共查询到18条相似文献,搜索用时 109 毫秒
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本文介绍溶胶-凝胶法制备均匀PbZr-Ti-B-Si凝胶玻璃,并通过适当热处理在凝胶玻璃中原位生长Pb(Zr;Ti)O3微晶的新工艺·利用IR谱考察了凝胶玻璃中的元素键合结构随温度的变化.结合热分析和XRD;SEM技术,研究了Pb(Zr,Ti)O3微晶在凝胶玻璃中的生长过程及该材料的结构特点.发现Pb2(Zr,Ti)2O6+x立方焦绿石介稳过渡相的纳米微晶首先出现于该体系中,并在更高的温度下先后完全转变成三方和四方Pb(Zr,Ti)O3钙钛矿相.电子显微观察结果表明,该工艺制备的Ph(Zr;Ti)O3玻璃陶瓷具有均匀的细晶结构. 相似文献
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溶胶—凝胶法制备含PbTiO3微晶的玻璃陶瓷 总被引:2,自引:0,他引:2
采用溶胶-凝胶工艺低温合成含有Pb,Ti成份和玻璃相组成成份的均匀透明凝胶,并通过热处理在凝胶玻璃中原位生长出纯净的铁电PbTiO3微晶。利用热分析手段和IR谱分析了凝胶在热处理过程中有机基团的分解及内部元素键合方式的演变。 相似文献
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用溶胶-凝胶方法在Si上成功地制备了钙钛矿型的PbTiO3薄膜。X射线衍射结果显示,在热处理温度为750 ̄900℃范围内,随温度升高,薄膜由多晶转变为定向结晶。X射线光电子能谱分析发现,薄膜表面存在SiO2薄层,其厚度大约为0.6nm,该薄层是在制膜过程中衬底Si通过PbTiO3薄膜扩散到表面与大气中的O2反应而形成的。在750℃热处理的薄膜,膜层中不含SiO2,但温度升高,膜层中存在SiO2成分 相似文献
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溶胶—凝胶法制备纯PbTiO3超细粉的研究 总被引:8,自引:1,他引:7
以金属醇盐和无机盐为原料,用溶胶-凝胶法制备合成了粒径小于50nm的纯PbTiO3超细粉,探讨了溶胶-凝胶过程反应机理,并对制备过程中的一些主要因素如pH值、溶液浓度和温度等进行了讨论,采用热分析、X-Ray衍射分析和TEM等测试手段对PbTiO3超细粉进行了分析。 相似文献
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光色玻璃结构因子[Ψ]与材料改性的研究 总被引:1,自引:1,他引:0
本文研究了R2O(RO)-Al2O3-B2O3-SiO2系光色玻璃基础组成、结构因子[Ψ]与光色玻璃饱和变暗透射率(TD)的温度系数f(TD)(简称温度系数)的相互关系。研究结果表明,光色玻璃的温度系数f(TD)随结构因子[Ψ]的变化具有一定的规律性。随着结构因子[Ψ]的增大,即当[Ψ]=0.28 ̄0.35时,光色玻璃的温度系数f(TD)出现了较小值。根据以上结构,探索并研制出了具有较好光色性能即 相似文献
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采用气相法对PbTiO3陶瓷扩渗Nd元素 ,经Nd扩渗 ,PbTiO3陶瓷的电性能发生了十分显著的变化。通过正交实验 ,确定了最佳扩渗条件 ,当Nd的浓度为 1.5 % (w) ,扩渗时间为 4h ,扩渗温度为 86 0℃时 ,PbTiO3陶瓷的导电性最好 ,其室温电阻率从 2 .0× 10 1 0 Ω·m下降为 10 .5Ω·m。经Nd扩渗的PbTiO3陶瓷的晶粒电阻随着温度的变化 ,呈现PTC效应 ,而晶界电阻随着温度的升高 ,呈急剧连续降低状态 ,总电阻的变化规律与晶界电阻的变化相一致 ,但PTC效应已不存在 ,有向导电体过渡的趋势。 相似文献
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Grain oriented multicomponent polar glass-ceramics have been prepared by crystallizing the glasses in a temperature gradient. Inexpensive, large area piezoelectric and pyroelectric devices can be fabricated by this method, and by adjusting the composition of the glasses and crystallization conditions, it is possible to tailor the properties to meet device requirements. Based on the growth characteristics and the connectivity pattern of the crystallites, the piezoelectric, pyroelectric and dielectric properties of glass-ceramic composites can be predicted. Two examples discussed in this paper are piezoelectric glass-ceramics which are not pyroelectric, and pyroelectric glass-ceramics which are not piezoelectric. 相似文献
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Anisotropic piezoelectric effect in modified PbTiO(3) ceramics 总被引:1,自引:0,他引:1
Wersing W Lubitz K Mohaupt J 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1989,36(4):424-433
Experimental and theoretical investigations of the electromechanical anisotropy of ceramics modified with Ca, Ni-Nb, and Mn are presented. It is demonstrated that the large anisotropy of these ceramics is neither a bulk property of the PbTiO(3)-crystallites nor a domain wall effect. The anisotropy is caused by the statistical orientation of the crystallites in the ceramics and by the material properties due to this orientation. The ratio of electrostrictive coefficients and the ratio of single-crystal permittivities in these ceramics also play a decisive role. The result enables one to comprehend easily the dependence of the ceramic's electromechanical anisotropy on the material composition, the degree of poling, and the temperature. 相似文献
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利用传统固相烧结法制备了Bi(Mg2/3Nb1/3)O3-PbTiO3(BMN-PT)压电陶瓷, 分析了不同PbTiO3含量对BMN-PT压电陶瓷的晶体结构、介电、压电及铁电性能的影响. XRD结果表明: 合成的BMN-PT陶瓷具有纯钙钛矿结构, 并且在PbTiO3含量为x=0.60时, 其组分的XRD图谱在衍射角2θ=45°出现明显的分峰, 说明该组分相结构中存在三方和四方相的共存. 压电铁电性能显示, BMN-0.60PT有最大的压电常数d33(~170pC/N)和平面机电耦合系数kp(0.35), 最小的矫顽场Ec(29.4 kV/cm)及最大的剩余极化Pr(31.4 μC/cm2). 确定了BMN-PT压电陶瓷的准同型相界(MPB)为PbTiO3含量x=0.60的组分. 介电系数温谱表明介电系数峰值温度(Tm)随着PbTiO3含量的增大而升高, MPB组分的Tm约为276℃. 相似文献
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A. Halliyal A. S. Bhalla L. E. Cross R. E. Newnham 《Journal of Materials Science》1985,20(10):3745-3749
Polar Sr2TiSi2O8 glass-ceramics were prepared by recrystallizing glasses in a steep temperature gradient. The dielectric, piezoelectric and pyroelectric properties were studied as a function of temperature in the temperature range –150 to 200 C. The sign of the pyroelectric coefficient is positive at room temperature and is attributed to the dominance of the secondary pyroelectric effect over the primary effect. Anomalies were observed in the dielectric, pyroelectric and piezoelectric properties and a large hysteresis was observed in all these properties. Probable causes for the anomalies are discussed. 相似文献
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