Zirconia Toughened Alumina

Zirconia toughened alumina (ZTA) yog cov khoom siv ceramic siab heev uas tau siv dav hauv valve seals, bushings, cov twj tso kua mis thiab cov cuab yeej txiav vim nws lub zog thiab tshuaj lom neeg ruaj khov – raws li pov thawj los ntawm nws muaj peev xwm tiv taus hnyav loads yam tsis muaj degradation tseem ceeb.

ZTA boasts impressive thermal shock kuj thiab tuaj yeem tiv taus kev hloov pauv ntawm qhov kub thiab txias, nrog rau qhov kub ceev viav vias. Nyeem rau kom paub ntau ntxiv txog nws cov khoom siv tshuab!

Hardness

Zirconia ntxiv rau alumina matrix nce nws hardness, tawg toughness thiab flexural lub zog thaum nce kev tiv thaiv hnav thiab yaig. Cov txheej txheem feem ntau koom nrog yog theem kev hloov pauv raws li kev tsim microcrack tab sis kuj tseem tuaj yeem koom nrog kev ntxhov siab kev xav theories raws li siv tau.

Metastable tetragonal zirconia precipitates uas tsim kom zoo dispersion nyob rau hauv ib tug alumina matrix tuaj yeem raug hloov pauv hloov mus rau hauv cov ntaub ntawv monoclinic thaum lawv txwv tau nqa thaum lub sijhawm tawg., muab lub zog tawm tsam kev ntxhov siab ua rau kev tawg tawg.

ZTA ceramics muaj superior tawg toughness thiab hardness piv rau lwm yam oxide-based engineering ceramics, zoo li ob zaug lub zog cyclic qaug zog ntawm Y-TZP. Xws li, nws cov khoom ua rau nws haum rau cov ntawv thov uas yuav tsum tau hnav tsis kam, chemical inertness thiab tsis tshua muaj kev sib txhuam nrog rau siab zog thiab nruj.

Flexural zog

ZTA ceramics tuaj yeem tsim los ntawm kev hloov pauv qhov piv ntawm yttria stabilized zirconia (Y-TZP) nyob rau hauv ib qho alumina matrix siv kub isostatic nias, kom optimize hardness-fracture toughness-flexural zog ua ke ua ke uas ua rau unparalleled cyclic qaug zog tiv taus tshaj feem ntau advanced technical ceramics.

Metastable Y-TZP nyob rau hauv alumina matrix tshwm sim nyob rau hauv tsim ntawm tetragonal-monoclinic transformation theem agglomerates uas ua rau kom pob txha toughness los ntawm theem transformation stiffening (Clausen 1976). Nyiam hla cov kab nrib pleb, cov kev hloov pauv agglomerate no yuav ua rau thaj tsam ua ntej ntawm qhov tawg pem hauv ntej thiab txo nws txoj kev loj hlob, Thaum kawg nce pob txha toughness.

Cov khoom siv no tau coj mus rau kev tsim cov alumina-zirconia composites xws li BIOLOX Delta, siv dav rau tag nrho lub duav hloov thiab lwm yam load-bearing orthopedic Cheebtsam. Qhov no ceramic biomaterial nta zoo heev hnav tsis kam, tshuaj inertness ntawm chav tsev kub, thermal shock kuj thiab zoo heev tshuaj inertness nyob rau hauv tag nrho cov kub.

Corrosion Resistance

Chemically inert thiab resistant rau kub thiab hnav, nws muab superior kev ua tau zoo piv rau 99 alumina ceramics thiab yog tus nqi ntau dua thiab.

Zirconia kuj boasts impressive tensile zog, flexural thiab elasticity zog thiab biocompatibility – ua rau nws zoo tagnrho rau kev siv kho mob xws li kev hloov lub duav. Vim transformation toughening nyob rau hauv kev nyuaj siab tej yam kev mob, zirconia hais hloov los ntawm metastable tetragonal daim ntawv rau hauv daim ntawv monoclinic, pab kaw cov kab nrib pleb zoo dua thaum ua kom tawg toughness.

CeramTec (Biolox Delta) ua lag luam ua ib qho alumina-zirconia composite qhov twg unstabilized zirconia tseem nyob rau hauv tetragonal theem los tswj qhov kev hloov no thiab muab cov pob tawg blunting thiab tawg sib txawv., txhim kho toughness ntawm alumina matrix. Zirconia cov ntsiab lus ntawm cov khoom tuaj yeem hloov pauv los ntawm kev npaj hmoov thiab cov txheej txheem densification.

Thermal Shock Resistance

Zirconia ntxiv rau thawj alumina matrix thaum sintering tuaj yeem txhim kho nws lub zog thiab tawv., tsim qhov hu ua ZTA (Zirconia Toughened Alumina), outperforming li niaj zaus alumina ceramics nyob rau hauv ob qho tib si mechanical thiab hnav daim ntaub ntawv.

Zirconia toughened alumina tau sau tseg rau nws cov khoom tshwj xeeb xws li kub kub hardness thiab zoo heev lub zog., tshuaj inertness ntawm chav tsev kub, Tsawg thermal expansion tus nqi thiab zoo heev thermal shock kuj – Cov khoom zoo tagnrho rau cov khoom siv milling nrog rau cov khoom hnav uas xav tau cov tshuab cua txias.

CeramTec ua lag luam ZTA hu ua Biolox delta uas nta cov alumina matrix nrog dispersed Y-TZP hais (17 qhov hnyav / wt%) thiab strontium aluminate platelets (0.5 qhov hnyav / wt%), muab kev sib xyaw ua ke zoo ntawm tetragonal-rau-monoclinic theem transformation mechanisms thiab tawg deflection mechanisms los muab kev txhim kho toughness, uas ua rau qhov no zoo tagnrho rau thawj THA cov txheej txheem ntawm femoral bearing nto.

Hluav taws xob rwb thaiv tsev

Zirconia-toughened alumina tuaj yeem tiv taus thermal poob siab yam tsis muaj kev tawg lossis tawg nyob rau hauv kev hloov pauv ntawm qhov kub thiab txias., ua tsaug rau dispersed alumina particles dispersed nyob rau hauv nws matrix uas nqus lub thermal zog thiab tsim compressive kev nyuaj siab uas tiv thaiv puas..

Alumina-zirconia ceramic yog ntom dua li nws cov ntshiab zirconia counterpart, ua rau nws zoo tagnrho rau kev siv hluav taws xob rwb thaiv tsev. Tsis tas li ntawd xwb, nws qis thermal expansion dua zirconia ua rau nws haum rau qhov chaw uas yuav tsum tau txias.

Transformation toughening ntawm Alumina-zirconia composites muaj qhov zoo ntxiv; ntawm no, zirconia nplej hauv alumina matrix tau dhau los ua theem metastable uas lawv cov nplej tau hloov pauv los ntawm tetragonal mus rau monoclinic cov qauv., yog li txo qis kev ntxhov siab vim tawg los ntawm kev ua kom tsis muaj zog tiv thaiv kev puas tsuaj thiab cuam tshuam. Alumina toughened zirconia feem ntau tshwm sim los ntawm pyrophoric cov tshuaj tiv thaiv nrog Zirconium(IV) oxide octahydrate, Aluminium Nitrate Nanohydrate Triethylamine thiab HNO3(Nitric Acid); nce particle loj ntxiv pab dispersion ntawm metastable zirconia nplej.