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Viscosity modulation by camphor during stereolithography printing of advanced ceramic materials
Sokola, Patrik ; Roleček, Jakub (oponent) ; Salamon, David (vedoucí práce)
This bachelor's thesis deals with the preparation of printing suspensions containing ceramics, their subsequent printing and evaluation of the properties of sintered ceramics. In the preparation of the printing suspension using zirconium powder stabilized with yttrium, the influence of the viscosity modulator, in particular the camphor, on the properties of the suspension and the final microstructure of the extruded and sintered objects was investigated. Samples with different contents of ceramic particles were prepared and the effect of camphor on the rheological properties of the suspension was determined. It has been found that camphor always has a positive effect on reducing the viscosity of a selected volume of ceramic, and the maximum amount of zirconium powder in the epoxy resin has been determined to make the suspension usable for stereolithographic printing. After printing, the density of the samples, their porosity, particle size, defects in the microstructure, visual quality and percentage shrinkage were evaluated. The camphor samples showed better properties for different volumetric contents of zirconium ceramics for all the mentioned factors.
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Physico-Chemical Characterization of Suspensions Based on Zirconium Oxide for the Use in Stereolithographic Printing Systems
Sokola, Patrik ; Švec, Jiří (oponent) ; Kalina, Michal (vedoucí práce)
The presented diploma thesis deals with the optimization and characterization of suspensions with zirconium oxide stabilized by trimolar yttrium (d50 = 300 nm) using Disperbyk – 103 and Disperbyk – 111 reagents. Kinetic stability and appropriate rheological properties are important prerequisites for successful stereolithographic printing. The main goal of the work was to find a suspension suitable for practical 3D applications, to find a correlation between the performed analyses and to confirm the suitability of the prepared suspensions by mechanical tests of high-temperature processed 3D printed bodies. As part of the optical analysis performed using Fourier transform infrared spectrometry (FTIR), it was confirmed that both types of agents are successfully adsorbed on the powder surface. As part of the kinetic stability of suspensions performed using an analytical centrifuge, it was found that the agent Disperbyk - 103 is a suitable candidate for the creation of highly stable ceramic suspensions. Considering the measured and published results, the stability analysis can be considered as a complementary analysis to the traditional analysis for the assessment of suspensions - rheological measurement. Particle size analysis confirmed that Disperbyk - 103 prevents agglomerations in the entire investigated range, while Disperbyk - 111 showed a decreasing trend in mean particle size with increasing agent content. Reagent Disperbyk – 103 showed values of dynamic viscosity suitable for 3D printing of ceramics (0.93 Pa·s) when filled with ceramics (30 vol.%), in contrast to Reagent Disperbyk – 111, which can no longer be considered suitable at the same filling for the preparation of suspensions, due to the higher value of dynamic viscosity (3.09 Pa·s). Stereolithographically printed and high-temperature processed samples for both types of reagents were subjected to mechanical tests, and samples containing the Disperbyk-103 reagent achieved high Vickers hardness (1299–1315 HV), relative density (98.2%) and low defectivity confirmed by scanning electron microscope images, which determined the given agent as a suitable adept for 3D printing. The samples containing Disperbyk – 111 could be assessed as defective already visually, while the defectiveness of the microstructure was also confirmed microscopically. In addition, they achieved lower Vickers hardness (951–1037 HV) and lower values of relative density (92.8%). The greatest contribution of the publication is the provision of a hitherto unpublished view of stability analysis as a useful tool for the assessment of ceramic suspensions.
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Viscosity modulation by camphor during stereolithography printing of advanced ceramic materials
Sokola, Patrik ; Roleček, Jakub (oponent) ; Salamon, David (vedoucí práce)
This bachelor's thesis deals with the preparation of printing suspensions containing ceramics, their subsequent printing and evaluation of the properties of sintered ceramics. In the preparation of the printing suspension using zirconium powder stabilized with yttrium, the influence of the viscosity modulator, in particular the camphor, on the properties of the suspension and the final microstructure of the extruded and sintered objects was investigated. Samples with different contents of ceramic particles were prepared and the effect of camphor on the rheological properties of the suspension was determined. It has been found that camphor always has a positive effect on reducing the viscosity of a selected volume of ceramic, and the maximum amount of zirconium powder in the epoxy resin has been determined to make the suspension usable for stereolithographic printing. After printing, the density of the samples, their porosity, particle size, defects in the microstructure, visual quality and percentage shrinkage were evaluated. The camphor samples showed better properties for different volumetric contents of zirconium ceramics for all the mentioned factors.
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