No abstract

Aluminum powder, cellulose acetate, and acetone were used to have the desired coating microstructure, suitable viscosity, and good wettability. The as‐cast IN‐738 was used as the substrate. Different holes with a diameter of 1 mm were drilled. The results of scanning electron microscopy and X‐ray diffraction analyses show that a uniform aluminide coating with a thickness of about 100–120 μm covers the entire inner surface of the hole and the desired β‐NiAl phase is formed. An artificial neural network was used in MATLAB software, and according to surface drawn obtained from mathematical modeling, it was concluded that with slurry viscosity in the range of 200–250 cp and the amount of applied slurry with a value of 20–30 mg cm−2 a suitable coating can be obtained. The oxidation test at 1000°C was performed by the thermogravimetric method for 150 h and the Kp constant for aluminide coatings and uncoated superalloy are successfully calculated to be 0.0034 and 0.0086 mg2 cm−4 h, respectively.