Detailed Analysis of the Forming Process of Zirconia Ceramics

I believe everyone has some understanding of the forming method of zirconia ceramics, but I'm not sure if you are familiar with this process. Below, Kezhong Ceramic Factory will give you a detailed introduction to its forming process.

The ZrO2 powder with an average particle size of 20nm is used for plastic extrusion forming. Within the range of 2%~6% (mass fraction) of adhesive content, the gullibility index (1.04.0) is equivalent to that of plastic clay, but it also has a high water content of 40%~60% (mass fraction), a sintering relative density of 99.5% at 1650 ℃ for 4h, and a small particle size of 3~10m nanometer powder, which leads to high surface tension of the clay, making it highly plastic, However, the sliding interface formed by the adsorption of a large amount of water (volume fraction>80%) on the surface of nano particles is the cause of quasi superplasticity and low green density.

Zirconia ceramic tube

Tetragonal polycrystalline zirconia (prepared by the coprecipitation method of Y-TZP, Y2O) mole fraction 2.8%, impurity content less than 0.1%, specific surface area 40.37m2· The powder morphology is shown in Figure 3-7. The powder is first wet ball milled for 5 hours, filtered, anionic to semi dry, and then mixed with 10% (mass fraction) polyvinyl alcohol (PVA, polymerization degree 1500-3000, imported packaging) aqueous solution and water to a certain amount of water. The powder is then vacuum mixed and aged for 24 hours.

Make a ball with a diameter of 4.5mm from extruded and aged clay strips, and measure the plasticity index above the plasticity measurement, which is the product of the initial crack adaptability and strain of the clay under external force under working water. Extrusion molding is carried out on a self-made vacuum extrusion molding machine, with an inner diameter of 15mm and a cone angle of 20 °;. The extruded solid columnar billets are first insulated for 2 hours to remove moisture and PVA, then heated to 1350~1650 ℃, and sintered in air for 4 hours.

Measure the open porosity and relative density using the drainage method, and observe the surface microstructure of the sintered body using a scanning electron microscope. The figure shows the relationship between the amount of PVA added (calculated as ZrO2 powder dry powder, added amount) and the plasticity index. The plasticity index first increases with the increase of PVA content, reaches its maximum value, and then decreases again. As the water content increases, the position of the maximum value moves towards the direction of high PVA content.

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