Preparation, Characterization And Stress Sensing Application Of Nanocrystalline Y₂O₃:Er,Yb

Stress sensor is an indispensable method in measurement of intensity of aerospace machineryand reliability prediction. Stress sensor can conveniently be transformed into the inertialmeasurement device and apply to in the field of navigation, attitude control, vibration and impactsensing.Based on crystal field theory, the relationship between frequency shift of fluorescence peak ofrare ions and lattice constant of host materials corresponds to the regulation of nephelauxetic effect.In order to improve the stress sensitive coefficient, nano rare-earth luminescence materials which arelattice softening are used as sensitive materials. When spectrums of rare earth ions influenced by theenvironment, the barycenter of2S+1LJenergy level used as stress sensor, So that the problem offluorescence peak overlapped, which reduce the accuracy of spectral line wavelength measurementcan be solved. Then the relation equation between the position of barycenter and stress can be fittedfrom experimental laws.Y₂O₃:Er,Yb phosphors with high stress sensitivity were completely mixed and cured with theH610epoxy resin adhesive. Absorption and emission spectrums are measured in three differentstates. And stress response of fluorescence intensity were analyzed at room temperature. Consideringthe effect of temperature on center of gravity of rare earth ions, temperature-dependent fluorescencespectrums were measured and analyzed.The content of the thesis can be divided into three parts:Part one: Six stress measurement technique based on fluorescence are presented from technicalprinciple, measurement system and development. Especially, rare earth fluorescencepiezo-spectroscopy effect is emphasized.Part two discussed the principle of rare earth fluorescence sensing, including the principle ofrare earth fluorescence, level splitting and translation center of gravity of rare earth ions resultedfrom stress.Part three: The stress-fluorescence measurement system which we designed is introduced.Emission and absorption spectrums of luminescent materials under different stress and temperatureare analyzed. The system realizes the semi-quantitative measurement of stress by means offluorescence.