Department of Mechanical Engineering, Covenant University, Ota, Ogun State, Nigeria.
PLoS One. 2018 Apr 19;13(4):e0195870. doi: 10.1371/journal.pone.0195870. eCollection 2018.
Inhibition effect of trypsin complex (TC) on the pitting corrosion of martensitic stainless steel (type 420) in 1M H2SO4 solution was studied with potentiodynamic polarization, open circuit potential measurement and optical microscopy. TC reduced the corrosion rate of the steel with maximum inhibition efficiency of 80.75%. Corrosion potential shifted anodically due to the electrochemical action of TC. The pitting potential increased from 1.088VAg/AgCl (3M) at 0% TC to 1.365VAg/AgCl(3M) at 4% TC. TC shifts the open circuit corrosion potential from -0.270s at 0% TC concentration to -0.255V at 5% TC. The compound completely adsorbed onto the steel according to Langmuir, Frumkin and Temkin isotherms. ATF-FTIR spectroscopy confirmed the inhibition mode to be through surface coverage. Thermodynamic calculations showed physisorption molecular interaction. Corrosion pits are present on the uninhibited 420 morphology in comparison to TC inhibited surface which slightly deteriorated.
采用动电位极化、开路电位测量和光学显微镜研究了胰蛋白酶复合物 (TC) 对 1M H2SO4 溶液中马氏体不锈钢 (420 型) 点蚀的抑制作用。TC 降低了钢的腐蚀速率，最大抑制效率为 80.75%。由于 TC 的电化学作用，腐蚀电位向阳极移动。点蚀电位从 0% TC 时的 1.088VAg/AgCl(3M) 增加到 4% TC 时的 1.365VAg/AgCl(3M)。TC 将开路腐蚀电位从 0% TC 浓度下的-0.270s 移至 5% TC 下的-0.255V。根据 Langmuir、Frumkin 和 Temkin 等温线，TC 完全吸附在钢上。ATF-FTIR 光谱证实了抑制模式是通过表面覆盖。热力学计算表明存在物理吸附分子相互作用。与 TC 抑制表面相比，未抑制的 420 形态存在腐蚀坑，而 TC 抑制表面略有恶化。
