of less than 0.5%, and add it to the holes of the combined mold; combine the three-layer molds together and hang them into the hot-press sintering furnace.

[0028] Vacuumize the sintering furnace to below 100pa, heat up to 1000°C at a heating rate of 10°C / min, fill it with high-purity argon to gauge pressure -0.1Mpa, continue to heat up to 1400°C, evacuate, and heat up to 2100°C for 0.5 hours , natural cooling, out of the oven. The mechanical p...

Embodiment 3

[0030] Assemble the mold, each layer of mold is composed of a lower support plate, a porous mold plate and an upper cover plate, the parallelism of the mold is less than 0.05mm; the porous mold plate contains 3 holes, each hole is equipped with a combined mold, the volume of the hole in the combined mold The deviation is less than 0.5%; a gap of 2mm should be reserved between the components of the composite mold. Select nuclear-grade boron carbide powder with a particle size D50 of 50 μm, weigh the powder with a mass deviation of less than 0.5%, and add it to the holes of the combined mold; combine the three-layer molds together and hang them into the hot-press sintering furnace.

[0031] Vacuumize the sintering furnace to below 100pa, heat up to 1000°C at a heating rate of 40°C / min, fill it with high-purity argon to gauge pressure -0.1Mpa, continue to heat up to 1400°C, evacuate, and heat up to 1900°C for 0.5 hours , natural cooling, out of the oven. The mechanical pressure ...

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Abstract

The invention belongs to the technical field of preparation of special materials, and particularly relates to a multi-layer sintering mold for boron carbide absorbers for a nuclear reactor. Each layer of the multi-layer sintering mold comprises a porous mold plate (2), a lower supporting plate (3) and an upper cover plate (1), wherein the porous mold plate (2) is provided with multiple holes, and a matched combined mold body is arranged in each hole. Each combined mold body comprises a protection sleeve (5), a mandrel (7), an upper pressing head (4) and a lower pressing head (6), wherein the protection sleeve (5) is matched with the corresponding hole in shape, the mandrel (7) is arranged in the protection sleeve (5), and an annular cavity (8) for accommodating boron carbide powder is defined between the mandrel (7) and the protection sleeve (5); and the upper pressing head (4) and the lower pressing head (6) are located at the top and the bottom of the annular cavity (8) correspondingly and matched with the annular cavity in shape. The invention further discloses a sintering method adopting the multi-layer sintering mold for the boron carbide absorbers for the nuclear reactor.

Description

technical field [0001] The invention relates to a multilayer sintering mold and a sintering method for a boron carbide absorber used in a nuclear reactor, and belongs to the technical field of special material preparation. Background technique [0002] The molecular formula of boron carbide is B 4 C is one of the three hardest materials known, with a Mohs hardness of 9.3, second only to diamond and cubic boron nitride as important superhard materials. At the same time, it has the properties of light weight, wear resistance and corrosion resistance, and is used in the armor of tanks, body armor and many industrial applications. At the same time, boron carbide can absorb a large amount of neutrons without forming any radioactive isotopes. It is an ideal neutron absorber in reactors. Boron carbide mainly exists in the form of rods in reactors. [0003] However, the covalent bond in the boron carbide structure is strong, and its melting point reaches 2450°C, making it a diffic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B28B7/42B28B7/18B28B7/24C04B35/645
CPCB28B7/18B28B7/24B28B7/42C04B35/645C04B2235/6562C04B2235/6581
Inventor 党杰陈镇王融修黎明张力生
Owner BEIJING TSINGNENG CHUANGXIN SCI & TECH CO LTD
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