Zirconia dur\u0103 Alumina matrice ceramic\u0103 compozit\u0103 cu arm\u0103tur\u0103 de zirconiu ofer\u0103 caracteristici optime de duritate - rezisten\u021b\u0103 la fractur\u0103 - rezisten\u021b\u0103 flexural\u0103. acest tip de ceramic\u0103 de zirconiu tinde s\u0103 fie mai pu\u021bin susceptibil\u0103 la degradarea la temperaturi sc\u0103zute \u0219i la deteriorarea asistat\u0103 de stres \u0219i prezint\u0103, de asemenea, propriet\u0103\u021bi mecanice puternice.<\/p>\n
Zirconia Toughened Alumina prezint\u0103 o matrice de alumin\u0103 dopat\u0103 cu aditivi de oxid de ytriu \u0219i crom pentru a proteja zirconia de degradarea hidrotermal\u0103 prin captarea moleculelor de umiditate pe suprafe\u021bele lor, \u00eempiedic\u00e2nd difuzarea lor \u00een faza de zirconie. \u00cen plus, se \u0219tie c\u0103 ace\u0219ti aditivi reduc cinetica transform\u0103rii fazelor (Pezzotti et al, 2010a).<\/p>\n
Ceramica ZTA prezint\u0103 o rezisten\u021b\u0103 mecanic\u0103 ridicat\u0103 prin \u00eent\u0103rirea prin transformare. Sub tensiune, particulele de zirconiu \u00ee\u0219i schimb\u0103 structura cristalin\u0103 de la structuri cristaline tetragonale metastabile la structuri cristaline monoclinice, provoc\u00e2nd o expansiune a volumului care comprim\u0103 matricea de alumin\u0103 \u00eenconjur\u0103toare, \u00eempiedic\u00e2nd propagarea fisurilor \u0219i cresc\u00e2nd tenacitatea la fractur\u0103.<\/p>\n
Ad\u0103ugarea de oxid de ytriu \u0219i crom la matricea de alumin\u0103 poate cre\u0219te rezisten\u021ba acesteia la atacul chimic din partea apei sau a fluidelor corporale, ceea ce este deosebit de relevant \u00een aplica\u021biile medicale \u00een care coroziunea asistat\u0103 de tensiuni a aluminei poate ap\u0103rea \u00een contact cu apa\/fluidele corporale. Aceast\u0103 caracteristic\u0103 face ca materialul s\u0103 fie \u0219i mai potrivit pentru protec\u021bia \u00eempotriva coroziunii asistate de tensiuni \u00een mediile medicale \u00een care contactul dintre ap\u0103\/fluide corporale ar putea duce la coroziunea asistat\u0103 de tensiuni a substraturilor de alumin\u0103.<\/p>\n
Biolox Delta de la CeramTec este un exemplu de material ceramic ZTA \u0219i a fost implantat \u00een peste 320.000 de capete femurale \u0219i 160.000 de c\u0103ptu\u0219eli acetabulare pentru a oferi rezisten\u021b\u0103, duritate, rezisten\u021b\u0103 la fractur\u0103 \u0219i rezisten\u021b\u0103 la uzur\u0103 care o dep\u0103\u0219esc pe cea a aluminei pure - ceea ce niciun alt biomaterial ceramic utilizat \u00een prezent \u00een aplica\u021bii ortopedice nu poate egala.<\/p>\n
Combina\u021bia de duritate \u0219i rezisten\u021b\u0103 a zirconiului \u00eel face un material de t\u0103iere excelent, \u00een special pentru t\u0103ierea materialelor de \u00eenalt\u0103 performan\u021b\u0103, cum ar fi nitrurile cubice de bor (CBN). Rezisten\u021ba sa superioar\u0103 la uzur\u0103 \u00eei permite s\u0103 suporte viteze mari cu c\u0103ldur\u0103 \u0219i vibra\u021bii reduse fa\u021b\u0103 de sculele din carbur\u0103 de tungsten, fiind \u00een acela\u0219i timp inert din punct de vedere chimic, cu frecare redus\u0103, inert din punct de vedere chimic \u0219i prezent\u00e2nd o duritate la cald, o rezisten\u021b\u0103 la rapire, precum \u0219i o duritate la cald \u0219i o rezisten\u021b\u0103 la rapire bune comparativ cu metalele. \u00cen plus, ZTA prezint\u0103 o dilatare termic\u0103 relativ sc\u0103zut\u0103, ceea ce \u00eel face potrivit pentru prelucrarea mediilor cu con\u021binut de umiditate, cum ar fi CBN sau suprafe\u021bele prelucrabile ale metalelor.<\/p>\n
Garvie et al. (1975) au constatat c\u0103 precipitatele metastabile tetragonale fin dispersate pot fi transformate \u00een faz\u0103 monoclinic\u0103 prin tratamente chimice, oferind propriet\u0103\u021bi mecanice \u00eembun\u0103t\u0103\u021bite, precum rezisten\u021ba la flexiune \u0219i duritatea. Aplica\u021biile comerciale utilizeaz\u0103 stabilizatori pentru a gestiona acest proces de transformare \u0219i a cre\u0219te tenacitatea - de exemplu, CeramTec a comercializat Biolox Delta ZTA cu ytriu ca stabilizator, precum \u0219i aditivi care con\u021bin crom \u0219i stron\u021biu pentru a stimula mecanismele de \u00eent\u0103rire \u00een matricea sa de alumin\u0103.<\/p>\n
Dimensiunile particulelor de zirconiu joac\u0103 un rol esen\u021bial \u00een \u00eent\u0103rire, particulele mai mici asigur\u00e2nd o dispersie mai bun\u0103 \u0219i formarea de microfisuri. \u00cen plus, modificarea raportului dintre zirconiu \u0219i alumin\u0103 permite proiectan\u021bilor s\u0103 adapteze propriet\u0103\u021bile ceramicii \u00een mod specific pentru aplica\u021bii individuale - tije \u0219i tuburi pentru implanturi medicale, man\u0219oane izolatoare pentru componente de aeronave de mare altitudine sau componente auto - toate pot beneficia de piese personalizate create special cu ceramic\u0103 de zirconiu.<\/p>\n
Ceramica de zirconiu este un material dur, rezistent la uzur\u0103 \u0219i stabil termic, care ofer\u0103 o rezisten\u021b\u0103 remarcabil\u0103 la frecare, ceea ce \u00eel face potrivit pentru uneltele de t\u0103iere. Propriet\u0103\u021bile lor - combinate cu elasticitatea ridicat\u0103 \u0219i rezisten\u021ba la fractur\u0103 - fac, de asemenea, din ZTA un material excelent. Atunci c\u00e2nd este \u00eenc\u0103lzit la temperaturi normale, ZTA ofer\u0103 performan\u021be \u00eembun\u0103t\u0103\u021bite fa\u021b\u0103 de alumina pur\u0103, oferind o rezisten\u021b\u0103 la flexiune \u0219i o tenacitate la fractur\u0103 mai ridicate; propriet\u0103\u021bile sale mecanice pot fi chiar adaptate \u00een func\u021bie de nevoile specifice ale aplica\u021biei, pe baza cantit\u0103\u021bii de zirconiu fa\u021b\u0103 de alumin\u0103 prezent\u0103 \u00een compozi\u021bia sa.<\/p>\n
Alumina \u00eent\u0103rit\u0103 cu zirconiu se remarc\u0103 ca o op\u021biune atractiv\u0103 fa\u021b\u0103 de zirconiul monolitic prin propriet\u0103\u021bile sale de \u00eencapsulare. \u00cen timp ce zirconia monolitic\u0103 este susceptibil\u0103 la chimisorb\u021bia moleculelor de ap\u0103 \u0219i la degradarea la temperaturi sc\u0103zute, ZTA ofer\u0103 o matrice protectoare care \u00eencapsuleaz\u0103 transform\u0103rile locale \u00een interiorul s\u0103u, limit\u00e2nd astfel propagarea transform\u0103rilor.<\/p>\n
Mecanismul de \u00eencapsulare al ZTA nu numai c\u0103 previne degradarea la temperaturi sc\u0103zute, dar face, de asemenea, materialul mai pu\u021bin vulnerabil la coroziunea asistat\u0103 de stres \u00een ap\u0103 sau fluide corporale, datorit\u0103 transform\u0103rii localizate de la granule de zirconiu tetragonal la granule de zirconiu monoclinic, care are loc \u00een interiorul fiec\u0103rui gr\u0103unte de zirconiu, \u00een loc s\u0103 se r\u0103sp\u00e2ndeasc\u0103 \u00een \u00eentregul material. \u00cen plus, ZTA este mai pu\u021bin predispus la propagarea fisurilor sub sarcini de oboseal\u0103 datorit\u0103 capacit\u0103\u021bii sale de a rezista la deformare la temperaturi ridicate.<\/p>\n
Alumina \u00eent\u0103rit\u0103 cu zirconiu (ZTA) este rezultatul combin\u0103rii rezisten\u021bei \u0219i durabilit\u0103\u021bii zirconiului cu rezisten\u021ba la abraziune a aluminei pentru un material tehnic avansat care dep\u0103\u0219e\u0219te ambele materiale de unul singur. O ceramic\u0103 compozit\u0103 pe baz\u0103 de zirconiu, ZTA este mult mai durabil\u0103 dec\u00e2t oricare dintre componentele sale individuale; cu o rezisten\u021b\u0103 sporit\u0103 la coroziune, precum \u0219i o rezisten\u021b\u0103 la c\u0103ldur\u0103 mai mare dec\u00e2t aluminele standard.<\/p>\n
Un factor esen\u021bial al durabilit\u0103\u021bii ZTA const\u0103 \u00een capacitatea sa de a-\u0219i men\u021bine faza metastabil\u0103 tetragonal\u0103 chiar \u0219i la temperaturi ridicate, datorit\u0103 \u00eencorpor\u0103rii aluminei ca agent stabilizator \u00een matricea sa. Alumina are, de asemenea, un modul de elasticitate mult mai mare dec\u00e2t zirconiul monolitic, contribuind la absorb\u021bia energiei chimice \u0219i mecanice care, \u00een caz contrar, ar provoca transformarea \u00een faze monoclinice \u0219i degradarea suplimentar\u0103 a Zirconia Toughened Alumina. Testele statice \u0219i ciclice efectuate at\u00e2t pe alumin\u0103, c\u00e2t \u0219i pe zirconiu monolitic au demonstrat c\u0103 ZTA ofer\u0103 o tenacitate \u0219i o tensiune de prag pentru propagarea fisurilor semnificativ superioare celor ale zirconiului monolitic. Combina\u021bia de rezisten\u021b\u0103 ridicat\u0103 \u0219i tenacitate a zirconiului \u0219i aluminei asigur\u0103 o rezisten\u021b\u0103 superioar\u0103 la uzur\u0103 pentru aplica\u021bii purt\u0103toare de sarcin\u0103, ceea ce o face perfect\u0103 pentru utilizarea \u00een componente ortopedice, cum ar fi protezele de \u0219old sau \u00een freze \u0219i unelte industriale, garnituri rezistente la abraziune sau aplica\u021bii miniere.<\/p>","protected":false},"excerpt":{"rendered":"
Zirconia Toughened Alumina (ZTA) – Revolutionizing Strength and Durability Zirconia Toughened Alumina matrix composite ceramic with zirconia reinforcement offers optimal […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[4],"tags":[],"class_list":["post-367","post","type-post","status-publish","format-standard","hentry","category-product-related"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/posts\/367","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/comments?post=367"}],"version-history":[{"count":1,"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/posts\/367\/revisions"}],"predecessor-version":[{"id":368,"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/posts\/367\/revisions\/368"}],"wp:attachment":[{"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/media?parent=367"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/categories?post=367"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aluminaceramics.net\/ro\/wp-json\/wp\/v2\/tags?post=367"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}