Titanium wire and carbon form a stable carbide with higher hardness. The growth of the carbonized layer between titanium and carbon is determined by the diffusion rate of titanium in the carbonized layer.
The solubility of carbon in titanium is small, at 850X: a total of 0.3%, and at 600C it drops to about 0.1% B. Because the solubility of carbon in titanium is small, so basically only through the titanium carbide layer and its lower fork domain Deposit a layer to achieve the purpose of surface hardening. Carburization must be carried out under the condition of deoxygenation, because the powder suitable for common carburization of steel faces the surface of carbon monoxide or oxygen-containing carbon monoxide and the hardness of the surface layer reaches 2700MPa and 8500MPa, and it is easy to peel off.
Compared with this, under deoxidation or decarburization conditions, a thin layer of titanium carbide may be formed when carburizing in charcoal. The hardness of this layer is 32OUOMPa, which is consistent with the hardness of titanium carbide. The depth of the carburized layer is roughly greater than the depth of the nitrided layer when nitriding with nitrogen under the same conditions. Under the condition of oxygen enrichment, it must be considered that the absorption of oxygen affects the depth of hardening. Only in the case of very thin layer thickness, the carburizing of carbon powder in vacuum or argon-methane atmosphere can form sufficient adhesion strength. Compared with this, the use of gas carburizing agent may form particularly hard and good adhesion Hardened layer of titanium carbide. At the same time, the hardening expansion formed under the temperature between 950T: and 10201: is between 50fim and. As the thickness of the layer increases, the titanium carbide layer becomes more brittle and tends to flake. To avoid carbon inclusions intruding into the titanium carbide layer due to the decomposition of ritane, the rule of approximately 2% volane should be adopted. The dosage additive is gas carburized in an inert gas. When using methane carburization with propane additives, a lower surface hardness is formed. When the bonding strength reaches 90 OkPa when using gas carburized propane, although the thickness of the hardened layer measured is very thin, it has the best wear resistance. Hydrogen is absorbed under the condition of gas carburizing agent, but it has to be removed again during vacuum annealing.