TP32 : Investigation of hot corrosion behavior and oxidation of Zr2La2O7 / TiC self-healing thermal barrier composite
Thesis > Central Library of Shahrood University > Chemical and Materials Engineering > MSc > 2021
Authors:
[Author], [Supervisor], Mojtaba Ghatee[Advisor]
Abstarct: Thermal Barrier Coatings (TBCs) are thin ceramic coatings whose main task is to reduce the heat of substrate temperature from rising against high temperatures. Some applications of this type of coating on superalloys, such as gas turbine blades for electricity generation or aircraft turbines and combustion chamber components. So far, several compounds have been used as TBCs. Ceramic materials used as TBCs should have low thermal conductivity, high thermal expansion coefficient, heat shock tolerance and hot corrosion resistance. In this study, hot corrosion behavior and oxidation of Zr2La2O7 / TiC self-healing thermal barrier composite were investigated. Synthesis of Lanthanum Zirconate (LZ) was performed using mechanical milling method and solid state diffusion. Disc samples were fabricated with different combinations of LZ and TiC using a pressure and perforation process in a controlled atmosphere furnace. The results of property analysis including microstructure, surface morphology and phases formed in the samples were analyzed using FESEM, XRD, hot corrosion analysis of molten Na2SO4 and V2O5 salts and density test. The results of XRD analysis showed successful synthesis of LZ phase using two-stage purification so that a large percentage of LZ phase was generated in the samples. The LZ-TiC composite was synthesized with a suitable distribution of TiC particles in the LZ field so that an acceptable density was obtained for these ceramics. The results of the hot corrosion test showed better hot corrosion behavior for LZ ceramics, and the composite specimens peeled and cracked after 50 hours of hot corrosion. The presence of TiC particles with larger dimensions than usual, of this type of ceramics led to poor hot corrosion properties in these ceramics.
Keywords:
#Thermal barrier coating; hot corrosion; oxidation; self-healing ceramic; lanthanum zirconate Keeping place: Central Library of Shahrood University
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