چكيده به لاتين
Ceramics, due to their unique and distinctive properties such as corrosion resistance, excellent abrasion resistance, low thermal and electrical conductivity, encourage engineers to use both ceramic and metal together. There have been many advances in this subject, but there are many problems with this process. Some of these problems are the nature of the atomic bond, the difference between the melting point and the wettability. The main focus of this study is to improve the alumina wettability by molten Aluminum. Sessile drop Method has been used to measure contact angle and wettability. For this purpose, tube furnace, high-purity gas, and a high-quality camera are used to record the shape of the droplet at different temperatures. X-ray diffraction and Scanning Electron microscope (SEM) used to investigate Alumina and aluminum interface. Various methods can be used to improve wettability. One of the methods used in the present project is to metalize the ceramic surface with Ni and copper by the electroless plating method. The heat of formation of the NiAl3 phase at the interface between Aluminum and Ni-coated alumina is exothermic. and it increases the temperature at the interface. So, Formation of this reaction products improves wettability and contact angle decreased to 85˚ from 110˚. Also, the heat of formation of the CuAl2 phase at the interface between Aluminum and Cu-coated alumina is exothermic, and contact angle decreased to 105˚. The addition of Mg to aluminum due to the formation of the MgAl2O4 at the interface between alumina and aluminum improves wettability and Contact angle reached to 87˚. Intermetallic phases can wet ceramic surfaces better than metals due to the establishment of chemical bonds at the interface.
Keywords: corrosion resistance, atomic bond, wettability, spinel, sessile drop method
