Old Zhang anakhala ntchito yake yonse ku Aerospace Materials Institute. Asanapume pantchito, nthawi yake yomwe ankakonda kwambiri inali kupita ndi ophunzira ake ku nyumba yosungiramo zinthu kuti akapeze zipangizo. Anamasula chidebe choyera cha pulasitiki chopanda chinyengo, anatenga supuni yodzaza ndi ufa woyera wosalala ndi supuni yoyezera, ndipo pang'onopang'ono anauponya pansi pa kuwala. Fumbi linakhazikika pang'onopang'ono mu kuwala, kunyezimira pang'onopang'ono. "Musanyoze ufa woyera uwu," Old Zhang nthawi zonse ankanena, akusuzumira maso ake. "Kaya ndege ndi maroketi omwe timamanga amatha kupirira zinthu zakuthambo nthawi zina zimadalira mphamvu ya 'ufa' uwu.
“Ufa woyera” umene ankanena unaliufa wa alumina. Zikumveka zachilendo—kodi sizimangokonzedwa kuchokera ku bauxite? Koma ufa wa alumina womwe umagwiritsidwa ntchito mumlengalenga ndi wosiyana kwambiri ndi alumina wamba wa mafakitale. Kuyera kwake kuli pafupifupi ma nine anayi pambuyo pa mfundo ya decimal; kukula kwa tinthu tating'onoting'ono kumayesedwa mu nanometers ndi micrometers; mawonekedwe ake—kaya ndi ma sphere, flakes, kapena singano—zonse zimaganiziridwa mosamala. M'mawu a Lao Zhang, “Ichi ndi chakudya chabwino chomwe 'chimawonjezera calcium' pazida zolemera za dzikolo.”
Ponena za zomwe izi zingachite m'munda wa ndege, pali ntchito zambirimbiri. Tiyeni tiyambe ndi "zolimba kwambiri" - kupereka "zida" za ndege. Kodi mantha akulu a chilichonse chomwe chimauluka mlengalenga ndi ati, kaya ndi ndege ya anthu wamba kapena ndege yankhondo yankhondo? Kutentha kwambiri komanso kuwonongeka. Masamba a injini ya turbine amazungulira mofulumira kwambiri mu mpweya wotulutsa utsi pa madigiri Celsius masauzande ambiri; zitsulo wamba zikanafewa ndikusungunuka kalekale. Chochita? Mainjiniya adabwera ndi yankho labwino kwambiri: kuphimba pamwamba pa tsamba ndi chophimba chapadera cha ceramic. Kapangidwe kake ka chophimba ichi nthawi zambiri ndi ufa wa alumina.
Chifukwa chiyani muyenera kusankha? Choyamba, sichimatentha kwambiri, ndipo kutentha kwake kumapitirira madigiri 2000 Celsius, zomwe zimapangitsa kuti ikhale "suti yotetezera kutentha." Chachiwiri, ndi yolimba komanso yosatha, yoteteza masamba kuti asawonongeke ndi fumbi mumlengalenga wothamanga kwambiri. Chabwinonso, posintha kukula kwa tinthu ta ufa wa alumina ndikuwonjezera zinthu zina, porosity, kulimba, ndi kumamatira ku chitsulo cha pulasitiki ya pulasitikiyo zitha kulamulidwa. Monga momwe wantchito wakale wa workshop adanenera moseka, "Zili ngati kupaka wosanjikiza wa ceramic sunscreen wapamwamba kwambiri pa masamba a turbine—ndizoteteza dzuwa komanso sizimakanda." Kodi "sunscreen iyi ndi yofunika bwanji"? Imalola masamba a turbine kugwira ntchito kutentha kwambiri, ndipo pa madigiri khumi aliwonse kutentha kwa injini kumawonjezeka, kuponderezedwa kumawonjezeka kwambiri, pomwe kugwiritsa ntchito mafuta kumachepa. Kwa ndege zomwe zimauluka makilomita masauzande ambiri, kusunga mafuta ndi kusintha magwiridwe antchito ndizambiri. Ngati chophimba chotchinga kutentha ndi "ntchito yakunja," ndiye kuti ntchito ya ufa wa alumina muzinthu zophatikizika ndi "chowonjezera chamkati."
Ndege zamakono, ma satellite, ndi ma roketi amagwiritsa ntchito kwambiri zinthu zophatikizika kuti achepetse kulemera. Komabe, zinthu zopangidwa ndi utomonizi izi zili ndi kufooka—sizitha kutha, sizimavutika ndi kutentha kwambiri, komanso sizimalimba mokwanira. Asayansi anzeru agwiritsa ntchito ufa wa alumina, makamaka waukulu kwambiri.ufa wa alumina, mofanana mu utomoni, monga mtanda wokanda. Kuphatikizidwa kumeneku kumakhala ndi zotsatira zodabwitsa: kuuma kwa chinthucho, kukana kuwonongeka, kukana kutentha, komanso kukhazikika kwa mawonekedwe ake zonse zimakula kwambiri.
Mwachitsanzo, pansi pa nyumba za ndege, zinthu zina zamkati, komanso ziwalo zina zosanyamula katundu zimagwiritsa ntchito zinthu zopangidwa ndi alumina zomwe zimalimbikitsidwa ndi alumina. Izi sizimangopangitsa kuti zikhale zopepuka komanso zolimba komanso zoletsa, zomwe zimapangitsa kuti chitetezo chikhale cholimba kwambiri. Chipangizo cholondola chomwe chimathandizira pa ma satellite, omwe amafunika kusintha pang'ono pang'onopang'ono kutentha kwambiri, chimathandizanso kwambiri chifukwa cha izi. Zili ngati "kulowetsa" chigoba mu pulasitiki yosinthasintha, ndikuchipatsa mphamvu komanso kusinthasintha.
Ufa wa alumina ulinso ndi "luso lobisika," lofunika kwambiri pa ntchito ya ndege—ndi chinthu chabwino kwambiri choteteza kutentha komanso chosapsa.
Pamene chombo chamlengalenga chilowanso mumlengalenga kuchokera mumlengalenga, zimakhala ngati chikugwera mu ng'anjo ya plasma ya madigiri zikwizikwi. Chipolopolo chakunja cha kapisozi cholowanso chiyenera kukhala ndi gawo losatentha lomwe "limadzipereka lokha kuti likhale labwino kwambiri." Ufa wa alumina umagwira ntchito yofunika kwambiri popanga zinthu zambiri zosatentha. Ukaphatikizidwa ndi zinthu zina, umapanga gawo lolimba, lokhala ndi mabowo, komanso loteteza kwambiri pamwamba. Gawoli limayaka pang'onopang'ono kutentha kwambiri, kunyamula kutentha ndikusunga kutentha kwa chipinda mkati mwa malo opulumukira a astronaut kudzera mukugwiritsa ntchito kwake. "Nthawi iliyonse ndikawona kapisozi yobwerera ikutera bwino, ndipo gawo lakunja la zinthu zosatentha ndi lakuda, ndimaganiza za njira zopangira alumina zomwe timazikonza mobwerezabwereza," adatero mainjiniya wamkulu woyang'anira zinthu zosatentha. "Inayaka, koma ntchito yake inakwaniritsidwa bwino kwambiri."
Kupitilira pa mapulogalamu ovuta awa "otsogola",ufa wa aluminandi chinthu chofunikira kwambiri "kuseri kwa zochitika." Mwachitsanzo, popanga zida zolondola za ndege ndi ma roketi, ma alloy ambiri amphamvu amafunika kusunthidwa. Pakusunthidwa, zida zachitsulo cha ufa ziyenera kuthandizidwa mu ng'anjo yotentha kwambiri pogwiritsa ntchito "shims" kapena "mbale zoyatsira moto." Ma mbale awa ayenera kukhala osatentha, osasinthika, komanso osamamatira ku chinthucho. Ma mbale oyatsira moto opangidwa ndi alumina ceramic yoyera kwambiri amakhala chisankho chabwino kwambiri. Kuphatikiza apo, pogaya ndi kupukuta ziwalo zina zolondola kwambiri, alumina micropowder yoyera kwambiri ndi njira yotetezera komanso yothandiza yopukuta.
Zachidziwikire, chinthu chamtengo wapatali chotere sichingagwiritsidwe ntchito mosasamala. Kodi kuyera kwake n'kokwanira? Kodi kukula kwa tinthu tating'onoting'ono timeneti kumafanana? Kodi pali kusonkhana kulikonse? Kodi kufalikira kwake kuli bwino? Chizindikiro chilichonse chimakhudza momwe chinthu chomaliza chimagwirira ntchito. Mu gawo la ndege, ngakhale cholakwika chochepa kwambiri chingayambitse zotsatirapo zoopsa. Chifukwa chake, kuyambira kusankha zinthu zopangira ndi kusintha njira zogwiritsira ntchito mpaka njira zogwiritsira ntchito, sitepe iliyonse imatsatiridwa ndi miyezo yokhwima komanso yovuta kwambiri.
Mutaimirira mu fakitale yamakono yopangira ndege, mukuyang'ana fuselage yowongoka yomwe ikuwala mozizira pansi pa magetsi, mukuzindikira kuti dongosolo lovutali lomwe likuuluka mumlengalenga ndi zotsatira za zinthu zambiri wamba monga ufa wa alumina, chilichonse chikuchita gawo lake mokwanira. Sichimapanga chimango chachikulu, koma chimalimbitsa kapangidwe kake; sichipereka mphamvu zambiri, koma chimateteza pakati pa dongosolo loyendetsa; sichimasankha mwachindunji njira, koma chimatsimikizira chitetezo cha ndege.
Kuyambira zokutira zoteteza kutentha kwambiri mpaka zinthu zophatikizika zolimba, komanso ngakhale zigawo zodzitetezera kutentha, kugwiritsa ntchitoufa wa aluminaM'munda wa ndege, zinthu zopepuka, zolimba, komanso zotetezeka ku malo oopsa kwambiri. M'tsogolomu, chifukwa cha kupangidwa kwa zinthu za alumina zokhala ndi chiyero chapamwamba komanso mawonekedwe apadera (monga mawaya ang'onoang'ono ndi ma nanosheet), zitha kukhala ndi maudindo osayembekezereka pakuwongolera kutentha, kuwononga kutentha kwa zida zamagetsi, komanso kupanga zinthu mumlengalenga.
Ufa woyera uwu, wopanda phokoso komanso wokhazikika, uli ndi mphamvu zambiri zomwe zimathandiza anthu kufufuza zakumwamba. Umatikumbutsa kuti paulendo wopita ku nyenyezi, sitifunikira masomphenya akuluakulu ndi mphamvu zokwera, komanso "mapiko osaoneka" osakhazikika komanso osagwedezeka omwe amakulitsa magwiridwe antchito a zinthu zoyambira. Nthawi ina mukayang'ana ndege ikuuluka pamwamba kapena kuonera chiwonetsero chokongola cha roketi ikuwomberedwa, mungakumbukire kuti mkati mwa thupi lachitsulo ndi zinthu zopangidwa ndi zinthu zosiyanasiyana, muli "mzimu woyera," womwe umateteza mwakachetechete chitetezo ndi ubwino wa ulendo uliwonse.