一次烧成法制备钛酸锶双功能压敏陶瓷工艺及性能研究

【作者】 陈朝霞；

【导师】 甘国友；

【作者基本信息】 昆明理工大学 ， 材料学， 2003， 硕士

【摘要】 钛酸锶压敏陶瓷是一种具有压敏性和电容性双功能的材料，它具有利于低压化，静电容大，对低于标称电压的杂波有抑制作用，而且在吸收陡脉冲时不会出现过渡特性上冲等优点，同时非常有利于电子元件的小型化和集成化。其优良的电性能已得到广泛应用，在各种便携通讯机，计算机系统，汽车中大量应用。目前，已发展了多种方法来制备钛酸锶粉料。其中，化学共沉淀法和水热法由于生产成本低、产品质量高，成为引起特别重视的二种生产方法。现在大多采用一次烧成法了生产钛酸锶陶瓷，其工艺比传统的二次烧成法简单。生产过程中，还原性气氛通常由H₂提供，这不仅增加了制备成本和工艺控制的难度，而且还存在制备过程中的安全性问题。本实验不通入氢气，用氮气和石墨也能制造出符合实验要求的还原性气氛。为了发挥钛酸锶压敏陶瓷低压化的优势，以降低压敏电压为主要目的，同时兼顾其它性能参数，分别用CuO和MnCO₃作受主掺杂，发现用CuO作受主掺杂可大大降低压敏电压。加入Li₂CO₃作烧结助剂，虽然能有效地促进晶粒长大，但由于Li⁺离子半径小，在烧结过程中易进入晶粒内部，影响半导化，使压敏电压升高，改变烧结助剂后，制备出了压敏电压为5.75V／mm，介电常数为87425.83的试样。对实验结果进行分析，得出在施主掺杂、受主掺杂、烧结温度这三类影响因素中，影响压敏电压的主要因素为受主掺杂，影响非线性系数的主要因素为烧结温度，影响介电常数的主要因素为受主掺杂，影响压敏电压的主要因素也为受主掺杂。因此，受主种类的选择及掺杂量的大小，对钛酸锶压敏陶瓷的双功能特性起着至关重要的作用。实验证明镧铜组合是一个极有前途的低压压敏陶瓷配方，同时采用Nb₂O₅和La₂O₃的双施主掺杂，材料的综合性能要优于La₂O₃的单施主掺杂。采用双施主掺杂时，以“0.6mol％Nb₂O₅+0.3mol％La₂O₃”为佳；采用单施主掺杂，La₂O₃掺入量以1.2mol％为佳。更多还原

【Abstract】 ceramic varistor is a kind of material with double functions. It can be used as capacitor and varistor. It has a great deal of characteristic, such as low sensing-voltage, big dielectric constant and restraining the wave which voltage is lower than the standard. Its good properties have been utilized widely. Now, SrTiO3 powder can be produced by many means, of which water-heating and chemical codeposition are most important. At the present, SrTiO3 ceramic varistor is often prepared by the single-fired method. During the production, reducing atmosphere is created by H2. But H2 can bring about big danger. To avoid this sequent, N2 and lead are adopted to create reducing atmosphere. The effect is good. To decrease the sensing-voltage, CuO and MnCO3 are used as acceptors. We found the effect of doped CuO was better. At the same time, the experiment results indicate that acceptor doping is very important for SrTiOs ceramic, and that La-Cu combination is a prospective ingredient makeup. Doping with two donors is better than with single donor. "0.6mol%Nb2O5+0.3mol%La2O3" is the most arrangement of former and The most arrangement of latter is 1.2mol%La2O3.更多还原