About Chromium Carbide Cr3C2
Chromium Carbide is a refractory compound with extremely hardness and corrosion resistant , which means that it retains its strength at high temperatures as well.
Cr23C6 has a cubic crystal structure and a Vickers hardness of 976 kg/mm2. Cr7C3 has a hexagonal crystal structure and a microhardness of 1336 kg/mm2.
Cr3C2 is the most durable of the three compositions, and has an orthorhombic crystal structure with a microhardness of 2280 kg/mm2
Cr3C2 powder is mixed with solid nickel-chromium. This mixture is then heated to very high temperatures and sprayed onto the object being coated where it forms a protective layer. This layer is essentially its own metal matrix composite, consisting of hard ceramic Cr3C2 particles embedded in a nickel-chromium matrix.
The primary constituent in most extremely hard cutting tools is tungsten carbide The tungsten carbide is combined with other carbides such as titanium carbide, niobium carbide, and chromium carbide and sintered together with a cobalt matrix
Undesired formation of chromium carbides in stainless steel and other alloys can lead to intergranular corrosion.
Chromium Carbide Coating
Thermal sprayed chromium carbide coatings combat high-temperature wear because of the high wear resistance imparted by the hard carbide particles and the high temperature oxidation resistant nature of the Cr2O3 oxide formed over both phases of Cr3C2-NiCr.
The coating process, which determines the coating characteristics such as: Phase composition , Density ,Hardness ,Bond strength and The residual stresses
It can be used as Pump impellers , Nozzles ,Gas turbine blades ,Ball valves and seats Piston rings.
1.It is used to coat the surface of another metal in a technique known as thermal spraying.
2.It is used as an additive in cutting tools in order to improve toughness by preventing the growth of large grains.
3.Another technique utilizes chromium carbide in the form of overlay plates. These are prefabricated chromium carbide-coated steel plates, which are meant to be welded onto existing structures or machinery in order to improve performance.
4.used in surface treatment.