{"id":62671,"date":"2022-10-11T20:38:48","date_gmt":"2022-10-12T01:38:48","guid":{"rendered":"https:\/\/www.bjultrasonic.com\/piezo-ceramics-reason-to-the-existence-of-piezoelectricity\/"},"modified":"2025-01-27T06:14:54","modified_gmt":"2025-01-27T11:14:54","slug":"piezo-ceramics-reason-to-the-existence-of-piezoelectricity","status":"publish","type":"post","link":"https:\/\/www.bjultrasonic.com\/cs\/piezo-ceramics-reason-to-the-existence-of-piezoelectricity\/","title":{"rendered":"Piezokeradika: Podstata piezoelektrick\u00e9ho jevu"},"content":{"rendered":"<p>Piezoelekt\u0159ina, jev, p\u0159i kter\u00e9m se v n\u011bkter\u00fdch materi\u00e1lech objevuje elektrick\u00e9 nap\u011bt\u00ed v d\u016fsledku mechanick\u00e9ho nam\u00e1h\u00e1n\u00ed, a naopak, mechanick\u00e1 deformace v d\u016fsledku p\u016fsoben\u00ed elektrick\u00e9ho pole, je fascinuj\u00edc\u00ed oblast\u00ed fyziky s rozs\u00e1hl\u00fdmi aplikacemi.  Jedn\u00edm z kl\u00ed\u010dov\u00fdch materi\u00e1l\u016f, kter\u00e9 tento jev vykazuj\u00ed, jsou piezoelektrick\u00e9 keramiky. Jejich existence a schopnost generovat piezoelekt\u0159inu je \u00fazce spjata s jejich krystalovou strukturou a specifick\u00fdmi chemick\u00fdmi vlastnostmi.<\/p>\n<h3>Krystalov\u00e1 struktura a polarizace<\/h3>\n<p>Piezoelektrick\u00e9 vlastnosti keramiky vypl\u00fdvaj\u00ed z asymetrie jejich krystalov\u00e9 m\u0159\u00ed\u017eky. Na rozd\u00edl od materi\u00e1l\u016f s centrovanou kubickou m\u0159\u00ed\u017ekou, kter\u00e9 nejsou piezoelektrick\u00e9, piezoelektrick\u00e9 keramiky, jako je nap\u0159\u00edklad titan\u00e1t barnat\u00fd (BaTiO\u2083) nebo zirkon\u00e1t olovnat\u00fd titani\u010dit\u00fd (PZT), vykazuj\u00ed necentrovanou krystalovou strukturu.  Tato asymetrie umo\u017e\u0148uje existenci spont\u00e1nn\u00ed polarizace, co\u017e znamen\u00e1, \u017ee elektrick\u00e9 dip\u00f3ly v krystalov\u00e9 m\u0159\u00ed\u017ece jsou uspo\u0159\u00e1d\u00e1ny ne n\u00e1hodn\u011b, ale preferen\u010dn\u011b v jednom sm\u011bru.  Toto uspo\u0159\u00e1d\u00e1n\u00ed je kl\u00ed\u010dov\u00e9 pro vznik piezoelektrick\u00e9ho efektu.  Mechanick\u00e9 nam\u00e1h\u00e1n\u00ed naru\u0161uje tuto uspo\u0159\u00e1danost a vede k vzniku elektrick\u00e9ho n\u00e1boje.<\/p>\n<h3>Dom\u00e9ny a pol\u00e1rn\u00ed orientace<\/h3>\n<p>V nepolarizovan\u00e9 piezoelektrick\u00e9 keramice jsou jednotliv\u00e9 krystalov\u00e9 oblasti, tzv. dom\u00e9ny, orientov\u00e1ny n\u00e1hodn\u011b. To znamen\u00e1, \u017ee spont\u00e1nn\u00ed polarizace jednotliv\u00fdch dom\u00e9n se navz\u00e1jem ru\u0161\u00ed a makroskopicky se keramika jev\u00ed jako nepolarizovan\u00e1.  Aby se projevil piezoelektrick\u00fd efekt, je nutn\u00e9 keramiku polarizovat. To se prov\u00e1d\u00ed aplikac\u00ed siln\u00e9ho elektrick\u00e9ho pole p\u0159i vysok\u00e9 teplot\u011b, co\u017e vede k uspo\u0159\u00e1d\u00e1n\u00ed dom\u00e9n a vytvo\u0159en\u00ed preferen\u010dn\u00ed orientace spont\u00e1nn\u00edch dip\u00f3l\u016f.  Tento proces je nezbytn\u00fd pro dosa\u017een\u00ed v\u00fdrazn\u00e9ho piezoelektrick\u00e9ho efektu.<\/p>\n<h3>Chemick\u00e9 slo\u017een\u00ed a modifikace<\/h3>\n<p>Chemick\u00e9 slo\u017een\u00ed piezoelektrick\u00e9 keramiky hraje z\u00e1sadn\u00ed roli v ur\u010den\u00ed jejich piezoelektrick\u00fdch vlastnost\u00ed.  R\u016fzn\u00e9 kombinace prvk\u016f vedou k r\u016fzn\u00fdm krystalov\u00fdm struktur\u00e1m a intenzit\u011b spont\u00e1nn\u00ed polarizace.  V\u011bdci neust\u00e1le zkoumaj\u00ed nov\u00e9 kompozice a modifikace, aby optimalizovali vlastnosti keramiky pro specifick\u00e9 aplikace. Nap\u0159\u00edklad,  PZT keramika je zn\u00e1m\u00e1 svou vysokou piezoelektrickou aktivitou a pou\u017e\u00edv\u00e1 se v \u0161irok\u00e9 \u0161k\u00e1le aplikac\u00ed.<\/p>\n<table class=\"table table-striped table-bordered\">\n<thead>\n<tr>\n<th>Materi\u00e1l<\/th>\n<th>Chemick\u00fd vzorec<\/th>\n<th>Piezoelektrick\u00e1 konstanta (pC\/N)<\/th>\n<th>Aplikace<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Titan\u00e1t barnat\u00fd<\/td>\n<td>BaTiO\u2083<\/td>\n<td>190<\/td>\n<td>Senzory, aktu\u00e1tory<\/td>\n<\/tr>\n<tr>\n<td>Zirkon\u00e1t olovnat\u00fd titani\u010dit\u00fd (PZT)<\/td>\n<td>Pb(ZrxTi1-x)O\u2083<\/td>\n<td>200-700<\/td>\n<td>Ultrazvukov\u00e9 sn\u00edma\u010de, aktu\u00e1tory, zapalova\u010de<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Vyu\u017eit\u00ed piezoelektrick\u00fdch keramick\u00fdch materi\u00e1l\u016f<\/h3>\n<p>Piezoelektrick\u00e9 keramiky nach\u00e1zej\u00ed \u0161irok\u00e9 uplatn\u011bn\u00ed v mnoha oblastech techniky.  D\u00edky sv\u00e9 schopnosti p\u0159ev\u00e1d\u011bt mechanickou energii na elektrickou a naopak, se pou\u017e\u00edvaj\u00ed v senzorech tlaku, urychlen\u00ed, vibrac\u00ed, ale i v aktu\u00e1torech pro p\u0159esn\u00e9 polohov\u00e1n\u00ed, ultrazvukov\u00fdch za\u0159\u00edzen\u00edch a mnoha dal\u0161\u00edch aplikac\u00edch.  V oblasti ultrazvuku, nap\u0159\u00edklad u za\u0159\u00edzen\u00ed od Beijing Ultrasonic, jsou piezoelektrick\u00e9 keramiky kl\u00ed\u010dovou sou\u010d\u00e1st\u00ed pro generov\u00e1n\u00ed a detekci ultrazvukov\u00fdch vln.<\/p>\n<p>Piezoelektrick\u00e9 keramiky p\u0159edstavuj\u00ed fascinuj\u00edc\u00ed materi\u00e1l s jedine\u010dn\u00fdmi vlastnostmi, kter\u00e9 jsou d\u00e1ny jejich krystalovou strukturou, chemick\u00fdm slo\u017een\u00edm a polarizac\u00ed.  Pochopen\u00ed t\u011bchto faktor\u016f je kl\u00ed\u010dov\u00e9 pro dal\u0161\u00ed v\u00fdvoj a optimalizaci jejich vyu\u017eit\u00ed v \u0161irok\u00e9m spektru aplikac\u00ed. Jejich schopnost p\u0159em\u011b\u0148ovat mechanickou energii na energii elektrickou a naopak, d\u011bl\u00e1 z nich nepostradateln\u00fd materi\u00e1l modern\u00ed techniky.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Piezoelekt\u0159ina, jev, p\u0159i kter\u00e9m se v n\u011bkter\u00fdch materi\u00e1lech objevuje elektrick\u00e9 nap\u011bt\u00ed v d\u016fsledku mechanick\u00e9ho nam\u00e1h\u00e1n\u00ed, a naopak, mechanick\u00e1 deformace v d\u016fsledku p\u016fsoben\u00ed elektrick\u00e9ho pole, je fascinuj\u00edc\u00ed oblast\u00ed fyziky s rozs\u00e1hl\u00fdmi aplikacemi. Jedn\u00edm z kl\u00ed\u010dov\u00fdch materi\u00e1l\u016f, kter\u00e9 tento jev vykazuj\u00ed, jsou piezoelektrick\u00e9 keramiky. Jejich existence a schopnost generovat piezoelekt\u0159inu je \u00fazce spjata s jejich krystalovou strukturou<\/p>\n","protected":false},"author":1,"featured_media":557,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6415],"tags":[],"class_list":["post-62671","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","prodpage-classic"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts\/62671","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/comments?post=62671"}],"version-history":[{"count":0,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts\/62671\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/media\/557"}],"wp:attachment":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/media?parent=62671"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/categories?post=62671"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/tags?post=62671"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}