| A series of humidity-sensitive materials ZnCr2O4-V2O5-Li2O-ZnO which have glass-ceramic compound structure with different mole ratios were prepared. Humidity-sensing properties, response time, humidity lag and sensitivity were tested. Then the long-term follow testing was carried. It is showed that the better synthetic humidity-sensing properties are obtained when mole ratio is 96:4, humidity lag is low, response rate is fast, long-term stability is well.For optimizing properties of materials above, on the base of analysing the factor that affects properties of materials, two new thoughts with material design and one new system whth sintering technology were refined and studied in experiments(1) Mix SiO2into glass phase V2O5-Li2O-ZnO. Microcosmic structure of samples above are analyzed, then the cause of affected unhygroscopic course is obvious. On the base of analyzing physical properties of SiO2, a new ingredient was designed, and the similar work as above was carried. In the case of mix, the best synthetic humidity-sensing properties are still obtained when mole ratio is 96:4. Compared with un-mix, humidity lag decreases obviously, response rate accelerates.(2) Separate the crystalling course of crystal phase ZnCr2O4 and the wrapping and bond course by glass phase. For obtaining materials with larger mechanical intensity and pore, the raw materials ZnO and Cr2O3 were mixed, sheeted, and sintered in 1450℃, then crushed to replace the former powder, the consistency of material gets advance.(3) Under the flow course above, effect of sintering technology for properties of material was explored, reasonable sintering technology of 1260℃and 2h was picked up. It insures consistency and stability of material, as well as decreases humidity lag and accelerates response rate, optimizes humidity-sensitive properties of material much more.Academic analysis is made for the results of experiments, humidity-sensing mechanism is deeply explored. |
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