地熱発電プラントにおける酸性熱水からのシリカ付着低減のためのa-C:H合成法の検討

Abstract

In this study, in order to control the effects of hydrogen content and carbon network structure in the outermost layer of a-C:H film on silica scaling adhesion from geothermal steam, the effects of substrate bias during deposition on the hydrogen content and carbon network structure in the outermost layer of a-C:H were investigated. For this purpose, outermost layer and bulk layer of a-C:H were analyzed by surface-enhanced Raman spectroscopy and conventional Raman spectroscopy, respectively. Silica adhesion simulation tests were performed on a-C:H films deposited at substrate biases of -400 and -700 V by using DC plasma CVD using methane gas as a source gas. The a-C:H film deposited at 400 - V had a smaller amount of silica adhesion than that of the a-C:H film deposited at -700 V. The SERS spectra for the a–C:H films showed an increase in the amount of hydrogen and a decrease in the sp2/sp3 ratio in the outermost layer due to a decrease in the substrate bias, and thus we interpreted that these differences caused the decrease of the silica adhesion.