Investigation of NbC capability of armox 500 steel using TRD method

Box cementation, in other words, thermoreactive diffusion (TRD) method is a simpler and more economical coating method compared to other methods. It also provides a very high quality coating layer compared to other methods. In this thesis, ARMOX 500 armor steel was coated with NbC at different temperatures (950, 1000 and 1050 C ) and at different waiting times (1, 2 and 3 hours) using the TRD method. The coating thickness and microstructural morphology of the coated samples were examined by optical microscope after the process. In addition, the coatings produced in each parameter were analyzed with scanning electron microscopy (SEM), Energy dispersive spectrometer (EDS), X-ray diffraction (XRD) devices, and microstructure, elemental distribution and phase components. Hardness values were measured in order to determine the micro hardness values formed on the coating layer surface after coating. From the results of SEM and EDS analysis, it was determined that more uniform and homogeneous coatings were formed depending on the coating temperature and time. As can be seen from the EDS results, it has been determined that the Nb element decreases as we move from the coating layer to the substrate, and the Fe element is exhausted from the lower layer to the coating layer. It is thought that the C element continues to increase with the coating layer towards the lower parts of the interface, and the main reason for this is that the C element in the lower layer protrudes towards the surface. In addition, the fact that element C is determined together with Fe and Nb elements in the interface region indicates that diffusion takes place between the coating and the intermediate layer. As a result of XRD analysis, it was determined that the dominant phase in all samples was NbC, however, it was formed in the a-Fe phase. In the microhardness measurement results taken from the coating surfaces, the lowest hardness value is obtained from the substrate with 950 C temperature and 390 HV in the sample heat treated for 1 hour, while the highest hardness value is at 1050 C temperature and 3825 HV in the sample heat treated for 3 hours. Measured from the coating layer. As a result of the hardness values, it has been determined that depending on the applied sintering temperature, the coating layer surface is more homogeneous and results in a higher hardness value.