Zirconia and Nickel Based Thermal Barrier Coating

摘要

This research project focuses on thermal properties of Zirconium and nickel based materials. Zirconium ceramics with its low thermal conductivity, good adhesion properties with bond coat material which are nickel based alloys acts as a good thermal barrier coating material. Also, the focus on optimizing thermal barrier coating structure using Comsol Multiphysics 4.3 Software. Thermal barrier coating increase the engine operating temperatures hence increasing the efficiency and performance. Samples of Zirconium, Oxidised zirconium (zirconia) are prepared and thermal properties are found out using laser flash technique DLF-1200 equipment. Results show that oxidised zirconium with its very low thermal conductivity in the range 3.5-4.5 W/m.K for temperatures 25 degree C – 1000 degree C, is the suitable material to coat engine system components like piston, cylinder head, and exhaust manifold. Nickel super alloys used are Haynes 718,230,625 and nickel N out of which nickel n and nickel 718 have the lowest thermal conductivity ranging 5-22 W/m.K. More research should be done on the characteristic surface properties of oxidised zirconia to evaluate it as a thermal barrier coating material. Simulations are done for different values of thickness for bond coat and top coat of a thermal barrier coating and maximum and minimum von misses stress is calculated. Results show that optimized thickness for a thermal barrier coating is 60μm for bond coat and 120μm for the top coat which has the minimum stress value.