In Situ Deposition of Amorphous Al2O3-GAP Ceramic Coating with Excellent Microstructure Stability and Uniformity via Atmospheric Plasma Spraying

Abstract

A novel Al2O3-GdAlO3 (GAP) amorphous ceramic coating was in situ prepared via atmospheric plasma spraying (APS). The Al2O3/Gd2O3 sprayable powders possessed excellent sphericity and fluidity after heat treatment at 1173 K without solid-phase reaction, which indicated that the Al2O3-GAP coating deposition process was significantly simplified. The Al2O3-GAP amorphous coating showed high glass transition temperature (1155.1 K), initial crystallization temperature (1179.2 K), local activation energy (847.6 kJ/mol) and nucleation resistance (88.3). Compared with almost all amorphous materials, the Al2O3-GAP amorphous coating possessed greater crystallization activation energy, which was conducive to its high-temperature microstructure stability. Furthermore, the hardness and elastic modulus of Al2O3-GAP coating fluctuated with a tiny range when increasing the nanoindentation depth from 500 nm to 2000 nm, which exhibited excellent uniformity of microstructure and mechanical performance of the coating. Therefore, the results showed that the Al2O3-GAP amorphous coating had a better potential for large-scale engineering application under harsh service conditions.

A Selective Review of Ceramic, Glass and Glass–Ceramic Protective Coatings: General Properties and Specific Characteristics for Solar Cell Applications

“…Above 30% grain boundary cracking occurred due to the brittleness of the Al2O3 [47]. An amorphous ceramic coating comprising Al2O3-GdAlO3 (GAP) was prepared by APS from sprayable powder precursors [28]. This coating, as described by Qiang Anti-reflective coatings were formed by alternating layers of TiO2/SiO2, as reported by Zambrano et al, as shown in Figure 4 [58].…”

“…Above 30% grain boundary cracking occurred due to the brittleness of the Al 2 O 3 [47]. An amorphous ceramic coating comprising Al 2 O 3 -GdAlO 3 (GAP) was prepared by APS from sprayable powder precursors [28]. This coating, as described by Qiang et al, had an excellent microstructure uniformity and mechanical performance, as shown in Figure 3 temperature-stable coatings which required a transparent scratchproof coating or depositing at room temperature, where scratch resistance was not required.…”

Investigation of Thermal Shock Behavior of Multilayer Thermal Barrier Coatings with Superior Erosion Resistance Prepared by Atmospheric Plasma Spraying

“…Meanwhile, the left boundary of the model was set as a symmetric boundary, and the vertical displacement of the bottom boundary was set to zero. The material properties used in this FEM analysis were obtained from the literature [35][36][37][38].…”

Tribological and Mechanical Properties of Gradient Coating on Al2O3-Based Coating Produced by Detonation Spraying Methods

“…Recent studies [21,22] also indicate that it is possible to obtain coatings with the main α-Al 2 O 3 phase by plasma spraying using γ-Al 2 O 3 as a starting powder. These studies show that the variation of process parameters, such as firing frequency and barrel fill volume, affects the ratio of α-Al 2 O 3 and γ-Al 2 O 3 phases in the resulting coatings.…”