TiO_2基陶瓷湿敏元件的研究和发展

TiO2基湿敏陶瓷是一类十分重要的湿敏陶瓷,应用十分广泛。本文综述了TiO2基陶瓷湿敏元件的研究和发展。重点介绍了7种TiO2基陶瓷湿敏元件的材料配方、制备工艺、湿敏性能及研究进展。

Ta_2O_5对TiO_2基压敏陶瓷半导化的影响

研究T a2O5对(S r,B i,S i,T a)掺杂的T iO2基压敏陶瓷半导化的影响,发现随着T a2O5增加,晶粒电阻呈现“U”字型变化规律,按照配方T iO2+0.3%(S rCO3+B i2O3+S iO2)+0.1%T a2O5(摩尔分数)配制的样品的晶粒电阻最小,这表明适当增加施主T a2O5的含量有助于材料晶粒的半导化。

TiO_2基压敏陶瓷的研究进展

TiO2基压敏陶瓷的非线性伏安特性和介电性能优良,具有吸收高频噪声和过电压保护的功能。综述了此陶瓷的制备工艺、烧结制度、施主、受主掺杂和烧结助剂等对TiO2基压敏陶瓷电性能的影响之研究现状,并阐述了TiO2基压敏陶瓷未来的研究方向。

(Sr^(2+),Bi^(3+),Si^(4+),Ta^(5+))掺杂的TiO_2压敏陶瓷中Ta^(5+)的研究

研究Ta2 O5对 (Sr,Bi,Si,Ta)掺杂的TiO2 基压敏陶瓷压敏特性及电容特性的影响 ,发现按配方TiO2+0 .3%(SrCO3+Bi2 O3+SiO2 ) +0 .1 %Ta2 O5配制的样品具有最低压敏电压 (E1 0mA =1 .2V·mm- 1 )、最大相对介电常数 (εra=2 .0 0 2× 1 0 5)及较小非线性系数 (α =2 .6 )。考虑到材料的低压敏电压和大介电常数的要求 ,Ta2 O5最佳掺杂量在 0 .0 85mol%与 0 .1mol%之间。

Tribological properties of nanostructured Al_2O_3-40%TiO_2 multiphase ceramic particles reinforced Ni-based alloy composite coatings

The Ni-based alloy composite coatings reinforced by nanostructured Al2O3-40%TiO2 multiphase ceramic particles were prepared on the surface of 7005 aluminum alloy by plasma spray technology. The microstructure and tribological properties of the composite coatings were researched. The results show that the composite coatings mainly consist of γ-Ni, α-Al2O3, γ-Al2O3 and rutile-TiO2 etc, and exhibit lower friction coefficients and wear losses than the Ni-based alloy coatings at different loads and speeds. The composite coating bears low contact stress at 3 N and its wear mechanism is micro-cutting wear. As loads increase to 6-12 N, the contact stress is higher than the elastic limit stress of worn surface, and the wear mechanisms change into multi-plastic deformation wear, micro-brittle fracture wear and abrasive wear. With the increase of speeds, the contact temperature of worn surface increases. The composite coating experiences multi-plastic deformation wear, fatigue wear and adhesive wear.

不同烧结工艺对TiO_2基压敏陶瓷电性能的影响

分别采取四种不同的工艺过程,按照配方TiO2+0.3mol%(SrCO3+Bi2O3+SiO2)+0.075mol%Ta2O5制备四种试样。通过压敏电压、非线性系数、复阻抗特性、伏安特性、势垒高度、介电频率特性和损耗频率特性的测定,研究了一次烧成、粉料预烧及预烧方式对TiO2基压敏陶瓷电性能的不同影响。结果表明,采取一次烧成工艺制备的试样具有压敏电压较低(E10mA=7.9V·mm-1)、介电常数较大(εra=5.88×104)等特性,并从理论上对此作出一定的分析。