Khoom siv superhard

Dab tsi yog super hard material?

Cov khoom siv superhard yog cov khoom siv hardness ntau tshaj 40 gigapascals (GPa) thaum ntsuas los ntawm Vickers hardness test. Lawv yog cov khoom tsis sib haum xeeb nrog cov khoom siv hluav taws xob siab thiab cov khoom sib txuas siab. Raws li qhov tshwm sim ntawm lawv cov khoom tshwj xeeb, cov ntaub ntawv no muaj kev txaus siab rau ntau qhov chaw muaj xws li, tab sis tsis txwv rau, abrasives, polishing thiab txiav cov cuab yeej, disc nres, thiab hnav-tiv taus thiab tiv thaiv txheej.

Txoj kev mus nrhiav cov ntaub ntawv tshiab superhard

Hauv thawj txoj hauv kev, cov kws tshawb fawb tau ua raws li cov lus qhia luv luv, cov lus qhia cov pa roj carbon monoxide ntawm cov pob zeb diamond los ntawm kev sib txuas cov teeb pom kev zoo xws li boron, carbon, nitrogen, thiab oxygen.

Qhov thib ob txoj hauv kev suav nrog cov ntsiab lus sib zog (B, C, N, thiab O), tab sis kuj qhia txog kev hloov pauv hlau nrog siab valence electron densities los muab siab incompressibility. Nyob rau hauv txoj kev no, cov hlau uas muaj cov khoom loj loj tab sis tsis tshua muaj zog yog koom tes nrog covalent-forming atoms me me los tsim cov ntaub ntawv superhard. Tungsten carbide yog ib qho kev lag luam uas muaj feem cuam tshuam txog qhov kev qhia no, txawm hais tias nws tsis suav tias yog qhov nyuaj heev. Xwb, borides ua ke nrog cov hlau hloov pauv tau dhau los ua qhov chaw nplua nuj ntawm kev tshawb fawb superhard thiab tau coj mus rau kev tshawb pom xws liReB2,OsB2, thiabWB4.

Classification ntawm cov ntaub ntawv superhard

Cov ntaub ntawv superhard feem ntau tuaj yeem muab faib ua ob pawg: cov khoom siv sab hauv thiab cov khoom siv sab nraud. Cov pab pawg muaj xws li pob zeb diamond, cubic boron nitride (c-BN), carbon nitrides, thiab ternary tebchaw xws li B-N-C, uas muaj innate hardness. Conversely, cov ntaub ntawv extrinsic yog cov uas muaj super hardness thiab lwm yam mechanical zog uas yog txiav txim los ntawm lawv cov microstructure es tsis muaj pes tsawg leeg. Ib qho piv txwv ntawm cov khoom siv extrinsic superhard yog nanocrystalline pob zeb diamond hu ua aggregated pob zeb diamond nanorods.

Pob zeb diamond yog cov ntaub ntawv nyuaj tshaj plaws rau hnub tim, nrog Vickers hardness nyob rau hauv thaj tsam ntawm 70-150 GPa. Pob zeb diamond ua kom pom ob qho tib si thermal conductivity thiab hluav taws xob insulating zog, thiab ntau cov xim tau muab tso rau hauv kev nrhiav tswv yim rau cov khoom siv no. Cov khoom ntawm ib tug neeg tej yam ntuj tso pob zeb diamond los yog carbonado sib txawv heev dav rau kev lag luam lub hom phiaj, thiab yog li ntawd hluavtaws pob zeb diamond los ua ib tug loj kev tshawb fawb tsom.

Synthetic pob zeb diamond

Lub siab-siab synthesis ntawm pob zeb diamond nyob rau hauv 1953 nyob rau hauv Sweden thiab nyob rau hauv 1954 nyob rau hauv lub US ua tau los ntawm txoj kev loj hlob ntawm tshiab apparatus thiab cov tswv yim, los ua ib tug tseem ceeb nyob rau hauv lub synthesis ntawm dag superhard khoom. Lub synthesis tau pom meej meej pom lub peev xwm ntawm kev siv hluav taws xob siab rau kev lag luam thiab txhawb kev loj hlob ntawm kev lag luam.

PDC cutter yog ib yam ntawm cov khoom siv tawv tawv uas compacts polycrystalline pob zeb diamond nrog tungsten carbide substrate. Pob zeb diamond yog cov khoom siv tseem ceeb rau PDC cutters. Vim hais tias ntuj pob zeb diamonds nyuaj rau tsim thiab siv sij hawm ntev, lawv kim heev, thiab kim heev rau kev lag luam daim ntawv thov, nyob rau hauv cov ntaub ntawv no, Synthetic pob zeb diamond tau ua lub luag hauj lwm zoo nyob rau hauv kev lag luam.

Yog tias koj txaus siab rau cov khoom lag luam tungsten carbide thiab xav paub ntau ntxiv thiab cov ntsiab lus, koj tuaj yeem tiv tauj peb hauv xov tooj lossis xa ntawv ntawm sab laug, lossis xa mus rau US MAIL hauv qab ntawm nplooj ntawv.