The pres ent pa per dis cusses the ef fect of the geo met ri cal struc ture of the elec tric field on the cor ro sion of alu mi num cath odes by elec trol y sis of aque ous so lu tions of so dium chlo ride. A cor re la t ion be tween the mass of the alu mi num dis solved from the cath ode and the fac tors elec tric cur rent den sity, dis tance be tween the electrodes, elec trol y sis time and so dium chlo ride con cen tra tion by elec trol y sis with di rect cur rent in elec tric fields of var i ous ge om e tries was found.
IN TRO DUC TIONIt is well known that, by elec trol y sis of aque ous so lutions, the high rate of hy dro gen re leased from cath odes increases the con cen tra tion of hy drox ide ions near the metal sur face. The pro tec tive layer coat ing the metal in so lu tions with neu tral pH is ther mo dy nam i cally un sta ble in al ka line me dium and metal can pos si bly be dis solved if the layer is destroyed due to the al ka liz ing ef fect.1 The na ture and mech anism of cor ro sion of cath odes, as well as the fac tors de ter mining its rate have been stud ied for a long time. Cor ro sion studies usu ally aim at the de ter mi na tion of the func tional de pendence of cor ro sion rate on some ba sic pa ram e ters, e.g. electrode po ten tial of the sam ple, 2,3 elec tric cur rent den sity (quantity of elec tric ity), 1,4 im pu rity con tent of alu mi num, 5-7 pH, [8][9][10][11] tem per a ture, 9,12 elec tro lyte com po si tion, 13-15 type of the electric cur rent, 16,17 etc. In con tem po rary elec trol y sis tech nol ogy, how ever, the need to im prove tech ni cal and eco nom i cal charac ter is tics points to an other di rec tion for the in ves ti ga tions, namely: to study the ef fect of spa tial dis tri bu tion of cur rent den sity j(x,y,z) on the elec tro chem i cal be hav ior and cor rosion of alu mi num (which is the pre ferred elec trode ma te rial). In our pre vi ous work 18 a geo met ri cal (top o log i cal) ap proach was sug gested al low ing us to un am big u ously de ter mine electric field non-uniformity us ing char ac ter is tics: de gree of elec tric field non-uniformity, elec trode po lar ity and rel a tive length of the av er age cur rent line. This ap proach was used to study the ef fect of the quan tity of elec tric ity (or elec tric current den sity) on the an odic dis so lu tion and cor ro sion of alumi num 4 by elec trol y sis in 0.052 M aque ous so lu tions of sodium chlo ride. An ef fect of elec tric field non-uniformity on the rate of an odic dis so lu tion of alu mi num was also ob served by elec trol y sis re gimes de ter mined by the fac tors: elec tric cur rent den sity, dis tance be tween the elec trodes, elec trol y sis time and so dium chlo ride con cen tra tion.
19The aim of the pres ent work is to iden tify the ef fect of elec tric field ge om e try on the cor ro sion of alu mi num cathodes.
AP PROACH AND EX PER I MEN TAL PRO CE DUREThe ef fect of elec tric field ge om e try on the cor ro sion of cath odes of tech ni cally pure alu mi num was stud ied by di rect ...
