| Pb(Zri-xTix)O3piezoelectric ceramics is a kind of ferroelectric semiconductor material with good piezoelectric properties, high temperature stability and large electromechanical coupling coefficient. It can be used to make piezoelectric vibrator, piezoelectric transducers, sensors and electro-acoustic devices. It is widely applied in the areas of televisions, communication equipment, measuring instruments, automotive electronics, medical diagnosis and treatment, aerospace and so on.In order to extractionelectrode and polarization, both sides of the ceramic must be covered with conductive material.This process is called ceramics metallization. Ithas great impact on the performance and reliability of piezoelectric devices. Some developed countries as Japan have adopted the sputtering technique to metalize, greatly improving performance and reliability. Their products have dominated the international high-end market because sputtering has great impact on device. While in China, almost all of the PZT manufacturers still adopted the silver screen-printing metallization technology, which has disadvantages not only in poor-quality metalized film, high production costs and great energy consumption, but also serious environmental pollution as the process will volatilize large amounts of toxic gases like PbO and xylene. Using green sputtering technique to metalize and enhance the quality of the productsis imperative.In this paper, we led a systematic research to study the influence of the sputtering process, material and structure of electrode coating on performance of PZT piezoelectric buzzer. And then we applied this technology to a series of piezoelectric devices such as the piezoelectric ignition, piezoelectric resonator and piezoelectric ultrasonic transducer. The main work and research results are as follows:1. Analyzed the contact mechanism, corrosion and welding mechanism between metal electrode layer and PZT piezoelectric ceramic. We studied the influence of electrode materials, film thickness and different sputtering parameter on the performance of PZT piezoelectric buzzer. Experimental results indicated that the order of adhesive force transition layer metal to PZT piezoelectric ceramic:Ti> Cr> Al> Cu> Ni/V (7%)> Ni (28%)/Cu, and the adhesion force between Ti+Cu+Ag electrode and PZT piezoelectric ceramic is best, while tensile strength is up to13.5MPa, the average resonance resistance is less than25Ω, electromechanical coupling coefficient is greater than0.7. The quality of sputtering electrode is superior to conventional silver screen printing electrodes, and the film thickness is only1/4of silk sintering process, prepared cost is greatly reduced as well the methods with strong controllability and the feasibility of mass production. Research results have been published in [Journal of Functional Materials], and this study has ever been the first time in the country.2. Copper has low resistance, good weldability and inexpensive features, the ability to use single copper film to make electrode layer is a dream in the buzzer industry. Our research have studied and characterized the growth conditions of sputtering copper film under different argon pressure.We adopted the technique of sputtering copper film under low pressure and then thickening copper film under high pressure, and finally we got buzzer electrode layer with strong adhesion, good weldability and low resistivity. This process has made foundation for applications of making alumina CCL which has great application value.3. Transferred sputtering metallization achievement successfully from piezoelectric buzzer to a series of PZT ceramics such as piezoelectric ignition, resonator and ultrasonic vibrator, and proposed creatively to use cheap plaster coating as mask to sputter electrode layer with deposition of complex shape. |
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