磁(ci)致伸(shen)(shen)縮磁(ci)致伸(shen)(shen)縮有(you)(you)鎳(nie)片換能(neng)器(qi)(qi)(qi)(qi)和鐵(tie)(tie)氧(yang)體(ti)換能(neng)器(qi)(qi)(qi)(qi)。鐵(tie)(tie)氧(yang)體(ti)換能(neng)器(qi)(qi)(qi)(qi)的(de)(de)(de)(de)(de)電(dian)(dian)聲(sheng)(sheng)轉(zhuan)(zhuan)換效(xiao)率比較(jiao)低，使(shi)(shi)用(yong)一、二年后效(xiao)率下(xia)降，ptfe芯(xin)軸(zhou)(zhou)廠家(jia)，甚至幾乎喪失電(dian)(dian)聲(sheng)(sheng)轉(zhuan)(zhuan)換能(neng)力(li)。鎳(nie)片換能(neng)器(qi)(qi)(qi)(qi)的(de)(de)(de)(de)(de)工藝復雜(za)，價(jia)格(ge)昂貴，所以很少使(shi)(shi)用(yong)。壓(ya)(ya)電(dian)(dian)晶(jing)體(ti)成熟(shu)可靠的(de)(de)(de)(de)(de)是以壓(ya)(ya)電(dian)(dian)效(xiao)應實現電(dian)(dian)能(neng)與聲(sheng)(sheng)能(neng)相互轉(zhuan)(zhuan)換的(de)(de)(de)(de)(de)器(qi)(qi)(qi)(qi)件，ptfe芯(xin)軸(zhou)(zhou)哪(na)里有(you)(you)，稱為(wei)壓(ya)(ya)電(dian)(dian)換能(neng)器(qi)(qi)(qi)(qi)。壓(ya)(ya)電(dian)(dian)效(xiao)應將(jiang)電(dian)(dian)信號(hao)轉(zhuan)(zhuan)換為(wei)機械(xie)振動(dong)。這種換能(neng)器(qi)(qi)(qi)(qi)電(dian)(dian)聲(sheng)(sheng)轉(zhuan)(zhuan)換，原(yuan)材料價(jia)格(ge)便宜(yi)，制(zhi)作方便，也(ye)不(bu)容易(yi)老化(hua)。常用(yong)的(de)(de)(de)(de)(de)材料有(you)(you)石(shi)英晶(jing)體(ti)、鈦(tai)(tai)酸鋇和鋯(gao)鈦(tai)(tai)酸鉛(qian)。石(shi)英晶(jing)體(ti)的(de)(de)(de)(de)(de)伸(shen)(shen)縮量(liang)太小(xiao)，3000V電(dian)(dian)壓(ya)(ya)才產生(sheng)0.01um以下(xia)的(de)(de)(de)(de)(de)變形。鈦(tai)(tai)酸鋇的(de)(de)(de)(de)(de)壓(ya)(ya)電(dian)(dian)效(xiao)應比石(shi)英晶(jing)體(ti)大20-30倍，但效(xiao)率和機械(xie)強(qiang)度不(bu)如石(shi)英晶(jing)體(ti)。鋯(gao)鈦(tai)(tai)酸鉛(qian)具有(you)(you)二者的(de)(de)(de)(de)(de)優點，ptfe芯(xin)軸(zhou)(zhou)，可用(yong)作超聲(sheng)(sheng)波清洗，ptfe芯(xin)軸(zhou)(zhou)哪(na)家(jia)好，探傷和小(xiao)功率超聲(sheng)(sheng)波加工的(de)(de)(de)(de)(de)換能(neng)器(qi)(qi)(qi)(qi)。壓(ya)(ya)電(dian)(dian)換能(neng)器(qi)(qi)(qi)(qi)的(de)(de)(de)(de)(de)應用(yong)十分廣泛， 它按應用(yong)的(de)(de)(de)(de)(de)行業(ye)分為(wei)工業(ye)、 農業(ye)、 交通運(yun)輸、生(sheng)活、醫l療及(ji)等。

超聲(sheng)(sheng)(sheng)換(huan)能器的(de)(de)(de)結構壓(ya)電(dian)(dian)晶(jing)體(ti)(ti)是(shi)主體(ti)(ti)功能件，用來(lai)發射(she)(she)(she)和接收超聲(sheng)(sheng)(sheng)波(bo)，完(wan)成聲(sheng)(sheng)(sheng)-電(dian)(dian)和電(dian)(dian)-聲(sheng)(sheng)(sheng)轉換(huan)工(gong)作。其(qi)幾何(he)形(xing)狀(zhuang)和尺寸是(shi)根據診(zhen)斷要求(qiu)來(lai)設(she)計的(de)(de)(de)。由于壓(ya)電(dian)(dian)晶(jing)體(ti)(ti)較脆及要求(qiu)絕(jue)緣(yuan)、密封、防腐蝕(shi)等，故必須將(jiang)壓(ya)電(dian)(dian)晶(jing)體(ti)(ti)裝(zhuang)入殼(ke)體(ti)(ti)內。壓(ya)電(dian)(dian)晶(jing)體(ti)(ti)兩端鍍(du)上電(dian)(dian)極，上、下電(dian)(dian)極分別焊有一根引線，與殼(ke)體(ti)(ti)上的(de)(de)(de)電(dian)(dian)極插件相連，用來(lai)傳輸電(dian)(dian)信號(hao)。墊襯吸聲(sheng)(sheng)(sheng)材(cai)料(liao)(liao)（又稱為吸收塊、吸聲(sheng)(sheng)(sheng)塊）用于衰(shuai)(shuai)減并吸收壓(ya)電(dian)(dian)晶(jing)體(ti)(ti)背(bei)向(xiang)輻射(she)(she)(she)的(de)(de)(de)超聲(sheng)(sheng)(sheng)能量，使之不(bu)在探頭(tou)中來(lai)回反射(she)(she)(she)而使晶(jing)體(ti)(ti)的(de)(de)(de)振鈴時間(jian)加長，因此要求(qiu)墊襯具有較大的(de)(de)(de)衰(shuai)(shuai)減能力，并具有與壓(ya)電(dian)(dian)材(cai)料(liao)(liao)接近的(de)(de)(de)聲(sheng)(sheng)(sheng)阻(zu)抗(kang)，以(yi)使來(lai)自壓(ya)電(dian)(dian)晶(jing)體(ti)(ti)背(bei)向(xiang)輻射(she)(she)(she)的(de)(de)(de)聲(sheng)(sheng)(sheng)波(bo)全部進入墊襯中并不(bu)再反射(she)(she)(she)回到(dao)晶(jing)體(ti)(ti)中去吸聲(sheng)(sheng)(sheng)材(cai)料(liao)(liao)一般為環氧(yang)樹脂加鎢粉(fen)，或鐵氧(yang)體(ti)(ti)粉(fen)加橡膠(jiao)粉(fen)配(pei)合而成。

分類

元件(jian)形(xing)狀按(an)組成換(huan)能器(qi)的壓(ya)電(dian)元件(jian)形(xing)狀分(fen)為(wei)薄板形(xing)， 圓(yuan)片形(xing)， 圓(yuan)環形(xing)， 圓(yuan) 管形(xing)， 圓(yuan)棒形(xing)， 薄殼球形(xing)， 壓(ya)電(dian)薄膜(mo)等;振(zhen)(zhen)動(dong)(dong)模式按(an)振(zhen)(zhen)動(dong)(dong)模式分(fen)為(wei)伸縮振(zhen)(zhen)動(dong)(dong)， 彎曲振(zhen)(zhen)動(dong)(dong)， 扭轉振(zhen)(zhen)動(dong)(dong)等;振(zhen)(zhen)動(dong)(dong)方(fang)向按(an)伸縮振(zhen)(zhen)動(dong)(dong)的方(fang)向分(fen)為(wei)厚度(du)， 切向， 縱(zong)向， 徑向等;壓(ya)電(dian)轉換(huan)方(fang)式按(an)壓(ya)電(dian)轉換(huan)方(fang)式分(fen)為(wei)發射型 ( 電(dian)-聲轉換(huan)) ， 接收型 ( 聲-電(dian)轉換(huan)) ， 收發兼用型等。傳播介(jie)(jie)質按(an)傳播介(jie)(jie)質分(fen)為(wei)液(ye)介(jie)(jie)， 固介(jie)(jie)， 氣介(jie)(jie)等。