Nyob rau hauv xyoo tas los no, cov kws tshawb fawb ntawm Toyo Tanso Co., Ltd. hauv Nyij Pooj tau kawm txog combustion synthesis ntawm txhuas nitride. Lawv tau ua tiav npaj xoob, tsis yog -agglomerated AlN hmoov. Nyob rau hauv cov txheej txheem no, raw aluminium hmoov yog tov nrog ib qho tsim nyog tus nqi ntawm AlN hmoov ua ntej- npaj los ntawm combustion synthesis kom txo cov tshuaj tiv thaiv kub. Cov sib tov yog muab tso rau hauv ib lub tais graphite, thiab cov tshuaj nitridation yog pib los ntawm qhov luv luv -lub sij hawm tam sim no ntawm ntau kaum ntawm amperes los ntawm lub tshuab cua sov carbon. Tag nrho cov tshuaj tiv thaiv yog ua nyob rau hauv lub siab - lub siab cov tshuaj tiv thaiv chamber uas muaj nitrogen nyob rau hauv lub siab tshaj 1 MPa. Cov txiaj ntsig AlN yog tom qab ntawd crushed thiab cais los ntawm cov txheej txheem ib txwm ua raws li daim ntawv thov.
Los ntawm kev thauj khoom mus rau kev tshem tawm cov khoom tom qab txias, tag nrho cov txheej txheem yuav siv sij hawm tsis pub dhau ob teev. Kev tshuaj xyuas qhia tau hais tias piv nrog cov txheej txheem kev npaj AlN ib txwm, txoj kev sib xyaw ua ke no txo cov nqi kwv yees li 30-50%. Nyob rau hauv kev pom ntawm qhov zoo thiab cov txiaj ntsig ntawm txoj kev sib xyaw ua ke tshiab no, AlN ntau lawm tau pib los ntawm kev sib koom tes ua haujlwm nrog Shanghai Toyo Tanso Co., Ltd.
Aluminium nitride (AlN), vim nws cov thermal conductivity, zoo hluav taws xob rwb thaiv tsev, tsis tshua muaj dielectric tas li, coefficient ntawm thermal expansion txuam nrog silicon (Si), thiab ib puag ncig tus phooj ywg, tau dhau los ua cov khoom nyiam rau cov khoom siv hauv cov khoom siv hluav taws xob. Nws tuaj yeem daws cov teeb meem zoo xws li cov cua kub dissipation hauv siab - cov khoom siv hluav taws xob thiab thermal stress mismatch, thiab tau siv dav hauv cov haujlwm tseem ceeb xws li thib tsib - tiam kev sib txuas lus mobile (5G), tsheb tshiab, thiab aerospace.
Lub ntsiab synthesis txoj kev rau AlN hmoov muaj xws li ncaj qha nitridation thiab carbothermal txo.
Direct nitridation yuav tsum tso cov hmoov txhuas hauv cov nitrogen thiab ua kom sov rau qhov kub. Nws qhov zoo muaj xws li cov khoom siv raw, cov txheej txheem yooj yim, thiab tsis muaj kev cuam tshuam sab, ua rau nws tsim nyog rau kev tsim khoom.
Carbothermal txo siv alumina hmoov thiab carbon hmoov ua raw khoom. Tom qab sib tov sib xyaw, lawv raug txo thiab nitrided los ua AlN nyob rau hauv ib qho chaw nitrogen ntws ntawm qhov kub ntawm 1600-1800 degree. Tam sim no, feem ntau kev lag luam AlN hmoov yog npaj los ntawm kev txo qis carbothermal. AlN hmoov uas tsim los ntawm txoj kev no muaj qhov zoo xws li siab purity, zoo sphericity, yooj yim ntawm sintering, thiab muaj zog stability.
Ntxiv nrog rau cov tshuaj ncaj qha nitridation ntawm aluminium hmoov thiab txo cov carbothermal, combustion synthesis (CS) siv tus kheej -propagating exothermic cov tshuaj tiv thaiv ntawm txhuas hmoov thiab nitrogen kom zoo synthesis AlN hmoov. Nws kov yeej qhov tsis zoo ntawm cov txheej txheem tseem ceeb tam sim no AlN hmoov npaj, xws li complexity thiab siab zog noj, thiab muaj cov txiaj ntsig zoo nrog rau cov txheej txheem yooj yim, kev siv hluav taws xob tsawg, thiab lub voj voog luv luv. Nws qhia tau hais tias muaj peev xwm loj rau qhov loj -kev npaj ntawm AlN hmoov thiab tsim nyog tau txais kev saib xyuas thiab kev cia siab los ntawm kev lag luam.
Kev Tshawb Fawb Kev Txhim Kho hauv Kev Npaj AlN Hmoov los ntawm Kev Sib Txuas Sib Txuas
Txij li thaum lub tshuab no tau thov los ntawm Merzhanov pab neeg hauv Soviet Union, nws tau siv los npaj ntau yam ntaub ntawv thiab tau ua tiav kev tsim khoom, nrog rau nws tus kheej cov yam ntxwv thiab qhov zoo, tshwj xeeb tshaj yog nyob rau hauv ceramic hmoov, intermetallic compounds, ceramic coatings, thiab lwm yam.
Combustion synthesis ntawm AlN tuaj yeem suav tias yog ib txoj hauv kev txuas ntxiv ntawm kev ncaj qha nitridation ntawm Al hmoov. Nyob rau hauv txoj kev no, Al hmoov reacts nyob rau hauv siab - siab nitrogen. Cov tshuaj tiv thaiv yog ceev ceev, thiab cov cua kub uas tsim los ntawm cov tshuaj tiv thaiv ntawm Al thiab nitrogen tuaj yeem txhawb nqa cov tshuaj tiv thaiv kom txog thaum ua tiav. Cov txheej AlN tsim rau saum npoo ntawm Al hmoov tuaj yeem tawg vim yog cov tshuaj tiv thaiv hnyav, thiab cov khoom tshiab tuaj yeem tshwm sim ntxiv. Txoj kev no yog nrawm thiab ua haujlwm tau zoo thiab tau txais txiaj ntsig zoo. Txawm hais tias nws cov ntsiab lus zoo ib yam li cov nitridation ncaj qha ntawm Al hmoov, txoj kev no tsis tas yuav muaj lub zog sab nraud los tuav lub siab - qhov kub thiab txias uas xav tau rau Al nitridation; nws tsuas yog yuav tsum tau ignited nyob rau hauv thawj theem ntawm cov tshuaj tiv thaiv, yog li zoo heev txo lub zog noj.
Qhov teeb meem loj tshaj plaws nrog kev sib xyaw combustion yog tias nyob rau hauv Al-N2 roj- cov txheej txheem combustion khoom, yog tias cov tshuaj tiv thaiv tau ua tiav tsuas yog nyob rau ntawm N2 nyob rau hauv lub qhov hws ntawm thaj chaw tshuaj tiv thaiv, qhov xav tau N2 siab yuav ncav cuag ntau txhiab tus cua. Yog li ntawd, thaum ntxov combustion synthesis ntawm AlN hmoov feem ntau siv ultrahigh - siab synthesis, nrog N2 siab mus txog 310 MPa. Txawm li cas los xij, qhov hnyav ntawm qhov siab - cov kev mob tshwm sim siab ua rau muaj kev xav tau siab heev ntawm cov cuab yeej kev qhia tshwj xeeb thiab ua rau muaj kev pheej hmoo siab, txwv tsis pub nws loj - daim ntawv thov thiab kev loj hlob.
Hauv kev teb, cov kev tshawb fawb tom ntej feem ntau tsom rau kev ua kom zoo rau cov txheej txheem combustion. Hauv qhov tseem ceeb, qhov no yog kev coj ua kev tswj hwm ntawm lub zog thiab kev hloov pauv loj ntawm Al-N2 interface. Los ntawm synergistic optimization ntawm combustion yoj qauv tsis (combustion kub, propagation tshaj tawm, thiab lwm yam), ib tug correlation mechanism ntawm no tsis thiab cov yam ntxwv ntawm cov khoom (microstructure, particle loj tis, purity, thiab lwm yam) yog tsim.
Kev tuav cov Infiltration combustion yam ntxwv ntawm Al-N2
Gas noj nyob rau hauv cov tshuaj tiv thaiv cheeb tsam ua rau ib tug lub zos siab poob, thiab lub resulting siab gradient tsav N2 mus spontaneously infiltrate directionally mus rau hauv cov tshuaj tiv thaiv cheeb tsam. Txawm li cas los xij, cov nyhuv preheating ntawm combustion yoj pem hauv ntej ua rau Al hais kom yaj thiab coalesce, ua ib qho kev cuam tshuam. Yuav kom tswj tau cov yam ntxwv infiltration combustion ntawm Al-N2, nws yog ib qho tsim nyog yuav tsum sib npaug ntawm cov tshuaj tiv thaiv thermodynamics thiab interfacial kinetics ntawm Al-N2, inhibit qhov tsim ntawm Al yaj ntau dhau, thiab zam qhov pore channel blockage thiab cov tshuaj tiv thaiv kev sib tsoo. Inert diluents tuaj yeem ua kom muaj peev xwm ua kom sov ntawm cov tshuaj tiv thaiv combustion system. Los ntawm cov teebmeem endothermic, lawv txhim kho lub zog dissipation thiab tsis muaj zog cov tshuaj tiv thaiv kinetic kev ua haujlwm, txo qhov kub siab ntawm cov tshuaj tiv thaiv combustion thiab ua kom qeeb qeeb ntawm combustion yoj tshaj tawm tshaj tawm.
Tam sim no, cov khoom siv -theem diluent lub tswv yim tau ua tiav cov txiaj ntsig zoo thiab ua tiav nitridation ntawm Al hmoov nyob rau hauv qhov tsis tshua muaj siab / nyob ze ntawm lub siab, dhau los ua txoj hauv kev tseem ceeb rau kev ua tiav hauv Al-N2 cov tshuaj tiv thaiv kev sib cuam tshuam. Txawm li cas los xij, khoom-theem diluents inevitably txo cov khoom lag luam tawm los. Yog li ntawd, txhawm rau kom ntseeg tau cov khoom lag luam, cov kws tshawb fawb qhia cov pa roj xws li Ar thiab H2. Los ntawm diluting cov nitrogen ib nrab siab nyob rau hauv cov tshuaj tiv thaiv cheeb tsam thiab txo qhov kev sib tsoo tshwm sim ntawm reactant molecules, cov gases yuav ua tau zoo txo qhov kub thiab txias cov tshuaj tiv thaiv propagation tshaj tawm. Txawm li cas los xij, kev taw qhia ntawm H2 inhibits kev hloov pauv cov tshuaj tiv thaiv, ua rau muaj kev nce ntxiv hauv cov ntsiab lus txhuas seem. Cov txiaj ntsig saum toj no qhia tau hais tias kev tswj hwm tus yam ntxwv infiltration combustion ntawm Al-N2 yog qhov tseem ceeb rau kev ua tiav qhov loj -kev npaj ntawm AlN hmoov nyob rau hauv qis / ze ambient siab, taw qhia cov kev taw qhia rau cov txheej txheem optimization.
Combustion Reaction Kub
Under the infiltration combustion framework, regulating the aluminum powder content and nitrogen pressure is the most direct and controllable process means. Studies show that when the aluminum powder content decreases from 60% (mole fraction) to 40% (diluent content increases from 40% to 60%), the adiabatic temperature of the system significantly decreases from 4120 K to 2890 K, and the maximum combustion reaction temperature decreases from >2573 K txog 2057 K. Qhov txo qis hauv qhov kub thiab txias ua rau txo qis ntawm atomic diffusion tus nqi thiab kev loj hlob kinetics ntawm cov khoom AlN nplej nyob rau hauv qhov siab - qhov kub thiab txias, yog li no zoo refining lub AlN grain loj thiab txhim kho nws morphological uniformity.
Txawm hais tias qhov kub ntawm adiabatic ntawm qhov system tseem nyob tas li thaum nitrogen siab nce, cov tshuaj tiv thaiv combustion kub nce. Qhov nce hauv qhov kub ntawm cov tshuaj tiv thaiv combustion txhim kho atomic diffusion peev xwm thiab ncua sij hawm cov nplej siv nyob rau hauv qhov siab - qhov kub thiab txias, yog li txhawb kev loj hlob ntawm AlN nplej, nrog rau agglomeration los ntawm interparticle sintering. Qhov sib txawv no tshwm sim los ntawm kev nce hauv N2 molecular flux rau ib chav tsev ntim, uas txhim kho qhov sib txawv thiab kev hloov pauv loj ntawm cov pa roj-theem reactants ntawm cov tshuaj tiv thaiv cuam tshuam. Nws tuaj yeem pom tau tias qhov kub ntawm cov tshuaj tiv thaiv combustion tsis yog tsuas yog ib qho tseem ceeb rau kev tswj hwm Al-N2 infiltration combustion hom, tab sis kuj ncaj qha tswj cov particle loj tis thiab particle agglomeration xeev ntawm qhov kawg AlN hmoov khoom.
Combustion Additives
Kev hloov pauv ntawm peb -theem faib ntawm Al hmoov induced nyob rau hauv lub sij hawm thermal shock ntawm combustion nthwv dej, nrog rau melting lub cev qhuav dej ntawm lub cev pob txha, thaiv ntawm N2 infiltration flux los ntawm cov khoom-kua interface, thiab combustion yoj instability tshwm sim los ntawm cov pa roj-phase cov tshuaj tiv thaiv Al-kev coj tus cwj pwm. Qhov kev txwv nyuaj no ua rau qhov sib ntxiv ntawm cov kab ntxiv ib qho ntawm txoj hauv kev tseem ceeb rau kev tswj hwm peb -theem faib ntawm Al.
Ammonium halides, raws li feem ntau siv additives nyob rau hauv lub Al-N2 combustion system, feem ntau ntseeg hais tias yuav txo combustion kub thiab propagation tshaj tawm los ntawm endothermic decomposition, thaum lub gases generated los ntawm decomposition yuav tsim ib ntus microchannels thiab txhawb N2 infiltration. Txawm hais tias lub ntiaj teb morphology tswj mechanism tseem tsis tau tsim nyob rau hauv lub tshav pob ntawm combustion synthesis ntawm AlN, additives tseem dav lees paub tias yog ib txoj hauv kev los tswj cov combustion cov tshuaj tiv thaiv txoj kev uas combines yooj yim ntawm kev khiav hauj lwm thiab engineering adaptability.