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　　影(ying)響體積電(dian)阻測(ce)(ce)試儀測(ce)(ce)試的(de)(de)主要(yao)因(yin)素是(shi)溫度和濕(shi)度、電(dian)場強度、充電(dian)時間及殘(can)余(yu)電(dian)荷等。體積電(dian)阻率可作為(wei)選(xuan)擇絕緣材料(liao)的(de)(de)一(yi)個參數(shu)，電(dian)阻率隨(sui)溫度和濕(shi)度的(de)(de)變化(hua)而顯著變化(hua)。體積電(dian)阻率的(de)(de)測(ce)(ce)量常常用(yong)來檢(jian)查絕緣材料(liao)是(shi)否均勻，或者用(yong)來檢(jian)測(ce)(ce)那些能(neng)(neng)影(ying)響材料(liao)質量而又不能(neng)(neng)用(yong)其他方法檢(jian)測(ce)(ce)到的(de)(de)導電(dian)雜質。

　　由于體積電(dian)(dian)阻(zu)(zu)(zu)(zu)總是要(yao)被或(huo)(huo)多或(huo)(huo)少地(di)包(bao)括到(dao)表面(mian)電(dian)(dian)阻(zu)(zu)(zu)(zu)的(de)(de)測(ce)(ce)試中去，因此只能近似地(di)測(ce)(ce)量表面(mian)電(dian)(dian)阻(zu)(zu)(zu)(zu)，測(ce)(ce)得的(de)(de)表面(mian)電(dian)(dian)阻(zu)(zu)(zu)(zu)值(zhi)主要(yao)反(fan)映被測(ce)(ce)試樣(yang)表面(mian)污染的(de)(de)程度(du)。所(suo)以，表面(mian)電(dian)(dian)阻(zu)(zu)(zu)(zu)率(lv)不(bu)是表征材(cai)料(liao)本(ben)身特性(xing)的(de)(de)參(can)數(shu)，而是一個有關材(cai)料(liao)表面(mian)污染特性(xing)的(de)(de)參(can)數(shu)。當表面(mian)電(dian)(dian)阻(zu)(zu)(zu)(zu)較高時，它常隨時間以不(bu)規則的(de)(de)方式變化(hua)。

　　影響體積電阻測試儀測試的因素(su)主要有以下幾點：

　　1、溫度和濕度

　　固體(ti)絕(jue)(jue)緣(yuan)材(cai)料的(de)(de)(de)絕(jue)(jue)緣(yuan)電(dian)(dian)(dian)阻率(lv)(lv)隨(sui)溫(wen)度(du)和(he)濕度(du)的(de)(de)(de)升高而降低(di)，特(te)別(bie)是體(ti)積電(dian)(dian)(dian)阻率(lv)(lv)隨(sui)溫(wen)度(du)改變而變化非常(chang)大。因(yin)此(ci)，電(dian)(dian)(dian)瓷材(cai)料不但(dan)要測(ce)定常(chang)溫(wen)下的(de)(de)(de)體(ti)積電(dian)(dian)(dian)阻率(lv)(lv)，而且還要測(ce)定高溫(wen)下的(de)(de)(de)體(ti)積電(dian)(dian)(dian)阻率(lv)(lv)，以評定其(qi)絕(jue)(jue)緣(yuan)性能的(de)(de)(de)好壞(huai)。由于水的(de)(de)(de)電(dian)(dian)(dian)導大，隨(sui)著(zhu)濕度(du)增大，表面電(dian)(dian)(dian)阻率(lv)(lv)和(he)有開口(kou)孔隙的(de)(de)(de)電(dian)(dian)(dian)瓷材(cai)料的(de)(de)(de)體(ti)積電(dian)(dian)(dian)阻率(lv)(lv)急劇(ju)下降。因(yin)此(ci)，測(ce)定時應嚴格地按照規定的(de)(de)(de)試(shi)樣處理要求和(he)測(ce)試(shi)的(de)(de)(de)環(huan)境條件下進行。

　　2、殘余電荷

　　試(shi)樣在(zai)加(jia)工和(he)測(ce)試(shi)等過(guo)程中，可能產生(sheng)靜電(dian)(dian)，電(dian)(dian)阻越高越容易產生(sheng)靜電(dian)(dian)，影響測(ce)量的準確性。因此，體(ti)積電(dian)(dian)阻測(ce)試(shi)儀(yi)在(zai)測(ce)量時，試(shi)樣要*放電(dian)(dian)，即可將幾個(ge)電(dian)(dian)極連在(zai)一(yi)起進(jin)行短路。

　　3、電場強度

　　當電(dian)場(chang)強度比較(jiao)高時(shi)，離(li)子的(de)遷移率隨電(dian)場(chang)強度增(zeng)高而增(zeng)大(da)(da)，而且在接近擊穿(chuan)時(shi)還(huan)會(hui)出現大(da)(da)量(liang)的(de)電(dian)子遷移，這(zhe)時(shi)體積電(dian)阻率大(da)(da)大(da)(da)地降(jiang)低(di)。因此(ci)在測定(ding)時(shi)，施(shi)加(jia)的(de)電(dian)壓(ya)應不(bu)超過規定(ding)的(de)值(zhi)。

　　4、雜散電勢(shi)的(de)消除

　　在絕緣(yuan)電(dian)阻測量電(dian)路中，可能存在某些(xie)雜(za)(za)散電(dian)勢(shi)(shi)，如(ru)熱電(dian)勢(shi)(shi)、電(dian)解電(dian)勢(shi)(shi)、接(jie)觸電(dian)勢(shi)(shi)等(deng)，其中影響zui大的為電(dian)解電(dian)勢(shi)(shi)。用高阻計(ji)測量表(biao)面潮(chao)濕的試樣的體積(ji)電(dian)阻時，測量極(ji)(ji)與保(bao)護(hu)極(ji)(ji)間(jian)可產生20mv的電(dian)勢(shi)(shi)。試驗前應(ying)檢查有無(wu)(wu)雜(za)(za)散電(dian)勢(shi)(shi)。可根據試樣加壓前后高阻計(ji)的二(er)次指示是否相(xiang)同(tong)來判斷有無(wu)(wu)雜(za)(za)散電(dian)勢(shi)(shi)。如(ru)相(xiang)同(tong)，證(zheng)明(ming)無(wu)(wu)雜(za)(za)散電(dian)勢(shi)(shi);否則應(ying)當尋找并排除產生雜(za)(za)散電(dian)勢(shi)(shi)的根源(yuan)，才能進(jin)行測量。

　　5、防止漏(lou)電流的影響

　　對于高(gao)(gao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)材料，只(zhi)有采取(qu)保(bao)(bao)護(hu)技術才能去除漏(lou)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流對測(ce)(ce)量的(de)影響。保(bao)(bao)護(hu)技術就是在引(yin)起(qi)測(ce)(ce)量誤(wu)差的(de)漏(lou)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)徑上(shang)安置(zhi)保(bao)(bao)護(hu)導(dao)(dao)體(ti)，截住(zhu)可能引(yin)起(qi)測(ce)(ce)量誤(wu)差的(de)雜散電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流，使之不流經(jing)測(ce)(ce)量回路(lu)或儀表(biao)。保(bao)(bao)護(hu)導(dao)(dao)體(ti)連(lian)接(jie)(jie)在一起(qi)構成(cheng)保(bao)(bao)護(hu)端，通常保(bao)(bao)護(hu)端接(jie)(jie)地。體(ti)積(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)測(ce)(ce)試儀測(ce)(ce)量體(ti)積(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)時，三電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)系統的(de)保(bao)(bao)護(hu)極(ji)就是保(bao)(bao)護(hu)導(dao)(dao)體(ti)。此時要求保(bao)(bao)護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)和測(ce)(ce)量電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)間的(de)試樣表(biao)面電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)高(gao)(gao)于與它并聯元件的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)10～100倍。線路(lu)接(jie)(jie)好(hao)后，應首先檢查(cha)是否存在漏(lou)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。此時斷開與試樣連(lian)接(jie)(jie)的(de)高(gao)(gao)壓線，加上(shang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓。如在測(ce)(ce)量靈敏度范圍內，測(ce)(ce)量儀器指示的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)值為無(wu)限大(da)，則線路(lu)無(wu)漏(lou)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，可進行測(ce)(ce)量。

　　6、電化(hua)時(shi)間的規定

　　當(dang)直流(liu)電(dian)(dian)(dian)(dian)(dian)壓加到(dao)(dao)與試樣接觸的(de)(de)(de)兩電(dian)(dian)(dian)(dian)(dian)極間(jian)時(shi)(shi)(shi)，通過試樣的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)會指數(shu)式地衰減到(dao)(dao)一個(ge)穩定值。電(dian)(dian)(dian)(dian)(dian)流(liu)隨時(shi)(shi)(shi)間(jian)的(de)(de)(de)減小可能(neng)(neng)是由于電(dian)(dian)(dian)(dian)(dian)介質極化和可動離子位(wei)移到(dao)(dao)電(dian)(dian)(dian)(dian)(dian)極所致。對于體(ti)積電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)率小于1010Ω·m的(de)(de)(de)材(cai)料，其(qi)穩定狀態通常在1分鐘(zhong)(zhong)內達到(dao)(dao)。因(yin)此(ci)，要(yao)(yao)(yao)經(jing)過這個(ge)電(dian)(dian)(dian)(dian)(dian)化時(shi)(shi)(shi)間(jian)后測(ce)定電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)。對于電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)率較高(gao)(gao)的(de)(de)(de)材(cai)料，電(dian)(dian)(dian)(dian)(dian)流(liu)減小的(de)(de)(de)過程(cheng)可能(neng)(neng)會持續(xu)幾分鐘(zhong)(zhong)、幾小時(shi)(shi)(shi)、幾天(tian)，因(yin)此(ci)需要(yao)(yao)(yao)用(yong)較長的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)化時(shi)(shi)(shi)間(jian)。如果需要(yao)(yao)(yao)的(de)(de)(de)話(hua)，可用(yong)體(ti)積電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)率與時(shi)(shi)(shi)間(jian)的(de)(de)(de)關系來描述材(cai)料的(de)(de)(de)特(te)性。當(dang)表面(mian)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)較高(gao)(gao)時(shi)(shi)(shi)，它常隨時(shi)(shi)(shi)間(jian)以(yi)不規則的(de)(de)(de)方式變(bian)化。測(ce)量表面(mian)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)通常都規定1分鐘(zhong)(zhong)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)化時(shi)(shi)(shi)間(jian)。

　　7、條件處(chu)理(li)和測試條件的規定

　　固體絕(jue)緣材料(liao)(liao)(liao)的(de)電阻隨溫度、濕度的(de)增加而下(xia)降。試樣的(de)預(yu)(yu)(yu)處(chu)(chu)理條件(jian)(jian)取(qu)決于被測材料(liao)(liao)(liao)，這些條件(jian)(jian)在(zai)(zai)材料(liao)(liao)(liao)規范中規定。推薦(jian)使用GB10580《固體絕(jue)緣材料(liao)(liao)(liao)在(zai)(zai)試驗前和(he)(he)試驗時(shi)(shi)(shi)(shi)采(cai)用的(de)標準條件(jian)(jian)》中規定的(de)預(yu)(yu)(yu)處(chu)(chu)理方法。可(ke)使用甘油—水溶液潮濕箱(xiang)進行濕度預(yu)(yu)(yu)處(chu)(chu)理。測試條件(jian)(jian)應與(yu)預(yu)(yu)(yu)處(chu)(chu)理條件(jian)(jian)盡可(ke)能地一致，有些時(shi)(shi)(shi)(shi)候(hou)(如(ru)浸(jin)水處(chu)(chu)理)不能保持預(yu)(yu)(yu)處(chu)(chu)理條件(jian)(jian)和(he)(he)測試條件(jian)(jian)一致時(shi)(shi)(shi)(shi)，則應在(zai)(zai)從預(yu)(yu)(yu)處(chu)(chu)理環境中取(qu)出后(hou)在(zai)(zai)盡可(ke)能短時(shi)(shi)(shi)(shi)間內完成(cheng)測試，一般(ban)不超過5分鐘。

　　以上七個因素或多或少的影響體積電阻測試儀的使用，希(xi)望客(ke)戶能夠加以重(zhong)視(shi)。