Your current location錛?nbsp;> The preparation of zirconia powder is generally divided into physical methods and chemical methods. Physical methods include mechanical grinding, solid phase method, etc. Chemical methods include wet chemical method (including precipitation method, hydrothermal method, etc.), solvent evaporation method, etc.
The following is a brief introduction to several zirconia powder preparation technologies:
1. Hydrothermal method Hydrothermal method is a chemical reaction in aqueous solution under high temperature and high pressure, which is an advanced and mature technology for preparing inorganic materials. The method is suitable for the preparation of metal oxide and composite metal oxide nano-ceramic powders. In the autoclave, zirconium salt (ZrOCl2) and yttrium salt (Y(NO3)3) solution are added with appropriate chemical reagents, and nano-scale zirconia particles are directly generated under high temperature and high pressure to form yttrium-stable zirconia solid solution. The advantage is that the powder particle size is very fine, can reach the nanometer level, and the particle size distribution is narrow. The disadvantage is that the equipment is complex and expensive, and the reaction conditions are harsh.
2. Coprecipitation method The co-precipitation method is to add ammonia and other solutions into the mixed aqueous solution of water-soluble zirconium salt and stabilizer, and then produce water-insoluble hydroxide, carbonate, sulfate, etc., and then decompose by heating to obtain high-purity ultrafine powder. This method is widely used because of its simple equipment process, low production cost, and easy to obtain nanometer ultrafine powder with high purity. However, the main disadvantage of co-precipitation method is that it does not solve the problem of hard agglomeration of ultrafine powders.
3, sol-gel method Sol-gel method is a widely used method for preparing ultrafine powders. It is started from the solution of metal compounds, hydrolysis and other reactions at a low temperature, to obtain a uniform sol of metal oxides or hydroxides, and then concentrated into a transparent gel, gel after drying and heat treatment to obtain a particle size in the range of several to several hundred nanometers of oxide ultrafine powder. The process is simple, the reaction temperature is low, and the chemical composition of the product is uniform.
4, hydrolysis precipitation method The oxide ultrafine powder can be formed by the hydrolysis of alum salt solution, sulfate solution, chloride solution and nitrate solution at high temperature for a long time. The hydrolytic precipitation method is divided into two methods: zirconium salt water precipitation and zirconium alcohol salt water precipitation.
5. Metal alkoxide method Metal alkyd method is to make use of some metal organic alkyd can dissolve in organic reagents and hydrolyze in water to produce hydroxide or oxide precipitation, and prepare ultra-fine powder. Metallic alkanols are easily decomposed into alcohols and oxides or their hydrates after being exposed to water, which can be prepared by filtration, drying and roasting. Because alcohol is volatile, the advantage of this method **** is that the reaction speed is fast, and high purity nanoparticles can be directly separated from the mixture of the obtained substances. The obtained particles are almost all primary particles, and the size and shape of the particles are uniform.
The disadvantage of this method is that it is costly and easy to cause pollution.
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