Fabrication Of Ceramics Research Articles

Programmable and rapid fabrication of complex-shape ceramics

Programmable and rapid fabrication of complex-shape ceramics

Treating waste with waste: Treatment of textile wastewater using upcycled food waste as a pore-forming agent in the fabrication of ceramic membranes employing DOE/FFD design

This study investigates a novel method for food waste management by using it as a sustainable replacement for conventional pore-forming agents in ceramic membrane production. The membranes were analyzed using various techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and a universal testing machine. The morphologies of the membranes were observed using scan electron microscopy (SEM). The effects of particle size (45–125 μm), pore-forming agent (5–20 wt%), and sintering temperature (900–1150 °C) on the porosity and mechanical strength of the membranes were investigated using the Design of Experiments (DoE) and Response Surface Methodology (RSM). The optimized membrane was evaluated for its performance in filtering industrial textile wastewater. It achieved impressive results, with approximately 98.4 % removal of turbidity and 71.3 % removal of chemical oxygen demand. This research paves the way for optimizing ceramic membrane fabrication using upcycled food waste, promoting sustainability and offering potential solutions for both food waste management and industrial wastewater treatment challenges.

Facile and Scalable Fabrication of High Water Absorption Composite Electrothermal Porous Ceramics for Electrothermal De-icing

Facile and Scalable Fabrication of High Water Absorption Composite Electrothermal Porous Ceramics for Electrothermal De-icing

Fabrication and characterization of foam ceramics from recycled waste concrete powder and waste glass powder

Incorporating multi-solid wastes to prepare foam ceramics has attracted widespread attention due to its excellent characteristics and environmental protection. In this study, foam ceramics were prepared by sintering method using recycled waste concrete powder (RWCP) and waste glass power (WGP) as the major material, Na2CO3 as foaming agent and borax as fluxing agent. The effect of sintering temperature on the physical properties and pore structure of foam ceramics were studied. The phase transformation and reaction mechanism were also discussed. The results reveal that when the RWCP content was 40%, the WGP content was 60% and the sintering temperature was 890 °C, the foam ceramics showed the best overall performance. The compressive strength, bulk density, water absorption and porosity were 2.39MPa, 0.83g/cm3, 8.27% and 66.68%, respectively. At this time, the pore size distribution was optimal, and mesopore occupied the vast majority. The fractal dimension of pore reached the minimum of 1.09. In addition, The XRD results showed that WGP and RWCP gradually depolymerized and reconstructed under the action of flux. Then the foam ceramics with mullite, pyroxene and wollastonite as the main phases were formed. The experimental results showed that it was feasible to prepare foam ceramics using RWCP. This study can provide a new train of thought for the reuse of RWCP.

Comparative analysis of laser power, pure titanium, and titanium alloy effects on dendrite growth and surface morphology of TiO2-ceramic

Despite several challenges, including the inherent brittleness of ceramics, inadequate melting of the powder, and the formation of microstructural defects, laser powder bed fusion remains a promising method for ceramic fabrication. This research looks at the intricate relationship between laser power as a dominant factor in the energy density, the influence of pure titanium (Ti) and titanium alloy (Ti-6Al-4V) additives on the laser fabrication of TiO2-based ceramics, and the resultant microstructural aspects, with a particular emphasis on dendritic growth and solidification defects. The research findings revealed that changing the laser energy density has a substantial influence on the dendrite growth and solidification rate of TiO2 ceramic. However, in addition to optimizing the laser power, the addition of metal material additives also plays a significant role in regulating the melting state and controlling the part defects in ceramics. The findings support that the mixing of pure titanium showed a relatively favorable influence, enhancing the melting condition of TiO2 and yielding a smooth surface with reduced defects. Conversely, the addition of a titanium alloy (Ti-6Al-4V) has a comparatively lower positive effect and led to the formation of substantial dendrites, solidification shrinkage, and significant fractures. The change in the scanning strategy from zigzag to island has no noticeable effect on the surface morphology and dendrite formation but contributes to controlling the spattering and crack propagation.

Tri-axial magnetic alignment and magnetic anisotropies in misfit-layered calcium-based cobaltites doped with rare-earth ions

In this study, we introduce an original method for quantifying tri-axial magnetic anisotropy in [Ca2CoO3-δ]0.62CoO2, and its rare earth (RE)-doped variants, [(Ca1-xREx)2CoO3-δ]0.62CoO2, utilizing a modulated rotating magnetic field of 10 T. Our findings reveal a significant correlation between the magnetic anisotropy and local structure of RE ions, particularly bond lengths and coordination numbers, which influence the magnetization axes of these magnetically aligned powders. We introduce an analytical methodology employing linear equations to calculate the magnetic susceptibilities along distinct crystallographic axes, enabling the prediction of tri-axial magnetic anisotropies at elevated concentrations of Er ions. This research not only advances our understanding of magnetic anisotropy control but also paves the way for the successful fabrication of triaxially-aligned ceramics using magneto-science techniques.

Ceramics for Microelectromechanical Systems Applications: A Review

A comprehensive review of the application of different ceramics for MEMS devices is presented. Main ceramics materials used for MEMS systems and devices including alumina, zirconia, aluminum Nitride, Silicon Nitride, and LTCC are introduced. Conventional and new methods of fabricating each material are explained based on the literature, along with the advantages of the new approaches, mainly additive manufacturing, i.e., 3D-printing technologies. Various manufacturing processes with relevant sub-techniques are detailed and the ones that are more suitable to have an application for MEMS devices are highlighted with their properties. In the main body of this paper, each material with its application for MEMS is categorized and explained. The majority of works are within three main classifications, including the following: (i) using ceramics as a substrate for MEMS devices to be mounted or fabricated on top of it; (ii) ceramics are a part of the materials used for an MEMS device or a monolithic fabrication of MEMS and ceramics; and finally, (iii) using ceramics as packaging solution for MEMS devices. We elaborate on how ceramics may be superior substitutes over other materials when delicate MEMS-based systems need to be assembled or packaged by a simpler fabrication process as well as their advantages when they need to operate in harsh environments.

Waste-to-resource: Employing lime mud as a foaming agent in glass foam manufacturing

The paper industry globally releases vast amounts of lime mud waste annually, raising environmental concerns. Composed mainly of calcium carbonate, lime mud has been utilized in various research works, including catalyst synthesis, cement production, and ceramic fabrication. This study investigates the use of lime mud as an eco-friendly foaming additive in the production of glass foam. Glass foams were prepared through a simple sintering method, utilizing glass cullet collected from households and incorporating different lime mud contents (0.5–2.0 wt%). The effects of lime mud concentration on the density, porosity, and pore size distribution of the glass foams were examined. Additionally, the thermal conductivity, compressive strength, and Weibull modulus were investigated in relation to the average porosity. The results revealed that the pore size distribution was dependent on the amount of lime mud, exhibiting three distinct distributions: a positively skewed distribution, a non-symmetric bimodal distribution, and a positively skewed distribution with a wide range. The Weibull modulus markedly decreased with increasing pore size. The compressive strength of the prepared glass foams ranged from 5.53±0.40–12.73±0.46 MPa, while the bulk density and porosity fell within the ranges of 0.41±0.02–0.70±0.04 g/cm3 and 72.12±1.45–85.38±0.98 %, respectively. The thermal conductivity could be as low as 0.07 W/m·K, approaching the upper limit for commercial glass foams used in thermal energy storage systems and meeting the requirements for Type I cellular glass thermal insulation classified by ASTM C552–16.

Novel and practical fabrication of pre-seasoned Y2O3 ceramics through surface modification

In the semiconductor industry, the long “seasoning” time required after the installation of new ceramic components in etching equipment restricts the wafer production efficiency. This study proposes a novel and practical method for the fabrication of pre-seasoned ceramics through surface modification of Y2O3 ceramics. Fluorine-containing reactive vapors were produced by utilizing NH4F as the source. Further, the formation of yttrium oxyfluoride layers on the surfaces of Y2O3 ceramics was demonstrated. The modified surface comprises a single-crystalline phase near the interface with the Y2O3 substrate. The change in the composition, crystalline nature of the modified layer, and orientation relationship with the substrate were examined via transmission electron microscopy. The kinetics of the surface modification were studied for the sintered Y2O3 bulk as well as for practical coatings such as plasma-sprayed or PVD coatings. The proposed surface modification approach can be used to fabricate pre-seasoned Y2O3 coatings, which can significantly benefit the semiconductor industry.

Flash sintering of AlN ceramics with Y2O3 additive

This study demonstrates the fabrication of dense AlN-based ceramics through the flash sintering technique for the first time. Flash sintering was performed at a furnace temperature of 1500 °C with 10 wt% Y2O3 as a sintering aid in a nitrogen atmosphere. The effects of the current density and holding time on the microstructure evolution and mechanical properties were investigated. The results show that the relative density, grain size and Vickers hardness of specimens increase with increasing current density and holding time. The specimen showed the highest relative density of 98.6% and a Vickers hardness of 12.68 GPa when a current density of 100 mA/mm2 and a holding time of 60 min were used. Additionally, the grain sizes at the positive side of the electrodes were found to be larger than those at the negative side. These findings suggest that dense AlN-based ceramics can be fabricated in a rapid and efficient way through the flash sintering technique.

Wettability and infiltration of Si drop on Si3N4 ceramic containing BaSiO3 as sintering aid

As container for the photovoltaic (PV) Si growth, fused silica crucible can only be used once owing to crystallization breakage, which inevitably reduces the quality and yield of Si. To develop re-useable crucible, Si3N4 ceramics were successfully fabricated using novel BaSiO3 (0-8 wt%) as sintering aid. Higher BaSiO3 content promotes the densification and sintering of Si3N4 ceramic. Then, the wetting/infiltration behaviors of Si/Si3N4 binary systems were systematically investigated by sessile drop test and microstructural analysis technology. With 8 wt% BaSiO3 introduction, the Si3N4 ceramic displayed larger contact angle of Si drop and excellent Si infiltration resistance, which was determined by de-oxidation rate. Moreover, three type of infiltrations, including infiltrations under Si drop and beyond Si drop (on/under substrate surface), were found and systematically analyzed. In this work, novel sintering aid (BaSiO3) was developed for Si3N4 ceramic fabrication at relatively lower sintering temperature. Additionally, the data of wetting/infiltration behavior for Si/Si3N4 binary system can be used to guide the application of Si3N4 crucible in PV Si manufacture.

Gradient coating increases the temperature resistance of ceramic fiber fabric

Ceramic fiber fabric embrittlement at 1200 °C, resulting in poor tensile strength. In order to improve the tensile strength of ceramic fiber fabric after high temperature heat treatment. In this study, gradient coating is sprayed on the surface of ceramic fiber fabric by adjusting the composition of two kinds of slurry. The structure and property of ceramic fiber fabric with different coating are thoroughly investigated. The pore size of Al2O3-SiC porous transition layer is less than 1 μm, which limits the infiltration of the high-emission coating into the ceramic fiber fabric. A weak bond is formed between the ceramic fiber fabric and the porous transition layer, which induces the crack deflection. The flexibility of ceramic fiber fabric after heat treatment is significantly improved. After being heated by butane flame at 1200 °C for 20 min, the tensile strength of fiber fabric with gradient coating is double that of raw ceramic fiber fabric. The silicone cross-links to form a network, which improves the bonding strength of the gradient coating. Due to the high emissivity and low thermal conductivity of the gradient coating, the temperature of the ceramic fiber fabric is below 900 °C when heated by the butane flame.

Co-molding High Temperature Erosion Coatings for Thermoset Polyimide Composites

High temperature (200-260°C) military composite engine components made of carbon fiber thermoset materials are susceptible to erosion damage. Evidenced by wear seen during operation, erosion protection remains a challenge for composites in the engine air flow path. In this paper, we investigate polyetheretherketone (PEEK), thermoplastic polyimide (TPI), and ceramic fabric (Nextel™) as potential high temperature erosion coatings for thermoset polyimide composite engine components. We evaluate the erosion protection materials for two qualities: (1) co-moldability with thermoset polyimide composite panels, and (2) erosion resistance to a sandblasting test. Autoclave and compression molding were used to test co-moldability with different manufacturing methods. The compression molding process was optimized to reduce surface defects using a pre-imidization step before the erosion protection layer was applied and final cure was completed. Co-molded test panels were cut into small coupons for sandblasting. After 60 s of alumina sandblasting PEEK had negligible mass loss, whereas the TPI and ceramic fabric had roughly the same erosion rate as the uncoated polyimide laminate.

Improved mechanical properties of porous Si3N4 ceramics strengthened by β-Si3N4 seeds fabricated by vat photopolymerization

Porous Si3N4 ceramics are widely applied in aerospace and mechanical fields owing to their excellent properties. Furthermore, vat photopolymerization (VPP) technology can fabricate Si3N4 components with complicated structures and high precision, but its layer-by-layer printing method leads to poor mechanical properties of ceramics. In this study, porous Si3N4 ceramics with a porosity of 28.41 % strengthened by directional β-Si3N4 were fabricated by combining VPP technology and seeding method. Rheological behavior and curing properties of the slurry were explored, and the influence of β-Si3N4 content on the mechanical properties of printed Si3N4 ceramics was investigated systematically. With the increase of β-Si3N4 content, the orientation degree of β-Si3N4 grains increased gradually, while fracture toughness and flexural strength of the ceramics exhibited a trend of increased first and then decreased and Vickers hardness gradually decreased. As β-Si3N4 content increased to 5 wt%, the fracture toughness and flexural strength of porous Si3N4 ceramics were improved from 4.23 MPa m1/2 and 214.7 MPa–5.65 MPa m1/2 and 272.0 MPa, respectively. Therefore, this work indicates that vat photopolymerization combined with seeding method is a promising approach for the fabrication of porous Si3N4 ceramics with high performance and complex structures.

Enhancing thermal conductivity of AlN ceramics via vat photopolymerization through refractive index coupling and oxygen fixation

Despite the growing development of ceramic fabrication by vat photopolymerization (VP), major gaps remain in application. Particularly in the case of VP-printed aluminum nitride (AlN) ceramic, the thermal conductivity is still below 170 W·m−1·K−1, a critical benchmark for efficient heat dissipation. To address this challenge, here we prepared an AlN slurry with high curing thickness through RI coupling between liquid-solid phase, and took into account of the rheological property under high solid loading. Full dense AlN green bodies with solid loading up to 50 vol% were successfully printed. Aiming to to tackle the degradation of thermal conductivity issue caused by oxygen increment of AlN via VP, we systemically studied the form of oxygen in AlN preparation processes. Through the sintering optimization, the oxygen element from the hydrolysis of AlN surface was fixated in the sintering aid Y2O3. Eventually, without any special process control or additional treatment, the final sintered AlN ceramics prepared by the developed slurry present a full densification and the highest thermal conductivity (up to 187.9 W∙m−1∙K−1) of any known additive manufactured ceramics.

Individual or communal? Exploring the social dynamics of ceramic production at the Lengyel circular-enclosure site of Těšetice-Kyjovice – Sutny, South Moravia

Although ceramic vessels form the majority of artifact assemblages in the Neolithic, little is known about their production beyond the assumption that they were made in a domestic context. Characterizing the scale of ceramic production is important for understanding Neolithic social and economic processes, particularly at sites with enclosure systems that indicate an increased degree of social organization. Nevertheless, characterizing the complexity and social entanglements of ceramic production is a difficult task in the absence of primary production locales.In this study, we provide a working hypothesis and use ceramic and clay petrographic data to highlight the variability in ceramic technological practices, and in turn, identify the organization of ceramic production at the Late Neolithic (Lengyel I; 4750–4500 BCE) site of Těšetice-Kyjovice – Sutny, South Moravia, Czech Republic. The site is characterised by a large circular enclosure, the construction of which required a high level of social cooperation. It is still under scrutiny whether the cooperation required for building the enclosure system was only temporary and related to this construction activity, or if it reflects a higher degree of social organization in general.By understanding ceramic production, we may clarify the complexity of the most common production processes that took place at the site. Large-scale ceramic and clay petrographic data provide information on the first steps of the chaîne opératoire in ceramic fabrication, which can be used to assess the organization of production. A systematic analysis of a large number of ceramic samples, representing all basic typological and macroscopically distinguishable fabric groups, revealed a high degree of individuality in choices of raw materials and tempers. Ceramic petrographic data, compared with the petrographic data of local sediment sources, further highlighted individuality in raw material and temper preferences, and even mixing of raw materials was identified.Our analyses suggest that Lengyel culture potters likely produced their vessels on a household level, with no evidence suggesting non-domestic production. These data, in conjunction with ceramic petrographic data from Hungarian Late Neolithic sites, suggest that Late Neolithic communities were self-sufficient in terms of utilitarian pottery production. Ceramic petrographic data also indicate interaction between the inhabitants of Těšetice and other Lengyel culture communities in the vicinity, perhaps further indicating a higher degree of social organization at the site.

Synthesis of TaB2-TaC nanocomposite powders by a boro-carbothermal reduction route

This paper introduces the boron/carbon thermal reduction reaction, represented by the equation 2Ta2O5+ B4C + 11 C = 2TaB2 + 2TaC + 10CO (g), as a novel reaction pathway for synthesizing TaB2₋TaC composite powders. Subsequently, the SPS technique is employed for the fabrication of TaB2-TaC composite ceramics via sintering. The article begins by elucidating the fundamental process of this reaction and constructing a phase diagram through thermodynamic calculations. The experimental results demonstrate that adjusting the synthesis temperature and the proportion of the boron source in the raw materials enables effective control over the ratio of the two phases within the composite materials, allowing the TaB2 phase content to be tailored within the range of 38.1–60 %. Moreover, elevating the synthesis temperature and increasing the proportion of the boron source effectively mitigate the C,O impurity content in the composite powders and facilitate the TaB2 step-growth process. It is noteworthy that the hardness of TaB2-TaC composite ceramics sintered at 2000°C using the optimized complex-phase powder as the precursor reaches 21.7±0.5 GPa, and the fracture toughness attains 5.2±0.2 MPa⋅m1/2.

Prediction and fabrication of textured Si3N4 ceramics via grain rotation model

The grain preferential orientation has a significant influence on the mechanical properties of silicon nitride (Si3N4) ceramics. Based on the Jeffery’s theory, a grain rotation model under uniaxial compression is created to predict the texture evolution mechanism during sintering of Si3N4 ceramics. With deformation, the grain orientation was predicted to rotate towards the plane perpendicular to the pressure direction, and large strain was favorable for the formation of strong texture. According to guidance of the model, the weakly textured microstructure prepared by normal hot pressing is attributed to the limited strain, due to the constrains of graphite die. Therefore, a new PHIP (pseudo-hot isostatic pressing) process with the large deformation is guided to fabricate the strongly textured ceramics by promoting the grain rotation and dynamic grain growth. Generally, the experimental results are well accordance with the model prediction. Furthermore, this model could be applied to guide the design and fabrication of other isotropic and anisotropic ceramic materials.

Titania and zirconia ceramic nanofiltration membrane fabrication by coating method on mullite and mullite-alumina microfiltration supports for industrial wastewater treatment

Industrial wastewater treatment increasingly relies on membrane separation, with ceramic membranes offering many advantages such as thermal stability and pH resistance. The resistance of ceramic membranes to extreme pH conditions indicates their ability to maintain structure and performance when exposed to highly acidic or alkaline environments. A high-permeability ceramic nanofiltration membrane was developed, boasting excellent rejection rates through a multilayer asymmetric design. Initially, two tubular porous supports, mullite and mullite-alumina, with a weight percent of 50, were fabricated using the extrusion method. Subsequently, a colloidal sol of titania (TiO2) and titania-zirconia (TiO2- ZrO2) was prepared via the sol–gel method and coated on the ceramic supports using the dip-coating method. After analyzing the membrane microstructure using SEM, XRD, and BET, the efficiency of the membranes in treating synthetic oily wastewater was evaluated. The results underscore the significant impact of the Donnan exclusion mechanism on the rejection of nanofiltration (NF) membranes. An increase in pressure led to a rise in rejection rates up to 7 bars. The Chemical Oxygen Demand (COD) rejection for mullite-titania zirconia (MTZ) and mullite-alumina-titania zirconia (MATZ) membranes was 98.65 % and 98 %, respectively. The pure water permeability test results for mullite and mullite-alumina supports, as well as MTZ and MATZ membranes, were recorded as 254, 382, 70, and 89 L bar-1m-2h−1, respectively.

Optimization of Yb:CaF2 Transparent Ceramics by Air Pre-Sintering and Hot Isostatic Pressing

Yb:CaF2 transparent ceramics represent a promising laser gain medium for ultra-short lasers due to their characteristics: low phonon energy, relatively high thermal conductivity, negative thermo-optical coefficient, and low refractive index. Compared to single crystals, Yb:CaF2 ceramics offer superior mechanical properties, lower cost, and it is easier to obtain large-sized samples with proper shape and uniform Yb3+ doping at high concentrations. The combination of air pre-sintering and Hot Isostatic Pressing (HIP) emerges as a viable strategy for achieving high optical quality and fine-grained structure of ceramics at lower sintering temperatures. The properties of the powders used in ceramic fabrication critically influence both optical quality and laser performance of Yb:CaF2 ceramics. In this study, the 5 atomic percentage (at.%) Yb:CaF2 transparent ceramics were fabricated by air pre-sintering and hot isostatic pressing (HIP) using nano-powders synthesized through the co-precipitation method. The co-precipitated powders were optimized by studying air calcination temperature (from 350 to 550 °C). The influence of calcination temperature on the microstructure and laser performance of Yb:CaF2 ceramics was studied in detail. The 5 at.% Yb:CaF2 transparent ceramics air pre-sintered at 625 °C from powders air calcined at 400 °C and HIP post-treated at 600 °C exhibited the highest in-line transmittance of 91.5% at 1200 nm (3.0 mm thickness) and the best laser performance. Specifically, a maximum output power of 0.47 W with a maximum slope efficiency of 9.2% at 1029 nm under quasi-CW (QCW) pumping was measured.