Chromium Carbide - Synthesis

Synthesis

Synthesis of chromium carbide can be achieved through mechanical alloying. In this type of process metallic chromium and pure carbon in the form of graphite are loaded into a ball mill and ground into a fine powder. After the components have been ground they are pressed into a pellet and subjected to hot isostatic pressing. Hot isostatic pressing utilizes an inert gas, primarily argon, in a sealed oven. This pressurized gas applies pressure to the sample from all directions while the oven is heated. The heat and pressure cause the graphite and metallic chromium to react with one another and form chromium carbide. Decreasing the percentage of carbon content in the initial mixture results in an increase in the yield of the Cr₇C₃, and Cr₂₃C₆ forms of chromium carbide.

Another method for the synthesis of chromium carbide utilizes chromium oxide, pure aluminum, and graphite in a self-propagating exothermic reaction that proceeds as follows:

3Cr₂O₃ + 6Al + 4C → 2Cr₃C₂ + 3Al₂O₃

In this method the reactants are ground and blended in a ball mill. The blended powder is then pressed into a pellet and placed under an inert atmosphere of argon. The sample is then heated. A heated wire, a spark, a laser, or an oven may provide the heat. The exothermic reaction is initiated, and the resulting heat propagates the reaction throughout the rest of the sample.