利用原子力显微镜低频声学模式观察氧化锌压敏电阻陶瓷晶界处纳米尺度弹性响应

摘要

介绍在商用原子力显微镜上建立的低频声学成像模式,并利用其对氧化锌压敏电阻陶瓷晶界处进行了弹性性能成像.声学像中晶界处微晶的衬度反映了添加物的分布.而晶界处的衬度增强现象可能说明样品经热处理后发生富铋相的相变.结果显示低频声成像的分辨率达到了纳米量级,在功能材料的微区力学性能表征方面具有良好的应用前景.%Low-frequency acoustic mode atomic force microscopy was successfully developed based on the commercial AFM. The experimental results on nanometer scale elastic response at the grain boundaries in ZnO varistors assessed by the technique were presented. Different acoustic contrast of the individual micro-grains at grain boundaries were examined which reflected the distribution of additives. The acoustic contrasts enhanced at the grain boundaries can be observed clearly, which present possi-bility of crystal lattice expanding of Bi-rich phase caused by phase transition in the heat treatment. The lateral resolution of a-coustic image is down to nanometer scale. The results show the application perspective of low-frequency scanning probe acoustic microscopy in functional materials at submicro-or nanometer scale.