Titanium immersion heaters yog dav siv rau acidic txheej txheem cua sov vim muaj zog titanium dioxide passive zaj duab xis. Kev saib xyuas corrosion feem ntau tsom rau pom pitting thiab crevice nres, thaum saib xyuas hydrogen absorption thaum cathodic polarization lossis galvanic coupling. Hauv cov tshuaj acidic, hydrogen ions txo ntawm titanium nto thiab atomic hydrogen diffuses rau hauv cov hlau lattice. Absorbed hydrogen reacts nrog titanium los tsim titanium hydride theem hauv qab ntawm qhov chaw. Cov khaubncaws sab nraud povtseg no txo cov ductility thiab tuaj yeem tawg nyob rau hauv thermal lossis mechanical stress, ua rau lub tshuab hluav taws xob tsis zoo.
Hydrogen embrittlement nce mus txog theem subsurface transformation. Atomic hydrogen generated ntawm lub cathode nkag mus rau hauv zaj duab xis passive thiab nkag mus rau hauv titanium matrix. Nws ua ke nrog titanium los tsim TiH₂ precipitates raws lis ciam teb thiab ze ntawm qhov chaw. Hydride theem yog nkig ntau dua li lub hauv paus titanium alloy. Tsis zoo li cov txheej saum npoo corrosion, hydrogen kev puas tsuaj accumulates sab hauv yam tsis muaj cov khoom siv sab nraud. Lub tshuab rhaub cua sov tuaj yeem khaws cov xim zoo nkauj zoo nkauj thaum cov khoom siv subsurface poob toughness zuj zus.
Hydrogen-induced embrittlement ua rau muaj kev dag ntxias thaum ntxov. Lub titanium nto qhia tsis pom qhov pits, tawg los yog discoloration nyob rau hauv thaum ntxov absorption theem. Tus qauv da dej tshuaj ntsuam xyuas tsis tuaj yeem kuaj xyuas hydrogen uptake los ntawm cov hlau. Kev ntsuas tuab tuab tseem tsis hloov pauv vim tsis muaj cov khoom raug tshem tawm. Thaum hydride concentration nce mus txog qhov tseem ceeb, me me thermal cycling los yog mechanical vibration ua rau subsurface cracking, uas propagates rau saum npoo thiab ua rau lub raj rupture. Cov pab pawg tu feem ntau misdiagnose qhov no yog txhua yam qaug zog es tsis yog hydrogen embrittlement.
Ntau qhov kev ntsuas tsim nyog siv tau tuaj yeem txo cov kev pheej hmoo ntawm kev nqus hydrogen. Tsis txhob galvanic coupling ntawm titanium thiab tsawg noble hlau uas yuav ua rau titanium cathodic. Tswj kev khiav hauj lwm muaj peev xwm tiv thaiv ntau dhau cathodic polarization. Siv cov tshuaj oxidation saum npoo los txhim kho cov zaj duab xis passive tiv thaiv hydrogen ingress. Teem caij ib ntus metallographic qauv rau cov cua sov ua haujlwm rau cov acidic ib puag ncig. Rau cov txheej txheem nrog kev tsim cov hydrogen tsis tu ncua, ntsuas cov khoom siv hluav taws xob hloov nrog qis dua hydrogen absorption nyiam.
表格
| Cua sov hom | Cathodic Hydrogen Embrittlement Risk | Core Degradation Mechanism | Thaum ntxov - theem kev kuaj mob | Qhov Tseem Ceeb Mitigation Engineering Measure |
|---|---|---|---|---|
| Titanium | Nruab nrab-High | Atomic hydrogen diffuses mus rau hauv lattice, ua nkig TiH₂ theem thiab txo subsurface toughness | Smooth tsis zoo; Invisible Internal hydride nag lossis daus | Tsis txhob cathodic coupling + nto oxidation + metallographic sampling |
| 316L Stainless hlau | Nruab nrab | Hydrogen tuaj yeem ua rau tawg hauv siab -lub zog stainless hlau, tshwj xeeb tshaj yog ntawm weld HAZ | Subsurface microcracks ze weld seams | Tshaj tawm -weld nyem nyem thiab tswj kev tiv thaiv cathodic |
| PFA-Jacketed | Tsis tsim nyog | Polymer sheath cais hlau los ntawm hydrogen tiam; txaus ntshai tsuas yog tom qab sheath rupture | Maj mam rwb thaiv tsev tsis kam poob thaum txheej tsis tiav | Tiv thaiv kom tsis txhob khawb thiab tswj lub tsho kom ncaj ncees |
| Fused Quartz | Tsis tsim nyog | Inorganic silica tsis nqus hydrogen; kev ua tsis tiav yog devitrification thiab particle yaig | Hloov maj mam milky nto thaj ua rau thaj nyob rau hauv lub kaum sab xis | Alkali impurity tswj thiab zoo pom |
Los xaus, cathodic hydrogen absorption thiab subsurface hydride tsim sawv cev rau ib tug zais txhua yam degradation hom rau titanium immersion heaters nyob rau hauv acidic kev pab cuam. Smooth sab nrauv tsis tuaj yeem txiav txim siab sab hauv embrittlement. Tiv thaiv cathodic polarization thiab ua raws li cov txheej txheem tshuaj ntsuam xyuas metallographic zoo kom tsis txhob muaj hydrogen-induced brittle rupture ntawm titanium cua sov los ua ke.
