Purpose

The purpose of this study is to evaluate different 3D structures for humidity sensing that will enable the fabrication of complex geometries with high moisture sensitivity.

Design/methodology/approach

Humidity sensors based on alumina ceramics were fabricated using direct ink write (DIW) technique. Different engineered surface area, polymer binder ratio and post-processing treatment were considered to increase moisture sensitivity.

Findings

It was found that the binder ratio plays an important role in controlling the rheology of the paste during printing and determining the pore size after post-processing treatment. The sensibility of the fabricated humidity sensor was investigated by measuring its capacitance response toward relative humidity (RH) varying from 40% to 90% RH at 25°C. It is shown that using 3D lattice design, printed alumina humidity sensor could improve sensitivity up to 31.6 pF/RH%, over an order of magnitude higher than solid alumina.

Originality/value

Most of the alumina humidity sensors available are films in nature because of manufacturing difficulties, which limited its potential of higher sensitivity, and thus broader applications. In this paper, a novel 3D alumina humidity sensor was fabricated using DIW 3D printing technology.

中文翻译：

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使用直接墨水写入技术制造具有湿度传感能力的大块氧化铝结构

目的

本研究的目的是评估用于湿度传感的不同 3D 结构，这将使制造具有高湿度敏感性的复杂几何形状成为可能。

设计/方法/方法

使用直接墨水写入 (DIW) 技术制造基于氧化铝陶瓷的湿度传感器。不同的工程表面积、聚合物粘合剂比例和后加工处理被认为会增加水分敏感性。

发现

研究发现，粘合剂比例在控制印刷过程中浆料的流变性和确定后加工处理后的孔径方面起着重要作用。通过测量其对 25°C 下从 40% 到 90% RH 的相对湿度 (RH) 的电容响应来研究制造的湿度传感器的灵敏度。结果表明，使用 3D 晶格设计，印刷氧化铝湿度传感器可以将灵敏度提高到 31.6 pF/RH%，比固体氧化铝高一个数量级。

原创性/价值

由于制造困难，大多数可用的氧化铝湿度传感器本质上都是薄膜，这限制了其更高灵敏度的潜力，从而限制了更广泛的应用。在本文中，使用 DIW 3D 打印技术制造了一种新型 3D 氧化铝湿度传感器。