Tsarin kera filastik na polyether ether ketone (PEEK) da aikace-aikacensa a masana'antar sararin samaniya
Polyether ether ketone (PEEK) wani filastik ne mai inganci wanda ake amfani da shi sosai lokacin da kayan dole ne ya kasance mai ƙarfi, tsayayye, kuma mai jure zafi a ƙarƙashin yanayi mai tsauri. A cikin masana'antar sararin samaniya, PEEK ya jawo hankali saboda yana iya maye gurbin ƙarfe kaɗan a wasu sassan, yayin da yake ba da fa'idodi kamar nauyi mai sauƙi, juriyar sinadarai mai yawa, da juriya ga gajiya da lalacewa. Wannan labarin ya tattauna tsarin kera PEEK daga mahangar sinadarai-polymer, matakan masana'antu, da kuma yadda ake amfani da wannan kayan a duniyar sararin samaniya.
Duba PEEK da halayensa
PEEK na cikin dangin polymers masu ƙamshi na semicrystalline. Tsarin sarkar sa ya ƙunshi ƙungiyoyin ether (-O-) da ketone (-CO-) waɗanda aka shirya a kan zoben ƙamshi. Wannan haɗin yana haifar da ƙarfin kayan injiniya da kwanciyar hankali mai zafi. Gabaɗaya, PEEK an san shi da babban wurin narkewa (kusan 343°C), kyakkyawan juriyar zafi na dogon lokaci, da juriya ga abubuwa masu narkewa da sinadarai masu ƙarfi. Bugu da ƙari, PEEK yana da juriya ga radiation kuma ana iya tsara shi don biyan buƙatun aminci kamar juriyar wuta, hayaƙi, da guba (FST), waɗanda suke da mahimmanci a cikin ɗakunan jirgin sama.
Waɗannan kyawawan halaye suna sanya PEEK "masu amfani da thermoplastic mai ƙarfi." Ba kamar thermosets ba, waɗanda da zarar sun taurare suna da wahalar sake amfani da su, PEEK, a matsayin thermoplastic, ana iya sake sarrafa shi ta hanyar dumamawa, yana ba da sassaucin masana'antu (misali, allura, fitarwa, matsawa, ko wasu aikace-aikacen bugawa na 3D), kodayake yana buƙatar kayan aiki waɗanda ke iya jure yanayin zafi mai yawa.
Kayan aiki da ƙa'idodin amsawa don ƙirƙirar PEEK
A fannin masana'antu, ana samar da PEEK ta hanyar polymerization na matakin girma wanda ya haɗa da monomers masu aiki da aromatic. Wata hanyar roba da aka sani sosai ta ƙunshi amsawar dihalides mai ƙanshi tare da gishirin bisphenolate a cikin ruwan da ke narkewa a cikin polar aprotic a yanayin zafi mai yawa. A ra'ayina, samuwar haɗin ether yana faruwa ta hanyar maye gurbin aromatic nucleophilic (SNar), wanda ke da tasiri akan zoben aromatic tare da ƙungiyoyi masu kyau na electron-withdrawings da barin su.
A fannin masana'antu, zaɓin monomer, nau'in tushe, zaɓin sinadaran da ke narkewa, da kuma kula da tsarki suna tasiri sosai ga nauyin ƙwayoyin polymer, rarraba nauyin ƙwayoyin halitta, launi, da kuma aikin ƙarshe. Saboda an yi nufin PEEK ne don aikace-aikace masu mahimmanci (gami da sararin samaniya), dole ne a sarrafa ƙazanta na ionic, danshi, da matakan ragowar sinadaran da ke narkewa sosai.
Matakan tsarin masana'antu na PEEK
Duk da cewa kowane masana'anta na iya samun bambance-bambance a cikin hanyoyin kariya da girke-girke, tsarin PEEK na gabaɗaya za a iya taƙaita shi zuwa matakai masu zuwa.
1) Shiri da tsarkake kayan aiki
Matakan farko sun haɗa da busar da monomer da sauran sinadarai, da kuma tsarkakewa don cire gurɓatattun abubuwa kamar ruwa, ions na ƙarfe, ko mahadi waɗanda za su iya dakatar da haɓakar sarka (masu ƙare sarka). Ruwa shine babban abokin gaba a cikin yawancin hanyoyin polymerization na condensation saboda yana iya canza amsawar amsawa kuma yana shafar nauyin kwayoyin halitta na samfurin. Saboda haka, tsarin yawanci ana kiyaye shi bushe sosai, gami da amfani da iskar gas mara aiki don rufewa.
2) Samar da gishirin bisphenolate (kunna nucleophile)
Ana canza ƙwayoyin halittar phenolic zuwa siffar gishirinsu ta amfani da tushe (misali, carbonate). Manufar ita ce samar da wani ƙarfi mai suna nucleophile (phenolate) wanda ke kai hari ga monomer mai ƙanshi na halogenated cikin sauƙi. Wannan matakin kuma yana buƙatar daidaitaccen sarrafa stoichiometric, saboda rashin daidaito a cikin rabon aiki na iya rage matakin polymerization da tasirin halayen injiniya.
3) Haɗakar polymerization a babban zafin jiki
Babban abin da ke faruwa yana faruwa ne a yanayin zafi mai yawa a cikin wani reactor mai jure tsatsa wanda zai iya tayar da ɗanɗano mai yawa. Masu narkewar iskar polar suna taimakawa wajen narkar da nau'in mai amsawa da wuri, wanda hakan ke ba da damar amsawar ta ci gaba cikin sauƙi. Yayin da sarkar polymer ke girma, ɗanɗano yana ƙaruwa sosai, kuma sarrafa zafi yana ƙara zama mahimmanci don hana wuraren zafi ko lalacewar zafi.
A wannan matakin, sigogin tsari kamar zafin jiki, lokacin zama, da saurin juyawa suna shafar nauyin kwayoyin halitta. Masana'antun galibi suna mai da hankali kan takamaiman kewayon narkewar narkewa saboda yana da alaƙa da sauƙin sarrafawa na gaba (misali, fitarwa) da aikin ƙarshe.
4) Karewa, sanyaya, da kuma lalata ƙasa (keɓewa)
Bayan ya kai matakin da ake so na polymerization, ana dakatar da amsawar kuma a sanyaya cakuda. Sannan ana ware polymer ɗin, sau da yawa ta hanyar ruwan sama zuwa wani wuri mara narkewa ko ta wani takamaiman matakin rabuwa. Manufar ita ce a raba PEEK daga sinadaran narkewa, gishirin da ba na halitta ba, da ragowar amsawa.
5) Wankewa da busarwa
Ana wanke polymer ɗin da aka keɓe akai-akai don rage yawan ionic da ragowar mai narkewa. Ana yin matakin bushewa a ƙarƙashin yanayi wanda ke tabbatar da ƙarancin danshi. Don aikace-aikacen sararin samaniya, sarrafa iska mai canzawa da gurɓatawa yana da mahimmanci domin suna iya shafar fitar da iskar gas, ingancin saman, da kwanciyar hankali na dogon lokaci.
6) Haɗawa: ƙara ƙari da ƙarfafawa
Pure PEEK ya riga ya yi ƙarfi sosai, amma a aikace-aikace da yawa ana ƙara shi da abubuwan cikawa/ƙarfafawa kamar carbon fiber, fiberglass, ko PTFE don rage yawan gogayya da ƙara juriya ga lalacewa. Ana yin haɗaka ta amfani da na'urar fitar da zafi mai zafi. Dole ne haɗin ƙarfafawa ya kasance daidai, daidaiton watsawa, kuma tsawon zaren ya kasance mai dorewa don cimma halayen injiniya da ake so.
7) Tsaftacewa da kuma kula da inganci
Ana yin samfurin ƙarshe a cikin nau'in pellet don sauƙaƙe ƙarin sarrafawa. Kula da inganci ya haɗa da ma'aunin danko, nazarin abun ciki na toka (don cikewa), DSC don lu'ulu'u da wurin narkewa, TGA don kwanciyar hankali na zafi, gwajin injiniya (tensile, lankwasawa, tasiri), da gwajin FST idan an yi niyya ga cikin jirgin sama.
Ana sarrafa PEEK cikin abubuwan haɗin
A cikin kera kayan aiki, ana iya sarrafa PEEK ta hanyar:
– Yin allurar da za a yi amfani da ita wajen yin abubuwa masu rikitarwa yana buƙatar ƙira da injuna waɗanda za su iya jure yanayin zafi mai yawa.
- Fitarwa don ƙirƙirar bayanan martaba, bututu, fina-finai, ko siffofi marasa ƙarewa.
- Tsarin matsi don zanen gado ko wasu siffofi.
- Yin amfani da sandunan PEEK/faranti na ƙarshen-ƙarshe don jure wa daidaito.
– Wasu masana'antun ƙari (misali FFF/FGF na masana'antu) waɗanda ke buƙatar sarrafa zafin ɗakin bugawa mai yawa don rage warpage da delamination.
Saboda PEEK semicrystalline ne, saurin sanyaya yana shafar lu'ulu'u, wanda a ƙarshe ke shafar tauri, juriya ga sinadarai, da kwanciyar hankali na girma. Sau da yawa ana amfani da sarrafa zafin jiki na mold da kuma bayan annabta shi don cimma kyawawan halaye.
Aikace-aikacen PEEK a cikin masana'antar sararin samaniya
A fannin sararin samaniya, ana zaɓar kayan aiki bisa ga ƙarfinsu da nauyinsu, juriyar zafi, juriyar harshen wuta, juriyar ruwa, da kuma amincinsu na dogon lokaci. PEEK ya cika da yawancin waɗannan sharuɗɗa, musamman a cikin matakan haɗaka ko na musamman.
1) Abubuwan da aka gyara da kuma maƙallan haske
Ana amfani da PEEK (musamman carbon fiber-reinforced) don maƙallan ƙarfe, maƙallan ƙarfe, da kayan tallafi da aka yi da aluminum ko ƙarfe a wasu wurare. Babban fa'idodinsa sune rage nauyi, juriya ga tsatsa, da kwanciyar hankali a lokacin zagayowar zafin jiki.
2) Tsarin kebul, masu haɗawa da kuma rufin
Ana amfani da PEEK sosai a cikin na'urorin rufewa, masu haɗawa, da kuma rufin kebul saboda kwanciyar hankali na dielectric da juriyar zafin jiki. A cikin jiragen sama na zamani, waɗanda ke ƙara samun wutar lantarki, buƙatar kayan rufewa masu inganci yana ci gaba da ƙaruwa.
3) Bearings, bushings, da kuma tribological sassan
Ana amfani da ma'aunin PEEK da aka gyara da PTFE/carbon fiber a cikin bushings, washers, da sauran abubuwan gogayya. Waɗannan kayan suna ba da juriya mai kyau ga lalacewa, ƙarancin yawan gogayya, da kuma aiki mai dorewa a wasu muhallin sinadarai.
4) Bukatun cikin jirgin sama da FST
Ga cikin gida, ƙa'idodin FST (harsashi, hayaƙi, guba) suna da tsauri sosai. Ana iya tsara PEEK don biyan waɗannan buƙatu, wanda hakan ya sa ya dace da aikace-aikacen ciki iri-iri, gami da sassan da ke buƙatar juriya ga zafi da ƙarfin injina ba tare da ƙara nauyi mai yawa ba.
5) Haɗaɗɗun kayan thermoplastic don gine-gine
Wani babban abin da ke faruwa shi ne amfani da haɗakar matrix na carbon fiber tare da PEEK (Carbon Fiber Reinforced PEEK/CFR-PEEK). Idan aka kwatanta da thermosets, haɗakar thermoplastic suna ba da damar walda mai zafi, zagayowar samarwa cikin sauri, da kuma juriya mai kyau ga tasiri. A cikin yanayin sararin samaniya, wannan yana da kyau ga bangarori, masu tauri, da wasu sassan da ke buƙatar haɗin ƙarfi da ƙarfin samarwa mafi inganci.
Kalubale da la'akari da amfani da PEEK a fannin sararin samaniya
Duk da fa'idodinsa, PEEK yana fuskantar ƙalubale da dama. Na farko, farashin kayan aiki da sarrafawa suna da yawa saboda yawan zafin jiki da buƙatun kula da inganci masu tsauri. Na biyu, ƙirar kayan aiki dole ne ta yi la'akari da anisotropy mai haɗaka da canje-canje a cikin halaye saboda yanayin zare ko yanayin sanyaya. Na uku, don aikace-aikacen da aka tabbatar, kayan aiki da tsarin dole ne su wuce dogon jerin gwaje-gwaje da takardu.
Penutup
PEEK wani robobi ne na injiniya mai inganci wanda ke da haɗin gwiwa na musamman na ƙarfi, juriyar zafi, juriyar sinadarai, da kuma ikon sarrafawa azaman thermoplastic. Tsarin kera shi ya haɗa da polymerization na yawan zafin jiki mai ƙarfi tare da cikakken iko akan tsarki, stoichiometry, da kuma rufin samfurin. Da zarar an yi pellet ko/ko an haɗa shi, ana iya ƙirƙirar PEEK zuwa sassa ta hanyar yin allura, fitarwa, injina, ko azaman mahaɗin matrix na carbon fiber. A cikin masana'antar sararin samaniya, ana amfani da PEEK don rage nauyi, inganta juriyar tsatsa, da biyan buƙatun aiki da aminci, tun daga maƙallan ƙarfe da insulators zuwa bearings da mahaɗin thermoplastic mai ɗorewa. Tare da yanayin zuwa ga jiragen sama mafi inganci da ƙaruwar wutar lantarki, ana sa ran rawar PEEK da danginta na thermoplastics masu aiki mai girma za su ci gaba da girma.
Idan kuna so, zan iya daidaita wannan labarin zuwa salon takarda na kimiyya (tare da ambato da kuma rubutun littattafai), ko ƙara ƙananan sassa na musamman kamar sigogin tsari (zafin zafin jiki, sarrafa lu'ulu'u), nazarin shari'o'i na aikace-aikacen haɗakar CFR-PEEK, ko kwatanta PEEK da PEI, PPS, da PTFE don aikace-aikacen sararin samaniya.
