季鏻盐与阴离子CNS^-及I^-对碳钢缓蚀作用的协同效应

THE SYNERGISTIC EFFECT BETWEEN ANIONS AND PHOSPHONIUM SALTS FOR CORROSION INHIBITION OF CARBON STEEL

采用失重法、极化曲线法和交流阻抗法研究了在0.5M磷酸溶液中CNS^-、I^-对溴化苄基三苯基鏻(BPB)和1.4一双(溴化三苯基鏻)丁烷(DPBB)缓蚀效率的影响及BPB和DPBB在碳钢/溶液界面上的吸附规律。结果表明,CNS^-及I^-明显提高季鏻盐对碳钢的缓蚀效率。协同效应的大小与季鏻盐对阴离子的浓度比密切相关。在磷酸溶液中,BPB和DPBB在碳钢/溶液界面上的吸附遵循Bockris-Swinkels吸附等温式。当磷酸溶液中含有一定量的CNS^-或I^-时,由于吸附粒子间的相互作用,季鏻盐在碳钢/溶液界面的吸附遵循校正的Bockris-Swinkels吸附等温式。

The corrosion inhibition of carbon steel by benzyltripenyl phosphonium bromide (BPB) and 1,4-di(triphenyl phosphonium bromide) butylane (DPBB)in 0.5MH_3PO_4 solution Containing CNS-,I^- was investigated by gravimetric, potentiodynamic and impedance determination techniques. The experimental results show that the synergistic effect of corrosio inhibition appears between above-mentioned anions and phosphonium salts. The synergistic effect was closely relevant to the concentratio ratio of anion to phosphonium salt. The adsorption of BPB or DPBB on carbon steel follows Bockris-Swinkels isotherm in 0.5MH_3PO_4 solution without anion at 25℃. But adding anions into 0.5M H_3PO_4 solution containing BPB or DPBB, the interaction among adsorbed species became significant. Thus, a free energy parameter f was introduced into the Bockris-Swinkels isotherm as follows θ/(1-θ)~n·[θ+n(1-θ]^(n-1)/n^1·exp (-fθ)=C/55.5exp(-△G_a^0/RT)