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针对补给水中典型有机物一腐植酸,进行了350℃、10个浓度(0～20 mg/L)下的高压釜分解实验,并进行了350℃、典型浓度7.5 mg/L下间隔时间取样的分解实验,采用离子色谱仪、TOC分析仪测定高温分解后的汽、液相分解样,根据分解产物组分含量,利用电化学及微观表征(SEM,EDS,XRD等)研究了低分子有机酸+杂质离子对汽轮机材质腐蚀行为的影响.结果表明:腐植酸高温分解产物中低分子有机酸主要为乙酸、甲酸,杂质阴离子主要为SO42-,C1-,NO3-,F-4种;其中SO42-,NO3-,Cl-的存在对汽轮机叶片钢的腐蚀有明显的促进作用,但随着F-浓度的增大出现抑制作用.“,”Since the retrofitting of a thermal power unit for heat delivery,correspondingly,the supplied water of boiler significantly increased from ordinary 3％～5％ to above 50％,thereby the conductivity of the water generally exceeded,resulting in serious acid corrosion troubles in low pressure cylinder of the steam turbine.It is known that humic acid is a typical organic substance related with corrosion troubles in the water system,thus the decomposition behavior of humic acid at 350 ℃ was studied in concentration range 0～20 mg/L,while decomposition products specially from the test by 7.5 mg/L of humic acid at different time intervals were extracted for composition determination with ion chromatography and TOC analyzer.Thereafter the effect of low molecular organic acids with impurities on the corrosion behavior of steel 1Cr13 was characterized by means of electrochemical methods as well as SEM,EDS and XRD.The results showed that high temperature decomposition products of humic acid contained low molecular organic acids mainly of acetic acid and formic acid,and impudty ions of SO42-,Cl-,NO3-and F.Obviously,the ions of SO42-,NO3-and Cl-were aggressive to the steel 1Cr13,in the contrary,F-exhibited inhibition effect with the increasing concentration.