牡丹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1Cr18Ni9Ti不(bu)鏽(xiu)鋼(gang)製(zhi)成(cheng)的(de)多(duo)彈(dan)簧(huang)，在(zai)稀(xi)硫(liu)酸(suan)中(zhong)使(shi)用(yong)會(hui)出(chu)現(xian)這(zhe)種(zhong)情(qing)況(kuang)。局(ju)部(bu)腐(fu)蝕(shi)可(ke)以(yi)簡(jian)單(dan)地(di)通(tong)過(guo)零(ling)件(jian)上(shang)的(de)腐(fu)蝕(shi)點(dian)和(he)孔(kong)來(lai)識(shi)別(bie)。局(ju)部(bu)腐(fu)蝕(shi)是(shi)多(duo)相(xiang)合(he)金(jin)中(zhong)的(de)某(mou)一(yi)相(xiang)或(huo)單(dan)相(xiang)固(gu)溶(rong)體(ti)中(zhong)的(de)某(mou)一(yi)元(yuan)素(su)被(bei)介(jie)質(zhi)選(xuan)擇(ze)性(xing)溶(rong)解(jie)的(de)腐(fu)蝕(shi)形(xing)式(shi)。如(ru)鈷(gu)基(ji)硬(ying)質(zhi)合(he)金(jin)在(zai)高(gao)溫(wen)強(qiang)堿(jian)條(tiao)件(jian)下(xia)使(shi)用(yong)
，粘(zhan)結(jie)相(xiang)金(jin)屬(shu)鈷(gu)容(rong)易(yi)被(bei)腐(fu)蝕(shi)

，硬(ying)質(zhi)相(xiang)碳(tan)化(hua)鎢(wu)骨(gu)架(jia)失(shi)去(qu)強(qiang)度(du)
，在(zai)機(ji)械(xie)力(li)的(de)作(zuo)用(yong)下(xia)導(dao)致(zhi)晶(jing)粒(li)剝(bo)落(luo)。作(zuo)為(wei)另(ling)一(yi)個(ge)例(li)子(zi)，由(you)於(yu)遊(you)離(li)矽(gui)的(de)腐(fu)蝕(shi)，反(fan)應(ying)燒(shao)結(jie)碳(tan)化(hua)矽(gui)的(de)表(biao)麵(mian)顯(xian)示(shi)麻(ma)點(dian)(PH>10時).
　　fushiduimifengjiandexingnengyouhendayingxiang。youyumifengbizhujidelingjiangengxiao
，jingdugenggao
，suoyitongchangxuanzebizhujimifengnaifushidecailiao。duiyuyujiezhizhijiejiechudemifengjian
，kecankaoxiangguanfushishoucezhongdeshujuxuanzeheshidecailiao。raner
，zhexieshujukenengyu牡丹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型牡丹機械密封的傳動套筒，由1Cr18Ni9Ti製zhi成cheng。在zai氨an水shui泵beng中zhong使shi用yong時shi
，傳chuan動dong套tao筒tong的de傳chuan動dong耳er環huan最zui容rong易yi產chan生sheng應ying力li腐fu蝕shi裂lie紋wen，從cong而er損sun壞huai耳er環huan。所suo以yi把ba凹ao耳er釘ding換huan成cheng實shi心xin耳er片pian可ke以yi防fang止zhi這zhe種zhong應ying力li腐fu蝕shi。
　　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牡丹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.間jian隙xi腐fu蝕shi。當dang介jie質zhi處chu於yu金jin屬shu與yu金jin屬shu或huo非fei金jin屬shu構gou件jian之zhi間jian，且qie存cun在zai小xiao間jian隙xi時shi，由you於yu介jie質zhi處chu於yu停ting滯zhi狀zhuang態tai，間jian隙xi內nei金jin屬shu的de腐fu蝕shi會hui加jia速su，這zhe種zhong現xian象xiang稱cheng為wei間jian隙xi腐fu蝕shi。例li如ru牡丹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)jiushidianxingdelizi。yuanyinshijietouneidejiezhichuyutingzhizhuangtai，shidecanyufushifanyingdewuzhinanyijiarujietounei，jietouneidefushichanwunanyixiangwaikuosan。suizhefushidejinxing
，jietouzhongdejiezhizaichengfennongduhePHzhishangyuzhenggejiezhiyuelaiyuebutong
，daozhijietouzhongjinshubiaomiandefushijiaju。jianxifushiduimifengxingnengfeichangyouhai。mifengquanyushuangzhouzhijiandeaocaohuidaozhibuchanghuanwufazhouxiangweiyi

，shiqusuidongxing
，daozhiduanmianfenlihexielou。jianxifushitongchangkeyitongguoshidangdecailiaoxuanzehehelidejiegoushejilaihuanjie。biruxuanzekangjianxifushixingnenghaodecailiao；zaijiegoushejizhong，yingjinkenengbimianyetijijudejianxihesiqu。caiyongzichongxixunhuan
，shimifengqiangneidejiezhichuyubuduangenghuanheliudongdezhuangtai，fangzhijiezhichengfendenongdubianhua
；duiyuchangqitingyongdebeng，yingjishipaichujijudeyetideng。bukenengwanquanxiaochujiegoushangdechaju。suoyiyibancaiyongfanghuzhoucheng，keyizaimifengquananzhuangbuweipentunaifushicailiaolaifangzhi。
　　5.電化學腐蝕。事實上，牡丹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。就牡丹機械密封摩(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。