Ntev- lub sijhawm khaws cia (5 xyoos) ntawm PFA cov cua sov hauv lub tsev khaws khoom kub (30–40℃, 70–95% RH) ua rau ntsuas tau tab sis feem ntau lees txais kev degradation ntawm cov khoom siv tshuab. Lub zog tensile txo los ntawm 5-10%, elongation ntawm tawg poob los ntawm 10-20%, thiab nto hardness nce los ntawm 2-5 Shore D. Thawj degradation mechanisms yog noo noo nqus (0.1-0.3% los ntawm qhov hnyav) thiab qeeb oxidation ntawm siab kub. Tsis muaj cracking lossis embrittlement tshwm sim tshwj tsis yog tias lub tshuab cua sov tau raug UV teeb (hnub ci los ntawm qhov rais) lossis tshuaj lom neeg (ze chlorine lossis acid cia). Tom qab 5 xyoos ntawm qhov chaw sov sov, lub tshuab cua sov PFA tseem siv tau rau feem ntau cov ntawv thov kev lag luam, tab sis nws yuav tsum tau qhuav (lub tshuab nqus tsev ci - tawm ntawm 50℃, 24 teev) kom rov ua kom cov rwb thaiv tsev. Rau cov ntawv thov tseem ceeb (semiconductor, tshuaj), lub neej cia yuav tsum txwv rau 2-3 xyoos.
Cov khoom hloov pauv tom qab 5 xyoos Kev Tiv Thaiv Kab Mob Hlwb (35 degree, 85% RH, tsis muaj UV)
| Khoom | Lub rhaub dej tshiab | Tom qab 5 Xyoo Cia | Hloov pauv (%) | Txais siv tau? |
|---|---|---|---|---|
| Tensile zog (MPa) | 28 | 25–27 | –5–10% | Yog lawm |
| Elongation ntawm tawg (%) | 320 | 260–300 | –10–20% | Yog lawm |
| Hardness (Shore D) | 66 | 68–71 | +2–5 | Yog lawm |
| Kev nqus dej (%) | 0.02 | 0.12–0.25 | +0.1–0.2% | Txais tau (qhuav ua ntej siv) |
| Rwb thaiv tsev tsis kam (MΩ) | >1,000 | 100-500 (vim noo noo) | Txo | Restorable los ntawm ziab |
| Dielectric zog (kV / mm) | 18 | 16–18 | 0–10% | Yog lawm |
| Kub siab (bar) | 45 | 40–43 | –5–10% | Yog lawm |
Degradation Mechanisms nyob rau hauv Tropical Storage
| Mechanism | Ua rau | Qhov cuam tshuam rau PFA | Qhov hnyav |
|---|---|---|---|
| Kev nqus dej noo | Cov av noo siab (85% RH) | Plasticization (ib ntus), txo IR | Mild (rov qab los ntawm ziab) |
| Hydrolysis ntawm cov pab pawg kawg | Dej + cua sov (40 degree) | Chain scission, txo lub zog | Tsawg (5-10% poob) |
| Oxidation | Cua + cua sov | Deg hardening, discoloration | Yooj yim (daj) |
| UV degradation (yog tias raug) | Hnub ci ntawm qhov rais | Deg cracking, embrittlement | Severe (tsis lees paub) |
| Tshuaj tua kab mob (ze HCl, Cl₂) | Cov pa taws los ntawm cov tshuaj uas khaws cia | Deg etching, tawg | Nruab nrab mus rau hnyav |
| Creep (yog tias khaws cia hauv load) | Cua sov stacked nyob rau hauv hnyav | Permanent deformation | Avoidable (khoom upright) |
Restoration Procedure Tom qab Ntev - Lub Sij Hawm Cia
Before installing a heater stored for >2 xyoos nyob rau hauv tropical tej yam kev mob:
Qhuav lub rhaub: Lub tshuab nqus tsev ci - tawm ntawm 50℃, 1 mbar, 24 teev (saib Tshooj #69). Xwb, qhov cub qhuav ntawm 80℃rau 48 teev (tsis muaj lub tshuab nqus tsev).
Ntsuas cov rwb thaiv tsev tiv thaiv (500 V DC). Accept if >100 MΩ.
Tshawb pom qhov muag: Saib daj, dawb hmoov (bloom), nto tawg. Yog tias muaj kab nrib pleb, tsis lees txais.
Ua ib qho kev kuaj hipot(1,500 VAC rau 1 feeb). Yog tias kis tau, lub tshuab rhaub muaj kev nyab xeeb rau kev siv.
Ntsuas lub siab tawg (destructive, sample only). If >35 bar (rau 2 hli phab ntsa), txais.
Cov lus pom zoo khaws cia rau huab cua sov
| Kev cia khoom | Pom zoo Max Duration | Ntim | Sau ntawv |
|---|---|---|---|
| Muab ntim rau hauv lub hnab ntawv nrog desiccant | 5-7 xyoo | Nqus - kaw, 10 g silica gel | Qhov zoo tshaj plaws (tsawg kawg degradation) |
| Lub hnab yas kaw (tsis muaj desiccant) | 2-3 xyoos | Polyethylene hnab, khi | Txais tau |
| Qhib txee, cua -conditioned (25 degree, 50% RH) | 3-5 xyoos | Tsis muaj | Zoo |
| Qhib txee, tropical (35 degree, 85% RH) | 1-2 xyoos | Tsis muaj | Marginal; ziab kom qhuav |
| Qhib txee, nrog UV raug | <6 months | Tsis muaj | Tsis txhob khaws cia rau hauv tshav ntuj |
Piv txwv teb
Cov nroj tsuag tshuaj tau khaws 20 PFA lub tso cua sov hauv lub tsev khaws khoom kub (Singapore, 32 degree, 85% RH) rau 5 xyoos. Thaum qhib, cov cua sov tau daj me ntsis thiab muaj kev tiv thaiv kev tiv thaiv ntawm 50-200 MΩ. Lub tshuab nqus tsev vacuum ci lawv ntawm 50℃rau 24 teev. IR nce mus txog 300-800 MΩ. Cov cua sov tau muab tso rau hauv 80℃dej tso tsheb hlau luam. Tom qab 2 xyoos ntawm kev pabcuam, tsis muaj qhov ua tsis tiav ntxov tshwm sim piv rau cov cua sov tshiab. Cov nroj tsuag tam sim no khaws cov cua sov hauv cov hnab ntim cov ntawv ntim nrog cov khoom siv desiccant, txwv kev cia rau 3 xyoos.
Thaum Tsis Muaj Cov Cuab Yeej Cuab Yeej
Pom pom qhov tawg (txhua qhov ntev) - tsis lees paub
Cov hmoov dawb uas tsis so (hydrolysis) - tsis kam yog hnyav
Tsaus xim av lossis xim dub (oxidation) - tsis lees paub
Rwb thaiv tsev tsis kam<10 MΩ after drying – reject (moisture has caused corrosion)
Ib qho blistering lossis delamination - tsis lees paub
Cov ntsiab lus: Tshav kub cia rau 5 xyoos yog txais tau nrog ziab
Ntev- lub sij hawm cia (5 xyoos) ntawm PFA cov cua sov hauv lub tsev khaws khoom kub (30-40℃, 85% RH) ua rau me me degradation: tensile zog poob 5-10%, elongation poob 10-20%, thiab noo noo absorbs txo cov rwb thaiv tsev tsis kam. Tom qab lub tshuab nqus tsev ci -tawm (50 degree, 24 teev), cov cua sov siv tau rau feem ntau cov ntawv thov. Rau cov ntawv thov tseem ceeb (semiconductor, kws tshuaj), txwv kev cia rau 2-3 xyoos lossis khaws cia rau hauv lub hnab ntim khoom ntim. Lub tshuab cua sov tsis rot, tab sis nws muaj hnub nyoog. Moisture yog tus yeeb ncuab; ziab yog qhov kho. Kev khaws cia tsis tas mus li; 5 xyoo yog qhov txwv. Tshawb xyuas, qhuav, sim, thiab siv. Koj lub rhaub yuav laus dua, tab sis nws tsis tuag. Kho kom raug, thiab nws yuav sov. Nyob rau hauv lub tropics, lub hnub thiab av noo coj lawv tus xov tooj hu. Tab sis PFA yog qhov nyuaj. Tsib xyoos hauv hav zoov, nws tseem ua haujlwm. Qhuav nws, sim nws, ntseeg nws. Los yog yuav tshiab. Koj hu.
