چكيده به لاتين
In this study, pack aluminizing is used on the nickel foam in order to investigate the conditions for the formation of intermetallic compounds in the Ni-Al binary system. Initially, electroless plating and electroplating were used on the polymer substrate to produce nickel foam, and the optimal conditions for the production of nickel foam were obtained. In the next step, the polymer substrate was removed and nickel foam was produced with a single stage thermal treatment under argon atmosphere and a temperature of 600 . Aluminizing the nickel foam was carried out at 900 and 950 °C at different times in a powde mixture of nickel, ammonium chloride, aluminum powder, and alumina with a ratio of 5-5-10-80 respectively. Optical microscope, scanning electron microscope and X-ray Diffraction were used in order to investigate the thickness and type of coating layers. The coating produced in the aluminizing process was independent of time and temperature and consists of three separate layers, including Ni2Al3, NiAl and Ni3Al phases.a thin layer of NiAl and Ni3Al was formed between the Ni2Al3 and pure Ni. Based on the results of this investigation, it can be concluded that the Ni2Al3 was the main phase of the coating. Subsequently, by evaluating the changes in the weight of Ni-Al foam before and after aluminizing, the required temperature and time for penetrating sufficient amount of aluminum into the nickel substrate in order to produce the NiAl and Ni3Al foam were calculated. By using the results of variations in the samples weight, single stage NiAl foam was produced by heat treatment in three hours at 1000 oC.
