Chinese Name: hafnium boride
Foreign name: hafnium diboride
CAS ：12007-23-7
Molecular formula: b2hf
Molecular weight: 200.112
Melting point: 3250 ° C
Appearance: gray metal solid
Density: 10.5g/cm3
Relative molecular weight: 200.112
Main features:
Hafnium diboride (HfB2) is a gray black crystal with metallic luster. Its crystal structure belongs to hexagonal system. As an excellent ultra-high temperature ceramic material, hafnium diboride (HfB2) has a high melting point (3380 ℃), high purity, small particle size, uniform distribution, large specific surface area, high surface activity, low bulk density, high conductivity and stable chemical properties. It hardly reacts with all chemical reagents (except HF) at room temperature. New ceramic materials with high melting point, high thermal conductivity and oxidation resistance
Main purpose:
1. Since HfB2 has a melting point of up to 3000 ℃, it used to be used as an ablative material in high-temperature oxidation environment as a high-temperature boride ceramic matrix. In the study, SiC was added to HfB2 ceramics as an additive to increase its oxidation resistance. Dense HfB2 SiC composite ceramics were prepared by hot pressing. The oxidation resistance of this composite ceramic is higher than that of HfB2 ceramic without SiC. Like other ceramics, the powder performance is also one of the key factors for preparing ceramics. The ultra-high temperature ceramic materials based on hafnium diboride (HfB2) and zirconium diboride (ZrB2) can be used as thermal protection system materials for hypersonic vehicles in the atmosphere, and the application prospect is immeasurable.
2. The existing preparation methods of hafnium boride composite coating include electrophoretic deposition, laser cladding, slurry brushing, in-situ reaction and thermal spraying.
3. Hafnium boride (HfB2) has high temperature properties and good oxidation resistance. It can be used as a high-speed space rocket material. It is a potential candidate material for ultra-high temperature ceramics in the fields of ultra-high temperature ceramics, high-speed aircraft nose cone, aviation, aerospace and so on. It is often used as an ablative material in high-temperature oxidation environment. At the same time, it has the characteristics of high hardness, high modulus, high thermal conductivity and high conductivity.
4. Hafnium boride can be compounded with other materials to prepare fiber materials, such as composite carbon fibers.
Physicochemical properties:
Properties and stability: it will not decompose when used and stored according to the specifications. It will not react with the mixture of concentrated sulfuric acid and potassium sulfate and phosphoric acid at room temperature, but with the mixture of concentrated hydrochloric acid and concentrated nitric acid.
Packaging and storage: This product is packed in inert gas aluminum foil bags, sealed and stored in a dry and cool environment. It should not be exposed to the air to prevent oxidative agglomeration due to moisture, which will affect the dispersion and use effect.
