Akademik Veri Yönetim Sistemi
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING, 2025 (SCI-Expanded)
By aluminizing at varying temperature (600-700 degrees C) and time (2-6 h) cycles, defect-free, continuous and homogeneous thick Ni-Al deposition layers are obtained on Hastelloy C276 surface. Metallurgical analysis performed on surface/sub-surface indicates that NiAl3 and Ni2Al3 phases are the dominant phases within aluminide coatings (11-41 mu m). Since the experimental aluminizing process is a diffusion-controlled process, the processing output with variable temperature and time parameters made it possible to study the process kinetics, and the process-specific activation energy is calculated as 51 kJ/mol. An equation is also derived from the regression model to estimate the coating thickness, and there is a good agreement between the coating thicknesses determined by the experimental and calculated values. The effect of temperature/time on the layer thickness is investigated with variance analysis. Although no significant change in the surface hardness value (similar to 800 HV) is measured regardless of the layer thickness, an increase in the layer thickness over time on material surface processed at the lowest temperature causes a significant decrease in the oxidation rate due to the presence of a stable Al-rich oxide. All these findings reveal the lowest cost coating conditions that can reduce the chemical degradation of Hastelloy C276 caused by oxidation at high temperatures.