| In the field of aerospace, mechanical components manufacturing and repair, the use ofnanostructured thermal barrier coatings can greatly improve the performance of the traditionalthermal barrier coatings (TBCs). The solution precursor plasma spraying is emerging inrecent years, which is very suitable for the preparation of nano coatings. This articlesuccessfully prepared the whisker enhanced nanostructured ZrO2/Y2O3TBCs based onsolution precursor plasma spray method, meanwhile overcame the defects in coatings. Usingscanning electron microscope, energy spectrum analyzer, X-ray diffraction analyzed theorganizational structures of coatings. In the meantime, through microscopic hardness test,thermal shock test, heat insulation test and antioxidant experiment analyzed the mechanismand the properties of coatings.The research results indicated that with ZrOCl2·8H2O and Y2O3hydrolysis reaction inwater, combined with NH3·H2O as promoter, sol-gel can be prepared. Meanwhile, the use ofdispersants adjusted the colloid particle’s charge balance and prevented colloid from reuniting.Also found that the adding of hydrogen peroxide can not only accelerate colloid reaction andpurification, but also accelerate the hydrolysis reaction through its hydroxyl complexation.Precursor particles atomized into the flame, went through a series of procedures of dry,hydrolysis, condensation, decomposition, melting and deposition reactions.Microstructure morphology observation showed that the honeycomb, polyporous and thecascade surfaces are the typical microstructure of SPPS zirconia coating. And the spray inputpower must match the feed speed. With the constant feeding speed, when the power is toosmall, the particles may deposite unmelted. When the power is too large, the powder may beoxidated and the substrate will be overheated. In this experiment, the43kW input power, 100mm spray distance,50%alcohol content,0.3~0.4MPa liquid pressure,560A sprayelectric current,78V voltage are thought to be the best adaptive spray parameters with thehighest coating deposition rate.X-ray diffraction analysis results showed that the composition of SPPS coating ist-ZrO2/Y2O3. Through the calculation by formula Scherrer, the coating’s grain sizes keeps in25nm or so. The EDS analysis results demonstrated that due to the stability of the Y2O3makes elements Y difficult to be detected, and the content ratio of elements Zr and O is1:2.The microhardness of the solution precursor plasma spray coating is lower than that ofthe APS TBCs, which comes up to280HV0.2, but higher than that of the substrate. Thecoating can enhance the substrate greatly. The antioxidant properties of SPPS nanostructuredcoating is superior to the traditional APS coatings. The weight increase of the the coatingsafter100hours’ heat treatment under the temperature of1100℃indicated that the SPPScoatings had2.258mg/mm2weight gain less than the APS coatings’5.386mg/mm2. Due tothe whisker’s high heat conductivity, the heat insulation performance of whisker enhancedSPPS coating is slightly declined compared with the traditional SPPS coating. However theformer coating is still superior to the APS one. the add of Whisker significantly improved thethermal shock resistance of the SPPS TBCs. which has a average36.33thermal shockfrequency, higher than the APS coating’s15.67the effect of the whisker is significant. |
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