1. Thermal Stress thaum lub sij hawm txias (Piv txwv li)
Fused quartz ua rau muaj kev ntxhov siab nyob rau hauv cov xwm txheej tsis sib xws. Nyob rau ntawm txhua qhov ntsuas kub, cov qauv atomic ntawm fused quartz ncav cuag qhov "zoo" spatial configuration. Raws li qhov kub hloov pauv, atomic qhov sib txawv hloov raws li qhov tshwm sim - ib qho tshwm sim feem ntau hu ua thermal expansion. Thaum fused quartz tsis sib npaug los yog txias, qhov tsis sib xws tshwm sim.
Kev ntxhov siab kub feem ntau tshwm sim thaum cov cheeb tsam kub kub sim nthuav tab sis raug txwv los ntawm cov cheeb tsam txias dua. Qhov no tsim compressive kev nyuaj siab, uas feem ntau tsis ua kev puas tsuaj. Yog tias qhov kub thiab txias txaus los ua kom lub khob muag muag, qhov kev ntxhov siab tuaj yeem txo tau. Txawm li cas los xij, yog tias qhov txias txias nrawm dhau, qhov viscosity nce nrawm, thiab cov qauv atomic sab hauv tsis tuaj yeem hloov kho lub sijhawm rau qhov txo qis. Qhov no ua rau muaj kev ntxhov siab tensile, uas feem ntau yuav ua rau tawg lossis ua tsis tiav.
Xws li kev ntxhov siab hnyav zuj zus raws li qhov kub thiab txias, nce mus txog qib siab thaum kawg ntawm cov txheej txheem txias. Qhov kub ntawm lub iav quartz ncav cuag viscosity saum 10^4.6 poise yog hu uastrain point. Nyob rau lub sijhawm no, cov khoom siv viscosity siab heev uas cov kev ntxhov siab sab hauv tuaj yeem ua haujlwm tau zoo thiab tsis tuaj yeem tawg.
2. Kev ntxhov siab los ntawm Kev Hloov Pauv thiab Kev Ua Haujlwm Zoo
Metastable Structural Relaxation:
Nyob rau hauv lub xeev molten, fused quartz qhia txog kev tsis sib haum xeeb atomic heev. Thaum txias, atoms nyiam so mus rau qhov chaw ruaj khov dua. Txawm li cas los xij, lub siab viscosity ntawm lub xeev glassy cuam tshuam atomic zog, uas ua rau lub cev metastable sab hauv thiab tsim kom muaj kev ntxhov siab. Nyob rau tib lub sijhawm, qhov kev ntxhov siab no yuav maj mam tso tawm, qhov tshwm sim hu uaiav aging.
Crystallization Tendency:
Yog hais tias fused quartz nyob rau hauv tej qhov kub thiab txias (xws li nyob ze ntawm qhov kub ntawm crystallization) rau lub sij hawm ntev, microcrystallization yuav tshwm sim - piv txwv li, nag lossis daus ntawm cristobalite microcrystals. Lub volumetric mismatch ntawm crystalline thiab amorphous theem tsimtheem hloov kev ntxhov siab.
3. Mechanical Load thiab External Force
1. Kev ntxhov siab los ntawm kev ua:
Mechanical quab yuam siv thaum txiav, sib tsoo, lossis polishing tuaj yeem ua kom pom qhov sib txawv ntawm cov lattice thiab kev ua haujlwm nyuaj. Piv txwv li, thaum lub sij hawm txiav nrog ib tug sib tsoo log, localized tshav kub thiab mechanical siab ntawm ntug induce stress concentration. Cov txheej txheem tsis raug hauv kev drilling lossis slotting tuaj yeem ua rau muaj kev ntxhov siab ntawm qhov tsis zoo, ua haujlwm ua cov ntsiab lus tawg.
2. Kev ntxhov siab los ntawm Cov Kev Pabcuam:
Thaum siv los ua cov khoom siv, fused quartz tuaj yeem ntsib kev ntxhov siab vim yog cov khoom siv xws li siab lossis khoov. Piv txwv li, quartz glassware tuaj yeem txhim kho kev nyuaj siab thaum tuav cov ntsiab lus hnyav.
4. Thermal Shock thiab ceev ceev kub hloov
1. Instantaneous Stress los ntawm cua sov / txias:
Txawm hais tias fused quartz muaj qhov thermal expansion coefficient (~ 0.5 × 10⁻⁶ / ° C), qhov kub thiab txias hloov pauv sai (xws li, cua sov los ntawm chav tsev kub mus rau qhov kub siab, lossis immersion hauv dej khov) tseem tuaj yeem ua rau qhov kub thiab txias gradients. Cov gradients no ua rau muaj thermal expansion lossis contraction, ua rau muaj kev ntxhov siab sai sai. Ib qho piv txwv zoo yog kuaj quartzware fracturing vim thermal shock.
2. Cyclic Thermal Fatigue:
Thaum raug rau lub sij hawm ntev, rov hloov qhov kub thiab txias-xws li hauv qhov cub hauv ob sab phlu los yog qhov kub kub saib qhov rais-fused quartz undergoes cyclic expansion thiab contraction. Qhov no ua rau qaug zog kev ntxhov siab, ua rau kom muaj kev laus thiab muaj kev pheej hmoo ntawm kev tawg.
5. Chemically Induced Stress
1. Corrosion thiab Dissolution Stress:
Thaum fused quartz los rau hauv kev sib cuag nrog cov tshuaj alkaline muaj zog (piv txwv li, NaOH) lossis cov kua qaub kub kub (xws li, HF), nto corrosion thiab dissolution tshwm sim. Qhov no cuam tshuam cov qauv kev sib xws thiab ua rau muaj kev ntxhov siab chemical. Piv txwv li, alkali corrosion tuaj yeem ua rau qhov ntim ntawm qhov chaw hloov pauv lossis tsim microcrack.
2. CVD-Induced Stress:
Chemical Vapor Deposition (CVD) cov txheej txheem uas tso cov txheej txheem (piv txwv li, SiC) mus rau fused quartz tuaj yeem qhia txog kev ntxhov siab cuam tshuam vim qhov sib txawv ntawm thermal expansion coefficients lossis elastic moduli ntawm ob cov ntaub ntawv. Thaum lub caij txias, qhov kev ntxhov siab no tuaj yeem ua rau delamination lossis tawg ntawm cov txheej lossis substrate.
6. Internal Defects thiab impurities
1. Npuas thiab suav nrog:
Residual gas npuas los yog impurities (xws li, metallic ions los yog unmelted hais) qhia thaum lub sij hawm melting yuav pab raws li kev ntxhov siab concentrators. Qhov sib txawv ntawm thermal expansion los yog elasticity ntawm cov inclusions thiab cov iav matrix ua rau muaj kev ntxhov siab hauv zos. Cracks feem ntau pib ntawm cov npoo ntawm cov kev tsis zoo no.
2. Microcracks thiab Structural Flaws:
impurities los yog flaws nyob rau hauv raw khoom los yog los ntawm cov txheej txheem melting yuav ua rau hauv microcracks. Nyob rau hauv cov neeg kho tshuab loads lossis thermal cycling, kev ntxhov siab ntawm cov lus qhia tawg tuaj yeem txhawb kev tawg tawm, txo cov khoom siv.
Lub sij hawm xa tuaj: Plaub Hlis-04-2025