Distribution of water in ceramic green bodies during drying

Oummadi, Siham; Naït-Ali, Benoît; Alzina, Arnaud; Victor, Jean-Louis; Launay, Yann; Mirdrikvand, Mojtaba; Dreher, Wolfgang; Rezwan, Kurosch; Smith, David Stanley

doi:10.1016/j.jeurceramsoc.2019.04.005

Cited by 17 publications

(23 citation statements)

References 15 publications

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“…Traditionally, fully convective drying of ceramic green bodies is an essential process step in their manufacture. Understanding the drying mechanisms first starts with the movements of liquid within porous ceramics [ 41 ]. In an environment with constant conditions, three different stages corresponding to different drying rates are divided.…”

Section: Extrusion-based 3d-printing Methods With In Situ Hot Air Fmentioning

confidence: 99%

“…The most important point is that mechanical stresses occur within the material during drying due to water removal and shrinkage. This may cause warping or cracks in the final product if the drying conditions are not carefully chosen and controlled [ 41 ]. In our initial experiments with naturally drying to remove 98 wt.% water content for more than 48 h, during this long and uncontrollable process, cracks often occurred as suggested in Figure 6 .…”

Section: Limitations Of Extrusion-based 3d-printing Without Shape-mentioning

confidence: 99%

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Extrusion-Based 3D Printing of Ceramic Pastes: Mathematical Modeling and In Situ Shaping Retention Approach

Mikołajczyk

Pimenov

et al. 2021

Materials

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Extrusion-based three-dimensional (3D) printing methods are preferred and emerging approaches for freely digital fabrication of ceramics due to ease of use, low investment, high utilization of materials, and good adaptability to multi-materials. However, systematic knowledge still lacks an explanation for what is their 3D printability. Moreover, some uncontrollable factors including extrudate shape retention and nonuniform drying inevitably limit their industrial applications. The purpose of this research was to present a new shaping retention method based on mathematical synthesis modeling for extrusion-based 3D-printing of ceramic pastes. Firstly, the steady-state equilibrium equation of the extrusion process was derived to provide clearer theoretical indications than purely experimental methods. Furthermore, a mathematical description framework was synthesized to better understand the extrusion-based 3D-printing of ceramic pastes from several realms: pastes rheology, extrudability, shape-holdability, and drying kinetics. Secondly, for eliminating shaping drawbacks (e.g., deformation and cracks) originating from non-digital control factors, we put forward a digital shape-retention technology inspired by the generalized drying kinetics of porous materials, which was different from existing retention solutions, e.g., freezing retention, thermally induced gelation, and using removable support structures. In addition, we developed an in situ hot air flow drying device easily attached to the nozzle of existing 3D printers. Confirmatory 3D-printing experiments of thin-walled cone-shape benchmark parts and the fire arrowhead-like object clearly demonstrated that the presented shape-retention method not only upgraded layer-by-layer forming capability but also enabled digital control of extrudate solidification. In addition, many more experimental results statistically showed that both fully solid parts and purely thin-wall parts had higher dimensional accuracy and better surface quality than the offline drying method. The 3D printed ceramic products with complex profiled surfaces conceivably demonstrated that our improved extrusion-based 3D-printing process of ceramic pastes has game-changing potentials beyond the traditional craftsmanship capacity.

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Section: Extrusion-based 3d-printing Methods With In Situ Hot Air Fmentioning

confidence: 99%

Section: Limitations Of Extrusion-based 3d-printing Without Shape-mentioning

confidence: 99%

Extrusion-Based 3D Printing of Ceramic Pastes: Mathematical Modeling and In Situ Shaping Retention Approach

Mikołajczyk

Pimenov

et al. 2021

Materials

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“…The mixing stage of refractory castables requires the addition of water or some other liquid to help mold it into the desired shape. After that, drying becomes the most important processing step, as the added water must be withdrawn from the microstructure before firing, which implicates in heat and mass transfers of H2O in liquid or vapor form [1,2]. According to Oummadi et al [2], two main issues can be related to drying: (i) it requires significant energy consumption, and (ii) it may lead to mechanical stresses (due to pressure build-up associated with steam trapped inside the dense structure) and eventually the spalling and/or explosion of the ceramic.…”

Section: Introductionmentioning

confidence: 99%

“…After that, drying becomes the most important processing step, as the added water must be withdrawn from the microstructure before firing, which implicates in heat and mass transfers of H2O in liquid or vapor form [1,2]. According to Oummadi et al [2], two main issues can be related to drying: (i) it requires significant energy consumption, and (ii) it may lead to mechanical stresses (due to pressure build-up associated with steam trapped inside the dense structure) and eventually the spalling and/or explosion of the ceramic. Thus, this subject has motivated many studies focused on better understanding the water distribution and advance of the drying front in green ceramic bodies, by using alternative experimental techniques (i.e., magnetic resonance imaging and neutron tomography) [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…According to Oummadi et al [2], two main issues can be related to drying: (i) it requires significant energy consumption, and (ii) it may lead to mechanical stresses (due to pressure build-up associated with steam trapped inside the dense structure) and eventually the spalling and/or explosion of the ceramic. Thus, this subject has motivated many studies focused on better understanding the water distribution and advance of the drying front in green ceramic bodies, by using alternative experimental techniques (i.e., magnetic resonance imaging and neutron tomography) [2][3][4][5]. Moreover, other research groups have also been developing numerical models of heat and mass transfers in moist ceramics in order to predict safe and optimized heating schedules for refractory compositions [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Fast drying of high-alumina MgO-bonded refractory castables

Pinto

Fini

Miguel

et al. 2020

Ceramics International

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Refractory producers face many challenges in terms of producing MgO-containing castables due to the high likelihood of magnesia to hydrate in contact with water, resulting in Mg(OH)2 generation. The expansive feature of this transformation affects the performance of such refractories, as (i) if this hydrated phase is not accommodated in the formed microstructure, ceramic linings with cracks and low green mechanical strength will be obtained; and (ii) if crack-free pieces are prepared, they should present low porosity and reduced permeability, which require special attention when heating these materials. In both cases, spalling/explosion may be favored during the drying step of MgO-containing compositions. Hence, this work investigated the ability of various additives in the optimization of the drying behavior of Al2O3-MgO castables. Vibratable compositions were tested after incorporating polymeric fibers (PF), an organic salt (OAS), SiO2-based additive (SM) or permeability enhancing active compound (MP) into the dry-mixtures. Various experimental measurements were performed to infer the role of the drying agents to prevent the samples' explosion and whether they would also influence other properties of the castables. As observed, OAS and MP helped to inhibit the MgO-bonded samples' explosion even under severe heating conditions (2-20°C/min) and increased their green mechanical strength and slag infiltration resistance when compared to the additive-free composition. On the other hand, the addition of polymeric fibers (PF) or silica-based compound (SM) to the formulations was not able to prevent the castables' explosion when using a high heating rate and other side effects (samples' cracking during drying at 110°C, high linear expansion and increased slag penetration during corrosion tests) could also be observed when testing these materials. Thus, the selection of suitable drying 2 agents is a key issue, as they may allow the development of MgO-bonded castables with enhanced properties and lower spalling risk during their first thermal treatment.

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Printed Carbon Nanotube and Graphene Heaters for Drying Ceramics

Sherif

Patsavellas

Salonitis

2023

The Minerals, Metals &Amp; Materials Series

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The ceramic manufacturing process has been subject to many advances with the evolution of new technologies. However, there are still some delays and losses in the fundamental process which may be mitigated by deploying alternative technical tools and methods . One such stage is the sensitive pre-drying phase in which ceramic bodies can sustain drying defects such as microcracking and fractures due to lack of fine process control. This project investigates the feasibility of using Longwave infrared (LWIR) radiation emitted by a printed Carbon Nanotubes and Graphene (CNTG) heater for pre-drying a clay sample. The CNTG heater emits infrared radiation with a relatively low DC voltage power supply. By radiant heat transfer, homogeneous and uniform drying has been observed in the sample. The penetrative capability of the infrared energy which warms the inside of the sample is presented, as along with the results of comparing the CNTG heater with a Silicon mat heater that also emits infrared radiation. The study establishes that the CNTG heater is not only capable of reducing the lead time of ceramics drying using penetrative IR, but also as an efficient and versatile option that can be economically deployed in the pre-drying stage of a ceramic manufacturing process.

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Distribution of water in ceramic green bodies during drying

Cited by 17 publications

References 15 publications

Extrusion-Based 3D Printing of Ceramic Pastes: Mathematical Modeling and In Situ Shaping Retention Approach

Extrusion-Based 3D Printing of Ceramic Pastes: Mathematical Modeling and In Situ Shaping Retention Approach

Fast drying of high-alumina MgO-bonded refractory castables

Printed Carbon Nanotube and Graphene Heaters for Drying Ceramics

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