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采用模拟闭塞区溶液研究NO_3~-对氯化钠溶液中0Cr18Ni9Ti钢的缓蚀作用及机理。结果表明,随着(NO_3~-)_(bulk)(主体溶液中NO_3~-的浓度)增高,闭塞区内金属的腐蚀速率减小,腐蚀电位向正方向移动。50℃时,若[NO_3~-]_(bulk)≥0.025或90℃时[NO_3~-]_(bulk)≥0.2M,闭塞区内金属由活态转变为钝态。当50℃、[NO_3~-]_(bulk)≥0.3M或90℃、[NO_3~-]_(bulk)≥0.5M时,其动电位极化曲线上的钝化区增宽、致钝电流密度和维钝电流密度变小,缓蚀率高达90％以上。因此,在主体溶液中加入适量NO_3~-能导致闭塞区钝化,从而对孔蚀、缝隙腐蚀及应力腐蚀破裂起缓蚀作用。
Inhibitory effect and mechanism of NO_3 ~ - on 0Cr18Ni9Ti steel in sodium chloride solution by using simulated occlusion zone solution. The results show that the corrosion rate of metal decreases in the occluded region and the corrosion potential moves in the positive direction as (NO_3 ~ -) bulk (concentration of NO_3 ~ - in the host solution) increases. At 50 ℃, if [NO_3 ~ -] _ (bulk) ≥0.025 or 90 ℃, [NO_3 ~ -] _ (bulk) ≥0.2M, the metal in the occluded region changes from active state to passive state. When 50 ℃, [NO_3 ~ -] _ (bulk) ≥0.3M or 90 ℃, [NO_3 ~ -] _ (bulk) ≥0.5M, the passivation region on the Zeta potential curve broadens, resulting in blunt Current density and the dimension of the current density of diminished blunt, corrosion inhibition rate as high as 90%. Therefore, adding proper amount of NO_3 ~ into the host solution can lead to the passivation of the occlusion zone, thus inhibiting pitting corrosion, crevice corrosion and stress corrosion cracking.