再生可能エネルギー固定買取制度を背景に，太陽光発電設備は急増した．太陽光発電設備の基礎杭は，浅層土壌中に金属表面が接し，地際部より突出している．本研究では，この環境における腐食の把握を目的に，杭状試験体の暴露試験と暴露試験場土壌の分析を行った．浅層土壌中の腐食量は，土壌中の腐食量として一般的に示される年間0.02 mmの腐食量を上回った．それらの腐食量は各土壌を電解質とした分極抵抗測定結果と良い相関を得た．地際部のマクロセル腐食は，土地造成など人為的な作用により土壌の化学組成が大きく変化することが一因であると考えられる．

抄録全体を表示

Solar selective black Cr-Co alloy coatings have been prepared from the tri-valent chromiumformate/acetate or -oxalate baths containing a small amount of cobalt chloride. The black Cr-Co alloy coating electrodeposited with a plating time of about 1min and at current densities from 15 to 50 Adm^-2 from the formate bath and that obtained at current densities from 30 to 50 Adm^-2 from the oxalate bath have a solar absorptance of 0.92-0.96 and thermal emittance of 0.10. The alloy coatings thus prepared also have excellent thermal stability. ESCA study reveals that the Cr and Co in the alloy coatings exsist as oxides. The bath composition, especially its Co content, seems to affect the composition, thickness and therefore the optical characteristics of the alloy coatings.

抄録全体を表示

The behavior and composition of a cathode film formed on a steel cathode during chromium plating were studied with radioactive tracers. A special cell with a rapid washing compartment was used for preventing the cathode film from dissolving in electrolyte after plating. The cathode film was composed of two layers. The outer layer facing to the electrolyte had a loose structure and contained more sulfuric anions than the inner layer, for sulfuric acid probably concentrated in the outer layer. This outer layer is called L-film in this paper. The L-film was easily dissolved in the electrolyte solution. The inner layer (called C-film, compact film) was stable against electrolytes and contained less anions than that of L-film. The C-film had a thickness equivalent to 5mg/m² and the concentration of anions unaffected by the composition of electrolytes. The C-film was not reduced to metallic chromium, but it remained in the cathode film during and after plating. This suggests that chromic acid in the cathode film is not reduced to metallic chromium, that metallic chromium is deposited from chromium complexes reaching the cathode surface through the cathode film, and that the complexes do not play a role on the construction of the cathode film.

抄録全体を表示