氧(yang)化(hua)鋯(gao)(gao)(gao)器的(de)(de)測(ce)量原理以及結構特點：氧(yang)化(hua)鋯(gao)(gao)(gao)傳(chuan)感(gan)器的(de)(de)核心構件(jian)是氧(yang)化(hua)鋯(gao)(gao)(gao)固體(ti)電(dian)(dian)解(jie)(jie)質，氧(yang)化(hua)鋯(gao)(gao)(gao)固體(ti)電(dian)(dian)解(jie)(jie)質是由(you)多元氧(yang)化(hua)物組(zu)成(cheng)的(de)(de)。常用的(de)(de)這類電(dian)(dian)解(jie)(jie)質有ZrO2·Y2O3，它由(you)二元氧(yang)化(hua)物組(zu)成(cheng)，其(qi)中(zhong)，ZrO2稱(cheng)(cheng)為(wei)基體(ti)，Y2O3稱(cheng)(cheng)為(wei)穩定劑。ZrO2在常溫下是單斜(xie)晶體(ti)，在高溫下它變成(cheng)立方晶體(ti)(螢石(shi)型(xing))，但(dan)當它冷卻后又(you)變為(wei)單斜(xie)晶體(ti)，因此純氧(yang)化(hua)鋯(gao)(gao)(gao)的(de)(de)晶型(xing)是不穩定的(de)(de)。

    所以當在(zai)ZrO2中摻人一(yi)定量(liang)的(de)(de)穩定劑Y2O3時，由于Y置換了Zr的(de)(de)位置，一(yi)方面(mian)在(zai)晶(jing)(jing)體中留下(xia)了氧離子(zi)(zi)空穴(xue)，另一(yi)方面(mian)由于晶(jing)(jing)體內部(bu)應(ying)力變化(hua)的(de)(de)原因，該(gai)晶(jing)(jing)體冷卻后仍保留立方晶(jing)(jing)體，因此又稱它為穩定氧化(hua)鋯(gao)。據上分析(xi)，穩定氧化(hua)鋯(gao)在(zai)高溫(wen)下(xia)(650℃以上)是氧離子(zi)(zi)的(de)(de)良好導(dao)體。

    典(dian)型(xing)的氧(yang)(yang)化鋯(gao)傳(chuan)感器(qi)是 Pt,P''O2│ZrO2·Y2O3│P'O2,Pt 　　在上述電(dian)(dian)池中，Pt表示兩個(ge)鉑電(dian)(dian)極，它是涂制(zhi)在氧(yang)(yang)化鋯(gao)電(dian)(dian)解質的兩邊，兩種(zhong)氧(yang)(yang)分壓(ya)為P''O2和P'O2的氣(qi)(qi)體分別(bie)通過電(dian)(dian)解質的兩邊。作(zuo)為氧(yang)(yang)傳(chuan)感器(qi)，其中P''O2是參比(bi)氣(qi)(qi)，例(li)如通人空氣(qi)(qi)(20.6%O2)，P'O2是待測(ce)氣(qi)(qi)，例(li)如通入煙氣(qi)(qi)。在高溫(wen)下(xia)，由于氧(yang)(yang)化鋯(gao)電(dian)(dian)解質是良(liang)好(hao)的氧(yang)(yang)離子(zi)導體，上述電(dian)(dian)池便(bian)是一(yi)個(ge)典(dian)型(xing)的氧(yang)(yang)濃差(cha)電(dian)(dian)池。

   在高(gao)溫下(650---850℃)，氧(yang)就會從(cong)分壓(ya)大(da)的(de)(de)P''O2一側(ce)(ce)(ce)向(xiang)分壓(ya)小的(de)(de)P'O2側(ce)(ce)(ce)擴(kuo)散(san)，這種擴(kuo)散(san)，不(bu)是(shi)氧(yang)分子(zi)透(tou)過(guo)(guo)氧(yang)化鋯(gao)從(cong)P''O2側(ce)(ce)(ce)到P'O2側(ce)(ce)(ce)，而是(shi)氧(yang)分子(zi)離(li)(li)解成(cheng)(cheng)(cheng)氧(yang)離(li)(li)子(zi)后，通過(guo)(guo)氧(yang)化鋯(gao)的(de)(de)過(guo)(guo)程。在750℃左右的(de)(de)高(gao)溫中，在鉑(bo)電(dian)(dian)極(ji)的(de)(de)催(cui)化作用下，在電(dian)(dian)池(chi)的(de)(de)P''O2側(ce)(ce)(ce)發生還原反應，一個氧(yang)分子(zi)從(cong)鉑(bo)電(dian)(dian)極(ji)取得4個電(dian)(dian)子(zi)，變成(cheng)(cheng)(cheng)兩(liang)個氧(yang)離(li)(li)子(zi)(O2-)進入(ru)電(dian)(dian)解質(zhi)，即：O2(P''O2)+4e→2O2- P''O2側(ce)(ce)(ce)鉑(bo)電(dian)(dian)極(ji)由于(yu)大(da)量給出電(dian)(dian)子(zi)而帶正電(dian)(dian)，成(cheng)(cheng)(cheng)為氧(yang)濃差電(dian)(dian)池(chi)的(de)(de)正極(ji)或陽極(ji)。

    這些氧(yang)(yang)(yang)離子進入電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)質(zhi)后，通過(guo)晶體中的(de)空穴向(xiang)前運動到達右側的(de)鉑(bo)電(dian)(dian)(dian)(dian)(dian)(dian)極，在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)P'O2側發生氧(yang)(yang)(yang)化反應(ying)，氧(yang)(yang)(yang)離子在(zai)鉑(bo)電(dian)(dian)(dian)(dian)(dian)(dian)極上(shang)釋放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)子并結合成(cheng)(cheng)(cheng)氧(yang)(yang)(yang)分子析(xi)出，即： 　　2O－4e→O2(P'O2) 　　P'O2側鉑(bo)電(dian)(dian)(dian)(dian)(dian)(dian)極由于(yu)大量得到電(dian)(dian)(dian)(dian)(dian)(dian)子而帶負(fu)(fu)電(dian)(dian)(dian)(dian)(dian)(dian)，成(cheng)(cheng)(cheng)為氧(yang)(yang)(yang)濃差(cha)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)負(fu)(fu)極或(huo)陰極。這樣在(zai)兩個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)極上(shang)，由于(yu)正負(fu)(fu)電(dian)(dian)(dian)(dian)(dian)(dian)荷的(de)堆積而形成(cheng)(cheng)(cheng)一(yi)個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)，稱之為氧(yang)(yang)(yang)濃差(cha)電(dian)(dian)(dian)(dian)(dian)(dian)動勢(shi)。當(dang)用導(dao)線(xian)將兩個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)極連成(cheng)(cheng)(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)時，負(fu)(fu)極上(shang)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)子就(jiu)(jiu)會通過(guo)外(wai)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)流(liu)(liu)到正極，再(zai)供(gong)給氧(yang)(yang)(yang)分子形成(cheng)(cheng)(cheng)離子，電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中就(jiu)(jiu)有(you)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)通過(guo)。

    其池電(dian)勢(shi)由(you)(you)能斯特方(fang)程給(gei)出(chu)： 　　E=RT/4F×ln(P''O2/P'O2) 　　式中(zhong)(zhong)R為(wei)(wei)氣(qi)(qi)體(ti)常數，T為(wei)(wei)電(dian)池的(de)(de)熱(re)力學(xue)溫度(du)(K)，F為(wei)(wei)法拉第常數．(1)式是在(zai)理想(xiang)狀態下導出(chu)的(de)(de)， 必須具有四個條件：(1)兩邊的(de)(de)氣(qi)(qi)體(ti)均為(wei)(wei)理想(xiang)氣(qi)(qi)體(ti)；(2)整個電(dian)池處于恒溫恒壓系統中(zhong)(zhong)；(3)濃差電(dian)池是可逆的(de)(de)；(4)電(dian)池中(zhong)(zhong)不(bu)存在(zai)任何(he)附加電(dian)勢(shi)。因此稱(1)式為(wei)(wei)氧(yang)化鋯傳感器的(de)(de)理論(lun)方(fang)程。由(you)(you)(1)式可見(jian)由(you)(you)于參比氣(qi)(qi)氧(yang)含量P''O2是已知的(de)(de)，因此測得E值后(hou)便可求得待測氣(qi)(qi)體(ti)氧(yang)含量P'O2值。

    當電(dian)池工作(zuo)溫度固(gu)定于700℃時，上式為(wei)： 　　E=48.26lg(P''O2/P'O2) 　　由上式，在(zai)溫度700℃時，當固(gu)體電(dian)介(jie)質一(yi)(yi)側氧(yang)(yang)分壓為(wei)空氣(20.6%) 時，由濃差電(dian)池輸出(chu)電(dian)動(dong)勢(shi)E，就可(ke)以計算出(chu)固(gu)體電(dian)介(jie)質另(ling)一(yi)(yi)側氧(yang)(yang)分壓，這(zhe)就是氧(yang)(yang)化鋯氧(yang)(yang)量分析儀的測氧(yang)(yang)原理。

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