Thaum lub sij hawm roasting txheej txheem, ntau yam ntxhia cov khoom sib cuam tshuam nrog ib leeg. Nyob rau hauv tib lub roasting kub, huab cua thiab siab tej yam kev mob, ib txhia tsuas yog ib nrab melting. Tom qab txias, lub molten binder los ua ib tug vitreous lub cev, uas yog tusyees faib nyob ib ncig ntawm lub abrasive particle thiab consolidates lub abrasive particle. Rau cov binder uas nws qhov refractoriness qis dua qhov kub ntawm qhov hluav taws kub, nws dhau los ua ib qho kev tua hluav taws. Yog hais tias qhov refractoriness siab tshaj qhov kub ntawm qhov cub, nws yuav dhau los ua sintering binder. Ib tug binder uas nws refractoriness nyob ze los yog sib npaug rau qhov kub thiab txias yuav ua ib tug semi-sintered binder.
(1) Binder rau corundum abrasives
Roasting binder feem ntau yog siv raucorundum abrasives, uas muaj ntau hom av nplaum-feldspar (K2O·Al2O3·SiO2) thiab av nplaum-feldspar - boron iav (K2O·Al2O3·B2O3·SiO2).
Qhov piv ntawm av nplaum-feldspar binder yog 20% ~ 50% rau av nplaum thiab 50% ~ 80% rau feldspar. Ntawm lawv, cov ntsiab lus viscosity hauv qab 30% yog sintering binder, thiab cov ntsiab lus siab yog sintering binder. Lub refractoriness ntawm lub binder nce nrog qhov nce ntawm av nplaum cov ntsiab lus thiab txo nrog qhov nce ntawm feldspar cov ntsiab lus. Cov av nplaum-feldspar binder muaj tus nqi qis thiab tuaj yeem ua tau raws li qhov yuav tsum tau ua ntawm cov corundum abrasives, tab sis nws tsis tuaj yeem tsim cov cuab yeej abrasive nrog coarse particle loj thiab mos hardness.
boron iav nyob rau hauv av nplaum-feldspar-boron iav binder muaj ib tug refractoriness ntawm 640 ~ 690 degree, uas yog ib tug muaj zog flux accelerator. Lub boron-muaj binder yog ib tug sintered binder, uas muaj fluidity loj, zoo kub wettability thiab muaj zog tshuaj tiv thaiv muaj peev xwm, thiab yog tsim nyog rau kev txhim kho lub zog ntawm abrasive cov cuab yeej. Nws feem ntau yog siv los txhim kho lub zog ntawm cov cuab yeej abrasive thiab coarse-grained thiab mos-qib hardness abrasives, high-speed sib tsoo lub log thiab super-hard abrasives nrog tsawg binder ntau npaum.
(2) Bonding tus neeg sawv cev rau silicon carbide abrasive cov cuab yeej
SiC abrasives feem ntau yog siv los ua sintered bonds. SiC yog decomposed rau hauv C thiab Si ntawm qhov kub thiab txias, thiab cov decomposition yog intensified nrog rau qhov nce ntawm cov kua theem ntawm cov binder. Thaum cov pa oxygen tsis txaus, nws yuav tsim cov khoom pov tseg "lub siab dub", qhov refractoriness ntawm sintered daim ntawv cog lus siab tshaj qhov kub thiab txias, thiab daim ntawv cog lus tsuas yog ua rau me me ntawm cov kua theem thiab sintering. Qhov me me ntawm C decomposed los ntawm cov khoom yog oxidized thiab SiC zaj duab xis yog tsim nyob rau saum npoo ntawm SiC hais los tiv thaiv ntxiv decomposition ntawm SiC. Lub fluidity, reactivity thiab kub siab wettability ntawm sintered daim ntawv cog lus tsis zoo. Nws cov cuab yeej sib tsoo muaj qhov porosity tsawg, kev sib tsoo tsis zoo, thiab yooj yim rau hlawv lub workpiece, thiab feem ntau yog siv rau SiC sib tsoo cov cuab yeej nrog siab hardness.
Cov khoom siv feem ntau siv rau SiC abrasives yog av nplaum-feldspar-quartz, av nplaum-feldspar-quartz-talc, av nplaum-feldspar-boron iav, thiab lwm yam. Cov khoom siv raw ntawm av nplaum-feldspar quartz binder yog li ntawm 15% mus rau 30% rau quartz, 40% mus rau 65% rau feldspar, thiab 20% mus rau 35% rau av nplaum, feem ntau yog sintered binders. Lub sintered binder yog nkig, thiab cov cuab yeej sib tsoo yog tsim rau kev sib tsoo nyuaj workpieces. Clay-feldspar - quartz-talc binder yog sintered binder, feem ntau yog siv rau hauv kev tsim cov SiC abrasives saum toj no hardness theem, nrog ib tug loj acid-base piv, thiab muaj zog muaj peev xwm los tiv thaiv "lub siab dub" thiab tiv thaiv abrasives los ntawm redness. Lub zog ntawm cov av nplaum-feldspar-boron iav daim ntawv cog lus yog siab, haum rau kev tsim 60m / s high-speed SiC sib tsoo log, hom kev sib cog lus no yog sintered daim ntawv cog lus, cov kua qaub-puag piv yog loj, cov khoom tsis yooj yim rau tsim "black heart" phenomenon.
(3) Binder rau pob zeb diamond thiab cubic boron nitride abrasive cov cuab yeej
Vim tias qhov tsis zoo thermal stability ntawm pob zeb diamond thiab cubic boron nitride, lub ultra-hard abrasive binder yuav tsum raug rho tawm ntawm qhov kub thiab txias, thiab qhov kub ntawm qhov hluav taws kub tsis tshua muaj melting binder muaj cov yam ntxwv hauv qab no.
① Cov hluav taws kub tsis tshua muaj hluav taws xob tsawg tuaj yeem txuag cov nqi roj thiab txo lub voj voog hluav taws xob.
② tuaj yeem txhim kho qhov zoo ntawm cov cuab yeej abrasive, txo cov khoom pov tseg. Kev tua hluav taws kub tsawg tuaj yeem zam lub pob zeb diamond, cubic boron nitride kub thermal stability tsis zoo
③ Cov binders uas tsis tshua muaj melting nyob rau hauv chav tsev kub yog av nplaum-feldspar-boron iav-fluorite, boron iav-quartz - corundum hmoov - dej khov iav, av nplaum - boron-muaj koob raj mis iav, av nplaum - feldspar - qhov rais iav.
Cov khoom siv iav feem ntau siv hauv pob zeb diamond abrasive khi yog SiO2·ZnO·B2O3 series iav, Na2O·Al2O3·B2O3·SiO2 series iav, SiO2·Al2O3·TiO2·BaO·B2O3 series iav, Cubic boron nitride abrasive feem ntau siv iav khoom SiO2· B2O3·Na2O·PbO·ZnO series iav, vim lub softening kub ntawm sodium borosilicate iav yog tsawg, siab zog, zoo tshuaj stability, yog li feem ntau xaiv rau pob zeb diamond thiab cubic boron nitride ceramic bonding puag iav, thiab ces raws li cov binder tsawg melting point, tsawg expansion. Lub zog siab thiab zoo wettability xav tau qhov sib ntxiv thiab hloov ntawm lwm cov khoom xyaw. Tam sim no, kev siv iav-ceramics ua tus neeg sawv cev ntawm cov ntaub ntawv iav rau kev tsim cov pob zeb diamond thiab cubic boron nitride abrasives. Cov iav-ceramics suav nrog silicate, aluminosilicate, fluorosilicate, borate thiab lwm yam iav-ceramics. Ntawm lawv, fluoro-silicate iav-ceramics feem ntau yog siv los ua cov khoom sib txuas. Nws yog ua raws li MgO· Al2O3-sio2 system, ntxiv zog co-solvent fluorine thiab poov tshuaj kom txo cov av noo thiab crystallization kub ntawm fluoro-silicate iav-ceramics, kom nws ncav cuag qhov qis melting point. los ntawm superhard material bonding agents.
