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Boron Carbide Ceramic Properties And Application

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Boron carbide ceramic is an critical a part of new ceramics, which has a high  melting point, excessive hardness, low density, wear resistance, and corrosion  resistance. it's miles broadly used within the subject of nuclear strength,  bulletproof armor, and wear-resistant materials.

At present, the depth and energy of the research on boron carbide ceramics  are growing. further to the emergence of recent methods for the synthesis of  high-purity and extremely-first-rate boron carbide powder, researchers also are  dedicated to the development of superior and realistic sintering generation.

Ceramics boron carbide characteristics

Boron carbide ceramics are very difficult. Its microhardness is set 50000mpa  (50gpa), subsequent to diamond (ninety-100gpa), and CBN (eighty-90gpa). Its  grinding efficiency can attain 60% - 70% of a diamond, 1-2 instances of SiC, 1-2  times of corundum's grinding capacity. It has extremely good acid-base  resistance and a small coefficient of thermal enlargement (4.5x10-6 ℃), so it  has awesome thermal balance. it is able to take in thermal neutron  qualitatively, but it has a vulnerable effect on resistance and high  brittleness.



Boron carbide can resist air corrosion at a thousand ℃, however it is simple  to oxidize in an oxidation environment at higher temperatures. Boron carbide has  a excessive resistance to acid and alkali, and isn't wetted through maximum of  the molten metals, and has excessive balance in contact with these  materials.

instruction of boron carbide ceramics

Boron carbide ceramics may be created through various methods. To acquire  dense B4C, hot pressing sintering is commonly used.

The B4C acquired by means of hot pressing sintering can attain 98% of the  theoretical density. The training is accomplished in a vacuum burning urgent  furnace or a widespread fiery urgent furnace. the nice and cozy pressing  temperature is 2100 ℃, the stress is 80-100mpa, the temperature is saved for  numerous minutes, and the pressure needs to be maintained when the warmth is  reduced.

due to the vulnerable thermal shock resistance of B4C, the cooling need to be  gradual. the hot urgent temperature should no longer be too excessive. while it  reaches 2150 ℃, the B4C-C eutectic liquid phase will seem, but if the  temperature is just too low, the product density will below. Boron carbide  ceramic merchandise with high density and hardness may be received through the  usage of B4C ultrafine powder.

In addition to warm urgent sintering, there is no pressing sintering. however  the requirements of pressureless sintering for carbide powder and sintering  temperature variety are very excessive. The consequences display that an vital  condition for the densification of natural boron carbide through pressureless  sintering is to apply ultrafine powder ≤ 3um, and the oxygen content is low  enough. The sintering temperature range is 2250-2350 ℃.

The number one way of pressureless sintering with additives is to eliminate  the oxide layer of boron carbide through components, to improve the activation  of grain boundary and volume diffusion by using increasing the density of point  defects or dislocations, to reap a higher frequency (90-ninety five%) at a  barely lower temperature (2000-2200 ℃). The effects show that once Al and Si are  used as sintering aids respectively and sintered at 2050 ℃ and atmospheric  strain for 180min, the relative density of the composite ceramics is extra than  ninety three%, such as 298mpa bending energy of the boron carbide ceramics  containing Al and 344mpa bending electricity of the boron carbide ceramics  containing Si.

Except, there also are warm isostatic pressing sintering and discharge plasma  sintering techniques for boron carbide ceramics, in order to now not be defined  right here. but, warm pressing is a preferred approach to prepare natural boron  carbide ceramics.



utility of boron carbide ceramics

1. Bulletproof armor subject

Because of its lightweight, awesome high hardness, and high elastic modulus,  B4C ceramics are the satisfactory substances for a bulletproof vest, helmet, and  armor.

At present, boron carbide ceramics are widely used in ceramic armor  materials. compared with different bulletproof substances, B4C ceramics are  lighter and more tough. it's far particularly appropriate for armed helicopters  and other aircraft as bulletproof armor materials, that can successfully face up  to shells. Boron carbide ceramics, produced with the aid of BAE systems advanced  Ceramics, had been used because the "interceptor" bulletproof garb for the  united states army.

2. Wear-resistant era

Inside the discipline of wear-resistant era and engineering, diverse nozzles  made of B4C with excessive hardness are used for the desander nozzle and the  nozzle for excessive-stress jet water cutting of deliver rust elimination. Boron  carbide is used as the abrasive material for other hard substances along with  cemented carbide and engineering ceramics in the technique of sharpening,  satisfactory grinding or grinding, which could notably reduce the cost of  grinding process.

3. Thermoelectric couple

Based totally on the thermoelectric belongings of B4C, a temperature  differential couple able to measuring 2200 ℃ become prepared via sintering in  Japan and Germany, which changed into used for the measurement and manipulate of  excessive temperature. because of its excessive thermal electricity and balance,  it is able to be used reliably for a long time, and the temperature may be  measured repeatedly.

Boron carbide ceramics is a great deal good sized, which has many great  houses and has been widely used. And in the future, it will be greater.

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