Microstructures and mechanical properties evaluation of hard chromized austenitic Fe-Mn-Al alloys

Engineering components with hard coatings usually exhibit improved service behavior and increased lifetime. Hard chromizing technique is employed to deposit chromium nitride and carbides layer on the surface of an austenitic Fe-30.6Mn-6.8Al-0.9C alloy. The (Cr, Fe)2N1−x and (Cr, Fe)23C6 phases are found on the chromized surface, while the internal part of chromized layer is (Cr, Fe)7C3 phase. The thickness of the chromized layer obeys the parabolic rate law. For the specimen chromized at 1000 °C for 4 h, the hardness of the coating is 19.6 GPa. A mixed cohesive-adhesive failure and an adhesion strength quality related to HF2 are observed on the coating. The wear resistance of the chromized layer is also improved at least three times better than the substrate.