Nano-Microstructural Characterization of Inconel-718 with Thermal- Barrier Coatings After Thermal Shock Tests
Vibha1, Vijay Kumar Dwivedi2, Dipak Kumar3

1Dr. Dipak Kumar, Assistant Professor, RKGIT, Ghaziabad (Uttar Pradesh), India.
2Dr. Vijay Kumar Dwivedi, Associate Professor, GLA University, Mathura (Uttar Pradesh), India.
3Ms. Vibha, M.Tech Student, GLA University, B.Tech. KIET, Ghaziabad AKTU Lucknow (Uttar Pradesh), India.
Manuscript received on 07 March 2019 | Revised Manuscript received on 20 March 2019 | Manuscript published on 30 March 2019 | PP: 36-41 | Volume-8 Issue-5, March 2019 | Retrieval Number: D2798028419/19©BEIESP
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Abstract: The immovability and permanence of thermal barrier coatings is very significant parameter for turbo machinery used at high atmospheric temperature such as turbine, compressor used in power generation and space industry. In this paper nano-structured ceramic pinnacle coating of 8YSZ (8wt%Y2O3ZrO2) and NiCoCrAlY atomic bond is deposit on Ni based super alloy INCONEL718 by air plasma spray (APS). Thermal shock test of INCONEL718 has been performed as a function of temperature at 1100°C. This thermal shock testing is performed with 45 min heating and 15 min cooling in water and air separately. Delamination is observed due to thermal fatigue damage on 8YSZ coating. Damage of work piece is originated at the corner due to thermal fatigue and is sustained upto 20 cycles, 8 cycles for air and water cooling respectively. Nano-Microstructure characterization was done by high resolution scanning electron microscopy-energy dispersive x-ray (HRSEM-EDX). Result from HRSEM-EDX is co-related to nano and Micro structural development of thermal barrier coatings. After conducting of water and air cooling, lots of non-regular shaped nano size agglomerated clusters were observed in the 8YSZ coating. These non-regular structured leads to the formation of weak in the bond which cause delamination of coatings.
Keyword: Delamination, Nano-Sized APS Coating, Thermal Barrier Coating, Thermal Shock.
Scope of the Article: Thermal Engineering