Hafnium Carbide (HfC) 
Specification: 0.8-10um (D50) 
Appearance: Irregular 
Color: Black Grey 
Features: high melting point, high hardness, excellent chemical stability, good physical properties 
Application: Aerospace, industrial ceramics, cutting tools and molds, and other fields

Hafnium carbide 

Molecular formula: HfC 

Appearance: Grey black powder 

CAS:12069-85-1 

EINECS:235-114-1 

Molecular weight: 190.5325 

Melting point: 3890 ℃ 

Theoretical density: 12.7g/cm3 

Thermal conductivity: 6.28 [W (m · K) -1] 

Volume resistivity: 1.95 × 10-4 Ω· cm (2900 ℃) 

Thermal expansion coefficient: 6.73 × 10-6/℃ 

Electrical resistivity: 40-50/μ Ω· cm, 

Elastic modulus: 35.9 × 103MPa 

Pressure resistance strength: 1380MPa 

Property: Hafnium carbide is an inorganic substance that is soluble in hydrofluoric acid, hot concentrated sulfuric acid, and nitric acid. Belonging to non-metallic carbides, its structure is NaCl type face centered cubic structure, which is a metastable structure. 

Preparation method 

1. Carbon thermal reduction method: Hafnium oxide (HfO ₂) reacts with carbon (graphite or carbon black) at high temperatures (1700-2200 ° C). 

2. Chemical Vapor Deposition (CVD): Using a gaseous hafnium source (such as HfCl ₄) to react with hydrocarbons (such as CH ₄) at high temperatures to generate HfC coatings. 

3. Mechanical alloying: High energy ball milling of hafnium powder and carbon powder, followed by heat treatment to synthesize nanoscale HfC. 

4. Sol gel method: The precursor is prepared by the sol gel process, and the high-purity HfC powder is obtained by high-temperature calcination. 

Purpose: 

1. HfC hafnium carbide powder material is added as an additive to solid rocket engine throat lining materials due to its superior high-temperature thermophysical and mechanical properties compared to other materials, making it a solid rocket engine nozzle throat lining material. During the operation of the engine, the carbon/carbon composite material throat liner is subjected to harsh thermal environments, and the inner surface is damaged due to high temperature, high pressure, high speed, and corrosive particle containing heat flow erosion, resulting in enlarged throat diameter, rough and uneven surface, irregular surface, etc., which affects the working pressure of the engine and reduces the efficiency of the nozzle. When adding 8% -10% HfC hafnium carbide powder material to the nozzle throat lining carbon matrix of a certain type of weapon system, the anti ablation performance of HfC-C/C composite material can be greatly improved. The contribution of HfC hafnium carbide powder material to the erosion resistance of HfC-C/C composite throat lining mainly includes two aspects: 

(1) At an ablation temperature of 3500 ℃, HfC hafnium carbide powder material preferentially reacts with oxygen to form HfO2 during high-temperature ablation, effectively preventing the oxidation of carbon matrix and carbon fibers in the composite material by aerobic atmosphere; 

(2) Due to the high strength and hardness of HfC hafnium carbide powder material, which effectively improves the overall mechanical abrasion and erosion resistance of the material, the mechanical erosion of the inner surface of the throat liner by gas is effectively suppressed. Obviously, the anti ablation performance of HfC-C/C composite materials increases with the increase of HfC content. Experimental results show that when the HfC content reaches 8% -10%, the linear ablation rate of the HfC-C/C composite throat liner will enter a stable ablation stage that is approximately constant. Under the test conditions of solid rocket engines, the HfC-C/C composite throat liner as a whole has good anti ablation performance. 

2. The compound carbide 4TaC · HfC composed of 1 atom hafnium carbide and 4 atoms tantalum carbide is tested for its heat resistance using laser heating technology, with a melting point of 4215 degrees Celsius. It is a composite material compound and refractory ceramic material with a high melting point. 

3. HfC hafnium carbide powder material is an important functional material for the control rods and protective devices of atomic nuclear reactors. It is also an important material in the atomic energy industry and can be used as a rocket booster. It is particularly suitable for rocket nozzles, throat materials of rocket nozzles, and nose cone parts of space rockets that re-enter the atmosphere. The alloy containing hafnium carbide can be used as a forward protective layer for rocket nozzles and gliding reentry vehicles. 

4. HfC hafnium carbide powder material, due to its high hardness and melting point, is used as an additive in hard alloy cutting tools, metal ceramic cutting tools, powder metallurgy products, high-temperature structural component materials, and high-temperature resistant spraying materials; Hf Ta alloy with added hafnium carbide can be used to manufacture tool steel and resistance materials; Adding hafnium carbide to heat-resistant alloys, such as tungsten, molybdenum, and tantalum alloys, can improve the hardness, strength, erosion resistance, and high temperature resistance of the material. 

5. HfC hafnium carbide powder material, due to its high melting point, is used as an additive in the steelmaking industry as a deoxidizer, which can significantly improve the quality of steel. 

6. In the electrical industry, it is used to manufacture cathode materials for X-ray tubes and microwave tubes. 

Storage method: This product should be sealed and stored in a dry and cool environment. It should not be exposed to air for a long time to prevent moisture from causing aggregation, affecting dispersion performance and usage effect. In addition, it should be avoided from heavy pressure and not in contact with oxidants. It should be transported as ordinary goods.