EFFECT OF ADDITION VANADIUM ALLOY ELEMENTS ON HOT CORROSION RESISTANCE OF Ni-30Fe-20Cr-2,2Ti-2Al-0,3Y ALLOY WITH SALT SPRAYING METHOD AT TEMPERATURE 900?

• Main Author: Wusko, Kandaka
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/42043
• Institution: Institut Teknologi Bandung

Technological developments that occurred in the power generation, automotive, and aerospace industries a few decades ago experienced very rapid growth. This development is inseparable from the use of materials as the basis for these technologies. In the power generation sector, energy security combined with lower carbon dioxide (CO2) emissions is increasingly needed to protect global environmental conditions in the 21st century. Coal is a cheap energy source but behind that, coal power plants emitting gases that can damage the environment such as CO2, NOX, and SOX with a higher intensity compared to other power generation options. Thus, the application of an ultra-supercritical (USC) power plant with an increase in steam parameters significantly increases efficiency. This plant is designed to be able to operate in conditions of vapor pressure up to 30MPa and more than 750? to achieve thermal efficiency of more than 50%. But corrosive environments are a problem that causes hot corrosion of metal alloys, and also high temperatures and pressures increase the chance of occurrence creep failure. In this study an experiment was conducted to determine the effect of adding vanadium to cyclic hot corrosion resistance in Ni-Fe metal alloys and also to determine the characteristics of the oxides formed. The alloy composition used is Ni-30Fe-20Cr-2,2Ti-2Al-0,3Y with variations of vanadium 0.2%, 0.5%, and 0.7% mass. The experiment was started by making a sample of the superalloy Ni-30Fe-20Cr-2,2Ti-2Al-0,3Y button using a mini DC electric arc furnace. Then the button is homogenized at 1100 ? for 12 hours, then cut into 4 pieces and sanded to 1200 grits. Furthermore, samples of each alloy will be tested for cyclic hot corrosion at 900? for 36 cycles (2 hours/cycle). Then, Samples were characterized using x-ray diffraction (XRD) and scanning electron microscope (SEM) - energy dispersive spectroscopy (EDS). The sample with the addition of vanadium shows the diffusion of vanadium toward the surface so that it undergoes oxidation and causes the environment to become more corrosive. In samples with the addition of vanadium a higher level of spalling was also found. It can be concluded that the addition of vanadium will worsen the hot corrosion resistance properties of the Ni-30Fe-20Cr-2,2Ti-2Al-0,3Y alloy and in this study, cyclic hot corrosion resistance starts from the best that is 0V, 0.7V, 0.5V, and 0.2V.