Spark plasma sintering of dense alumina ceramics from industrial waste scraps

Vukšić, Milan; Žmak, Irena; Ćurković, Lidija; Kocjan, Andraž

doi:10.1016/j.oceram.2021.100076

Cited by 8 publications

(9 citation statements)

References 43 publications

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“…However, the sintering of alumina using the conventional method at lower temperatures frequently resulted in lower density, fracture toughness and flexural strength. As such, various sintering techniques and approaches have been employed to enhance its mechanical properties, such as addition of dopants [3], microwave sintering [4], spark plasma sintering [5] and two-step sintering [6]. Since high sintering temperatures (>1450 °C) were generally required to produce high-density alumina ceramics using pressureless sintering [7], two-step sintering has been experimented to lower the densification temperatures and suppressing abnormal grain growth in order to retain a fine microstructure [8].…”

Section: Introductionmentioning

confidence: 99%

Densification and Mechanical Properties of Alumina Ceramics via Two-Step Sintering With Different Holding Times

Saufi

Ramesh

Lee

et al. 2021

IJEMM

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The densification and mechanical properties of alumina ceramics were investigated via two-step sintering (TSS) with different holding time. The alumina ceramics were sintered at 1450 Â°C for 1 min during the first stage, followed by sintering at 1350 Â°C with different holding times (2-24h). Conventional sintering (CS) was also performed on the alumina ceramics at 1450 Â°C for 2 h for comparison purpose. It was found that dense alumina with a relative density above 98% could be attained when TSS with a holding time of more than 12 h. The samples exhibited Vickers hardness between 5-8 GPa and fracture toughness of about 6 MPa.m1/2. In contrast, conventional sintered alumina yielded low relative density (85%), large grain size (2 Î¼m), low Vickers hardness (4.23 GPa) and fracture toughness (4.73 MPa.m1/2). This study revealed that TSS is a viable approach in aiding densification, suppressing grain growth, and improving the mechanical properties of alumina ceramics.

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Section: Introductionmentioning

confidence: 99%

Densification and Mechanical Properties of Alumina Ceramics via Two-Step Sintering With Different Holding Times

Saufi

Ramesh

Lee

et al. 2021

IJEMM

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“…One contributing factor is the presence of stearic acid or carnauba wax (acting as a surfactant/dispersant), as mentioned by Hnatkova et al 48 and Gorjan et al, 49 and demonstrated in the work of Faccio et al, 26 in which the presence of stearic acid decreased the viscosity, increasing the fluidity of mixtures of ABS with alumina. The percentage increase of surfactant/dispersant from 15 to 25% on the amount of filler in the composites with basic bismuth carbonate was necessary to aid the production of a filament with adequate cylindrical geometry since the increase in the percentage of stearic acid and carnauba wax helps to reduce viscosity 25 . Carnauba wax (a natural product) acted in the same way as stearic acid, allowing good ease of extrusion and making a suitable filament for the FFF process.…”

Section: Resultsmentioning

confidence: 99%

“…An important factor for 3D printing processing is related to the mixture's viscosity, which decreases as the amount of filler in the mix increases 24 . Furthermore, the addition of waxes and carboxylic acids (with the function of surfactants) helps in solving problems of dispersion and agglomeration of the added charge 24–26 …”

Section: Introductionmentioning

confidence: 99%

Acrylonitrile‐butadiene‐styrene‐based composites for the manufacture of anthropomorphic simulators

Thomazi,

Roman,

Vanni

et al. 2024

Polymer Composites

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The development of functional compounds for extrusion applied in the additive manufacturing of anthropomorphic simulators is interesting, as it guarantees the manufacture of a 3D model similar to the patient. These simulators find applications in therapies or laboratory tests involving x‐rays. In order to replicate human conditions in these tests, it is essential to create materials that closely match the properties of human tissue, including the smoothness of soft tissues and the hardness of the bone tissue. This study developed ceramic‐polymeric composites, where the tomography intensity of each mixture was measured experimentally. Combinations of acrylonitrile butadiene styrene (ABS) with zirconium oxide and basic bismuth carbonate allowed imitation of bone tissue. The samples containing zirconium oxide and basic bismuth carbonate presented results that exceeded the minimum limit and reached a value close to 2000 Hounsfield units (HU) with 12% basic bismuth carbonate content. Combinations of ABS with hydroxyapatite and aluminum oxide can imitate soft tissues. The use of a surfactant facilitated the mixing of ceramic filler with polymer. Finally, 3D printing of a physical model was performed using a dual extruder printer, allowing simultaneous printing of bone and soft tissue components.Highlights Material mimicking x‐ray attenuation similar to bone tissue. Relation between 3D printing porosity and intensity in Hounsfield unit. Computed tomography tests on a 3D printed anthropomorphic phantom. Creating a 3D model from a Computed Tomography scan. Double extruder for 3D printing of two tissue simultaneously.

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“…The high-purity (99.9% α-Al 2 O 3 , Alcan Chemicals, Stamford, CT, USA) alumina powder with average particle size from 0.4 μm to 1.2 μm and WAP with average particle size from 2.32 μm to 4.37 μm were used for the green body sample preparation. The WAP was collected after machining of green compacts during the industrial manufacturing process of engineering alumina ceramics, as described in our previous work [ 15 ].…”

Section: Methodsmentioning

confidence: 99%

Effect of Two-Step Sintering on Properties of Alumina Ceramics Containing Waste Alumina Powder

et al. 2022

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This study aims to evaluate the recycling potential of solid waste alumina powder (WAP) by utilization of the two-step sintering (TSS) process. For the study, WAP was collected as an industrial scrap after the machining process for the formation of green alumina compacts. The alumina samples were prepared according to the slip casting method by preparing suspensions containing commercial alumina with 0.8 μm average particle size and by adding up to 20 dwb. % (i.e., expressed on a dry weight basis) of WAP with 3.4 μm average particle size. The samples were sintered at optimized TSS conditions and compared with conventional one-step sintering (OSS) by conducting morphological analyses. The average grain size (AGS) was determined from the obtained field emission scanning electron microscopy (FESEM) images, while the sample porosity was calculated based on apparent densities. The obtained micrographs after TSS implementation revealed a partially textured microstructure. Furthermore, a comparison of the mechanical properties of alumina samples lacking or containing 20 dwb. % of WAP obtained after sintering is presented. The indentation fracture toughness (~3.2 MPa m1/2) and Vickers hardness data (~14.5 GPa) showed a positive effect of adding WAP to alumina samples. The slightly improved mechanical properties of ceramic samples containing waste alumina are a consequence of lower porosity, which is due to the remaining sintering additives in WAP. The collected results demonstrate the possibility of using TSS for sintering ceramic materials that contain WAP.

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Spark plasma sintering of dense alumina ceramics from industrial waste scraps

Cited by 8 publications

References 43 publications

Densification and Mechanical Properties of Alumina Ceramics via Two-Step Sintering With Different Holding Times

Densification and Mechanical Properties of Alumina Ceramics via Two-Step Sintering With Different Holding Times

Acrylonitrile‐butadiene‐styrene‐based composites for the manufacture of anthropomorphic simulators

Effect of Two-Step Sintering on Properties of Alumina Ceramics Containing Waste Alumina Powder

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