Introduction to the most comprehensive polishing methods for ceramic processing

Fully stabilized zirconia ceramics can be used in many industries because of its special structure and superior oxygen ion conductivity. The following Kezhong Ceramics Factory will briefly introduce the preparation technology and characteristics of fully stabilized zirconia ceramics.

Fully stabilized zirconia ceramics belong to cubic fluorite structure. Due to the existence of oxygen octahedral voids in fluorite structure, this relaxed structure is conducive to the diffusion and migration of cations, and has strong solid electrolyte conductivity, especially after solid solution doping with stabilizers, a large number of oxygen vacancies are formed, forming good oxygen ion conductivity.

At present, the fully stable zirconia oxygen sensor doped with yttrium oxide has been used as the basic means of oxygen quantitative analysis in many work analysis processes, and the temperature is between room temperature and 900℃. The particularity of working conditions requires that the material has certain thermal shock resistance. However, the fully stable zirconia ceramics have large thermal expansion coefficient and low thermal conductivity. After being impacted, the strength decreases rapidly, and the products will fail after micro-cracks or macro-cracks appear inside. Generally, the automobile oxygen sensor is replaced once a year, and some industrial oxygen sensors for measuring molten steel fail even after being used once. Therefore, the development of fully stable zirconia with high thermal shock resistance is extremely important.

A patent document will be cited below to briefly introduce the preparation process of a fully stable zirconia ceramic material with high thermal shock resistance. The main characteristics of fully stable zirconia products prepared by this process are that the products include matrix and whiskers distributed in the whole matrix. The matrix is yttria-doped fully stable zirconia, and the whiskers mentioned above have an average length of 1-50μ M α Alumina whisker, the doping mole percentage of yttrium oxide (accounting for the total matrix) is 4-12mol%, and the weight percentage of alumina whisker is 5-25wt%. In addition, the ceramic material may also contain 0-3wt% of one or more sintering aid components of MgO, SiO2, CaO and Al2O3.

The process mainly comprises the following three steps:

1. batching: mixing the matrix, α Alumina whisker and adhesive are mechanically mixed in proportion, and the mixing equipment can be a stirring ball mill, a V-type mixer, a planetary ball mill and the like.

2. Molding: In the molding machine, the mixed ingredients are made into blanks. The molding method can be selected from compression molding, isostatic pressing, hot die casting, injection molding, slurry molding, etc.

3. Sintering: put the blank in a sintering furnace at 1300-1800℃ for 1-3 hours. It can be sintered in vacuum, partial pressure, no pressure or pressurized environment. The sintering atmosphere can be air or nitrogen. Generally, pressureless sintering in air atmosphere can be used, and the sintering temperature is between 1550 and 1670℃.

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