前郭機械密封的腐蝕類型

　　1.整體腐蝕和局部腐蝕。綜合腐蝕，即與介質接觸的零件表麵發生均勻腐蝕
，其特點是零件重量減輕
，甚至完全腐蝕；失去力量；降低硬度。如1Cr18Ni9Tibuxiugangzhichengdeduodanhuang，zaixiliusuanzhongshiyonghuichuxianzhezhongqingkuang。jubufushikeyijiandanditongguolingjianshangdefushidianhekonglaishibie。jubufushishiduoxianghejinzhongdemouyixianghuodanxianggurongtizhongdemouyiyuansubeijiezhixuanzexingrongjiedefushixingshi。rugujiyingzhihejinzaigaowenqiangjiantiaojianxiashiyong，zhanjiexiangjinshugurongyibeifushi
，yingzhixiangtanhuawugujiashiquqiangdu，zaijixielidezuoyongxiadaozhijingliboluo。zuoweilingyigelizi，youyuyouliguidefushi，fanyingshaojietanhuaguidebiaomianxianshimadian(PH>10時).
　　fushiduimifengjiandexingnengyouhendayingxiang。youyumifengbizhujidelingjiangengxiao，jingdugenggao，suoyitongchangxuanzebizhujimifengnaifushidecailiao。duiyuyujiezhizhijiejiechudemifengjian，kecankaoxiangguanfushishoucezhongdeshujuxuanzeheshidecailiao。raner，zhexieshujukenengyu前郭機械密封係統中使用的條件不一致，因為它們大多是靜態條件下的腐蝕數據，並且工藝流程中的介質包含雜質或二次化合物。經驗表明，壓力、溫度和滑動速度都會加速腐蝕。隨著溫度的升高，密封件的腐蝕速率呈指數增長。
　　在zai處chu理li強qiang腐fu蝕shi性xing流liu體ti時shi

，采cai用yong外wai密mi封feng或huo雙shuang端duan密mi封feng可ke以yi最zui大da限xian度du地di減jian少shao腐fu蝕shi對dui密mi封feng的de影ying響xiang，因yin為wei它ta與yu工gong藝yi流liu體ti接jie觸chu的de零ling件jian數shu量liang最zui少shao。這zhe也ye是shi在zai強qiang腐fu蝕shi條tiao件jian下xia選xuan擇ze密mi封feng結jie構gou最zui古gu老lao的de窯yao理li之zhi一yi。
　　2.應力腐蝕。應力腐蝕是金屬材料在應力作用下在腐蝕環境中的腐蝕現象。無論是外載荷還是殘餘應力，都會加劇腐蝕。奧氏體不鏽鋼、銅tong合he金jin等deng。容rong易yi產chan生sheng應ying力li腐fu蝕shi。在zai應ying力li腐fu蝕shi過guo程cheng中zhong
，一yi般ban在zai金jin屬shu表biao麵mian形xing成cheng選xuan擇ze性xing腐fu蝕shi槽cao

，然ran後hou繼ji續xu局ju部bu腐fu蝕shi，最zui後hou在zai應ying力li作zuo用yong下xia從cong槽cao底di產chan生sheng裂lie紋wen。典dian型xing的de例li子zi是shi104型前郭機械密封的傳動套筒
，由1Cr18Ni9Tizhicheng。zaianshuibengzhongshiyongshi，chuandongtaotongdechuandongerhuanzuirongyichanshengyinglifushiliewen
，congersunhuaierhuan。suoyibaaoerdinghuanchengshixinerpiankeyifangzhizhezhongyinglifushi。
　　3.介jie質zhi腐fu蝕shi。密mi封feng件jian和he流liu體ti之zhi間jian的de高gao速su運yun動dong導dao致zhi接jie觸chu表biao麵mian上shang的de微wei小xiao不bu均jun勻yun。當dang流liu體ti為wei腐fu蝕shi性xing介jie質zhi時shi，會hui加jia速su密mi封feng接jie觸chu麵mian的de化hua學xue反fan應ying

，有you時shi有you益yi，有you時shi有you害hai。如ru果guo形xing成cheng的de氧yang化hua層ceng被bei破po壞huai，就jiu會hui發fa生sheng腐fu蝕shi。磨mo損sun和he磨mo蝕shi交jiao替ti作zuo用yong對dui材cai料liao造zao成cheng的de損sun傷shang稱cheng為wei磨mo蝕shi。通tong常chang，磨mo損sun對dui前郭機械密封的非主要部件造成的損壞
，如彈簧座、推環、huanzuodeng。bingbunengxunsufanyingmifengxingnengdebianhua，danqueshimocafushixiaodezhuyaoxingshizhiyi。yinci，zaiqiangtidefushijiezhizhong
，mocafuyingyounaifushixinghaodecailiaozhicheng。liru
，shiyong99.5%高純度氧化鋁陶瓷或不含遊離矽的熱壓燒結碳化矽。
　　4.jianxifushi。dangjiezhichuyujinshuyujinshuhuofeijinshugoujianzhijian

，qiecunzaixiaojianxishi，youyujiezhichuyutingzhizhuangtai，jianxineijinshudefushihuijiasu

，zhezhongxianxiangchengweijianxifushi。liru前郭機械密封彈簧座與軸之間的溝槽或衝蝕點，補償環輔助密封環與軸之間的溝槽或衝蝕點(這裏當然有微動磨損)就jiu是shi典dian型xing的de例li子zi。原yuan因yin是shi接jie頭tou內nei的de介jie質zhi處chu於yu停ting滯zhi狀zhuang態tai，使shi得de參can與yu腐fu蝕shi反fan應ying的de物wu質zhi難nan以yi加jia入ru接jie頭tou內nei
，接jie頭tou內nei的de腐fu蝕shi產chan物wu難nan以yi向xiang外wai擴kuo散san。隨sui著zhe腐fu蝕shi的de進jin行xing，接jie頭tou中zhong的de介jie質zhi在zai成cheng分fen濃nong度du和hePH值zhi上shang與yu整zheng個ge介jie質zhi越yue來lai越yue不bu同tong

，導dao致zhi接jie頭tou中zhong金jin屬shu表biao麵mian的de腐fu蝕shi加jia劇ju。間jian隙xi腐fu蝕shi對dui密mi封feng性xing能neng非fei常chang有you害hai。密mi封feng圈quan與yu雙shuang軸zhou之zhi間jian的de凹ao槽cao會hui導dao致zhi補bu償chang環huan無wu法fa軸zhou向xiang位wei移yi
，失shi去qu隨sui動dong性xing，導dao致zhi端duan麵mian分fen離li和he泄xie漏lou。間jian隙xi腐fu蝕shi通tong常chang可ke以yi通tong過guo適shi當dang的de材cai料liao選xuan擇ze和he合he理li的de結jie構gou設she計ji來lai緩huan解jie。比bi如ru選xuan擇ze抗kang間jian隙xi腐fu蝕shi性xing能neng好hao的de材cai料liao；zaijiegoushejizhong，yingjinkenengbimianyetijijudejianxihesiqu。caiyongzichongxixunhuan

，shimifengqiangneidejiezhichuyubuduangenghuanheliudongdezhuangtai，fangzhijiezhichengfendenongdubianhua；對(dui)於(yu)長(chang)期(qi)停(ting)用(yong)的(de)泵(beng)，應(ying)及(ji)時(shi)排(pai)出(chu)積(ji)聚(ju)的(de)液(ye)體(ti)等(deng)。不(bu)可(ke)能(neng)完(wan)全(quan)消(xiao)除(chu)結(jie)構(gou)上(shang)的(de)差(cha)距(ju)。所(suo)以(yi)一(yi)般(ban)采(cai)用(yong)防(fang)護(hu)軸(zhou)承(cheng)
，可(ke)以(yi)在(zai)密(mi)封(feng)圈(quan)安(an)裝(zhuang)部(bu)位(wei)噴(pen)塗(tu)耐(nai)腐(fu)蝕(shi)材(cai)料(liao)來(lai)防(fang)止(zhi)。
　　5.電化學腐蝕。事實上，前郭機械密封的各種腐蝕形式或多或少都與銅的電化學腐蝕有關。就前郭機械密封摩mo擦ca副fu而er言yan，它ta們men經jing常chang受shou到dao電dian化hua學xue腐fu蝕shi的de損sun害hai，因yin為wei摩mo擦ca副fu中zhong通tong常chang使shi用yong不bu同tong的de材cai料liao。當dang它ta們men處chu於yu電dian解jie質zhi溶rong液ye中zhong時shi，不bu同tong材cai料liao接jie觸chu時shi會hui出chu現xian點dian耦ou合he效xiao應ying，即ji一yi種zhong材cai料liao的de腐fu蝕shi得de到dao促cu進jin，另ling一yi種zhong材cai料liao的de腐fu蝕shi得de到dao抑yi製zhi。例li如ru
，當dang銅tong和he鎳nie鉻ge鋼gang用yong於yu氧yang化hua介jie質zhi時shi
，鎳nie鎘ge鋼gang被bei電dian離li和he分fen解jie。鹽yan水shui
、海水、稀鹽酸、稀硫酸等。都是典型的電解質溶液，密封件容易發生電化學腐蝕。所以最好選擇材料或者電位相近的陶瓷，以及玻璃纖維填充的PTFE。