Structure–property differences between supersonic and conventional atmospheric plasma sprayed zirconia thermal barrier coatings

• Published in: Surface & coatings technology Vol. 205; no. 13-14; pp. 3833 - 3839
• Main Authors: Bai, Y., Han, Z.H., Li, H.Q., Xu, C., Xu, Y.L., Ding, C.H., Yang, J.F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25.03.2011; Elsevier
• Subjects: Applied sciences; Atmospherics; Coatings; Columnar structure; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Lamellar structure; Materials science; Metals. Metallurgy; Microstructure; Nonmetallic coatings; Physics; Plasma spraying; Production techniques; Shock resistance; Supersonic atmospheric plasma spraying; Surface treatment; Surface treatments; Thermal barrier coatings; Thermal cycling lives; Thermally grown oxide; Yttria stabilized zirconia; ZrO2; Thermal barrier coatings; ZrO2; Thermally grown oxide; Thermal cycling lives; Supersonic atmospheric plasma spraying; Plasma; Oxide layer; Growth; Spray coatings; Hot spraying; Thermal cycle; Surface treatments; Stabilized zirconia; Ceramics; Non metal coating; Zirconium oxide; ZrO; Thermal barriers; Plasma arc spraying
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2011.01.056

Yttria-stabilized zirconia (YSZ) based thermal barrier coatings (TBCs) were deposited by high efficiency supersonic atmospheric plasma spraying (SAPS) system. The microstructure and thermal shock resistance of the SAPS-TBCs were investigated. As compared to conventional atmospheric plasma sprayed TBCs (APS-TBCs) with the same composition, the microstructure of SAPS-TBCs was much finer. It was found that the thickness of lamellar structure consisted of columnar crystals in the SAPS- and APS-coatings was in the range of 1–4μm and 2–8μm, respectively. Besides, the statistical results revealed that the average thickness of the lamellar structure in SAPS-coating was 2.5±0.6μm, while that of APS-coating was 5.3±0.9μm. The desirable structure was attributed to higher impact velocity of in-flight particles during SAPS process, which resulted in the improvement of flattening degree of molten particles after impinging on the target. The well-adhered fine lamellar structures, fine micro-cracks and lower growth rate of thermally grown oxide (TGO) appeared to be responsible for greatly improved thermal cycling lives of SAPS-TBCs as compared to their conventional plasma sprayed counterparts. The results of water-quenching test from 1100°C into room temperature showed that SAPS-TBCs presented high thermal shock resistance, only 10% coating area spalled after 265 thermal cycles, about 90% higher than that of APS-TBCs. The SAPS method, which offered some unique advantages over the conventional plasma spraying process, is expected to be potentially used to deposit high-performance TBCs at lower cost. ► Thermal barrier coatings were deposited by supersonic atmospheric plasma spraying. ► The microstructure and thermal shock resistance of the SAPS-TBCs were investigated. ► The SAPS-TBCs exhibit higher thermal shock resistance than that of APS-TBCs.