不同pH值模拟混凝土孔隙液中镀锌层的阳极特性逆(5)

Journal of Materials Protection

（Monthly ，Started in 1960）

ISSN 1001-1560Feb．2013Vol．46No．2Serial No．409Contents ＆Abstracts

Reversion of Anode Characteristics of Galvanizing Coating in Simulated Concrete Pore Solution with Different pH Values YU Chang -chun 1，YOU Ge -xin 1，WANG Jian 1，LUO Peng -hua 2，LIU Jun -quan 1（1．School of Mechanical and Automotive Engineering ，South China University of Technology ，Guangzhou 510640，China ；2．Zhongshan Walsall Steel Pipe Industrial Com-pany Ltd．，Zhongshan 528000，China ）．Cailiao Baohu 2013，46（02），01 03（Ch ）．The backfill of the sand from the sea causes the local corrosion of galvanized steel pipes used in concrete -based buildings near the coast．Galvanized specimens were immersed into 6kinds of simulated concrete pore solution with different values ，while the steel substrate without galvanizing coating was immersed in the aqueous solution of 3．5%NaCl for 24h．After the electrolysis cell was linked with an electrolytic bridge ，the potential -time curves between the two kinds of speci-mens as well as the current of the galvanic couple were measured and compared with those in the absence of pre-immersion．It was found that ，in neutral solution containing Cl －and saturated Ca （OH ）2solution with pH =10．0，11．0，the galvanizing coat-ing acted as a sacrificial anode to well protect the steel substrate．However ，in saturated Ca （OH ）2solution with pH =12．0，wheth-er the galvanizing coating was pre -immersed or not ，its potential tended to reverse and relevant galvanic couple current was posi-tive ，which indicated that in this case the galvanizing coating accelerated the corrosion of the steel substrate．Moreover ，in saturated Ca （OH ）2solution with pH =12．5，the galvanizing coat-ing without pre -immersion was able to protect the steel substrate ；and still in such Ca （OH ）2solution ，the galvanizing coating after 24h of pre -immersion could protect the steel substrate only at the early stage ，and lost the ability after about 1650s of test while the corrosion of the steel was contrarily accelerated thereafter．Key words ：corrosion behavior ；reversion of anode characteris-tics ；concrete ；simulated pore solution ；galvanizing coating ；potential -time curve ；galvanic couple current

Effect of Nickel Content in Hot -Dip Galvanizing Solution on Morphology as well as Hardness and Wear Resistance of Zinc -Aluminum -Nickel Coating SHAO Da -wei ，HE Zhi -rong ，ZHANG Yong -hong （School of Materials Science and Engineering ，Shaanxi University of Tech-nology ，Hanzhong 723003，China ）．Cailiao Baohu 2013，46（02），04 06（Ch ）．A small amount of Ni was introduced into hot -dip galvanizing solution （Zn -0．01%Al bath ）to prepare Zn -Al -Ni coating ［Al content 0．01%（mass fraction ；the same hereafter ）；Ni content 0．02% 0．12%］so as to reduce the surface roughness and increase the hardness and wear resistance of hot -dip galvanizing coating．The morphology of as -prepared Zn -Al -Ni coating was observed with a metallurgical microscope ，while the hardness and wear resistance of the coating were evalua-ted with a Vickers hardness meter and a friction and wear tester as well．It was found that ，with increasing Ni content in the hot -dip galvanizing solution ，the grain size of Zn -Al -Ni coating ini-tially tended to decline but later to rise ；and the hardness initially tended to rise but later to decline therewith．The Zn-Al-Ni coat-ing prepared from the hot -dip galvanizing solution containing 0．05%Ni had the smallest grain size ，the highest hardness and extended antiwear lifetime．Moreover ，though the Zn -Al -Ni obtained from the galvanizing bath containing 0．12%Ni had the longest antiwear lifetime ，it possessed a relatively high friction coefficient．Key words ：hot -dip galvanizing ；Ni content ；morphology ；hard-ness ；wear resistance Effect of Rare Earth Salt Content in Fluxing Agent on Microstructure and Corrosion Resistance of Hot -Dip Galva-nizing Coating CAO Wen -ping ，HE Ming -yi ，LIU Hong -feng ，WANG Sheng -min ，ZHAO Xiao -jun （Institute of Material Protection ，Kunming University of Science and Technology ，Kunming 650093，Chi-na ）．Cailiao Baohu 2013，46（02），07 09（Ch ）．Hot -dip gal-vanizing coating was prepared by introducing rare earth salt into the fluxing agent．The morphology and microstructure of as -pre-pared hot-dip galvanizing coating were observed with a metallurgi-cal microscope and a scanning electron microscope．The corrosion resistance of as -prepared galvanizing coating was evaluated by conducting total immersion corrosion tests with an electrochemical test rig．Furthermore ，the effect of the content of the rare earth salt in the fluxing agent on the microstructure and corrosion resist-ance of as-prepared galvanizing coating was investigated．Results showed that introducing rare earth salt into the fluxing agent helped to reduce the thickness of the galvanizing coating ，improve its microstructure ，and inhibit the growth of brittle ζphase there-by affording galvanizing coating mainly consisting of δphase．In the meantime ，introducing rare earth salt also contributed to the improvement of corrosion resistance of galvanizing coating ，and the corrosion resistance of the galvanizing coating rose with in-creasing content of the rare earth salt．Particularly ，the galvani-zing coating obtained at a rare earth salt content of 0．2%had the best corrosion resistance ，and further increase in the content of the rare earth salt led to worsening in the corrosion resistance of the galvanizing coating．Key words ：hot -dip galvanizing ；coating ；fluxing agent ；rare earth salt ；microstructure ；corrosion resistance Effect of Rare Earth on Microstructure as well as Wea …… 此处隐藏：5365字，全部文档内容请下载后查看。喜欢就下载吧 ……