【作者】 柏自奎；

【导师】 谢长生；

【作者基本信息】 华中科技大学 ， 材料学， 2005， 硕士

【摘要】 本文利用脉冲YAG 激光微加工技术,以氧化Al2O3为基片,开槽填敷RuO2制作加热器,采用银浆料流延法制备电极膜,浆料滴定覆盖成膜制备了四单元纳米ZnO 气敏阵列,研究了阵列的加热特性、气敏特性及制备工艺的重复性,并着重探讨了电极及气敏膜的厚度对阵列的气敏特性及长期稳定性的影响。激光开槽填敷RuO2作加热器的气敏传感器阵列具有好的加热特性、热响应、温度分布。阵列单元平均能耗低于500 mW、热响应时间小于20 秒、平面温度梯度小于5℃/mm,阵列的灵敏度高、性能稳定、制备工艺重复性好。激光剥离银膜制备气敏电极稳定性、一致性好,电极间距可通过改变激光的离焦量而准确灵活调整。平行银电极能均匀拾取气敏膜各部分的气敏反应信息,充分发挥气敏材料的性能。通过模拟使用环境中的热冲击实验,对比不同厚度的银电极膜的形貌,研究发现电极膜厚度及均匀性对电极的稳定性具有决定性的影响。7--15μm 厚电极具有更好的长期稳定性,电极为密网状或薄膜状; 21μm 厚电极成三维多层片状,电极的稳定性最差。对此结果进行了初步的理论分析。对不同材料及不同厚度的气敏膜的敏感性及长期稳定性进行了对比研究,并进行了机理分析,发现在厚膜工艺中气敏膜太薄具有不稳定性,2、3、4 倍厚气敏膜的稳定性较好。膜越厚热冲击(即使用过程中)产生的应力越大,裂纹扩展的将越快,气敏膜的稳定期即使用寿命就越短。本文第一部分介绍了微气敏传感器及阵列的制备技术的研究现状,并阐述了本课题的研究目的及意义; 第二、三部分分别研究了激光开槽填敷RuO2加热电阻的制备工艺及特性、气敏电极的制备与可靠性; 第四部分探讨纳米ZnO 气敏传感器阵列的制备及气敏特性; 第五部分深入讨论了电极及敏感膜的厚度对阵列气敏特性和长期稳定性影响。更多还原

【Abstract】 Gas sensor arrays were manufactured through the pulsed YAG laser micro machining of Al2O3 plates, pasting technique, and the RuO2 heater and the electrodes integrated onto two sides of plates, respectively. Some important characteristics of the integrated sensor arrays, such as the heating properties, the sensitivity and the repetition of the technique, were investigated. Peculiarly, the effect on the integrated sensors arrays sensitivity and stability by the different thick electrode and sensitive film was studied. The buried RuO2 heater by laser micro machining makes the array have good characteristics, such as the heating properties, the heat response and the temperature distribution on the plate and the sensitivity of the integrated gas sensor arrays. The average power consumption per unit at 400℃, the thermal responsive time and the plane temperature distribution gradient are 500 mW, 20s and 5℃/mm, respectively. The sensitivity of the different arrays is high, stable, and repeatable. The Ag electrodes, which were fabricated through the laser ablation, are stable and uniform. Laser can adjust the space between the electrodes conveniently. The parallel electrode can equably pick up the information of the gas sensing reaction on the parts. Compared with the change of the different thick electrode appearance after the periodic heat impact from room temperature to 400℃, it shows that the stability of the electrode strongly depends on the thickness and uniformity of the electrode film. The dense network or thin film electrode between 7-15μm have better long-term stability. The electrode upper 21μm, which is three dimension multi-slice, has worse stability. The formation mechanism of this property is discussed. Contrasted the sensitivity and the long-term stability of the sensitive film with the different powder size and thickness, and through the mechanism analyzed, the results show that the extreme thin film is not reliable, while the 2, 3 and 4 times thick sensing films are comparatively reliable. Because the thicker the sensing film is, and the stronger the remainder stress becomes, the more rapidly the crack extends, and the shorter the gas sensor natural life is. In the first part of this paper, the gas sensor array and its fabrication in the world had been summarized before the purpose and importance of our research been presented. The second part investigated the fabrication and characteristics of the buried RuO2 heater by laser micro machining, and, the fabrication and reliability of the Ag electrode was researched in the third part. In the fourth part, the fabrication and characteristics of gas sensor array were shown. In the last part, the characteristics and long-term stability of the different thick electrode and sensitive film were discussed.更多还原