| Due to excellent thermal and chemical stability,biocompatibility,high temperature and corrosion resistance and good hardness and strength,zirconia ceramic materials have been widely used in aerospace,automotive,biomedical,electronic components and other Engineering fields.However,it is difficult to form and process ceramic parts with complex shape because of its high brittleness and hardness.Traditional ceramic processing technology such as mold manufacturing has the disadvantage of long production period and big cost.Traditional ceramic processing cannot fulfill the requirement of personalized ceramic parts with complex geometric structure and high precision.In order to overcome the difficulties in the traditional ceramic manufacturing,Three-dimensional(3D)printing technology based Digital Light Process(DLP)is one of the best solutions.The main purpose of this paper is to study the preparation technology of ceramic slurry using micro-nano 3 mol.%-yttria-stabilized zirconia powder with grain size less than 400 A,which should meet the requirements of DLP-3D printing technology.And after being UV cured,debinded and sintered,the self-made ZrO2 slurry should be used to make high performance ZrO2 Ceramics with fine grain strengthening and toughening effect.The main work and conclusions are as follows:(1)Preparation of UV curable ZrO2 ceramic slurry.The dispersion behavior of yttrium-stabilized zirconia powder in the photosensitive resin system was studied.The mechanism of different dispersants and their effects on the properties of the slurry were analyzed.The result showed that the slurry with 2 wt.%～5 wt.%dispersant DIPERBYK-110 has good flowability.TZ-3YSE powder which has large specific surface area,fine grain size and high sphericity is more favorable to the slurry preparation with low viscosity and excellent liquidity.By optimizing the volume fraction of ceramic powder,the slurry with high solid content was prepared and meet the needs of DLP-3D printing.The relationship between solid content and relative viscosity was in accordance with Krieger Dougherty model.Finally,the slurry with solid content of 40 vol.%,and viscosity of 1.79 Pa·s at shear rate 30 s-1 was prepared,which could meet the requirements of light curing process.(2)Study on UV curing process of ZrO2 ceramic slurry.By analyzing the change of chemical groups of ceramic resin slurry before and after UV curing,it is found that the curing principle is the breaking and polymerization of C=C bond and in the resin.Under the condition of adding a small amount of photoinitiator TPO,the conversion rate of double bond can reach more than 90%,and the curing effect is excellent.The relationship between the curing layer thickness and the exposure time was explored.The curing kinetics was studied by using the Beer-Lambert equation,which provided a theoretical basis for setting the curing parameters.It was found that ceramic green body with good curing properties can be obtained when the exposure time is fixed and the curing layer thickness is in the range of 30 μm～50 μm.(3)Study on debinding and sintering process of UV cured ZrO2 ceramic body.In order to fix the problem of cracks of UV curable ceramics when sintering,the debinding and sintering process was studied and optimized to make dense ZrO2 parts with good compactness and no defects.The properties of sintered ZrO2 ceramics were characterized,and the results showed that the average shrinkage is 23.5%±0.1,the density is 5.934 g/cm3,the relative density is 97.68%,the Vickers hardness is 12.94±0.186 GPa,and the fracture toughness is 5.63±0.015 MPa·m1/2. |
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