Niobium silicide
Molecular formula NbSi2
CAS Number 12034-80-9
Traits: gray black metal powder
Density: 5.7 g / cm3
Melting point: 1940°C
Uses: silicon niobium-based turbine components, integrated circuits, high temperature structural materials。
Property: gray hexagonal crystal. Relative density 5.7. Lattice constant aperture - 0.4863nm, C=0.6604nm. Melting point 1950 ℃, microhardness 10. 3GPa (1050kg/mm2), Vickers hardness 5. 88 ～ 6.88GPa (600 ～ 700kg/mm2), conductivity 50.4 × 10-4 S/m, coefficient of thermal expansion 7.3 × 10-6．℃_ 1。 It is insoluble in water, concentrated hydrochloric acid and concentrated sulfuric acid, but soluble in the mixed solution of hydrofluoric acid and sulfuric acid.
1. Niobium silicide composite binary alloy matrix composite is a promising high temperature structural material. In this dual phase composite, solid solution niobium provides room temperature toughness and Si2Nb provides high temperature strength. This composite has high thermodynamic stability and microstructural stability at high temperatures.
2. NbSi2 based superalloy has high melting point, low density and excellent comprehensive properties. Its target service temperature is 200~300 ℃ higher than that of Ni based superalloy. It is expected to be applied to gas turbine engine blades operating at 1300~1500 ℃ and hot end components of aerospace vehicle ramjet engines.
3. The research and development idea of NbSi2 based superalloy is mainly to form niobium based solid solution/Nb5Si3 dual phase composite by adding ductile solid solution phase, which can improve its room temperature toughness while maintaining excellent high temperature strength.
Preparation method: take metal niobium and silicon as raw materials, crush metal niobium and metal silicon, put them into a graphite furnace after full mixing, gradually heat them up, make them react when the temperature reaches 1000 ℃, then inject hydrogen, make the temperature rise to 1400 ～ 1900 ℃, and then continue the reaction to obtain niobium silicide. Niobium pentoxide and metal silicon can also be put into the reduction furnace and reduced at 1400 ℃ for more than 30min to obtain niobium silicide.
Application: It can be made into solid solution with zirconium disilicide, molybdenum disilicide and tungsten trisilicide, and used as raw material of fine ceramics. Niobium silicide based turbine components, integrated circuits, high-temperature structural materials, etc.
Packaging and storage: The product is packed in inert gas filled plastic bags, sealed and stored in a dry and cool environment. It should not be exposed to the air to prevent moisture and oxidation agglomeration, which will affect the dispersion performance and use effect; The number of packages can be provided according to the customer's requirements.
