Cdng trinh Khoa hpc DANH GIA KHA NANG BAO VE CHONG AN MON THEP CT3 CUA MANG SON LAI THI HOAN NGUYEN THI MAI Khoa Khoa hgc cff bdn Tru&ng Dgi hgc Giao thong Vgn tdi Tdm tdt: Gdn day, phd tong Ird dien hda dugc su dgng rong rdi nghien ciru dn mon, ddc biet la viec ddnh gid Idp phu hiru ca tren bi mat kim logi Trong bdo cdo ndy, chiing tdi trinh bdy cdc ung dung cua EIS viec ddnh gid ldp phii hiru ca Tir kit qud EIS cua hi ldp phti nghien ciru cho thdy Idp phii epoxy cd khd ndng ngdn ngira thep CT3 khdi bjdn mdn moi trudng clorua tot hem nhiiu so v&i ldp phti polyuretan Summary: Recently, the electrochemical impedance spectroscopy (EIS) has been widely used in corrosive researches, especially in evaluating organic coating on metal substrate In this article, we would like to introduce applications of EIS in evaluating organic coaling The results demonstrate the excellent ability of EIS in monitoring the degeneration of polyurethane and epoxy coatings on CT3 steel On the other hand, by monitoring EIS of this coating system, we realize that epoxy coating is much better than polyurethane coaling in preventing CT3 steel from corrosion in chloride medium I DAT VAN B E Da sd cdc kim loai va hgp kim de dang bi an mdn tiong dieu kien su dung San phu la mgl phuang phdp bdo ve chdng dn mdn kim loai phd bien Tuy nMen, lac dgng cua mdi trudng lam viec rad Idp son phu mdt din kha nang bao ve Da cd nhieu phuang phap danh gia kha nang bao ve chdng an mdn kim loai cua cdc mang son phii nhu: - Thd nghiem tai hien trudng (phoi mdu) - Cdc phuang phap gia ldc hdu (mu mudi, sdc nMet) - Cdc phuang phap dien hda (do the an mdn, dien trd mang son ) Trudc ddy, cac bien phap ddnh gid khd ndng bdo ve chong an mon kim loai cua mang son ddi hoi cin nhieu thdi gian, cdng siic Nhirng nam gin day phd EIS dugc su dung de nghien cuu an mdn EIS cho ket qua ve dien tid phan cgc, xdc dinh cac co che an mdn cho he nghien cuu ma cac phuang phap khdc chua dap ung dugc EIS da dugc sir dung de ddnh gia dn mdn ddng deu, an mdn rd be mat, an mdn be tdng, vd dn mdn ben dudi ldp son phii Ngudi ta ciing dua mgt sd md hinh mach Mong duang dugc sii dung dk md hinh hda cdc he thdng dn mdn [Loveday, et al 2004, tap I], l/u diem ciia EIS Id phuang phap nghien cdu khdng pha huy mdu, cho phep theo ddi dai han nhdm ddnh gia ttang thai suy thoai cua mang son phii va ldc dd dn mdn ciia kim loiii nen [Loveday, et al 2004, lap 2] Tap cM KHOA HOC GIAO THONG VAN TAI S6 dac biet - 11/2015 287 Cdng trinh Khoa hpc II GIAI QUYET VAN DE Trong bai bao cM sir dgng phuang phap tdng ttd dien hda cua mang son, dudi day tac gia trinh bay van tat ve nguyen Iy cua phuong phdp 2.1 Cdc thong so dien hda cua mang son Trong viec phd EIS, he dien hda dugc md ta bdng mgt md hinh mach Mang duong Mdi mdt phan tii ttong mach Mang duong ddc trung cho mdt qua trinh vat ly hoac hda hgc xac dinh Md Mnh mach Mong duong tdng qual ddi vdi mdt mang son ngam ttong dung dich dien ly dugc md ta nhu sau: - C^: Dien dung ciia mang phu (Coating capacitor) - Cd,: Dien dung ciia ldp dien kep (Double layer Capacitor) - R^: Dien ttd dung dich (Solution resistor) - Rpo! Dien ttd mang son (Pore resistor) - Rp' Dien trd phan cgc (Polarization resistor) Su thay ddi md Mnh mach Mong duang (cd mat vd khdng cd mat mgt sd phan tii hoac su thay ddi phd tdng ttd) va su thay ddi gid tri cua mdi phdn M la nhimg thdng tin qui gia cho biet su bien ddi ciia mang son tten nen kim loai qua cac gian doan sd dung Viec khao sat phd tdng ttd mang son de danh gia chat lugng cua mang son ttong qua trinh su dung Id can tMet vd cd hieu qud cao 2.2 Su* bien doi cua tong trd qua cac giai doan Loveday va cdng su [Loveday, et al 2004, tap 3] neu cdc giai doan thoai hda nhu sau: Giai doan ddu, chua cd su Iiep xiic kim loai nen vdi chat dien ly, phd EIS cho cac gia Iri Rpo Idn Md hinh mach Mong duang vd phd EIS cd dang nhu sau: Mgch tuang duang S