Silicon nitride ceramic yog ib qho kev ua haujlwm siab ntawm cov khoom siv ceramic muaj npe nrov rau nws cov khoom tshwj xeeb thiab ntau yam kev siv. Hauv tsab xov xwm no, muaj pes tsawg leeg ntawm silicon nitride ceramic, nrog rau nws cov qauv tshuaj, kev tsim khoom, thiab kev cuam tshuam ntawm kev sib xyaw ntawm nws cov khoom tau qhia.
Chemical Structure ntawm Silicon Nitride Ceramic
Silicon nitride ceramic (Si3N4) yog covalent compound uas muaj silicon (Si) thiab nitrogen (N) atoms. Cov tshuaj formula qhia tias qhov piv ntawm silicon rau nitrogen yog kwv yees li 3: 4, txawm hais tias qhov tseeb muaj pes tsawg leeg yuav txawv nyob ntawm cov txheej txheem tsim khoom thiab cov khoom xav tau. Kev sib koom ua ke ntawm silicon thiab nitrogen atoms tsim ib qho kev sib txuas ntawm peb-dimensional, uas ua rau cov khoom tshwj xeeb ntawm Si3N4 ceramic.
Kev sib xyaw Variations ntawm Silicon Nitride Ceramic
Cov muaj pes tsawg leeg ntawm Si3N4 ceramic tuaj yeem raug kho los ntawm kev kho ntau yam ntsiab lus thiab impurities. Qee qhov kev sib xyaw ua ke sib txawv muaj xws li:
1. Cov ntsiab lus Silicon;
Silicon nitride ceramics feem ntau muaj cov ntsiab lus silicon li ntawm 75 feem pua rau 90 feem pua. Cov ntsiab lus silicon siab dua txhim kho cov khoom toughness thiab thermal shock kuj.
2. Cov ntsiab lus nitrogen;
Nitrogen cov ntsiab lus feem ntau nyob ib ncig ntawm 25 feem pua rau 33 feem pua hauv silicon nitride ceramics. Cov ntsiab lus nitrogen ntau dua tuaj yeem ua kom tawv tawv thiab hnav tsis kam.
3. Dopants;
Dopants xws li txhuas (Al), yttrium (Y), thiab lub ntiaj teb tsis tshua muaj cov ntsiab lus feem ntau ntxiv rau silicon nitride ceramics los txhim kho cov khoom tshwj xeeb. Cov dopants no tuaj yeem hloov kho qhov loj me, txhim kho pob txha toughness, thiab txhawb cov theem stability.
4. Cov impurities.
Cov kab ntawm cov impurities, xws li oxygen (O), carbon (C), thiab lwm yam, tej zaum yuav muaj nyob rau hauv silicon nitride ceramics. Cov impurities no tuaj yeem cuam tshuam cov khoom siv thiab kev tsim khoom.
Kev tsim cov txheej txheem ntawm Silicon Nitride Ceramics
Cov muaj pes tsawg leeg ntawm Si3N4 ceramic yog ze rau kev tsim cov txheej txheem ua haujlwm. Ob txoj hauv kev uas siv tau yog:
1. Reaction-Bonded Silicon Nitride (RBSN);
Nyob rau hauv cov txheej txheem no, sib tov ntawm silicon hmoov thiab ib tug nitrogen-muaj compound, xws li Si3N4, yog compacted thiab rhuab. Lub silicon reacts nrog nitrogen qhov chaw, ua rau tsim ntawm silicon nitride. Cov muaj pes tsawg leeg yog cuam tshuam los ntawm cov khoom pib thiab cov kev mob tshwm sim.
2. Kub nias thiab Sintering;
Txoj kev no suav nrog kev cog qoob loo silicon nitride hmoov nrog cov khoom siv ntxiv lossis dopants, ua raws li sintering ntawm qhov kub thiab txias. Cov muaj pes tsawg leeg tuaj yeem tswj tau los ntawm kev kho tus nqi thiab hom additives, nrog rau cov xwm txheej sintering.
Kev Sib Txuas-Txoj Kev Sib Raug Zoo
Cov muaj pes tsawg leeg ntawm silicon nitride ceramic muaj qhov cuam tshuam loj rau nws cov khoom:
1. Mechanical Properties;
Ntxiv cov ntsiab lus silicon txhim kho cov khoom tawg toughness thiab flexural zog. Cov ntsiab lus nitrogen siab dua txhim kho hardness thiab hnav tsis kam.
2. Cov khoom cua sov;
Si3N4 ceramics nrog ntau dua silicon cov ntsiab lus nthuav tawm superior thermal poob siab thiab thermal conductivity. Nitrogen-nplua nuj compositions muab zoo heev kub-kub lub zog thiab stability.
3. Cov khoom hluav taws xob;
Cov hluav taws xob resistivity ntawm Si3N4 ceramics yog cuam tshuam los ntawm dopants thiab impurities nyob rau hauv muaj pes tsawg leeg. Dopants tuaj yeem hloov kho cov khoom siv dielectric zog thiab hluav taws xob conductivity.
4. Tshuaj Stability.
Lub xub ntiag ntawm impurities nyob rau hauv muaj pes tsawg leeg tuaj yeem cuam tshuam cov tshuaj stability ntawm Si3N4 ceramics, tshwj xeeb tshaj yog nyob rau hauv corrosive ib puag ncig.
Nyob rau hauv luv luv, muaj pes tsawg leeg ntawm silicon nitride ceramic tuaj yeem raug txiav los ntawm ntau txoj kev tsim khoom thiab ntxiv cov dopants lossis impurities.
