A Study On The Effect Of Electrode Diameter And Thickness On The Maximum Value Of QCM Mass Sensitivity

Quartz crystal microbalance(QCM)has many advantages compared with the traditional experimental measurement instruments,mainly reflected in: the core component of QCM sensor system is a quartz crystal,the chemical properties of quartz crystal are not active,and the stability is good,so QCM can be applied in many occasions,greatly improving the application range of measurement.Secondly,the structure of QCM is relatively simple and easy to operate,which simplifies the difficulty of relevant personnel.The main contents of this paper are as follows:1.This paper first introduces the basic structure of QCM and the basic properties of quartz crystal.The basic working principle of QCM is based on the piezoelectric effect of quartz crystal.On this basis,the Sauerbrey equation is derived and the BVD equivalent circuit of QCM resonator is analyzed.2.This paper analyzes the quality sensitivity detection mechanism of QCM,and explains why QCM has high measurement accuracy.Then,the vibration of QCM in electrode region,partial electrode region and non electrode region is analyzed,and the calculation formula of QCM mass sensitivity distribution is given.Then,the energy trapping phenomenon is described.In the design process of QCM,the relationship between energy trapping effect and accuracy should be well balanced.3.The QCM of a typical circular electrode structure is calculated and simulated.In the radial direction,the mass sensitivity decays along the electrode center to both sides,showing a Gaussian distribution.The maximum mass sensitivity is obtained in the electrode center.Then the influence of electrode diameter and thickness on the maximum QCM mass sensitivity was analyzed and calculated,and then the experiment was carried out to verify the analysis.Through theoretical analysis and experiments,it is found that the electrode thickness has a significant effect on the mass sensitivity and maximum mass sensitivity of QCM.Thick electrode QCM has higher mass sensitivity than thin electrode QCM.In terms of diameter,QCM has the maximum mass sensitivity,and the diameter values corresponding to different electrode thicknesses are different.The influence of electrode thickness and diameter on QCM sensitivity is revealed.