Thermal barrier coatings with novel architectures for diesel engine applications

0540267 - ÚFP 2021 RIV CH eng J - Journal Article
Uczak de Goes, W. - Markocsan, N. - Gupta, M. - Vaßen, R. - Matsushita, T. - Illková, Ksenia
Thermal barrier coatings with novel architectures for diesel engine applications.
Surface and Coatings Technology. Roč. 396, August (2020), č. článku 125950. ISSN 0257-8972
Institutional support: RVO:61389021
Keywords : Diesel engine * Gadolinium zirconate * Sealing coating * Suspension plasma spray * Yttria stabilized zirconia
OECD category: Materials engineering
Impact factor: 4.158, year: 2020
Method of publishing: Open access
https://reader.elsevier.com/reader/sd/pii/S0257897220306198?token=7F625F0E59472EC0B86FE0BA8812042AECBC45C7AE47508840B965EB4FF29CFBEF6B7CF3D178289B48D4C5BED22509AE

The increased demands for higher efficiency and environmentally friendly diesel engines have led to a continuous search for new coating processing routes and new ceramic materials that can provide the required properties when applied on engine components such as pistons and exhaust manifolds. Although successful in gas turbine applications, thermal barrier coatings (TBCs) produced by suspension plasma spraying (SPS) processes have not been employed so far in the automotive industry. This work aims to achieve a better understanding of the role of thermal conductivity and thermal effusivity on the durability of SPS TBCs applied to pistons of diesel engines. Three different coating architectures were considered for this study. The first architecture was yttria-stabilized zirconia (YSZ) lamellar top coat deposited by APS (Atmospheric Plasma Spray) and used as a reference sample in this study. The second architecture was a columnar SPS top coat of either YSZ or gadolinium zirconate (GZO) while the third architecture was an SPS columnar top coat, “sealed” with a dense sealing layer deposited on the top coat. Two types of sealing layers were used, a metallic (M) or a ceramic thermal spray layer (C). Laser Flash Analysis (LFA) was used to determine the thermal conductivity and thermal effusivity of the coatings. Two different thermal cyclic tests were used to test the TBCs behavior under cyclic thermal loads. Microstructure analysis before and after the thermal cyclic tests were performed using SEM in different microstructures and materials. The thermal cyclic test results were correlated with coatings microstructure and thermophysical properties. It was observed that the columnar coatings produced by SPS had an enhanced service life in the thermal cyclic tests as compared to the APS coatings.
Permanent Link: http://hdl.handle.net/11104/0317901