Boron carbide is widely used as a new material with excellent mechanical properties, irradiation self-healing properties and the ability to absorb neutrons.
Since humans successfully synthesized boron carbide for the first time in the early 20th century, in the past 100 years, with the development of technology, the synthesis technology of boron carbide has not only been limited to the original element synthesis method but also with the selection of raw materials. With improved technologies such as the sintering process and reaction time, boron carbide powder preparation methods have become diverse. Obtaining boron carbide powder with desirable properties proves difficult due to its strong covalent bonds (over 90%) and the complex thermodynamic and kinetic conditions that govern its production. The following are the best quality methods that can be prepared at present. Several processing methods for boron carbide powder.
Direct synthesis method
The raw materials’ particle size and composition can be modified through pretreatment methods such as catalysis or nano-cutting, allowing them to achieve nanoscale dimensions. The treated elemental boron and carbon can react under the following conditions: 1) vacuum pulse current to obtain powder with a particle size of 400nm; 2) under reducing atmosphere conditions (such as hydrogen, carbon monoxide, etc.) at low temperature (800~900℃) Powder with a particle size of 100nm can be obtained; 3) Under inert atmosphere conditions (argon gas) at 1950°C, powder with a particle size of 150~500nm can be obtained.
For raw material selection, amorphous boron powder is often preferred as the raw material for boron. In contrast, graphite or high-purity carbon powder is chosen as the raw material for carbon. The purity of the product is high, but it is not widely used in industrial production due to the slow diffusion of raw materials during the process and expensive raw materials.
Carbothermal reduction method
The carbothermal reduction method is widely used and is the mainstream method in the production of boron carbide. Under inert atmosphere conditions (Ar), boric acid and boron oxide are reduced using petroleum coke and carbon powder, which can be obtained from the carbonized surface of crops. There are two main reaction conditions:
(1) Electric arc furnace carbothermal reduction method. The process employs three-phase alternating current to produce a high-temperature arc light within the furnace, creating the desired reaction conditions. Industrial electric arc furnaces typically have a 5,000 to 30,000 kVA capacity and can reach extreme temperatures of up to 2,500°C. This method produces a large amount of CO at high temperatures, and too high a temperature will reduce the utilization of raw materials.
(2) Carbon tube furnace carbothermal reduction method. Compared to the electric arc furnace, the advantage of this method is that there is no regional temperature unevenness that would cause the process to be incomplete, and the cost is higher.
Magnesia thermal reduction method (self-propagating high-temperature synthesis of SHS)
Self-propagation is the term used to describe the autonomous process where the heat produced by the reaction of reactants is used to generate heat for a particular process. Usually, carbon powder, boron oxide, and magnesium powder are used as raw materials to make pellets, which are carried out under an inert atmosphere (Ar) in a carbon tube furnace (other heat sources can also be used) at 1100°C and then pickled to remove impurities. The method can generate high-quality powder quickly and effectively. Still, the inconsistent particle size distribution of the resulting powder can make it difficult to control the size of the particles.
Chemical vapor deposition (CVD)
The principle of chemical vapor deposition involves the decomposition of gases on a solid surface at elevated temperatures to yield a thin film. Usually, atmospheres containing carbon and boron elements are used as raw materials. The most commonly used materials are boron trichloride and methane hydrogen atmosphere as raw materials to obtain films of a certain thickness. The most common ones are rod-shaped and fiber-shaped. The main factors affecting film thickness are time, catalyst and temperature.
Application areas of Peng powder
Boron powder is widely used in many fields, such as metal smelting, solid rocket fuel and steelmaking in the industrial field; composite materials and cermets in the field of material science; automobile airbags in the electronic and electrical field; etc. Preparation of high-purity boron halide, etc. crop yield increase in the agricultural field, radiotherapy in the medical field, etc. oil pollution removal in the environmental protection field, etc. Boron powder is also used in high-tech fields, such as smelting special alloy steel, gas scavenger for molten steel, and high-energy fuel for rocket spacecraft.
High-quality boron powder supplier
TRUNNANO is a reproducible global producer and supplier of chemical substances with over 12 years of experience in ultra-high quality nanomaterials and other chemicals. The company has developed several powder materials and chemicals and Provides OEM service. If you are looking for boron powder, you can contact us. You can click on the product to contact us.