Kanthal AF alloy 837 resistohm alchrome Y fecral alloy

Kanthal AF ndi ferritic iron-chromium-aluminium alloy (FeCrAl alloy) yogwiritsidwa ntchito kutentha mpaka 1300°C (2370°F). Alloy iyi imadziwika ndi kukana kwabwino kwa okosijeni komanso kukhazikika bwino kwa mawonekedwe komwe kumabweretsa moyo wautali wa zinthu.

Kan-thal AF nthawi zambiri imagwiritsidwa ntchito potenthetsera zinthu zamagetsi m'mafakitale ndi zida zapakhomo.

Zitsanzo za ntchito zomwe zimagwiritsidwa ntchito mumakampani opanga zida zamagetsi ndi monga zinthu zotseguka za mica za toasters, zowumitsira tsitsi, zinthu zozungulira za heaters za fan heaters komanso zinthu zotseguka za coil pa fiber insulation materials mu ceramic glass top heaters m'malo osiyanasiyana, mu ceramic heaters za mbale zowira, ma coil pa ulusi wa ceramic wopangidwa wa mbale zophikira zokhala ndi zitofu za ceramic, mu suspended coil za fan heaters, mu suspended straight wire elements za radiators, convection heaters, mu porcupine elements za hot air guns, radiators, tumble dryer.

Chidule Mu kafukufukuyu, njira yopangira dzimbiri ya alloy ya FeCrAl (Kanthal AF) yogulitsa panthawi yothira mpweya wa nayitrogeni (4.6) pa 900 °C ndi 1200 °C yafotokozedwa. Mayeso a Isothermal ndi thermo-cyclic okhala ndi nthawi zosiyanasiyana zowonekera, kutentha, ndi kutentha kwa annealing adachitika. Mayeso a oxidation mu mpweya ndi nayitrogeni adachitika pogwiritsa ntchito thermogravimetric analysis. Kapangidwe ka microstructure kamadziwika ndi scanning electron microscopy (SEM-EDX), Auger electron spectroscopy (AES), ndi focused ion beam (FIB-EDX) analysis. Zotsatira zake zikuwonetsa kuti kupita patsogolo kwa dzimbiri kumachitika kudzera mu mapangidwe a malo okhala ndi nitridation, opangidwa ndi tinthu ta AlN phase, zomwe zimachepetsa ntchito ya aluminiyamu ndikuyambitsa kuphulika ndi kufalikira. Njira zopangira Al-nitride ndi kukula kwa sikelo ya Al-oxide zimadalira kutentha kwa annealing ndi kutentha. Zinapezeka kuti nitridation ya aloyi ya FeCrAl ndi njira yachangu kuposa okosijeni panthawi yopopera mpweya wa nayitrogeni wokhala ndi mpweya wochepa wa okosijeni ndipo ndiye chifukwa chachikulu cha kuwonongeka kwa aloyi.

Mau Oyamba Ma alloy opangidwa ndi FeCrAl (Kanthal AF ®) amadziwika bwino chifukwa cha kukana kwawo kwambiri kwa okosijeni pa kutentha kokwera. Kapangidwe kabwino kameneka kakugwirizana ndi kupangika kwa alumina yokhazikika pa thermodynamically pamwamba, komwe kumateteza zinthuzo ku okosijeni wowonjezereka [1]. Ngakhale kuti ali ndi mphamvu zotsutsana ndi dzimbiri, nthawi yotsala ya zinthu zopangidwa kuchokera ku FeCrAl - zopangidwa ndi alloy zitha kuchepetsedwa ngati zigawozo nthawi zambiri zimakumana ndi kutentha kokwera pa kutentha kokwera [2]. Chimodzi mwa zifukwa za izi ndikuti chinthu chopanga sikelo, aluminiyamu, chimadyedwa mu alloy matrix m'dera la pansi pa nthaka chifukwa cha kusweka kwa thermo-shock mobwerezabwereza ndi kusintha kwa sikelo ya alumina. Ngati kuchuluka kwa aluminiyamu kotsalako kumachepa pansi pa kuchuluka kofunikira, alloyyo sangathenso kusintha sikelo yoteteza, zomwe zimapangitsa kuti okosijeni woopsa awonongeke mwa kupanga ma oxides opangidwa ndi iron ndi chromium omwe akukula mofulumira [3,4]. Kutengera mlengalenga wozungulira ndi kufalikira kwa ma oxides opangidwa pamwamba, izi zitha kuthandizira kupangika kwamkati kapena nitridation ndikupanga magawo osafunikira m'dera la pansi pa nthaka [5]. Han ndi Young asonyeza kuti mu sikelo ya alumina yomwe imapanga ma alloy a Ni Cr Al, njira yovuta ya oxidation yamkati ndi nitridation imayamba [6,7] panthawi ya kutentha kwa kutentha kwambiri mumlengalenga, makamaka mu ma alloy omwe ali ndi ma nitride formers amphamvu monga Al ndi Ti [4]. Ma chromium oxide scales amadziwika kuti ndi nayitrogeni wolowa, ndipo Cr2 N imapanga ngati sub-scale layer kapena ngati internal precipitate [8,9]. Zotsatirazi zitha kuyembekezeka kukhala zoopsa kwambiri pansi pa mikhalidwe ya kutentha kwa cyclic zomwe zimapangitsa kuti oxide scale cracking ndi kuchepetsa mphamvu yake ngati chotchinga ku nayitrogeni [6]. Chifukwa chake, khalidwe la dzimbiri limayendetsedwa ndi mpikisano pakati pa oxidation, zomwe zimapangitsa kuti alumina ipangidwe/kusamalira, ndi ingress ya nayitrogeni zomwe zimapangitsa kuti internal nitridation ya alloy matrix ipangidwe ndi gawo la AlN [6,10], zomwe zimapangitsa kuti dera limenelo liwonongeke chifukwa cha kutentha kwakukulu kwa gawo la AlN poyerekeza ndi matrix ya alloy [9]. Mukayika ma alloy a FeCrAl pamalo otentha kwambiri mumlengalenga wokhala ndi mpweya kapena opereka mpweya ena monga H2O kapena CO2, kukhuthala ndiye njira yolamulira, ndipo alumina scale imapangidwa, yomwe siilola mpweya kapena nayitrogeni kutentha kwambiri ndipo imateteza ku kulowa kwawo mu alloy matrix. Koma, ngati iwonetsedwa mumlengalenga wochepetsera (N2+H2), ndi kuphulika kwa alumina scale yoteteza, kukhuthala kwa m'deralo kumayamba ndi kupanga ma Cr ndi Ferich oxides osateteza, omwe amapereka njira yabwino yofalitsira nayitrogeni mu ferritic matrix ndi kupanga gawo la AlN [9]. Mlengalenga wa nayitrogeni woteteza (4.6) umagwiritsidwa ntchito nthawi zambiri pogwiritsira ntchito ma alloy a FeCrAl m'mafakitale. Mwachitsanzo, ma heater oletsa kutentha m'mafakitale ochizira kutentha okhala ndi mpweya woteteza nayitrogeni ndi chitsanzo cha kugwiritsidwa ntchito kwakukulu kwa ma alloy a FeCrAl m'malo otere. Olembawo akunena kuti kuchuluka kwa kukhuthala kwa ma alloy a FeCrAlY kumakhala kocheperako kwambiri akamalowa mumlengalenga wokhala ndi mpweya wochepa wa mpweya [11]. Cholinga cha kafukufukuyu chinali kudziwa ngati kulowetsa mpweya mu mpweya wa (99.996%) wa nayitrogeni (4.6) (Messer® spec. desity level O2 + H2O < 10 ppm) kumakhudza kukana kwa dzimbiri kwa alloy ya FeCrAl (Kanthal AF) komanso momwe zimakhalira ndi kutentha kwa annealing, kusintha kwake (kutentha kwa kutentha), ndi kuchuluka kwa kutentha.