The deposition of alumina on thermal barrier coatings can effectively avoid hot corrosion and increase durability. Al 2 O 3 coatings were prepared on an yttria-stabilized zirconia (YSZ) substrate by plasma chemical vapor deposition (CVD). The effects of microwave power (P M ) and total pressure (P tot ) on the crystalline phase and microstructure of Al 2 O 3 coatings were investigated, and the effect of the mechanism on the deposition rate was also analyzed. The α-Al 2 O 3 coatings with a needle-like microstructure were formed at a higher P M and P tot , whereas the γ-phase coatings exhibited a cauliflower-like microstructure at a lower P M and P tot . A maximum deposition rate (R dep ) of 58 μmh −1 was obtained, which is significantly higher than those of conventional CVD methods. K E Y W O R D S alumina, chemical vapor deposition, coatings | 1357 ZHANG et Al. How to cite this article: Zhang S, Zheng L, Wei G, et al. Structural investigation of Al 2 O 3 coatings by PECVD with a high deposition rate. Int J Appl Ceram

Aluminum acetylacetonate (Al(acac) 3 ) was used as a precursor to synthesize aluminum oxide (Al 2 O 3 ) coatings on Ti(C, N)-based ceramic by microwave plasma CVD (MPCVD). Al 2 O 3 coatings transformed from γ phase to δ phase and α phase and as microwave power (p M ) and total pressure (P tot ) increased. The effects of p M and P tot on the microstructure of the Al 2 O 3 coating and oxidation of the substrate have been investigated. The relationship between phase structure and adhesive strength of the coatings was also studied. Coatings deposited at p M = 1.0-1.2 kW and P tot = 400 Pa exhibited good adhesion strength (Class 1). K E Y W O R D S adhesion, Al 2 O 3 coating, microstructure, microwave plasma CVD, Ti(C, N) cermets

Thin films of organic-inorganic hybrids (CnH2n+1NH3)2PbX4(X=Cl, Br, I; n=4,6,8,10) were prepared by the spin-coating method. The influences of annealing temperature on the crystal structure of the films were analyzed by X-ray diffraction(XRD). The surface morphology of the films were observed using scanning electronic microscope(SEM). The room-temperature UV-Vis absorption spectra of the films were employed to examine the effect on the optical properties of different elements X (X=Cl,Br,I), and varying n from 4 to 10, respectively. The results showed that a significant red shift of the absorption peak was observed for different X in inorganic layers, and the position of the exciton absorption peaks did not shift obviously with the increasing of the alkyl chain length in organic layers. The results suggested that the exciton absorption arise from electronic transitions within the inorganic layer, rather than from the organic layer.