還原再氧化工藝制備Pr-ZnO基壓敏陶瓷
發(fā)布時間：2019-06-22 10:35
【摘要】：疊層片式壓敏電阻器具有非線性高、響應速度快、通流能力強等優(yōu)點,在電路中可以起到過電壓保護、吸收瞬間電壓浪涌等作用。目前疊層片式壓敏電阻器采用的內電極主要是貴金屬Ag或Ag/Pd合金,使用貴金屬不僅制造成本高,另外Ag在高溫下容易滲入疊層而惡化壓敏性能。而如果采用賤金屬作為內電極,由于賤金屬在傳統(tǒng)的在空氣氣氛中燒結極易被氧化,影響其導電性。因此,本文通過還原再氧化工藝制備出低電壓的壓敏陶瓷,即先在保護氣氛燒結保護賤金屬不被氧化,然后在空氣中較低溫度下熱處理提升壓敏性能。這種新的方法為制備疊層片式壓敏電阻采用賤金屬做電極提供了可能。首先研究了ZnO-Pr6O11-Co2O3-x MnO2材料在N2中燒結特性和電性能,發(fā)現N2中燒結后材料失重高、密度低、平均晶粒尺寸小、電阻率低。再氧化后材料可以獲得壓敏性能,并且在900℃范圍內,再氧化溫度升高材料的壓敏性能持續(xù)上升。此外,燒結溫度升高,出現由于密度上升而材料難以氧化的現象,最后在1230℃、MnO2摻雜量為0.25 mol%取得最佳壓敏性能(壓敏場強208 V/mm,非線性系數11,漏電流15.4?A)。液相高溫揮發(fā)和冷卻收縮給材料帶來氣孔和裂紋,可降低再氧化難度。所以又研究了可帶來液相的助燒劑BN對制備工藝的影響,發(fā)現BN的最佳摻雜量為1.5mol%,再氧化溫度和燒結溫度分別降低至850℃和1193℃。850℃可使材料均勻氧化,更高溫度氧化壓敏性能趨于穩(wěn)定(壓敏場強151 V/mm,非線性系數23,漏流3.7?A)。受液相的作用,燒結溫度對晶粒大小和電性能影響大幅提升。最后發(fā)現再氧化的作用主要包括:(1)促進晶間相沿晶界分布,(2)晶界富集的氧可使晶界中鋅填隙和氧空位的濃度降低,最終提高了勢壘高度和材料的壓敏性能。
[Abstract]:Laminated chip varistors have many advantages, such as high nonlinear, fast response speed, strong current flow ability and so on. They can play the role of overvoltage protection and instantaneous voltage surge in the circuit. At present, the inner electrode of laminated chip varistor is mainly precious metal Ag or Ag/Pd alloy. The use of precious metal not only has high manufacturing cost, but also Ag is easy to infiltrate into the stack at high temperature to deteriorate the varistor performance. If base metal is used as internal electrode, it is easy to be oxidized because base metal is sintered in air atmosphere, which affects its conductivity. Therefore, low voltage varistor ceramics were prepared by reduction and reoxidation process, that is, base metals were sintered in protective atmosphere to protect base metals from oxidation, and then heat treatment at lower temperature in air to improve varistor properties. This new method makes it possible to prepare laminated chip varistors using base metal as electrode. Firstly, the sintering characteristics and electrical properties of ZnO-Pr6O11-Co2O3-x MnO2 materials in N2 were studied. It was found that the sintered materials in N2 had high weightlessness, low density, small average grain size and low resistance. The varistor properties of the materials can be obtained after reoxidation, and the varistor properties of the materials increase with the increase of reoxidation temperature in the range of 900 鈩，
本文編號：2504500
[Abstract]:Laminated chip varistors have many advantages, such as high nonlinear, fast response speed, strong current flow ability and so on. They can play the role of overvoltage protection and instantaneous voltage surge in the circuit. At present, the inner electrode of laminated chip varistor is mainly precious metal Ag or Ag/Pd alloy. The use of precious metal not only has high manufacturing cost, but also Ag is easy to infiltrate into the stack at high temperature to deteriorate the varistor performance. If base metal is used as internal electrode, it is easy to be oxidized because base metal is sintered in air atmosphere, which affects its conductivity. Therefore, low voltage varistor ceramics were prepared by reduction and reoxidation process, that is, base metals were sintered in protective atmosphere to protect base metals from oxidation, and then heat treatment at lower temperature in air to improve varistor properties. This new method makes it possible to prepare laminated chip varistors using base metal as electrode. Firstly, the sintering characteristics and electrical properties of ZnO-Pr6O11-Co2O3-x MnO2 materials in N2 were studied. It was found that the sintered materials in N2 had high weightlessness, low density, small average grain size and low resistance. The varistor properties of the materials can be obtained after reoxidation, and the varistor properties of the materials increase with the increase of reoxidation temperature in the range of 900 鈩，
本文編號：2504500
本文鏈接：http://www.sikaile.net/kejilunwen/dianlilw/2504500.html
教材專著
