Tuesday, 30 May 2017
Grand Ballroom (Hilton New Orleans Riverside)
K. Kanomata (CREST, JST), M. Ishikawa, M. Miura (Yamagata University), B. Ahmmad, S. Kubota (CREST, JST), K. Hirahara (Yamagata University), and F. Hirose (CREST, JST)
A room-temperature atomic layer deposition (RT-ALD) of Al2O3 as an anticorrosion coating for metal surfaces was developed using trimethylaluminum (TMA) and a plasma excited humidified argon. The schematic of ALD system is shown in Fig.1. TMA as the aluminum precursor was introduced with a mass flow controller. A remote plasma system generating excited humidified argon was installed to the ALD chamber. The source gas for the oxidizing gas is a mixture of water vapor and argon. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56 MHz and a RF power of 100 W. For the Al2O3 deposition, we repeated the cycle of TMA saturation and oxidizing gas treatment at RT. The TMA exposure was set at 5.86×
10-3 Torr×
40 sec. The saturation of TMA on the hydroxylated surface was confirmed by the IR absorption spectroscopy. The plasma excited oxidizing gas was injected for 2 min. As a result, we show the anticorrosion test of ALD coated metal in a HCl solution. We used SUS430 plates with a size of 20×50×0.5 mm3 as the sample. In this test, we used a not-attenuated HCl solution with a concentration of 35 %. All the samples were immersed in the HCl solution for a certain amount of minutes at room temperature and we observed its surface coloring. Fig.2 shows a picture of the tested samples. The not-treated SUS430 sample clearly exhibits a white stain by the HCl corrosion. On the other hand, the Al2O3 coated sample maintained a mirror surface, which indicates that the RT-ALD coated film works as the anti-corrosion film against the acid solution. In the conference, we discuss the applicability of the RT-ALD to the anticorrosion coating for metal components.
Acknowledgements
This work was partly supported by JST-CREST, JSPS KAKENHI Grant Numbers 15H03536 and 15K13299.
