| 1. |
- An, Di, et al.
(författare)
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Additive manufacturing and characterization of complex Al2O3 parts based on a novel stereolithography method
- 2017
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Ingår i: International Journal of Applied Ceramic Technology. - : Wiley. - 1546-542X .- 1744-7402. ; 14:5, s. 836-844
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we prepared Al2O3 ceramic green parts with complex geometry and architecture using an additive manufacturing process based on stereolithography. The rheological and thermal behavior of Al2O3 slurry was firstly examined and used to establish the conditions for molding and debinding. As opposed to previous researches that only focused on manufacture techniques, the sintering behavior and densification process were systematically investigated. In addition, special attentions were paid to the evolution of microstructure between green bodies and sintered parts. The results showed that debound parts were equipped with uniform particle packing and narrow pore size distribution. The dimensions of the Al2O3 parts changed anisotropically with the different processing steps. The densification process was greatly accelerated by the decrease in pore size and annihilating of interconnected pores in which significant grain growth was observed above 1450 degrees C. The sintered part also had a homogeneous microstructure and no interface between adjacent layers. High densification (relative density of 99.1%) and much desirable Vickers hardness (17.9 GPa) of Al2O3 parts were achieved at the sintering temperature of 1650 degrees C.
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| 2. |
- Li, Hezhen, et al.
(författare)
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Asynchronous densification of zirconia ceramics formed by stereolithographic additive manufacturing
- 2021
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 41:8, s. 4666-4670
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Tidskriftsartikel (refereegranskat)abstract
- Stereolithography has been proven as a feasible approach to make crack-free ceramic macrostructure with customized designs, but the microstructure, especially pore structure remains to be tailored more precisely for better performance, where the sintering protocol and related densification characteristics could play a vital role as the slurry preparation and debinding protocol do. Herein we report a phenomenon named “asynchronous densification”, that is, the surface region of zirconia ceramics formed by stereolithographic additive manufacturing would be densified prior to the bulk at 1200°C during the conventional pressureless sintering in air. The cause of this asynchronism is unclear but supposed to be correlated with low packing density, high sintering activity, poor thermal conduction of ceramics and impurities. Early densification of the surface may have negative effects towards ceramic components with more homogeneous microstructure, suppressed pore coalescence and limited grain growth, and therefore needs to be better controlled through optimization in sintering protocol.
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| 3. |
- Li, Hezhen, et al.
(författare)
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Dental ceramic prostheses by stereolithography-based additive manufacturing : potentials and challenges
- 2019
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Ingår i: Advances in Applied Ceramics. - : Informa UK Limited. - 1743-6753 .- 1743-6761. ; 118:1-2, s. 30-36
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Tidskriftsartikel (refereegranskat)abstract
- The current method for making dental ceramic prostheses in a subtractive manner causes a severe waste of materials while requires excessive manual works that bring in the uncertainty for control of quality. The rapid development and commercialisation of additive manufacturing (AM) has aroused interest and wonders both in material and dental communities about their potentials and challenges in fabricating of ceramic prostheses in a materials-saving manner. In this work, AM approach was applied to fabricate the dental bridges and implants made of zirconia. The achieved geometries and dimensional accuracy are used to demonstrate the potential of this technique in fabricating of dental ceramic prostheses, whereas the observed macro and micro defects formed during the treatment process is used to reveal the challenges facing in order to adapt this technology into real dental practice. Suggestions are provided for future development of the technology, particularly on minimising the processing defects.
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| 4. |
- Li, Hezhen, et al.
(författare)
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Stereolithography-fabricated zirconia dental prostheses : concerns based on clinical requirements
- 2020
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Ingår i: Advances in Applied Ceramics. - : Informa UK Limited. - 1743-6753 .- 1743-6761. ; 119:5-6, s. 236-243
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Tidskriftsartikel (refereegranskat)abstract
- With the recent rapid development of the additive manufacturing family of technologies, the interest in application potential of stereolithography on producing ceramic dental prostheses has aroused and been widely discussed. While someone claimed the birth of 'stereolithography-fabricated ceramic dental prostheses', an overall evaluation based on the clinical requirements is lacking, making the optimism a kind of unrealistic. In this article, the prototypes of ceramic dental prostheses and standard specimens produced by the ceramic stereolithography approach are compared with those made by the classic subtractive manufacturing method by following the critical clinical requirements. Concerns on the upcoming challenges and future improvement towards clinical applications are presented that include productivity, delivery time, dimensional tolerance, mechanical and aesthetic properties. It is concluded that it is far too early to call 'stereolithography-fabricated ceramic dental prostheses' as a success as usable and competitive products for clinical applications.
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