Hot Pressing of Potassium‐Sodium Niobates
Hot Pressing of Potassium‐Sodium Niobates
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DOI：
10.1111/j.1151-2916.1962.tb11127.x
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发表时间：
1962-05
影响因子：
3.9
通讯作者：
R. E. Jaeger;L. Egerton
中科院分区：
文献类型：
--
作者：
R. E. Jaeger;L. Egerton
KNbO_3-NaNbO_2系统中的组分已被热压以产生相对密度大于99%的陶瓷。因为这些材料缺乏任何程度的热塑性行为，所以需要接近空气烧结所需的温度。这些热压试样表现出比通过常规处理获得的更精细的微观结构。增强的压电系数进行观察，并在某些组成区域的径向耦合系数已从32%增加到约48%。介电常数随着致密化而增加，并且交流损耗保持相对较高。精细结构和改善的压电活性，特别是接近等摩尔组成，使得这些材料对于机电换能器是理想的，特别是在10至20 Mc每秒范围内。Murray、Live和威廉姆斯提出的陶瓷热压速率方程适用于该体系。
Compositions in the system KNbO3-NaNbO2 have been hot-pressed to yield ceramics with relative densities greater than 99%. Because these materials lack any degree of pyroplastic behavior, temperatures approaching those required for air sintering are needed. These hot-pressed specimens exhibit a finer microstructure than that obtainable by conventional processing. Enhanced piezoelectric coefficients are observed, and in certain compositional regions radial coupling coefficients have been increased from 32 to approximately 48%. Dielectric constants increase with densification and ac losses remain relatively high. The fine structure and improved piezoelectric activity, especially near the equimolar composition, make these materials desirable for electromechanical transducers, particularly in the 10 to 20 Mc per second range. The rate equation of Murray, Live, and Williams for hot-pressing ceramics was found to apply in this system.