MICROSTRUCTURE ANALYSIS OF CR3C2 – NICR COATING DEPOSITED ON CARBON STEEL BY HVOF THERMAL SPRAY TECHNIQUE

• Main Author: Lauzuardy, Jason
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/72572
• Institution: Institut Teknologi Bandung

Thermal spray coating technologies on high temperature operations have been developed with the aim of protecting boiler tubes from aggressive environments, improving thermal efficiency, and reducing time losses from damage. Protecting boiler tubes from the high temperature erosion is a must to extend the boiler tubes lifetime. In the boiler furnace, sand will be used to increase efficiency of fuel burning, this sand circulation will be contacted with the boiler tubes and become the erodent for it. Composite matrix ceramic coating consisting of Cr3C2-NiCr has been carried out to obtain a material layer that has superior mechanical properties to improve the performance of components including boiler tubes. Boiler tubes ASTM SA210 grade C is used as substrate to develop bonding of the coating. Comparing the coating powder of Cr3C2-NiCr with different powder size to be applied on the substrates by High Velocity Oxygen Fuel (HVOF) technique. Microstructure analysis determined by using X-ray Fluorescence (XRF), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD). The result was discussed in relation of coating powder size which determines the grain size, porosity, and layer hardness. Coating with smaller powder sizes produce larger grain sizes and have fewer porosity areas. In this research also found that Manganese (Mn) element can be diffused from substrate into coating. The result also shown that the combination of 80% Cr3C2-NiCr + 20% NiCr coating powder can provide good protection against erosion at high temperatures with a high layer hardness value of 581.9 HV on average and a layer thickness reduction value of -0.007 mm.