Ceramic Manufacturing Research Articles

Manufacturing and decorating cardial pottery: shell tools at the Neolithic site of Cabecicos Negros (Vera, Almeria, Spain)

Traditional research approaches on pottery production based on typological and morphometric classifications have changed in favour of new lines of research. One of them is based on the study of the technological equipment used in ceramic manufacturing processes. For example, ethnographic evidence shows the use of shell tools as technological equipment in different phases of ceramic production. In this study, the methodology of use-wear analysis has been applied to the archaeomalacological material from the Neolithic site of Cabecicos Negros (Andalusia, Spain) to establish if the shells were used as work tools. This analysis has been completed with the development of an experimental program composed of two analytical and one prospective experiments, carried out to provide new data about the cardial decorative technique and to define the use-wear traces that appear on the active area of the shells after their technological use. The results obtained in this investigation show the use of shells in different stages of pottery production. On the one hand, during the modelling and regularization phase of the ceramic surface and, on the other hand, during the cardial decorative phase. In this way, through this work, it has been possible to establish that the archaeological site of Cabecicos Negros was a pottery production center where domestic pieces were made during its Neolithic occupation. In addition, these findings reaffirm the importance of shells in ceramic manufacture during the Neolithic period, mainly in terms of the technical process linked to the cardial-type of ceramic decoration.

Multi-material ceramic hybrid additive manufacturing based on vat photopolymerization and material extrusion compound process

Multi-material ceramic hybrid additive manufacturing based on vat photopolymerization and material extrusion compound process

Additive manufacturing of high-performance aluminium nitride ceramics using high solid loading and low viscosity slurry

ABSTRACT In this study, the complex aluminium nitride (AlN) components with performance comparable to those produced by conventional methods were fabricated through an improved additive manufacturing technique. The use of a novel surfactant (KMT3331) improved the dispersion of AlN powder in resin, enhancing the compatibility between the powder and the resin, resulting in a low-viscosity slurry with solid loading exceeding 60 vol.%. This approach improved the density and homogeneity of the green bodies, resulting in dense and microstructurally homogeneous AlN ceramics, as well as reduced the sintering shrinkage and grain size. Finally, by controlling oxygen impurities introduced from the debinding process, complex-shaped AlN ceramics with high thermal conductivity (184.56 ± 2.77 W·m−1·K−1), outstanding mechanical properties (bending strength of 458.09 ± 36.03 MPa, fracture toughness of 3.95 ± 0.26 MPa·m1/2) and high reliability (Weibull modulus of 14.89) were obtained, greatly broadening the prospect of AlN ceramics in advanced thermal management applications.

Topology optimisation and lithography-based ceramic manufacturing of short-stem hip prostheses with enhanced biomechanical and mechanobiological performance

ABSTRACT Virtual prototyping combined with additive manufacturing technologies are opening new horizons in healthcare and biomimetic medical device personalisation is becoming feasible and competitive. Finite element-based optimisation combined with metallic additive manufacturing has already demonstrated the physical prototyping of interesting topologies for innovative articular prostheses. However, metallic implants are biomechanically and biologically suboptimal and a shift to ceramic materials, for bone replacement and articular implants, could result interesting. To this end, challenges liked to the engineering design of large-sized topology optimised ceramic implants and their additive manufacture still need to be overcome and exemplified. Accordingly, the whole engineering design of innovative short stem hip prostheses is presented here. Different approaches to the virtual prototyping of massive ceramic implants, involving strategies for their topology optimisation, are tested and systematically compared from biomechanical and mechanobiological perspectives. After virtual validation, the selected alternatives are successfully prototyped employing lithography-based ceramic manufacturing of alumina-toughened zirconia, which constitutes a design-enabled manufacturing breakthrough considering the massive implants achieved. Non-destructive evaluation using X-ray computed tomography allows for quantitative quality control and defect detection. Summarising, the study provides a systematic knowledge-based methodology for the engineering of topology optimised ceramic implants for critically sized defects with remarkable biomechanical and mechanobiological performance.

A Review on Microwave Processing Technique in the Synthesis of CaCu3Ti4O12

Microwave heating has a high potential technique to be used as an effective substitute for traditional furnace heating techniques in today's ceramic industries, including the synthesis of promising very high dielectric materials with relative permittivity, er = 105 of CaCu3Ti4O12 (CCTO). The microwave processing approach employs microwave radiation to heat materials more efficiently and uniformly to promote uniform densification. Hence, this approach improved the material’s characteristics tremendously compared to the traditional furnace. As microwave heating lowers the reaction times, it has the potential to save both money and energy compared to conventional heating techniques. In CCTO processing, microwave energy was commonly used to replace the heating technique in the calcination stage, sintering stage, or both. This review delves into the historical development and advancements in microwave processing methods within ceramic manufacturing, particularly focusing on CCTO electroceramics. The aim is to assess the viability of microwave processing as a complete substitute for conventional furnace heating techniques in the production of CCTO.

An advanced retrieval-augmented generation system for manufacturing quality control

The rise of Large Language Models (LLMs) with generative artificial intelligence has revolutionized the development of knowledge-based systems, enabling intuitive interactions through natural language. This paper explores the implementation of an advanced Retrieval-Augmented Generation (RAG) system, designed to improve manufacturing quality control by utilizing the capabilities of LLMs, particularly OpenAI’s GPT models. We focus on the ceramic tile manufacturing process, where the system retrieves and analyzes specialized bibliographic sources to diagnose defects and propose solutions. In addition to core RAG functionalities, the system incorporates tailored pre-processing and post-processing mechanisms to optimize document retrieval and response generation. The system’s effectiveness in solving quality issues is demonstrated through its application in identifying defect causes and generating actionable solutions, significantly improving non-conformities management. This approach not only streamlines troubleshooting but also enhances the quality control system, providing a comprehensive, scalable tool for manufacturers.

On the production of powder raw materials by coprecipitation method for the manufacture of 3YSZ ceramics with reduced thermal conductivity

On the production of powder raw materials by coprecipitation method for the manufacture of 3YSZ ceramics with reduced thermal conductivity

Additive manufacturing of binder-coated zirconia on a freeform surface

Advanced ceramics have become indispensable materials for use in diverse industrial sectors due to their exceptional properties, including high mechanical strength, corrosion resistance, oxidation resistance, low thermal conductivity, and remarkable hardness and wear resistance. However, their intrinsic characteristics of high hardness and wear resistance have posed a formidable challenge to their more widespread utilization that is mainly driven by elevated production costs and difficulty in machining complex structures. This study explores the application of additive manufacturing (AM) technologies, specifically material extrusion, for the fabrication of freeform ceramics structures, with a particular focus on binder-coated zirconia. The concept of conformal AM—in which a structure is printed directly onto the surface of a freeform substrate by aligning the topography of the two surfaces—is also explored. Conformal AM overcomes the challenges faced by traditional AM for printing on freeform surfaces, which include weak interlayer bonding, lower surface finish, and high material requirement and printing time. This study explores the printability of the material and the feasibility of using this print process for manufacturing intricate and functional ceramic structures. The outcomes of this research may smooth the path toward more efficient and cost-effective manufacturing of advanced ceramics, thereby expanding their applicability in numerous industries.

Advancements in Thin Solid-State Electrolytes for High-Energy Lithium Metal Batteries

ABSTRACT In the next generation of lithium-ion batteries (LIBs) utilizing lithium metal as the anode material, a theoretical capacity of 3860 mAh·g-1 can be expected [1]. However, several challenges such as safety issues due to lithium dendrite diffusion during charge-discharge cycling still remain unresolved [2]. The penetration of lithium dendrites remains a concern in traditional solution-based LIBs [3]. As an alternative approach to address the challenges of LIBs, solid-state electrolytes (SSEs) with high ionic conductivity and lithium metal stability have garnered attention [4]. The SSE category includes polymer electrolytes, inorganic sulfide electrolytes, and inorganic oxide electrolytes [5]. Among SSEs, garnet-type Li7La3Zr2O7 (LLZO), is a promising candidate due to its high ionic conductivity within the range of 10- 4 to 10- 3 S∙cm- 1 as well as its thermodynamics reduction stability against Li metal [6, 7].The introduction of SSB oxide electrolytes would improve packing density and could potentially lead to batteries with negligible self-discharge and longer lifespan of over 104 cycles [8]. During cell operation, solid electrolytes should be mechanically robust and as thin as possible to maximize the valuable volume remaining for the electrodes in SSB cell designs [9]. To compete with the approximately 20μm-thick polymer separators in traditional LIBs, ceramic manufacturing strategies for SSB electrolytes are necessary [10]. Recent estimations suggest that assuming a 25μm-thick solid electrolyte, a lithium metal SSB pouch cell could offer an energy density of 350Wh/kg [11]. In our study, we achieved ultra-thin electrolytes via tape-casting technique into Li-metal battery system. Li symmetric cells based on the ultra-thin electrolyte show exceptional low bulk resistance, attributed to extremely thin electrolyte. Moreover, symmetrical Li cell maintains steady Li plating/stripping cycles for long duration. Keywords: Lithium-ion batteries, LLZTO, thick solid electrolyte References [1] J. M. Tarascon, M. Armand, Nat., 414, (2001) 359-367.[2] J. Qian, W. A. Henderson, W. Xu, P. Bhattacharya, M. Engelhard, O. Borodin, J. G. Zhang, Nat Commun., 6, (2015) 6362.[3] Y. Guo, H. Li, T. Zhai, Adv. Mater., 29, (2017) 29.[4] J. Janek, W. G. Zeier, Nat. Energy., 1, (2016) 16141.[5] L. J. Miara, S. P. Ong, Y. Mo, W. D. Richards, Y. Park, J. M. Lee, H. S. Lee, G. Ceder, Chem. Mater., 25, (2013) 3048-3055.[6] L. J. Miara, S. P. Ong, Y. Mo, W. D. Richards, Y. Park, J. M. Lee, H. S. Lee, G. Ceder, Chem. Mater., 25, (2013) 3048-3055.[7] Y. Zhu, X. He, Y. Mo, ACS Appl. Mater. Interfaces, 7, (2015) 23685-23693.[8] T. Mageto, S. D. Bhoyate, F. M. de Souza, K. Mensah-Darkwa, A. Kumar, R. K. Gupta, J. Energy Storage, 55, (2022) 105688.[9] M. Balaish, J. C. Gonzalez-Rosillo, K. J. Kim, Y. Zhu, Z. D. Hood, J. L. M. Rupp, Nat. Energy, 6, (2021), 227–239.[10] L. Li, Y. Dian, Polymers, 15, (2023) 3690.[11] X. Wu, K. Pan, M. Jia, Y. Ren, H. He, L. Zhang, S. J. Zhang, GEE, 4, (2019) 360-374.

Direct Ink Writing and Rapid Microwave Sintering of Alumina

The additive manufacturing of ceramics is gaining attention due to difficulties in fabricating complex ceramic parts because of its hard and brittle nature. Direct ink writing (DIW) is a unique process in which solid-loaded slurry is extruded to print complex-shaped ceramic parts directly. In the present work, a new composition of high-solid loaded (76 wt.%) alumina ink is prepared for printing ceramic parts with complex structures. The rheology of ink is optimized to ensure the shear thinning behavior of the ink, while thermogravimetric analysis (TGA) of the printed part was carried out to optimize the debinding temperature. The printed alumina part is sintered using the conventional furnace and rapid microwave sintering process, and a comparison has been made. Microwave, a rapid sintering method with a high heating rate, produced >97% dense specimen, while the hardness and flexural strength values of 15.18 ± 0.6 GPa and 148.87 ± 2.14 MPa were achieved, respectively. Rapid microwave sintering of additively manufactured ceramic parts can reduce the energy consumption and overall production time needed to manufacture ceramic parts.

Thin alumina wafer fabrication by vat photopolymerisation based additive manufacturing

In VAT Photopolymerization (VP), a ceramic slurry is cured layer by layer under light (200–760 nm) to fabricate ceramic parts from a 3D CAD model. Lithography-based Ceramic Manufacturing (LCM) a VP process presents a significant advancement over traditional tape-casting methods in the production of thin ceramic substrates. While tape casting is limited in its ability to produce substrates in a single step, with thickness in the range of 100s of microns, typically necessitating the lamination of multiple tapes to achieve greater thicknesses. LCM overcomes this limitation, and it offers precise control over layer thicknesses, ranging from 10 to 100 microns, and is capable of directly printing substrates in the range of several hundred microns. This capability not only streamlines the manufacturing process but also ensures more consistent quality and greater flexibility in substrate thickness, making LCM a superior technique for producing thin ceramic substrates. However, the main challenge in LCM is to make these substrates without any warpage. This study aims to nail down the root cause of the warpage by employing various characterization techniques (including FTIR, nano-indentation, SEM and TGA), and by identifying factors that contribute to the warpage. It is observed that layer-wise fabrication leads to a curing gradient owing to the multiple exposures of already cured layers, causing the final layers to cure less than the initial ones. Due to this, mechanical properties such as hardness and modulus are significantly different for the initial and final layers. In thin parts (<300 microns), a significant proportion of under-cured layers contribute to pronounced warpage. To make a warpage-free substrate, a post-curing strategy is proposed and examined. It is concluded that 80 % of the warpage can be reduced by the proposed post-curing method.

Interlaboratory study of flexural strength in additively manufactured alumina

AbstractWe report the results of an international interlaboratory study of the flexural strength of alumina fabricated across six laboratories using the vat photopolymerization ceramic additive manufacturing (AM) technology. The mechanical testing of all the specimens, 142 in total, was performed at the National Institute of Standards and Technology (NIST) according to the well‐established four‐point bending method standardized for traditional ceramics. Overall, the existing ASTM standard for the four‐point bend testing proved adequate for AM ceramics, with several modifications to the specimen requirements to account for the specifics of AM processes. Critical flaws that caused failure were identified in all but two cases using optical fractography augmented with the imaging of fracture surfaces in a scanning electron microscope. The flexural strength data, analyzed following the Weibull statistics, exhibited considerable variation among the specimen sets manufactured by different laboratories. This variability correlated with the presence of many distinct critical flaws. We identified seven types of flaws that accounted for the failure of 94% of specimens. The prevalent flaws depend on the printing direction relative to the specimen's geometry. We discuss the nature of these flaws and their relation to the printing and post‐processing conditions. Removal of several types of critical flaws will significantly improve mechanical properties of ceramic parts built using vat‐photopolymerization AM.

Use of volcanic ash and chamotte as substitute temper in the production of ceramic tiles

This paper explores the use of waste materials as substitutes in ceramic paste formulations. Building on previous research which has laid the groundwork for the use of volcanic ash as temper in ceramic tile manufacture, investigation is here extended to a broader spectrum of waste-based ceramic pastes. Specifically, five different mixtures have been manufactured through the hand-made technique by using Etna volcanic ash and/or tile processing residues (chamotte), mixed with clay in variable proportions. Physical-mechanical tests including flexural strength, water absorption, resistance to thermal shock, deep abrasion and impact, have been performed and results compared with those of reference tiles. Notably, ceramic pastes combining clay with chamotte or clay with chamotte and fine volcanic ash, show better performance. This is certainly due to the good physical-mechanical properties of chamotte which binds well with the clayey groundmass so reducing shrinkage / cracking and improving the overall quality of ceramic products. Conversely, volcanic ash does not show a high degree of union with the clayey matrix, particularly when occurring in larger grain size. However, when present in fine clasts and in combination with chamotte, the resulting products display good physical-mechanical characteristics.This study highlights once again the potential of waste materials in ceramic manufacturing, paving the way for a more sustainable and resource-efficient industry.

The Concept of Using 3D Printing Technology in Ceramic Foundry Filter Manufacturing

The article presents the concept of using 3D printing technology in ceramic foundry filter manufacturing. They are a crucial component for obtaining an acceptable quality of nickel superalloys by carrying out the process using the precision casting method. Commonly used filters of this type have a number of disadvantages. They are characterized by irregularity of the filtering structure, high brittleness, lack of resistance to mechanical shocks, and impacts of a stream of liquid metal. All these factors create a risk of introducing the material from the damaged filter into the casting mold, which translates into contamination of the casting alloy, and thus the occurrence of casting defects such as nonmetallic inclusions. The hope for a change in this state of affairs is the use of additive manufacturing technology in their production, which by assumption will allow to obtain a product with a repeatable shape, high mechanical resistance, and a specially designed structure regulating the flow of liquid metal into the mold during casting. The suitability of robocasting and binder jetting technology for producing filtration structures was initially assessed. The results have presented the selection of ceramic powder, as well as the development of the composition of the ceramic paste. The parameters of paste preparation and 3D printing individual processes were described. Moreover, the representative microstructures and basic mechanical properties of samples obtained by both of the compared technologies were presented. Furthermore, the final effect of prototype casting filters with a repeatable shape, manufactured with the use of both technologies, was presented, which were transferred for further technological research in a foundry producing critical aircraft engine parts. The possibilities of using each technology in various applications were also discussed.

Microstructure formation mechanisms and property regulation methods during ceramic additive manufacturing

Anisotropic surface lamellar defects, dimensional shrinkage, and bending strength are important scientific issues that constrain vat photopolymerization additive manufacturing of biological, electronic, and core ceramics with high precision and complex structures. Through the single-factor experiment of photoinitiator concentration, average particle size, volume fraction, and refractive index constant in ceramic-resin slurry, this work studies the photopolymerization characteristics and profile curves, surface lamellar defects, and crosslinking density, verifies the reliability of the photopolymerization profile equations affected by the slurry composition, and acquires the anisotropic property formation mechanisms and control methods. The single-point scanning photopolymerization profile shape is parabolic, resulting in x-, y-, and z-direction lamellar defects before and after sintering (1550 °C), with no obvious weakening. After the quantitative description of the lamellar defects, the average surface roughnesses before and after sintering of the green body are 6.82 and 4.92 μm, respectively. Additionally, the laser energy attenuation along the penetration direction induces a gradient distribution of crosslinking density in the photopolymerization profile region. The crosslinking density gradient distribution of the decay from the slurry surface toward the depth direction is influenced by the slurry component concentration, leading to a gradient of cured powder concentration, which induces anisotropic behaviors. Through the crosslinking density controlling, the average bending strength in x(y) and z directions is increased by 63.19 % (46 %), the difference in anisotropic strength is reduced by 22.55 %, and the dimensional shrinkage difference of x and z directions is reduced by 48.32 %. This provides a theoretical and experimental research basis for ceramic vat photopolymerization with high dimensional accuracy, excellent performance, and morphology control.

Hierarchical materials with interconnected pores from capillary suspensions for bone tissue engineering

AbstractThe increasing demand for bone grafts due to the aging population has opened new opportunities for the manufacture of porous ceramics to assist in bone reconstruction. In our study, we investigate a new, promising method to manufacture hierarchically porous structures in a straightforward and tunable way. It consists of combining the novel technology of capillary suspensions, formed by mixing solid particles and two immiscible liquids, one less than 5 vol%, with freeze casting. We have successfully achieved alumina and beta‐tricalcium phosphate (β‐TCP) materials with both &lt;2 µm and 20–50 µm as the smallest and largest pore sizes, respectively. The microstructure exhibits fully open pores and high levels of porosity (&gt;60%). The capillary suspensions’ rheological behavior indicates that silica nano‐suspensions as a secondary fluid creates a stronger internal particle network than sucrose for the alumina system. Conversely, the opposite was observed with the β‐TCP system. These differences were attributed to the change in affinity between the secondary fluids and the solid loading. In our study, both systems have served to deepen the knowledge about the new area of capillary suspensions and proved their use in hierarchical porous scaffolds for bone tissue engineering.

Versatile binder system as enabler for multi-material additive manufacturing of ceramics by vat photopolymerization

Vat photopolymerization is an additive manufacturing process for producing ceramics with high printing resolution. Extending this approach to multi-material additive manufacturing, the aim is to combine two or more different ceramics in a single component to aggregate their advantages. For this, binders for different ceramic materials are required. To enhance the debinding step, this work aimed to develop a versatile binder system suitable for different ceramic materials. Finally, a binder system was developed and qualified for several different ceramic materials. By thermogravimetrical analyses, a suitable temperature curve for debinding was derived. In a final sintering step, the components were densified almost defect-free. Therefore, this work serves as an enabler for multi-material vat photopolymerization.

Novel Ceramic Clay Automatic Feeding System and Simulation Analysis

This study aims to verify the feasibility and effectiveness of an automatic feeding system in the ceramic clay-forming process. Through a series of clay-forming experiments, the system’s performance under various process parameters was examined. Precision sensors and data recording devices were used to monitor and record key data during the experimental process in real-time. The results demonstrate that the automatic feeding system can supply clay steadily and continuously under set parameters, ensuring a smooth forming process and significantly improving efficiency. Quantitatively, the system achieved a 30% increase in Vickers hardness, reflecting enhanced mechanical properties of the formed clay bodies. Additionally, there was a notable improvement in axial stress–strain characteristics, indicating better structural integrity and consistency. These improvements reduced human errors and material waste, enhancing production efficiency and product quality. Future research will focus on further optimizing system design and exploring its applications in a broader range of ceramic manufacturing processes.

Research on Textured Polishing Wheel (TPW) patterns for polishing dental ceramic materials in anhydrous environments

Abstract Dental ceramics commonly utilize high-hardness fused silica materials for the fabrication of inlays, crowns, and artificial dental implants, with their processing efficiency and surface roughness (Ra) directly influencing manufacturing costs and product quality. This study presents the development of a Textured Polishing Wheel (TPW) featuring three distinct surface patterns (spiral, linear, and radial), achieved through single-point diamond and pulsed laser processing techniques. It investigates the effects of these patterns on the removal rate and surface roughness (Ra) of dental ceramics during the polishing process. Results indicate that while TPW demonstrates comparable material removal depth to non-textured polishing wheels, it marginally increases surface roughness (Ra). Moreover, TPW significantly reduces burning and wear on the wheel surface during polishing. Pulsed laser ablation of TPW leads to further improvement in surface roughness, thereby enhancing the processing of dental ceramics. Experimental findings highlight the superior performance of spiral TPW, achieving a material removal rate of 4.2 μm/h and a surface roughness (Ra) of approximately 2.2 nm , thus meeting the manufacturing and functional requirements of dental ceramics.

Extrusion‐based additive manufacturing of alumina ceramics through controlled extrusion pressure

AbstractThe development of dense alumina ceramics through additive manufacturing necessitates the careful analysis of various parameters. The extrusion pressure during printing is a crucial but often overlooked factor in the literature. This study investigates the impact of extrusion pressure on the densification and mechanical properties of alumina ceramics. The primary objective is to analyze extrusion pressure to achieve superior physical and mechanical characteristics while maintaining minimal shrinkage. All other printing parameters were kept constant, and the extrusion pressure was varied from 1 to 2.85 bar during the extrusion‐based additive manufacturing of alumina green bodies. The printed and sintered samples were analyzed for linear shrinkage, density, compressive strength, and microhardness. The results indicate that an extrusion pressure in the 2.2–2.5 bar range leads to alumina ceramics with the best combination of densification and other mechanical properties. Additionally, the interparticle bonding mechanisms contributing to the improved properties of the alumina ceramics were examined. This study provides valuable insights into the role of extrusion pressure in the additive manufacturing process, underscoring its significance in achieving high‐quality alumina ceramics.