压电陶瓷的性能老化与换能器性能的衰退

本文以编号为Fe1.5的发射型压电陶瓷材料为对象,采用标准试样和某种规格的压电振子,分别实验考察在不同温度(室温,60℃和100℃),压力(30kg/cm²)以及电功率密度(0.3W/cm³·KC和0.5W/cm³·KC)作用下,压电陶瓷材料和换能器性能随时间对数的变化.实验结果表明,导致压电陶瓷机电耦合系数和介电常数的老化原因不尽相同.在0.3W/cm³·KC电功率作用下陶瓷元件的老化行为与单一因素作用下的变化规律不同,机电耦合系数和介电常数稍有上升.看来这与发射型材料自身的内偏置电场有关.我们认为,在给定的应力、温度和电功率的综合作用下,压电陶瓷性能的劣化并不严重,它不会引起压电陶瓷换能器性能的衰退.适当的温度处理有助于压电陶瓷材料和换能器性能的稳定.

AGING OF PIEZOELECTRIC CERAMIC PARAMETERS AND DETERIORATION OF TRANSDUCER PERFORMANCES

The variations of parameters of piezoelectric ceramics Fe1.5 and corresponding high power transmitting transducers with the logarithm of time have been examined separately with normal specimens and a certain type of vibrator under defined temperatures (room temperatures, 60℃ and 100℃), pressure (30 kg/cm²) and electrical power densities (0.3W/cm³·KC and 0.5W/cm³·KC) in this paper. Experimental results show that the causes of aging of ε₃₃^T and k_p are not all the same. The varying tendency of the properties of ceramic elements after the cumulative action of the electrical power density of 0.3W/KC·cm³ is different from that of the normal specimens under each single condition. Both the value of k_p and ε₃₃^T are some what increased. It was considered that this aging behaviour was related to the internal bias electrical field of the ceramic material selves.We would conclude that the aging of properties of piezoceramics under the given temperature, pressure and electrical power density is not serious enough to cause the deterioration of performances of transducer. The appropriate heat treatment will be favourable to stabilizing the performances of ceramic materials and transducers.