Properties and application of Boron Carbide Ceramic

wallpapers Resource 2020-02-13

Boron carbide ceramic is a crucial part of new ceramics, which has an excessive melting point, excessive hardness, low density, put on resistance, and corrosion resistance. It is extensively used in the area of nuclear energy, bulletproof armor, and wear-resistant materials.

At gift, the depth and power of the studies on boron carbide ceramics are growing. Similar to the emergence of recent methods for the synthesis of excessive-purity and ultra-excellent boron carbide powder, researchers are also dedicated to the improvement of advanced and practical sintering generation.

Ceramics boron carbide residences

boron carbide ceramicss are very difficult. Its microhardness is about 50000mpa (50gpa), subsequent to diamond (90-100gpa), and CBN (80-90gpa). Its grinding efficiency can reach 60% - 70% of a diamond, 1-2 instances of SiC, 1-2 instances of corundum's grinding capability. It has fantastic acid-base resistance and a small coefficient of thermal expansion (4.5x10-6 ℃), so it has first-rate thermal stability. It could take in thermal neutron qualitatively, but it has a vulnerable impact on resistance and high brittleness.

Boron carbide can withstand air corrosion at a thousand ℃, but it is easy to oxidize in an oxidation ecosystem at higher temperatures. Boron carbide has a high resistance to acid and alkali, and isn't wetted via a maximum of the molten metals, and has high stability in touch with those materials.

guidance of boron carbide ceramics

Boron carbide ceramics may be created via numerous techniques. To acquire dense B4C, warm urgent sintering is typically used.

The B4C acquired with the aid of hot pressing sintering can attain ninety-eight % of the theoretical density. The practice is finished in a vacuum burning pressing furnace or a well known fiery pressing furnace. The nice and cozy urgent temperature is 2100 ℃, the strain is eighty-100mpa, the temperature is kept for several minutes, and the pressure needs to be maintained while the warmth is decreased.

Due to the weak thermal surprise resistance of B4C, the cooling must be slow. The hot, urgent temperature needs not to be too excessive. Whilst it reaches 2150 ℃, the B4C-C eutectic liquid phase will appear, but if the temperature is just too low, the product density will beneath. boron carbide ceramics merchandise with excessive density and hardness may be acquired with the aid of the usage of B4C ultrafine powder.

Further to hot, urgent sintering, there's no urgent sintering. But the requirements of pressureless sintering for carbide powder and sintering temperature range are very high. The results display that an important circumstance for the densification of natural boron carbide by pressureless sintering is to apply ultrafine powder ≤ 3um, and the oxygen content material is low enough. The sintering temperature range is 2250-2350 ℃.

The primary way of pressureless sintering with components is to remove the oxide layer of boron carbide through components, to improve the activation of grain boundary and extent diffusion by way of growing the density of factor defects or dislocations, to gain a better frequency (ninety-95%) at a slightly decrease temperature (2000-2200 ℃). The consequences display that when Al and Si are used as sintering aids respectively and sintered at 2050 ℃ and atmospheric pressure for 180min, the relative density of the composite ceramics is more than ninety-three %, consisting of 298mpa bending power of the boron carbide ceramics containing Al and 344mpa bending electricity of the boron carbide ceramics containing Si.

Except, there also are hot isostatic urgent sintering and discharge plasma sintering strategies for boron carbide ceramics with a purpose to now not be described right here. But, hot pressing is a general approach to prepare pure boron carbide ceramics.

the utility of boron carbide ceramics

1. Bulletproof armor field

because of its light-weight, first-rate excessive hardness, and high elastic modulus, B4C ceramics are the pleasant materials for a bulletproof vest, helmet, and armor.

At gift, boron carbide ceramics are broadly utilized in ceramic armor substances. Compared with different bulletproof materials, B4C ceramics are lighter and greater hard. It is, in particular, appropriate for armed helicopters and different aircraft as bulletproof armor materials that can correctly withstand shells. Boron carbide ceramics, produced by using BAE systems superior Ceramics, have been used as the "interceptor" bulletproof garb for our army.

2. put the on-resistant era

within the field of damage-resistant technology and engineering, various nozzles fabricated from B4C with excessive hardness are used for the desander nozzle and the nozzle for excessive-stress jet water-reducing of ship rust removal. Boron carbide is used as the abrasive cloth for different hard materials inclusive of cemented carbide and engineering ceramics in the method of sharpening, excellent grinding, or grinding, which could drastically reduce the fee of the grinding process.

3. Thermoelectric couple

based on the thermoelectric assets of B4C, a temperature differential couple capable of measuring 2200 ℃ became prepared by using sintering in Japan and Germany, which became used for the dimension and manipulate of high temperature. Due to its excessive thermal strength and stability, it can be used reliably for the long term, and the temperature can be measured time and again.

boron carbide ceramics is plenty massive, which has many extremely good houses and has been widely used. And inside the destiny, it is going to be extra.

Tag: Carbide   Boron   Ceramic