Enhanced 3D printed alumina ceramic cores via impregnation

Li, He; Colombo, Paolo; Li, Wenbo; Hu, Kehui; Lu, Zongqing

doi:10.1111/jace.18107

Cited by 10 publications

(2 citation statements)

References 51 publications

(97 reference statements)

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“…11 Typically, the fabrication of porous ceramic involves a direct sacrificial template method, 12,13 polymeric replication technique, 14 foaming method, 15 reaction sintering, 16 and so forth. Recently, the freeze casting method, 17 sol-gel method, 18,19 and additive manufacturing 20 technique also emerged as easy fabrication routes for the development of porous ceramic.…”

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confidence: 99%

Alumina dissolution process to fabricate bimodal pore architecture alumina with superior green and sintered properties

2023

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Herein, a straightforward, adaptable, and cost‐effective approach has been proposed to realize the concept of dissolution of alumina in acidic aqueous media to fabricate porous alumina showing exceptional green machining properties and exhibiting good thermomechanical properties through in situ generated blowing agents and thermo‐foaming process. The process involves dissolving alumina in concentrated sulfuric acid to generate aluminum hydroxide and aluminum sulfate, which act as blowing agents to produce pores in the final structure through a decomposition process at elevated temperatures. By varying the concentration of deionized water and acidification using sulfuric acid, different alumina slurries are prepared. Sintering shrinkage is well countered through simultaneous consolidation and decomposition process during the heat treatment, and a minimum shrinkage of 0.88% is achieved. In addition to its pore‐forming properties, aluminum sulfate also provides strong binding effects to green bodies, contributing to their exceptional green machining properties. The resulting porous alumina exhibits a green flexural strength of up to 17 MPa, making it capable of bearing loads and forces during green machining. The sintered porous alumina fabricated in the study has a porosity range of 34.43%–59.24% and a flexural strength of 27.84–53.21 MPa. The prepared porous alumina also exhibits satisfactory thermal resistivity, with a minimum thermal conductivity of 1.23 W/m K, and has intra/intergranular space in the nano range. The coexistence of a combination of bimodal pores in a single monolithic matrix makes it exceptionally porous and suitable for an extensive spectrum of applications.

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confidence: 99%

Alumina dissolution process to fabricate bimodal pore architecture alumina with superior green and sintered properties

2023

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“…catalytic applications [88][89][90][91][92], ceramic core for investment casting [93][94][95][96][97], dental restoration [6,7,98,99], solid oxide fuel [3,4,100,101], heat exchanger [75,[102][103][104], among others. Figure 5 illustrates some of these potential applications published in related articles.…”

Section: Ceramics By Vat Photopolymerizationmentioning

confidence: 99%

Additive manufacturing of advanced ceramics by digital light processing: equipment, slurry, and 3D printing

Camargo¹

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Additive manufacturing (AM) or 3D printing is a set of technologies that fabricate parts by successively adding layers. This technique is already applied in all classes of materials. In ceramic manufacturing, AM allows the fabrication of small series components with greater geometric freedom, lower cost, and reduced delivery time. Among the AM technologies, vat photopolymerization (VP) stands out for its ability to produce ceramic pieces with excellent dimensional accuracy and surface finish. However, there is a shortage of VP commercial equipment dedicated to producing ceramics at an affordable price, given the challenges of dealing with raw material with high particle loading. In this work, which approaches the fabrication of advanced ceramics by digital light processing VP, the feasibility of using a topdown 3D printer prototype and an ordinary commercial bottom-up printer (usually applied in polymer 3D printing) in the processing of ceramic materials was tested. For this, a 3D printer prototype was designed and built, creating an innovative recoating system (patent pending), composed of two blades with distinct and sequential functions. This system aims to overcome the challenge of creating layers for ceramic suspensions, which usually have high viscosity. In addition, photosensitive suspensions were developed seeking to meet process requirements related to high ceramic loading, rheological behavior, photosensitive parameters, and stability.The ceramic powders were selected to evaluate the process using distinct groups of advanced ceramics: nanometric powders (3Y-TZP) and submicrometric powders (electrofused mullite).Furthermore, a combination of natural raw material (zircon) with alumina was used to investigate the in-situ formation of mullite-zirconia composites in 3D printed parts. Thus, photosensitive ceramic suspensions based on a nanometric zirconia powder (3Y-TZP) were developed and characterized, selecting the appropriate components (monomer, photoinitiator, and dispersant). In this way, a ceramic slurry was obtained capable of validating the developed prototype and manufacturing green ceramic bodies. Nonetheless, the same formulation was not suitable for the commercial 3D printer, due to its rheological behavior not being compatible with the equipment. On the other hand, the submicrometric mullite powder allowed the preparation of formulations with high solid loading (up to 50 vol%). These new formulations were successfully used in both pieces of equipment tested. Furthermore, the formulation based on the mixture of ceramic powders (zircon and alumina) showed that the technique can be combined with reactive sintering to create in-situ mullite and zirconia composites. After analysis of the thermal decomposition, a protocol for the thermal treatment was created and the printed bodies were submitted to burning of the organic components and sintering. Both 3D printers tested proved capable of creating dense ceramic pieces (>95%) and with geometries that would be unfeasible or even impossible by other man...

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Repair of surface cracks in 3D-printed porous ceramic skeletons after sintering

Wang

Shang

et al. 2023

J Mater Sci

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Enhanced 3D printed alumina ceramic cores via impregnation

Cited by 10 publications

References 51 publications

Alumina dissolution process to fabricate bimodal pore architecture alumina with superior green and sintered properties

Alumina dissolution process to fabricate bimodal pore architecture alumina with superior green and sintered properties

Additive manufacturing of advanced ceramics by digital light processing: equipment, slurry, and 3D printing

Repair of surface cracks in 3D-printed porous ceramic skeletons after sintering

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