铌酸钾钠压电陶瓷的性能研究
时间:2019-12-08 14:46 来源:毕业论文 作者:毕业论文 点击:次
| 摘要压电、铁电陶瓷材料广泛应用在换能器、驱动器、滤波器、谐振器等频元件领域，是一种重要的功能材料。从环境保护和可持续展的角度出发，压电陶瓷的无铅化是压电陶瓷材料的发展方向。本课题从 KNN 基无铅压电陶瓷体系出发，采用固相烧结法，以K2CO3 、Na2CO3和Nb2O5为主要原料，制备(K0.5Na0.5)NbO3陶瓷。将原料经球磨、烘干、预烧、粉碎、成型、排塑、烧结和退火等工艺，在不同温度下烧结得到陶瓷样品。系统的研究烧结温度对所烧成的产品的结构与性能影响，找出其产品性能与结构最优的烧结温度范围。 根据实验结果，本课题得出以下结论： (1)固相烧结法制备的 KNN陶瓷，在 1085℃-1095℃烧结完全，样品结晶化完全，结构致密。在烧结温度比较低时，陶瓷晶粒未完全结晶；而在烧结温度较高时，会有部分陶瓷晶粒融化，导致晶粒再次细化。在 1090℃时烧结的样品晶粒较大，平均尺寸为 3-4μm；而1100℃与1080℃的晶粒较小，平均尺寸约为 2μm。 (2)在 1085℃-1985℃之间烧结 KNN 无铅压电陶瓷的压电性能也很好，d33值最高可达到 119pC/N，虽然在 1080℃以及 1100℃烧结的样品的数值较低，但是也优于熔盐法制备的样品。说明传统的固相烧结法还有很大的进步空间。 (3)在 1085℃-1095℃烧结的样品的介电性能较好。 介电常数在 1095℃达到最高，为εr=863.42 F/m。而在温度较低的 1080℃，以及温度较高的 1100℃，由于陶瓷内部晶粒的细化，非结晶化等原因，因此影响到陶瓷片的极化，从而导致样品的介电性能下降。同样的原因也会影响到KNN 无铅压电陶瓷的铁电性即电滞回线的表现。 42522 毕业论文 关键词 无铅压电陶瓷 (K0.5Na0.5)NbO3基 固相烧结法 烧结温度 Title Study on properties of potassium sodium niobate piezoelectric ceramics Abstract Piezoelectric and ferroelectric ceramic materials have been widely used in the fields of transducers, actuators, filters, resonators and other frequency components, and is a kind of important functional materials. From the environmental protection and sustainable development perspective, lead-free piezoelectric ceramics is the development direction of piezoelectric ceramic materials. This topic from the KNN based lead-free piezoelectric ceramics of using solid-phase sintering, with K2CO3 and Na2CO3 and Nb2O5 as the main raw material, the raw materials by ball milling, drying, calcining, crushing, forming, plastic drainage, sintering and annealing etc. process, under the different temperature sintered ceramic samples. The influence of sintering temperature on the structure and properties of the sintered products was studied. The optimum sintering temperature range of the product performance and structure was discovered. According to the experimental results, the following conclusions are drawn: (1) KNN ceramics prepared by solid state sintering method, the morphology and structure of the 1085℃-1095℃. When the sintering temperature is relatively low, the ceramic grains are not completely crystallized; while the sintering temperature is relatively high, some of the ceramic grain is melted, which leads to the grain refinement. (2) The piezoelectric properties of sintered KNN lead-free piezoelectric ceramics sintered at 1085 ℃ -1985 ℃ are also very good, although the samples sintered at 1080 ℃ and 1100 ℃ are lower, but they are better than the samples prepared by molten salt method. It shows that there is still much room for improvement in the traditional solid state sintering process. (3) The dielectric properties of sintered samples at 1085℃ -1095℃. At the lower temperature of 1080 ℃, and the higher temperature of 1100 ℃, due to the refinement of the ceramic internal grain, and other reasons, so that the polarization of the ceramic chip, which leads to the decrease of the dielectric properties of the sample. The same reason can also affect the performance of KNN lead-free piezoelectric ceramics ferroelectric hysteresis loop. (责任编辑：qin) |