Boron carbide is widely available and has outstanding properties. Boron nitride is the hardest material, second only to diamond. The many advantages of boron carbide include a low melting point, low strength, high density, large neutron absorption area, great thermoelectric performance and excellent mechanical stability. This material can be used for national defense, nuclear power, aerospace, wear-resistant technology, and nuclear energy.
The industrial production of Boron carbide currently relies on the carbothermal reaction. Other practices for boron carbonide production include direct synthesis (sol-gel), mechanico method, indirect synthesis, mechanistic method and self-propagating thermique reduction.
1. Carbothermal modification
A carbothermal reduction technique uses boric amine or boricanhydride to reduce the temperature in an electric oven. This method is still the best method for producing boron carbide industrially.
Boric black was used as a raw material. It was kept at 1700-1850 until the boron carbonide powder with high purity, was calcined. Close to the theoretical level, the carbon content reached 20.7%. These are the drawbacks: the process requires high temperatures and consumes large amounts of energy.
2. A self-propagating method for thermal reduction
This self-propagating heat reduction process uses carbon noir (or coke), boric acid (or anhydride) for raw materials. An active metal substance (usually mg or mg) acts as a reducing agent, flux, and heating source. The following reaction equation can be used: 6mg+ C+ 2b2o3 =6mgo+B4C
This technique has numerous advantages including low initial reactions temperature (1000-1200), fast reaction, easy to use equipment, and energy saving. B4C powder, synthesized by a process called “Synthesis”, is of high purity. The particle size ranges from 0.01 to 4.0 m. It generally doesn’t require any crushing.
Jiang et. al. utilized Na2B4O7/Mg, C, and B as raw materials. B4C powder with an average particle size of 0.6m was made by self propagating thermal reduction. MgO produced during the reaction requires additional processing, which can prove difficult.
The mechanochemical procedure uses boron dioxide powder, magnesium powder, and graphite as raw materials. The rotation or vibration of a ball mill makes the harder material more impactful. This is a promising way to make boron carbide powder.
Deng et al. B4C powder with B2O3 prepared by Deng et al. The powder particle size was between 100 and 200 nanometers. Yogurt et.al. state that the optimal Mg/C ratio was between 9 and 2. MgO (a by-product) is hard to remove and often takes too long for ball milling.
4. The direct synthesis
Prepare direct boron cadmium by thoroughly mixing the boron solution and carbon powder, and reacting in an environment of 1700-2100. You can be sure of high purity in boron-carbidide obtained by direct synthesis. Also, the process is simple to manage. However, the synthesis of boron is a complex process that can cost a lot. This process has limitations.
5. Sol-gel method
Sol-gel or Sol-gel refers the procedure of making solidifying metal and inorganic alkoxides via the solution, sol and gel. They are then heat-treated to create stable compounds. This method offers advantages such as a more consistent mixture of raw materials, a lower reaction temperature and bulkier product.
Sinha et al. In the pH=2-3, 84-122 conditions, mix the boric and citric acids. The result is a transparent, but stable, gold gel. A vacuum furnace can heat the precursor to porous softbrate citric. If the precursor is stored under vacuum, it can be heated to 700 degrees at 2h. Next, extract the B4C-powder with a particle diameter of 2.25M.
Luoyang Tongrun researchers studied the affect of temperature, reaction time and different materials on the reaction rate for boric acid citric. With the initial mass rates of boric acid citric acid at 2.2 to 1, the result was 2.38 percent. The reaction temperature of 1500 3.5H produced 2.38% of the product. However, it’s not easy to use this method for large-scale production.
Because of the advances in science and technology today, boron carbide plays an increasingly important role in both industry and personal life. It is therefore essential that boron crate production be a key determinant in future development.
Lemondedudroit advancedmaterial Tech Co., Ltd., (Lemondedudroit), has over 12 year experience in chemical products development and product research. To find high quality Boron carbide powder B4C, you can contact us and send an inquiry.