Domestic carbon / carbon composites
Suav kev tshawb fawb thiab kev loj hlob ntawm cov pa roj carbon / carbon sib xyaw pib thaum xyoo 1970s, tom qab ntau xyoo ntawm kev loj hlob, tau txais txiaj ntsig zoo, nce mus rau cov teb chaws tsim. Tam sim no, C919 tus nres disc yog ua los ntawm cov pa roj carbon / carbon cov ntaub ntawv ua nyob rau hauv Suav teb. Nws tus neeg muag khoom, Boyun Xinai, kuj muab cov khoom nres rau Boeing 757 thiab Airbus 320 lub dav hlau.
Raws li tus brake disc belongs rau consumables, hais txog ib los yog ob txhiab takeoff thiab tsaws yuav tsum tau hloov, tus nqi ntawm kev siv imported nres disc yog siab dua. Tsav los ntawm kev xav tau ntawm kev lag luam, cov khoom siv hauv tsev tau pib tsim cov dav hlau dav hlau carbon brake discs.
Cov pa roj carbon / carbon composite txheej tau ua kom pom tseeb ntawm kev tshawb fawb hauv tsev thiab txawv teb chaws. Txij li thaum carbon / carbon composites pib oxidize ntawm ib ncig ntawm 370 degrees, cov khoom siv poob qis. Yog li ntawd, nws yog ib qho tsim nyog los npaj cov txheej txheem los tiv thaiv oxidation ntawm qhov chaw thaum nws siv rau hauv ib puag ncig aerobic. Ntxiv rau qhov zoo oxidation tsis kam thiab ablative kuj, lub txheej yuav tsum muaj cov tshuaj zoo thiab lub cev sib xws thiab zoo sib xws expansion coefficient nrog carbon / carbon composites.
Qhov tsis muaj kev sib txhuam ntawm C919 nres disc yog coated nrog boron thiab phosphorus, uas tuaj yeem ncua kev nthuav dav ntawm cov pa hauv cov khoom thiab ua kom lub neej ntev ntawm cov khoom siv nyob rau hauv qhov chaw ua haujlwm kub. Txawm hais tias tus nres nres ib txwm yuav tsum tau hloov tom qab ntau dua 1, 000 tshem tawm thiab tsaws, C919's brake disc tau raug pov thawj muaj peev xwm ntawm 2, 000 takeoffs thiab landings los ntawm kev sim qaug zog.
Ntxiv nrog rau txheej txheej, carbon fiber prefabrication thiab densification txheej txheem kuj tseem muaj feem cuam tshuam rau cov khoom ntawm carbon / carbon composites. Nyob rau hauv txawv teb chaws, preoxidized hlau yog feem ntau siv los braid carbon fiber prefabricated, uas muaj qhov zoo ntawm fiber ntau yooj yooj yim, yooj yim rau kev tsim, tab sis tsis muaj zog. Lub C919 nres discs siv cov organic fibers woven rau hauv carbon fiber preforms, uas yog nyuaj rau weave, tab sis lub resulting preforms muaj zog npaum li cas. Nyob rau tib lub sijhawm, tshuaj lom neeg vapor nkag mus thiab ua kua impregnation tau siv los ua kom muaj zog ntawm cov khoom siv, thiab lub zog loj brake sefficient ntawm cov khoom tau nce heev.
