Niobium carbide is an inexperienced cubic crystal with metallic luster and belongs to the sodium chloride kind cubic crystal gadget. Niobium carbide is a metallic carbide with the chemical formula NbC.
Properties of Niobium Carbide:
The melting point of niobium carbide is 3500 ℃, and its microhardness is> 23.five Gpa (> 2400 kg / mm2), which is tougher than corundum. Niobium carbide has an elastic modulus of 338000 N / mm2, a thermal growth coefficient of 6.65 × 10 ^ (-6) / k, a thermal conductivity of 14 w / (m · ok), and a resistivity of 35 μΩ · cm.
Niobium carbide is insoluble in bloodless and warm hydrochloric acid, sulfuric acid, and nitric acid, and it’s far soluble in warm hydrofluoric acid and nitric acid combined solution. It’s miles strong at 1000 – 1100 ℃, and quickly oxidizes to niobium pentoxide above 1100 ℃. Niobium carbide is fusible in compounds such as titanium carbide, zirconium carbide, and tungsten carbide, and together bureaucracy a homogeneous stable solution mixture.
Fields of NbC application:
1.NbC application in composite substances
(1) Composite ceramics
As one of the raw substances of multiphase ceramic substances, the synthetic multiphase ceramic materials are frequently used within the fields of damage-resistant components, slicing equipment and electrodes due to their excessive hardness, excessive melting factor, splendid chemical balance, and conductivity.
(2) Hard alloy
Not simplest can be used as an inhibitor of cemented carbide grain boom but can also form a third dispersed phase excluding WC and Co together with other carbides, which can notably improve the thermal hardness and resistance to thermal shock Antioxidant ability. Because niobium carbide has the advantages of enhancing the hardness of the alloy and improving the fracture durability of the alloy, it can be used to prepare hard alloy reducing tool materials with exceptional slicing performance.
(3) Surfacing electrode
The difficult niobium carbide tough section enters the shape of the surfacing layer, in order that the welding layer has a better wear-resistant skeleton, and the wear resistance is greatly advanced. The damage resistance of this electrode surfacing is 1.2 – 1.eight times higher than that of quenched 45 steel (HRC50), and 2.4 – 3.6 instances higher than Fe-Cr-C-B type put on-resistant alloy.
(4) Aerospace additives
It is used as instruction cloth for parts of many aerospace equipments including turbine rotors, fuel rudders, blades, engine nozzle linings, and structural elements of nuclear reactors.
2. NbC application in coating materials
(1) mold metal surface coating
As a steel carbide, niobium carbide has high hardness, heat resistance, and abrasion resistance. consequently, coating it on steel indicates that it may improve the damage resistance of the mold surface.
(2) Coating of steel workpieces
The niobium carbide layer is compounded on the floor of the bottom of the metallic workpiece, which greatly improves the surface hardness that could reach HV2800 or higher, and at the same time, will increase the operating temperature and tissue density of the workpiece, thereby extending its service lifestyles.
(3) different niobium carbide coatings
The high-temperature components of the spacecraft are lined with niobium carbide, which can drastically growth their provider life. In the electronics industry, the material of the center layer of the electron emission tube makes use of ultra-first-rate cobalt-containing niobium carbide, which has a substantial effect on growing the emissivity of the gate surface, decreasing the gate temperature and lowering the thermal emission of the gate, thereby extending the electron emission tube’s existence.
3. NbC application in the production of metal niobium
We specifically make use of indirect discounts to produce metallic niobium. The produced niobium carbide is used as a decreasing agent, which interacts with niobium pentoxide to supply crude steel niobium, and then is subtle to gain metallic niobium with higher purity. Besides, niobium carbide can without delay lessen niobium pentoxide to form pure metallic niobium.