Study On The Al₂O₃doped ZnO Sputtering Target Prepared By Plasma Spray

Aluminum-doped zinc oxide（AZO）has increasingly received widespread attention,not only their excellent optical and electrical properties just like Tin-doped indium oxide,but also their abundant raw materials, lower prices and higher stability in a hydrogenplasma.In this paper, the AZO powder was prepared by solid-phase method. The influence ofdifferent process parameters on phase composition of the powder was studied, such as thedoping content, calcination temperature, holding time, etc. In addition, AZO coating wasprepared by plasma spraying technique. In this study we obtained the optimal process planof AZO coating preparation with plasma spraying by orthogonal experiment with spraypower, gun distance, Ar flow, which put the porosity and resistivity of AZO coating as thecoating quality standards. Finally, different coatings were prepared respectively by usingmicron powders and nano powders. The microstructure and phase composition of thecoatings were characterized with XRD and SEM. The valence state of the elements in thecoatings was analyzed with XPS. The porosity and resistivity of the coating were measuredand calculated. Main conclusions were obtained as follow:AZO powder was prepared by solid-phase method, not only includes ZnO phase, butalso contains a small amount of ZnAl2O4impurity phase. The content of ZnAl2O4is theleast when doping is2.0%, the calcination temperature is1100℃and the soaking time is120min.AZO coating preparation was optimized by the orthogonal experiment. The porosityand resistivity of the coating are smaller when the gun distance is80mm, the spray power is38kW, the Ar flow is2800L/h.Two different coatings were prepared by plasma spraying, respectively using the AZOfeedstock which was prepared with micron powder as raw material and the other AZOfeedstock which was prepared with nano powder as raw material. The porosity andresistivity of the AZO coating with nano powder as raw material was significantly less thanthe AZO coating with micron powder as raw material, their average porosity are4.19%and15.02%，average resistivity are0.78Ω·cm and88.4Ω·cm.Determined by XPS analysis was carried out that the valence state of Al and Zn in thecoatings is+3and+2respectively. Al-O bond generated from Al3+displace Zn2+has beenfound in both of the two kinds of coating.