Cov ntaub ntawv pob zeb diamond Flattened li cas?

Cov ntaub ntawv pob zeb diamond Flattened li cas?

 

Hailed raws li "qhov kawg ntawm cov khoom siv semiconductor," pob zeb diamond boasts lub hardness unrivaled los ntawm lwm yam khoom nyob rau hauv cov xwm, nrog rau tshwj xeeb tshuaj stability. Txawm hais tias cov yam ntxwv zoo siab heev ua rau nws yog cov khoom siv ntawm kev xaiv, lawv ib txhij nthuav tawm cov teeb meem loj heev thaum ua. Yuav ua li cas kom zoo thiab tsis yog -kev puas tsuaj ua rau qhov "nyuaj" ntawm cov ntaub ntawv tiaj tus thiab du tau ntev los ua ib qho kev sib tw tseem ceeb hauv thaj tsam ntawm ultra- precision machining. Tam sim no, muaj ntau tshaj li nees nkaum qhov sib txawv pob zeb diamond polishing cov txheej txheem raws li kev tshawb fawb thiab daim ntawv thov -xws li tshuab polishing, tshuaj- tshuab polishing, thiab laser polishing. Txawm hais tias cov txheej txheem sib txawv, cov txheej txheem tshem tawm cov txheej txheem hauv qab no tuaj yeem muab faib ua tsib hom: micro- tawg, graphitization, vaporization, sputtering, thiab tshuaj tiv thaiv.

Cov txheej txheem tshem tawm cov tsoos tshaj plaws thiab kev nkag siab zoo yog micro- tawg. Cov txheej txheem no zoo li ntaus ib lub pob zeb tawm tsam lwm tus; nws siv cov pob zeb diamond abrasive cov khoom- lossis txawm tias nyuaj dua ceramic polishing pads- los ua kev sib cuag nrog, compress, thiab abrade lub pob zeb diamond nto nyob rau hauv siab thov. Qhov tshwm sim ntawm cov tshuab shear quab yuam yog txaus los ntxias cov pob txha tawg thiab tawg ntawm cov khoom siv microscopic tawg ntawm pob zeb diamond nto, yog li ua tiav cov khoom tshem tawm. Qhov tseem ceeb tshaj plaws ntawm daim ntawv thov no yog pom nyob rau hauv mechanical lapping thiab polishing cov txheej txheem-txoj kev uas sawv cev rau qhov ntxov tshaj plaws thiab feem ntau siv los ua polishing. Txawm li cas los xij, qhov "nyuaj- ntawm- nyuaj" txoj hauv kev los nrog tus nqi: nws nquag tawm tom qab cov kab nrib pleb thiab cov txheej txheej puas ntawm pob zeb diamond, yog li cuam tshuam qhov kawg ntawm qhov zoo.

 

Qhov thib ob mechanism ingeniously exploits pob zeb diamond "Achilles 'heel": graphitization. Txawm hais tias pob zeb diamond thiab graphite yog allotropes-ob qho tib si tsim los ntawm carbon atoms nkaus xwb- lawv cov qauv atomic txawv heev. Nyob rau hauv pob zeb diamond, carbon atoms yog khi los ntawm robust sp³ hybrid bonds, ua ib tug nruj peb -siv lub lattice qauv uas ua rau cov khoom incredibly nyuaj; conversely, cov pa roj carbon atoms nyob rau hauv graphite siv sp² hybridization los tsim ib txheej txheej nyob rau hauv lub interlayer rog tsis muaj zog, uas ua rau ib tug mos mos zoo nkauj. Interestingly, lub zoo li indestructible pob zeb diamond yeej muaj nyob rau hauv ib tug "metastable lub xeev," whereas lub mos graphite sawv cev rau qhov tseeb "thermodynamically ruaj khov xeev" ntawm carbon. Qhov no txhais tau hais tias, nyob rau hauv tej yam kev mob, pob zeb diamond muaj peev xwm kov yeej nws lub zog barrier thiab undergo ib tug transformation rau hauv graphite. Piv txwv li, thaum tsis muaj catalyst, cua kub pob zeb diamond kom txog li 1500℃ua rau nws nto pib hloov mus rau hauv graphite; Txawm li cas los xij, nrog kev pab cuam catalytic ntawm cov hlau hloov pauv- xws li hlau, cobalt, lossis npib tsib xee- qhov kev hloov pauv no tuaj yeem txo qis mus rau ib puag ncig 700℃. Thermochemical polishing leverages precisely lub hauv paus ntsiab lus no: los ntawm kev ua hauj lwm kub thiab catalytic nkaus, nws "softens" pob zeb diamond nto rau hauv ib tug yooj yim tshem tawm txheej ntawm graphite, yog li ua tau zoo heev planarization.

 

Nrog rau kev nce qib siab ntawm - thev naus laus zis thev naus laus zis, cov kws tshawb fawb tau tshawb pom ob txoj kev tshem tawm "ntau dua" ntau dua: vaporization thiab sputtering. Thaum lub siab - siv lub laser beam tsom mus rau lub pob zeb diamond nto, nws instantaneously generates kub heev nyob rau hauv ib tug minuscule cheeb tsam - ncav cuag cov ntaub ntawv lub melting point (kwv yees li 4000–4500 K) los yog txawm nws boiling point (kwv yees li 5100 K) ncaj qha mus rau lub melting ntawm cov ntaub ntawv, porizing thiab evaporation ntawm cov khoom nyob rau hauv lub melting point (kwv yees li 5100 K). kev txiav zoo los yog tshem tawm cov khoom. Tshaj li cov teebmeem thermal no, luv - wavelength ultraviolet lasers kuj tseem tuaj yeem siv cov teebmeem photochemical kom ncaj qha tshem tawm cov tshuaj sib txuas ntawm cov pa roj carbon atoms, yog li ua kom muaj kev ua haujlwm "txias" ntau dua. Tsis zoo li vaporization, uas tso siab rau cov teebmeem thermal, sputtering (tseem hu ua sputter etching) yog txheej txheem kev sib tsoo lub cev. Nws siv lub siab -zog particle beam- xws li ion beam- txhawm rau foob pob zeb diamond nto; ua zoo li ceev ceev- hluav taws kub ntawm ultra- siab-ceev "molecular mos txwv," cov khoom no hloov lawv lub zog los cuam tshuam cov kev sib raug zoo ntawm cov pa roj carbon atoms, zoo "knocking" lawv tawm ntawm cov siv lead ua lattice. Ion beam polishing yog raws li qhov no heev mechanism; vim tias nws qhov kev tshem tawm qhov tseeb tuaj yeem ncav cuag qib atomic, nws ua rau thaj chaw ntawm qhov zoo tshaj plaws -txawm tias ntawm tus nqi ntawm kev ua haujlwm qis heev thiab kev siv nyiaj siab.

Cov txheej txheem kawg-thiab tam sim no lub hauv paus ntsiab lus tseem ceeb rau kev ua tiav ultra- du, kev puas tsuaj-dawb qhov chaw- yog tshuaj tiv thaiv. Qhov no tsis cuam tshuam rau lub pob zeb diamond ncaj qha rau cov kua qaub lossis cov hauv paus - nrog rau qhov uas nws cuam tshuam tsis zoo ntawm chav sov- tab sis siv cov tshuaj tiv thaiv redox los oxidize cov pa roj carbon atoms ntawm pob zeb diamond nto rau hauv cov khoom gaseous (xws li carbon monoxide lossis carbon dioxide) los yog rau hauv cov khoom siv tshem tawm, yog li kev tshem tawm. Nyob rau hauv cov ntsiab lus ntawm chemical- mechanical polishing, cov khoom tshem tawm tsis yog tsuas yog cov txheej txheem ntawm kev puas tsuaj, tab sis kuj yog kev sib koom ua ke ntawm cov tshuaj tiv thaiv thiab kev ua haujlwm. Ua ntej, muaj zog oxidizing cov neeg ua hauj lwm nyob rau hauv lub polishing kua oxidize lub pob zeb diamond nto, ua ib tug nyias oxide txheej. Tom qab ntawd, cov neeg kho tshuab abrasive kev txiav txim ntawm cov khoom polishing tshem tawm cov oxide txheej no, nthuav tawm cov pob zeb diamond tshiab thiab yog li tso cai rau cov tshuaj tiv thaiv mus tas li. Cov kev tshawb fawb qhia tias kev sib txhuam ntawm cov tshuab kuj tuaj yeem ua rau cov txheej txheem nanoscale ntawm cov lattice distortion ntawm pob zeb diamond nto, ntxiv txo nws cov tshuaj lom neeg ruaj khov thiab ua kom cov tshuaj tiv thaiv sai. Plasma-pab polishing, conversely, siv reactive oxygen los yog hydrogen atoms nyob rau hauv lub plasma los teb nrog cov pa roj carbon atoms ntawm lub pob zeb diamond nto, tsim volatile gases thiab yog li ua tiav kev puas tsuaj -dawb, atomic- teev cov ntaub ntawv tshem tawm.

 

Los ntawm cov txheej txheem kev sib tsoo thaum ub mus rau cov txheej txheem niaj hnub uas muaj kev sib koom ua ke ntawm siab - cov kab hluav taws xob thiab tshuaj lom neeg - cov teebmeem, cov txheej txheem tshem tawm cov khoom siv rau kev ua pob zeb diamond tau hloov zuj zus los ntawm kev vam meej: los ntawm kev cia siab rau lub cev nkaus xwb, mus rau ingeniously harnessing thermal zog, thiab thaum kawg mus rau cov tshuaj tiv thaiv precisely. Txawm hais tias los ntawm lub cev "sub" ntawm micro- tawg, qhov "theem transformation" tshem tawm ntawm graphitization thiab vaporization, los yog "hloov" tshem tawm los ntawm cov tshuaj tiv thaiv, tsib lub tswv yim no tsis muaj nyob hauv kev sib cais. Hauv cov txheej txheem sib xyaw polishing, ntau lub tshuab feem ntau ua haujlwm hauv kev hais kwv txhiaj- sib koom ua ke los ua kom zoo nkauj thiab ua kom zoo dua "Vajntxwv Cov Khoom." Kev nkag siab zoo ntawm cov txheej txheem microscopic no ua lub hauv paus theoretical rau kev ua tau zoo, meej, thiab qis-kev puas tsuaj ntawm cov khoom siv pob zeb diamond.