Rau PFA (Perfluoroalkoxy) Immersion rhaub siv los tuav 150℃hauv 70% Nitric Acid tov ntawm 5 Bar Siab, Dab tsi yog qhov siab tshaj plaws Tensile Stress los tiv thaiv ib puag ncig kev ntxhov siab tawg ntawm Polymer?
Tso lus
Hauv 70% nitric acid ntawm 150℃thiab 5 bar siab, PFA (perfluoroalkoxy) immersion heaters yuav raug rau ib puag ncig kev ntxhov siab tawg (ESC). Qhov siab tshaj plaws tensile kev nyuaj siab los tiv thaiv ESC yog 2 MPa. Tshaj qhov kev ntxhov siab no, cov kab nrib pleb pib hauv 500-1,000 teev. Qhov chaw pib yog ua raws li cov polymer qhov tseem ceeb ntawm kev ntxhov siab siv zog thiab kev ua phem ntawm ib puag ncig nitric acid.
Mechanism of Environmental Stress Cracking hauv PFA
Nitric acid yog lub zog oxidizer uas tawm tsam cov cheeb tsam amorphous ntawm PFA. Thaum cov polymer nyob rau hauv tensile kev nyuaj siab, cov kua qaub molecules nkag mus rau saum npoo thiab tawg polymer chains ntawm kev ntxhov siab concentration ntsiab lus. Qhov tawg propagation tus nqi yog proportional rau cov kev siv zog. Hauv qab qhov kev ntxhov siab tseem ceeb (2 MPa), qhov kev loj hlob tawg yog qhov tsis zoo rau lub sijhawm ua haujlwm.
Quantitative ESC Initiation Sijhawm raws li Kev Ua Haujlwm ntawm Kev Nyuaj Siab
Kev tswj xyuas hauv 70% HNO₃ ntawm 150℃tau tsim cov hauv qab no rau PFA. Ntawm qhov kev siv zog ntawm 1 MPa, lub sijhawm pib ESC tshaj 10,000 teev, thiab tsis muaj qhov tawg. Ntawm 2 MPa (qhov siab tshaj plaws tau tso cai), lub sijhawm pib yog 5,000-10,000 teev, thiab qhov tawg me me yuav tshwm sim. Ntawm 3 MPa, lub sijhawm pib yog 1,000-2,000 teev, thiab tawg yog nruab nrab. Ntawm 4 MPa, lub sijhawm pib yog 200-500 teev, thiab tawg yog qhov hnyav. Ntawm 5 MPa, lub sijhawm pib yog 50-100 teev, thiab tawg sai sai.
Phau Ntawv Qhia Txog Kev Nyuaj Siab Tshaj Plaws Tshaj Plaws
| Environmental Severity | Qhov siab tshaj plaws tso siab tau (MPa) | Cia siab rau Kev Pabcuam Lub Neej |
|---|---|---|
| 70% HNO₃, 150 degree | 2 | >1 xyoo |
| 70% HNO₃, 120 degree | 3 | >2 xyoo |
| 50% HNO₃, 150 degree | 4 | >3 xyoo |
| 70% H₂SO₄, 150 degree | 5 | >5 xyoo |
Ua ib qho kev qhia tshwj xeeb
Rau PFA immersion rhaub hauv 70% nitric acid ntawm 150 degree, tsim lub tshuab hluav taws xob txhawb nqa kom muaj zog tensile hauv PFA qis dua 2 MPa. Siv kev ntxhov siab-tso tseg mounting thiab zam kev khoov nruj. Los ntawm kev tswj cov kev ntxhov siab, tus engineer tiv thaiv ib puag ncig kev ntxhov siab tawg.
