Name | Chromium carbide |
Synonyms | CR3C2 160 CR3C2 300 CHROMIC CARBIDE CHROMIUM CARBIDE Chromium carbide CHROMIUM (IC) CARBIDE trichromium dicarbide chromiumcarbide(cr3c2) Chromiumcarbidegraypowder |
CAS | 12012-35-0 |
EINECS | 234-576-1 |
InChI | InChI=1/2C.3Cr/rC2Cr3/c3-1-5-2-4 |
InChIKey | UFGZSIPAQKLCGR-UHFFFAOYSA-N |
Molecular Formula | C2Cr3 |
Molar Mass | 180.01 |
Density | 6.68 g/mL at 25 °C (lit.) |
Melting Point | 1890°C |
Boling Point | 3800°C |
Water Solubility | Insoluble in water. |
Appearance | Grey powder |
Specific Gravity | 6.68 |
Color | gray |
Storage Condition | Room Temprature |
MDL | MFCD00016041 |
Physical and Chemical Properties | Gray powder, orthorhombic system, a = 2.821, B = 5.52, c = 11.46, relative density 6.68. Melting Point 1890 °c. Boiling point 3800 °c. Micro Vickers hardness (load 50g)2700kg/rnrn2, coefficient of thermal expansion 10.3 x 10-6/K. |
UN IDs | UN3178 |
WGK Germany | 3 |
TSCA | Yes |
Hazard Class | 4.1 |
Packing Group | III |
is gray-white, orthorhombic system. It has metallic luster, relative density of 6. 68, melting point of 1890 ℃, boiling point of 3800 ℃, microhardness of 2700kg/mmz, coefficient of thermal expansion of 11.7 × 10-6/℃. Acid-resistant, alkali-resistant, insoluble in water. High temperature oxidation resistance is good, in the air at 1100 C temperature to maintain 4H does not oxidize.
metal chromium powder or chromium oxide and carbon powder were mixed and press-molded, and sintered at a temperature of 1000 ° C. Or higher in a reducing atmosphere. Alternatively, the chromium oxide powder is mixed with graphite and water, then placed in a corundum crucible, covered with graphite, capped and burned at 1400 ° C. For 3H. After cooling and sieving, chromium oxide was obtained.
It is a kind of high melting point material with good wear resistance, corrosion resistance and oxidation resistance under high temperature environment, can be used as a high temperature, wear-resistant, oxidation-resistant and acid-resistant coating, widely used in aircraft engines and petrochemical machinery devices, can greatly improve the life of the machine. It is also commonly used as grain refiner of cemented carbide and other wear-resistant and corrosion-resistant components. The cermet based on Cr3 C2 has excellent oxidation resistance at high temperature.
crystal structure | Orthorhombic |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
overview | chromium carbide is an inorganic material with high melting point and good wear resistance, corrosion resistance and oxidation resistance under high temperature environment (1000~1100 ℃). it belongs to a kind of cermet. Because of its special high temperature performance, it is widely used as a thermal spray material for metal surface protection process and an additive in the cemented carbide industry. |
properties | gray powder with metallic luster; Rhombic crystal system; Density: 6.68g/cm3; Melting point: 1890 ℃; It has good wear resistance, corrosion resistance and oxidation resistance in high temperature environment (1000~1100 ℃). Belongs to a kind of cermet. |
preparation method | 1. chromium carbide is produced by the following process flow. fig. 1 shows the process flow of chromium carbide powder production, in which the carbonization temperature is 1450 ℃ ~ 1500 ℃ and the diffusion time is 45min. The ratio of raw materials is: metal chromium powder: graphite powder: binder = 86.5:13.5:3.5. (1) Mixing The weighed raw materials are added into the electric mixing barrel. The feeding sequence is to add graphite powder first, then metal chromium powder, and then paste. The volume of feeding should account for 1/3~2/5 of the volume of the mixing barrel. The mixing time is 20~30min, and the rotation direction of the mixing barrel is changed every 5min. (2) briquetting the mixed raw materials. The size of the material block is Φ φ90 × 60mm, and each piece weighs about 2.5kg. The formed material block should be handled with care, dried naturally for 48 hours, put into a drying oven for drying, the drying temperature is 110±10 ℃, the temperature is kept for 10 hours, the temperature is raised to 300 ℃, and the temperature is kept for 10 hours. (3) The carbonization equipment is a 0.15MVA vacuum resistance furnace. Vacuum should be pumped before power transmission. When the pressure in the furnace is less than 30Pa, power transmission can be used to raise the temperature. The input power at the beginning is determined as the 50% of all input power depending on the burning loss of the heating element. When the furnace temperature rises to 300 ℃, the input power increases to 80%, and the furnace temperature rises to 800 ℃ and uses full power to raise the temperature. At this time, the heating rate is generally about 10 ℃/h, and the constant temperature starts when the furnace temperature rises to 1450 ℃, and the constant temperature time is 10h. (4) After the crushing and carbonization is completed, the power will naturally cool down and continue to vacuum until the furnace temperature drops below 300 ℃ to stop the pump and destroy the vacuum. 2. Preparation by carbothermal reduction method: there are two reaction mechanisms. 3. Spontaneous propagation high-temperature synthesis method combines Cr2O3,CrO3,Al powder and carbon black with a ratio of 1:0.73:0.73:0.25, puts the prepared raw materials into a mixer and mixes for 6 hours, puts the mixed materials into a graphite crucible, compacts in a reactor, uses Ar as medium, and preforces the pressure to be 5MPa, ignition with the upper plane ignition source of the tungsten wire ring. When the temperature of the tungsten coil rises to 1500 ℃, the material is ignited and starts to burn, and the combustion wave spreads downward until the reaction ends. The combustion products are divided into upper and lower layers, and the lower layer is cast chromium carbide (Cr3C2). |
use | 1. it can be used as an additive for cemented carbide (such as tungsten carbide-based cemented carbide grain refiner), thus being applied to mining, mechanical processing, etc. 2. It can be used as an additive for welding materials. The welding rod made of it and surfacing welding on the working surface of some mechanical equipment (such as coal mill, ball mill, Hubei plate, etc.) can increase the service life by more than several times. 3. A large number of thermal spraying materials are used as metal surface protection processes. (2015-09-18) Used to produce anti-wear films and semiconductor films. |
toxicity | see chromic anhydride. |
production method | metal chromium powder carbonization method carbon black according to the ratio of 13.5% ~ 64% (mass) (more than the theoretical combined carbon 11.33%) and electrolytic chromium are crushed to form 325 metal chromium powder, which is dry mixed with a ball mill and used as raw material. Add 1% ~ 3% stearic acid as lubricant for molding. Pressurized molding with pressure above 1 T/cm2. The pressure molding powder is put into a graphite pan or a crucible, and is heated to 1500~1700 ℃ in a hydrogen flow (hydrogen dew point is about -35 ℃) with a Taman furnace or an induction heating furnace for 1h, so that chromium is carbonized to form chromium carbide, and chromium carbide is prepared by cooling. Its 3Cr + 2C → Cr3C2 |