Humidity sensor element with thick eucryptite film and preparation method thereof

The invention, which relates to humidity sensor elements and preparation methods thereof, provides a humidity sensor element with a thick eucryptite film and a preparation method of the humidity sensor element. The invention aims to solve the technical problem that eucryptite humidity sensors in the prior art are slow in response and difficult to prepare. The humidity sensor element with the thick eucryptite film in the invention is composed of an alumina ceramic base, an eucryptite coating covering the alumina ceramic base and electrodes welded on the alumina ceramic base, wherein the thickness of the eucryptite coating is 0.001 mm to 0.1 mm. The preparation method includes the steps of grinding eucryptite particles and eucryptite sol binder into pulp, coating the pulp onto the alumina ceramic base, sintering and then aging, so as to obtain the humidity sensor element with the thick eucryptite film. The element prepared in the method has a stable chemical property and a short responding time. The element is simple in preparation technique and can be applied to humidity detection in severe environment with high temperature.