Kanthal AF alloy 837 resistohm alchrome Y fecral alloy

Kanthal AF yog ferritic hlau-chromium-aluminium alloy (FeCrAl alloy) siv rau qhov kub txog li 1300 ° C (2370 ° F). Cov hlau yog tus cwj pwm los ntawm kev ua haujlwm zoo oxidation thiab zoo heev daim ntawv stability uas ua rau lub neej ntev.

Kan-thal AF feem ntau yog siv nyob rau hauv hluav taws xob cua sov ntsiab nyob rau hauv industrial furnaces thiab cov khoom siv hauv tsev.

Piv txwv ntawm cov ntawv thov hauv kev lag luam khoom siv yog nyob rau hauv qhib mica ntsiab rau toasters, plaub hau tshuab ziab khaub ncaws, nyob rau hauv meander zoo li lub ntsiab rau kiv cua cua sov thiab raws li qhib coil ntsiab ntawm fiber insulating cov ntaub ntawv nyob rau hauv ceramic iav sab saum toj cua sov nyob rau hauv ntau yam, nyob rau hauv ceramic heaters rau boiling phaj, coils. nyob rau hauv molded ceramic fiber rau ua noj daim hlau nrog ceramic hobs, nyob rau hauv ncua coil ntsiab rau kiv cua tso cua sov, nyob rau hauv suspended ncaj hlau ntsiab rau radiators, convection heaters, nyob rau hauv porcupine ntsiab rau kub cua phom, radiators, tumble dryers.

Nyob rau hauv txoj kev tshawb no, kev txhim kho corrosion ntawm kev lag luam FeCrAl alloy (Kanthal AF) thaum lub sij hawm annealing nyob rau hauv nitrogen gas (4.6) ntawm 900 ° C thiab 1200 ° C yog teev. Isothermal thiab thermo-cyclic xeem nrog sib txawv tag nrho lub sij hawm raug, cua kub tus nqi, thiab annealing kub tau ua. Kev ntsuas oxidation hauv huab cua thiab cov pa nitrogen tau ua los ntawm kev ntsuas thermogravimetric. Lub microstructure yog tus cwj pwm los ntawm kev tshuaj ntsuam xyuas electron microscopy (SEM-EDX), Auger electron spectroscopy (AES), thiab tsom ion beam (FIB-EDX). Cov txiaj ntsig tau pom tias kev txhim kho corrosion tshwm sim los ntawm kev tsim cov cheeb tsam hauv cheeb tsam subsurface nitridation, tsim los ntawm AlN theem hais, uas txo cov kev ua ntawm txhuas thiab ua rau embrittlement thiab spallation. Cov txheej txheem ntawm Al-nitride tsim thiab Al-oxide nplai loj hlob nyob ntawm qhov kub thiab txias thiab cua sov. Nws tau pom tias nitridation ntawm FeCrAl alloy yog txheej txheem sai dua li oxidation thaum lub sij hawm annealing nyob rau hauv ib tug nitrogen gas uas tsis tshua muaj oxygen ib nrab siab thiab sawv cev rau lub ntsiab ua rau degradation alloy.

Taw qhia FeCrAl - raws li cov alloys (Kanthal AF ®) paub zoo rau lawv cov oxidation zoo tshaj ntawm qhov kub siab. Cov cuab yeej zoo no muaj feem cuam tshuam rau kev tsim cov thermodynamically ruaj khov alumina nplai ntawm qhov chaw, uas tiv thaiv cov khoom tiv thaiv ntxiv oxidation [1]. Txawm hais tias muaj zog tiv thaiv corrosion, lub neej ntawm cov khoom tsim los ntawm FeCrAl - raws li cov alloys tuaj yeem raug txwv yog tias cov khoom feem ntau raug rau thermal cycling ntawm qhov kub siab [2]. Ib qho ntawm cov laj thawj rau qhov no yog tias cov nplai tsim cov khoom, txhuas, tau noj nyob rau hauv cov hlau matrix nyob rau hauv subsurface cheeb tsam vim qhov rov qab thermo-shock cracking thiab hloov kho ntawm alumina nplai. Yog hais tias cov ntsiab lus ntawm cov txhuas ntxiv txo qis hauv qab qhov tseem ceeb, cov hlau tsis tuaj yeem hloov kho qhov kev tiv thaiv, uas ua rau muaj kev puas tsuaj rau oxidation los ntawm kev tsim cov hlau loj thiab chromium-based oxides [3,4]. Nyob ntawm qhov chaw nyob ib puag ncig thiab permeability ntawm cov oxides saum npoo, qhov no tuaj yeem pab txhawb ntxiv oxidation sab hauv lossis nitridation thiab tsim cov theem uas tsis xav tau hauv cheeb tsam subsurface [5]. Han thiab Young tau qhia tias nyob rau hauv alumina scale tsim Ni Cr Al alloys, ib tug complex qauv ntawm sab hauv oxidation thiab nitridation tsim [6,7] thaum lub sij hawm thermal cycling ntawm siab kub nyob rau hauv ib tug huab cua huab cua, tshwj xeeb tshaj yog nyob rau hauv alloys uas muaj zog nitride qub xws li Al thiab Ti [4]. Chromium oxide nplai yog paub tias yog nitrogen permeable, thiab Cr2 N cov ntaub ntawv xws li ib tug sub-scale txheej los yog nyob rau hauv precipitate [8,9]. Qhov kev cuam tshuam no tuaj yeem xav tias yuav hnyav dua nyob rau hauv cov cua sov caij tsheb kauj vab uas ua rau oxide nplai tawg thiab txo nws txoj kev ua tau zoo raws li qhov cuam tshuam rau nitrogen [6]. Tus cwj pwm corrosion yog li tswj hwm los ntawm kev sib tw ntawm oxidation, uas ua rau kev tiv thaiv alumina tsim / tu, thiab nitrogen ingress ua rau sab hauv nitridation ntawm alloy matrix los ntawm kev tsim ntawm AlN theem [6,10], uas ua rau lub spallation ntawm thaj tsam ntawd vim muaj thermal expansion ntau dua ntawm AlN theem piv rau alloy matrix [9]. Thaum nthuav tawm FeCrAl alloys rau qhov kub thiab txias hauv huab cua nrog oxygen lossis lwm cov pa oxygen pub dawb xws li H2O lossis CO2, oxidation yog cov tshuaj tiv thaiv, thiab alumina nplai cov ntaub ntawv, uas yog impermeable rau oxygen los yog nitrogen ntawm qhov kub thiab txias thiab muab kev tiv thaiv tiv thaiv lawv intrusion rau hauv lub hlau matrix. Tab sis, yog tias raug txo qis hauv huab cua (N2 + H2), thiab tiv thaiv alumina nplai tawg, lub hauv paus tawg oxidation pib los ntawm kev tsim cov tsis tiv thaiv Cr thiab Ferich oxides, uas muab txoj hauv kev zoo rau nitrogen diffusion rau hauv ferritic matrix thiab tsim. ntawm AlN theem [9]. Kev tiv thaiv (4.6) nitrogen cua feem ntau siv rau hauv kev lag luam daim ntawv thov ntawm FeCrAl alloys. Piv txwv li, cov cua sov ua kom sov hauv cov cua sov kho cua sov nrog cov cua sov tiv thaiv nitrogen yog ib qho piv txwv ntawm kev siv dav dav ntawm FeCrAl alloys hauv ib puag ncig zoo li no. Cov kws sau ntawv tau tshaj tawm tias oxidation tus nqi ntawm FeCrAlY alloys qeeb qeeb thaum annealing nyob rau hauv ib qho chaw uas tsis tshua muaj oxygen ib nrab siab [11]. Lub hom phiaj ntawm txoj kev tshawb no yog los txiav txim seb puas muaj cov annealing hauv (99.996%) nitrogen (4.6) roj (Messer® spec. impurity theem O2 + H2O < 10 ppm) cuam tshuam rau corrosion kuj ntawm FeCrAl alloy (Kanthal AF) thiab seb nws nyob ntawm seb ntawm qhov kub thiab txias, nws qhov kev hloov pauv (thermal-cycling), thiab cua sov tus nqi.