Research On The Preparation And Dispersion Of ZrO₂Powder With Hydrothermal Synthesis

Hydrothermal synthesis is a common method for the preparation ofpowder. This method has many advantages: The process is so simple that it reducesthe impurities which come from the outside; it doesn’t need a ball mill and hightemperature, so that the reunion doesn’t appear in the process; the most crucial is themethod can change the sizes and shapes of the products. However, as the particles arefine and the surface energy between the particles is larger, it is easy to produce thereunion; therefore it needs to control the dispersion of ZrO2powders in the process ofthe preparation. Two methods could be adopted to disperse the power: one kind is thephysical dispersion; the other kind is the chemical dispersion. The ultrasonicdispersion and mechanical dispersion are commonly used among the physicalmethods; the method of adding different dispersants is the most extensive applicationof the chemical dispersions. The thesis has a study in-depth to generate the bestparticles and the best dispersion between the particles with the hydrothermal synthesismethod.The paper discussed the present situation of the common methods used for thepreparation of ZrO2powder.The morphology and particle size of ZrO2, prepared bythe method, are analyzed with the scanning electron microscope and laser particle sizedistribution technology. The reaction time, reaction temperature, reaction pressure,rotating speed and the influence of pH value of zirconia powder are researchedthrough single factor experiments and orthogonal experiments. Finally the influenceof dispersant to the dispersion of ZrO2powder, prepared using hydrothermal synthesismethod, is studied with the contrast tests.The following conclusions are made after the research about the preparation ofZrO2powder by the hydrothermal synthesis method.1) The best reaction conditions for preparation are obtained by orthogonalexperiments: the reaction temperature is220℃, the reaction time is60h, the pressureis3.0MPa, and the speed is140r/min. Under the experimental conditions, thedistribution range of powder is small, the dispersion is better, the mean particle size issmall to5.92um, and the quality of products is better.2) Through experimental contrasts, the influences of the dispersant to thedispersion are mainly shown in the following areas: Adding the same mass fraction ofpolyethylene glycol6000, polyethylene glycol4000and polyethylene glycol2000inthe process of preparation. the results show that the test, adding polyethylene glycol6000, gets the best particle dispersion; Adding different mass fractions ofpolyethylene glycol6000, and comparing the results, it can be find that the test withthe1.150%polyethylene glycol6000, could obtain the ZrO2powder of the bestdispersion in the water; Different dispersants with the same mass fraction ofpolyethylene glycol6000, the dispersion effect is: organic polymer> inorganicelectrolytes> organic anionic surfactant> isopropyl alcohol.