Rashin amsawa
A dauki sinteringsiliki carbide yumbusamar da tsari hada yumbu compacting, sintering juyi infiltration wakili compacting, dauki sintering yumbu samfurin shiri, silicon carbide itace yumbu shiri da sauran matakai.
Reaction sintering silicon carbide bututun ƙarfe
Na farko, 80-90% na yumbu foda (wanda ya ƙunshi foda ɗaya ko biyu nasiliki carbide fodada boron carbide foda), 3-15% na carbon tushen foda (wanda ya ƙunshi daya ko biyu na carbon baki da kuma phenolic guduro) da 5-15% na gyare-gyaren wakili (phenolic guduro, polyethylene glycol, hydroxymethyl cellulose ko paraffin) suna gauraye a ko'ina. Yin amfani da injin niƙa don samun foda mai gauraya, wanda aka fesa busasshe da granulated, sa'an nan kuma danna shi a cikin wani mold don samun ƙaramin yumbu tare da takamaiman takamaiman. siffofi.
Abu na biyu, 60-80% silicon foda, 3-10% silicon carbide foda da 37-10% boron nitride foda ana gauraye su daidai, kuma ana matse su a cikin wani nau'i don samun ƙarancin infiltration wakili mai ƙwanƙwasa.
Ƙaƙƙarfan yumbura da ƙananan infiltrant ɗin da aka yi amfani da su ana tara su tare, kuma ana ɗaga zafin jiki zuwa 1450-1750 ℃ a cikin tanderun injin da ba ta da ƙasa da 5 × 10-1 Pa don sintering da adana zafi don 1-3 hours don samun amsa sintered yumbu samfur. Ana cire ragowar ɓarna a saman yumbun da aka yi amfani da shi ta hanyar dannawa don samun takardar yumbu mai yawa, kuma ana kiyaye ainihin siffar ƙanƙara.
A ƙarshe, ana ɗaukar tsarin amsawar sinterin, wato, siliki na ruwa ko silicon gami tare da aikin amsawa a babban zafin jiki yana shiga cikin yumbu mara kyau wanda ke ɗauke da carbon ƙarƙashin aikin ƙarfin capillary, kuma yana amsawa tare da carbon ɗin da ke cikinsa don samar da silicon carbide, wanda ke haifar da silicon carbide. za su faɗaɗa cikin ƙara, kuma ragowar pores suna cike da siliki na asali. Bakin yumbu mai ƙyalli na iya zama tsantsar carbon ko silikon carbide/ kayan haɗakar carbon. Ana samun na farko ta hanyar warkewa da pyrolyzing wani resin kwayoyin halitta, tsohon pore da sauran ƙarfi. Ana samun ƙarshen ta hanyar pyrolying siliki carbide barbashi / kayan haɗin gwal na tushen guduro don samun kayan haɗin gwiwar silicon carbide / carbon-tushen kayan, ko ta amfani da α-SiC da carbon foda azaman kayan farawa da yin amfani da tsarin gyare-gyaren latsawa ko allura don samun abubuwan haɗin gwiwar. abu.
Rashin matsi
Tsarin sintering mara matsi na silicon carbide za a iya raba shi zuwa tsayayyen lokaci sintering da ruwa-lokaci sintering. A cikin 'yan shekarun nan, da bincike a kansilicon carbide ceramicsa cikin gida da waje ya fi mayar da hankali kan sarrafa ruwa-lokaci. Tsarin shirye-shiryen yumbu shine: gauraye kayan ball milling -> fesa granulation -> busassun latsawa -> ƙarfafa jiki -> vacuum sintering.
Kayayyakin siliki carbide mara ƙarfi mara ƙarfi
Add 96-99 sassa na silicon carbide ultrafine foda (50-500nm), 1-2 sassa na boron carbide ultrafine foda (50-500nm), 0.2-1 sassa na nano-titanium boride (30-80nm), 10-20 sassa. na ruwa mai narkewa phenolic guduro, da 0.1-0.5 sassa na high-inganci dispersant. zuwa injin niƙa don yin ƙwallo da haɗawa na tsawon awanni 24, sannan a saka slurry ɗin da aka gauraya a cikin ganga mai gauraya don motsawa na awanni 2 don cire kumfa a cikin slurry.
The sama cakuda ne fesa a cikin granulation hasumiya, da granulation foda da mai kyau barbashi ilimin halittar jiki, mai kyau fluidity, kunkuntar barbashi rarraba kewayon da matsakaici danshi samu ta iko da SPRAY matsa lamba, iska mashiga zafin jiki, iska kanti zazzabi da fesa takardar barbashi size. Canjin mitar centrifugal shine 26-32, zazzabi mai shigowa iska shine 250-280 ℃, zafin fitarwar iska shine 100-120 ℃, kuma matsa lamba mai shiga slurry shine 40-60.
Ana sanya foda na granulation na sama a cikin simintin simintin carbide don latsa don samun koren jiki. Hanyar latsawa ita ce matsa lamba biyu, kuma ton matsa lamba na kayan aikin injin shine ton 150-200.
Ana sanya jikin koren da aka danne a cikin tanda mai bushewa don bushewa da kuma warkewa don samun koren jiki mai kyau koren ƙarfin jiki.
Ana sanya jikin koren da aka warke a sama a cikin wanigraphite cruciblekuma an shirya shi da kyau da kyau, sa'an nan kuma graphite crucible tare da koren jiki an sanya shi a cikin tanderu mai zafi mai zafi don harbi. The harbe-harbe zafin jiki ne 2200-2250 ℃, da kuma rufi lokaci ne 1-2 hours. A ƙarshe, ana samun yumbu na siliki carbide mara ƙarfi mara ƙarfi.
M-lokaci sintering
Tsarin sintering mara matsi na silicon carbide za a iya raba shi zuwa tsayayyen lokaci sintering da ruwa-lokaci sintering. Liquid-phase sintering yana buƙatar ƙarin abubuwan haɓakawa na sintering, kamar Y2O3 binary da ternary additives, don yin SiC da kayan haɗin gwiwar sa suna gabatar da sintirin ruwa-lokaci da kuma cimma ƙima a ƙananan zafin jiki. Hanyar shirye-shirye na tukwane mai ƙarfi na silicon carbide tukwane ya haɗa da hadawa da albarkatun ƙasa, feshi granulation, gyare-gyaren, da kuma vacuum sintering. Takamammen tsarin samarwa shine kamar haka:
70-90% na submicron α silicon carbide (200-500nm), 0.1-5% na boron carbide, 4-20% na guduro, da 5-20% na kwayoyin daure ana sanya su a cikin mahautsini kuma an saka shi da ruwa mai tsabta don rigar. hadawa. Bayan sa'o'i 6-48, slurry gauraye yana wucewa ta hanyar 60-120 raga;
Ana fesa slurry ɗin da aka keɓe ta hanyar hasumiya mai feshi. The mashiga zafin jiki na fesa granulation hasumiya ne 180-260 ℃, da kanti zafin jiki ne 60-120 ℃; Babban yawa na kayan granulated shine 0.85-0.92g / cm3, ruwa shine 8-11s / 30g; kayan granulated an sike su ta hanyar sieve raga na 60-120 don amfani daga baya;
Zaɓi nau'in ƙira bisa ga siffar samfurin da ake so, ɗora kayan granulated a cikin rami, kuma yi gyare-gyaren yanayin zafin jiki a matsa lamba na 50-200MPa don samun jikin kore; ko sanya kore jiki bayan matsawa gyare-gyare a cikin wani isostatic latsa na'urar, yi isostatic latsa a matsa lamba na 200-300MPa, da samun wani kore jiki bayan sakandare latsa;
Sanya koren jikin da aka shirya a cikin matakan da ke sama a cikin injin daskarewa na murhu don sintering, kuma wanda ya cancanta shi ne yumbun siliki carbide da aka gama; a cikin tsarin sintirin da ke sama, da farko fitar da wutar lantarki, kuma lokacin da injin injin ya kai 3-5 × 10-2 Bayan Pa, iskar gas ɗin da ba ta dace ba ta shiga cikin tanderun da ke jujjuyawa zuwa matsa lamba na al'ada sannan kuma mai tsanani. Dangantaka tsakanin dumama zafin jiki da lokaci ne: dakin zafin jiki zuwa 800 ℃, 5-8 hours, zafi adana for 0.5-1 hour, daga 800 ℃ zuwa 2000-2300 ℃, 6-9 hours, zafi adana for 1 to 2 hours, sa'an nan kuma sanyaya tare da tanderun da kuma sauke zuwa dakin zafin jiki.
Microstructure da iyakar hatsi na siliki carbide da aka lalata a matsa lamba na al'ada
A takaice, yumbu da aka ƙera ta hanyar matsi mai zafi yana da mafi kyawun aiki, amma farashin samarwa kuma yana ƙaruwa sosai; yumbu da aka shirya ta hanyar sintering maras ƙarfi suna da buƙatun albarkatun ƙasa, babban zafin jiki mai ƙarfi, manyan canje-canjen girman samfur, tsari mai rikitarwa da ƙarancin aiki; yumbu kayayyakin samar da dauki sintering tsari da high yawa, mai kyau anti-ballistic yi, kuma in mun gwada da low shiri kudin. Daban-daban shirye-shiryen shirye-shiryen siliki carbide yumbu suna da fa'idodi da rashin amfani nasu, kuma yanayin aikace-aikacen kuma zai bambanta. Yana da mafi kyawun manufofin don zaɓar hanyar shiri daidai bisa ga samfurin kuma sami ma'auni tsakanin ƙananan farashi da babban aiki.
Lokacin aikawa: Oktoba-29-2024