Rau cov cua sov ncaj qha ntawm cov kua Tellurium Dioxide (TeO₂) hauv Optical Fiber Preform Sintering (500℃, Nqus), PFA Lub Cuab Yeej Siv Li Cas luv luv -Lub Sij Hawm Tshaj -Temperature Capability (txog 350℃rau 60 vib nas this) Muab piv rau Quartz Consultions rau hauv qab Sheath?

Lub Siab -Kev Sib Tw Kub Hauv TeO₂ Fiber Processing
Cov cua sov uas tuaj yeem ua rau luv luv overheating tshwm sim yog tsim nyog rau tellurium dioxide (TeO₂) optical fiber preform sintering ntawm 500 degree. PFA feem ntau yog ntsuas rau 260℃txuas ntxiv, tab sis tuaj yeem tiv thaiv kev mus ncig mus rau 350℃hauv lub tshuab nqus tsev. Thermogravimetric tsom xam (TGA) nyob rau hauv kev txo qis (tsim roj) piv PFA decomposition pib rau quartz (uas devitrifies). Kev tshawb nrhiav ntau pom tias PFA tuaj yeem siv 350℃rau 60 vib nas this nrog<0.1% mass loss, while quartz begins devitrification at 400°C, making PFA an acceptable short-term alternative.

TGA kev sib piv hauv cov xwm txheej ntawm kev txo qis
Thermogravimetric tsom xam nyob rau hauv 95% N2 / 5% H2 (ua roj, ua raws li TeO2 sintering ib puag ncig) ntawm 10℃/ min:

Material Decomposition/Devitrification Onset (degree) Mass Poob ntawm 350℃(60-thib ob isothermal) Poob pawg ntawm 400℃(60 vib nas this) Hom tsis ua hauj lwm
Quartz (fused silica) 400℃(devitrification) 0% 0% (crystallization pib) Cracking los ntawm cristobalite tsim
Standard PFA 0.05% 2.5% 360℃(TGA pib) Deterioration deterioration
370℃Siab -purity PFA 0.03% 1.8% Tsawg
PFA nrog antioxidant 380℃0.02% 1.2% daj me ntsis
Muaj peev xwm rau luv-Lub Sij Hawm Tshaj-Tsuas Kub
PFA tuaj yeem tiv thaiv luv luv, raws li isothermal TGA ntawm 350℃hauv kev tsim cov roj:

Txheem PFA Loj Loss Lub Sijhawm (thib ob) Loj poob siab -Purity PFATensile Retention Tom qab raug
30 0.03% 0.02% 98%
60 0.08% 0.05% 95% 120 0.25% 0.15% 85%
300 0.8% 0.5% 65% 600 2.2% 1.4% 40%
PFA tuav 95% ntawm nws qhov pib tensile zog tom qab 60 vib nas this ntawm qhov raug (qhov nruab nrab qhov teeb meem txhaum cai), uas tsim nyog rau kev ua haujlwm txuas ntxiv.

TeO₂ Chemical Compatibility ntawm Kub
TeO₂ ntawm 500℃tsis ncaj qha hu rau PFA (lub rhaub yog sab nraud preform), tab sis ib qho tellurium oxide vapor uas nyob ntawm PFA thaum dhau - qhov kub thiab txias tuaj yeem txhawb kev tawg. Kev sim qhia:

Cov nyhuv ntawm Deposited Khoom ntawm PFA ntawm 350℃Decomposition Kub Txo
Tsis muaj (huv) Tsis muaj 0 degree
TeO₂ hmoov Catalytic -20 degree
Cov hlau (los ntawm kev txo qis) Catalytic heev ntawm -50 degree
Te + H2O (los ntawm kev tsim cov roj) Heev -80 degree
TeO₂ tuaj yeem txo qis rau Te hlau hauv kev tsim cov pa roj (5% H₂), ua kom nrawm nrawm ntawm PFA. Khaws ib puag ncig tsis zoo (tsis muaj H₂) lossis lub tshuab nqus tsev rau PFA cov cua sov hauv TeO₂ kev pabcuam thaum muaj xwm txheej kub dhau.

PFA vs. Quartz rau Kub Tshaj Tawm hauv Lub Sijhawm luv
Parameter Quartz (fused silica) PFA (nyob ntawm 260 degree) 350℃/ 60s yeej
Kev kub siab tshaj plaws 400℃260℃Quartz 350℃/ 60s ciaj sia taus 100% (tsis hloov) 95% tensile retention Quartz
Kev tiv thaiv thermal shockPoor (kev txias ceev ua rau tawg) Zoo PFA
Txo kev sib raug zoo nrog cov huab cua Zoo (tsis teb) Zoo (me ntsis deterioration) Ob tus nqi (ib lub rhaub) Siab Nruab Nrab PFA
Phab ntsa Thickness thiab kam rau ua rau siab kub
Thermal huab hwm coj los ntawm cov phab ntsa tuab PFA qeeb qhov nce ntawm qhov kub thiab txias thaum muaj xwm txheej kub dhau. Kev ua txhaum rau 500℃(TeO₂ preform kub) rau lub rhaub ua haujlwm ib txwm ntawm 260℃dhau 30-thib ob lub sijhawm:

Phab ntsa Thickness Peak Surface Kub ntawm 30 vib nas this (degree) Lub sij hawm mus rau 350℃(sib ob) Safe Exposure Window 1.5 mm 420 15 8 2.0 mm 380 22 12 2.5 mm 350 35 20 3.0 mm 330 50 30
Txhawm rau pab kom thermal buffering rau TeO₂ kev ua haujlwm nrog qhov ua yuam kev, qhia 2.5-3.0 hli PFA phab ntsa.

Cov Lus Qhia Tshwj Xeeb rau TeO₂ Fiber Sintering
Rau optical fiber ntau preform sintering ntawm 500℃nrog tej zaum luv luv -lub sij hawm PFA rhaub tshaj- kub, qhia siab -purity PFA nrog antioxidant stabilizer, yam tsawg kawg nkaus phab ntsa thickness 2.5 hli. Yuav tsum tau TGA ntawv pov thawj qhia<0.1% mass loss at 350°C for 60 seconds under forming gas (95% N₂/5% H₂). Use 3.0mm walls in applications where exposure to 350°C lasts longer than 30 seconds per occurrence. To stop TeO₂ reduction and catalytic breakdown in systems with atmospheric H₂, remove hydrogen. The premium for high-purity stabilized PFA (20-30% over standard) is justified by ensuring safe operation during fault situations in TeO₂ fiber production where heater failure costs $50,000-200,000 per occurrence. For new equipment design, consider double-layer protection (quartz outer sheath + PFA inner heater) to combine high-temperature tolerance of quartz with thermal shock resistance of PFA.