Ceramic Manufacturing Research Articles

Land, Ceramics and Seigniorial Rents in the Late Middle Ages: the Manor of Manises in the Kingdom of Valencia, c. 1400-1575

During the last two centuries of the Late Middle Ages lords experienced a substantial fall in rents, which was exacerbated in the case of Valencia due to the small size of local manors. The will to keep their levels of incomes brought lords to demand higher burdens from their vassals, especially Muslims, while some nobles, in addition, invested in the productive structures of their estates. Such was the case in the manor of Manises, where since the early fourteenth century an important ceramic manufacturing had developed, which attracted the interest of buyers from all over Europe. This production took place in a medium-sized manorial village, inhabited by a mixed population of Muslims and Christians, which maintained its engagement with agricultural labour. The aim of this article is to analyse the rents of the manor of Manises through two unpublished and exceptional manorial sources, namely, two registries datable from the early fifteenth century and the early sixteenth century respectively, although the latter continued to be used until the end of the century. These allow the exploration of the structure of seigniorial revenues, showing the incidence that agrarian rents and those coming from ceramic production represented over the total. The tendency followed by the manorial rents in the long run is addressed and compared to those of other contemporary locations of the Kingdom of Valencia. Finally, the involvement of vassals in agriculture and ceramic manufacturing is also explored.

Manufacturing a Ceramic Turbine Rotor for a Compact Jet Engine

Abstract Compact military-grade jet engines offer many potential applications, including use in remotely piloted vehicles, but can be expensive to use for research and development purposes. A study aimed at increasing the power and thrust output of an inexpensive commercial compact engine found a material limitation issue in the turbomachinery. To gain the additional power, hotter turbine inlet temperatures were required. This temperature increase exceeded the limit of current uncooled metal turbine rotors but could be achieved through turbine rotors made from ceramics, such as silicon nitride, which would allow an increase in the thrust and power output by a factor of 1.44. Current ceramic turbine manufacturing methods are costly and time-consuming for rapid prototyping, but recent breakthroughs in ceramic additive manufacturing have allowed for cheaper methods and faster production which are beneficial for use in research and development when designs are being rapidly changed and tested. This research demonstrated, through finite element analysis, that a silicon nitride turbine rotor could meet the increased turbine inlet temperature conditions to provide the desired thrust and power increase. Furthermore, as a proof of concept, an additively manufactured drop-in replacement alumina turbine rotor was produced for the JetCat P400 small-scale engine in a manner that was cost-effective, timely, and potentially scalable for production. This compact engine was used to demonstrate that a cost-effective ceramic turbine could be manufactured. At the time of publication, the desired ceramic material, silicon nitride, was not available for additive manufacturing.

3D Printing of Hollow Microspheres into Strong Hierarchical Porous Ceramics

AbstractPorous ceramics are demanded in a wide range of high‐temperature, biological and energy‐related applications, but may show conflicting properties or suffer from poor mechanical properties. Introducing pores at different length scales has been shown to be a promising design strategy to combine antagonistic performance parameters and reach high porosity without severely compromising strength. Herein, a cost‐effective and simple process to create strong, highly porous ceramics via direct ink writing of suspensions of hollow microspheres into cellular architectures with pores at three hierarchical levels is reported. X‐ray diffraction, rheological measurements, scanning electron microscopy, and mechanical tests are conducted to thoroughly study the processing steps and morphology of the printed hierarchical porous ceramics. The presence of pores at multiple length scales increases significantly the mechanical strength of the porous structure, providing a useful platform for the manufacturing of lightweight ceramics from inexpensive and widely available feedstock materials.

Pressureless all‐solid‐state Na/S batteries with self‐supporting Na5YSi4O12 scaffolds

AbstractThe development of reliable and affordable all‐solid‐state sodium metal batteries (ASS‐SMBs) requires suitable solid‐state electrolytes with cost‐efficient processing and stabilized electrode/electrolyte interfaces. Here, an integrated porous/dense/porous Na5YSi4O12 (NYS) trilayered scaffold is designed and fabricated by tape casting using aqueous slurries. In this template‐based NYS scaffold, the dense layer in the middle serves as a separator and the porous layers on both sides accommodate the active materials with their volume changes during the charge/discharge processes, increasing the contact area and thus enhancing the utilization rate and homogenizing the current distribution. The Na/NYS/Na symmetric cells with the Pb‐coated NYS scaffold exhibit significantly reduced interfacial impedance and superior critical current density of up to 3.0 mA cm−2 against Na metal owing to enhanced wettability. Furthermore, the assembled Na/NYS/S full cells operated without external pressure at room temperature showed a high initial discharge capacity of 970 mAh g−1 and good cycling stability with a capacity of 600 mAh g−1 after 150 cycles (based on the mass of sulfur). This approach paves the way for the realization of economical and practical ASS‐SMBs from the perspective of ceramic manufacturing.

Polymer-derived Ni/SiOC materials structured by vat-based photopolymerization with catalytic activity in CO2 methanation

A new concept for the additive manufacturing of nickel-modified polymer-derived ceramics via vat-based photopolymerization is presented. A photoactive polysiloxane resin system modified by nickel nitrate via methacrylic acid complexation was developed and modified to facilitate vat-based photopolymerization. Through pyrolysis of the Ni-modified preceramic polymer at temperatures between 600 and 800 °C, amorphous SiOC components with well-dispersed Ni nanoparticles can be obtained. The modified polymer and the fabricated structures were characterized by photorheology, thermal analysis, scanning and transmission electron microscopy, optical coherence tomography, and powder X-ray diffraction. In addition, the effect of pyrolysis temperature on specific surface area, crystallinity, and shrinkage was investigated. The developed material systems enable additive manufacturing of porous SiOC structures containing crystalline, uniformly distributed, and bimodally sized Ni nanoparticles, exhibiting catalytic activity suitable for CO2 methanation. The developed printable SiOC/Ni materials represent a promising approach for combining metal-modified polymer-derived ceramic systems and additive manufacturing for prospective catalysis applications.

Hybridizing Lithography-Based Ceramic Additive Manufacturing with Two-Photon-Polymerization

Stereolithography processes such as lithography-based ceramic manufacturing (LCM) are technologies that can produce centimeter-sized structures in a reasonable time frame. However, for some parts specifications, they lack resolution. Two-photon-polymerization (2PP) ensures the highest geometric accuracy in additive manufacturing so far. Nevertheless, building up parts in sizes as large as a few millimeters or even centimeters is a time-consuming process, which makes the production of 2PP printed parts very costly. Regarding feedstock specification, the requirements for 2PP are different to those for LCM, and generally, feedstocks are designed to meet requirements for only one of these manufacturing technologies. In an attempt to fabricate highly precise ceramic components of a rather large size, it is necessary to develop a feedstock that suits both light-based technologies, taking advantage of LCM’s higher productivity and 2PP’s accuracy. Hybridization should bring the desired precision to the region of interest on reasonably large parts without escalating printing time and costs. In this study, specimens gained from a transparent feedstock with yttria stabilized zirconia (YSZ) particles of 5 nm at 70 wt% were presented. The resin was originally designed to suit 2PP, while being also printable with LCM. This work demonstrates how hybrid parts can be sintered into full YSZ ceramics.

A Novel Approach for Powder Bed Fusion of Ceramics Using Two Laser Systems

The one-step AM process is considered the goal many researchers seek in the field of Additive Manufacturing (AM) of high-technology ceramics. Among the several AM techniques, only Powder Bed Fusion (PBF) can directly print high-technology ceramics using one step. However, the PBF technique faces numerous challenges to efficiently be employed in the PBF of ceramics. These challenges include the formation of cracks, generated thermal stress, effective laser-powder interaction, and low acquired relative density. This study developed a new preheating mechanism for ceramic materials using two laser systems to surpass beyond these challenges and successfully print ceramics with a single-step AM method. One laser is used to preheat the powder particles before the second laser is utilised to complete the melting/sintering process. Both lasers travel along the same scanning path. There is a slight delay (0.0001 s) between the preheating laser and the melting/sintering laser to guarantee that the melting/sintering laser scans a properly preheated powder. To further facilitate testing of the preheating system, a numerical model has been developed to simulate the preheating and melting process and to acquire proper process parameters. The developed numerical model was shown to determine the correct process parameters without needing costly and time-consuming experiments. Alumina samples (10 × 10 × 6 mm3) were successfully printed using alumina powder as feedstock. The surface of the samples was nearly defect-free. The samples' relative densities exceeded 80%, the highest reported relative density for alumina produced by a single-step AM method. This discovery can significantly accelerate the transition to a one-step AM process of ceramics.

Strength of additively manufactured alumina with different debinding and sintering heat treatments

AbstractLithography‐based ceramic manufacturing (LCM) utilizes slurries with low solids loading, which makes pressureless sintering to full density especially difficult. A further compounding issue in sintering to full density and establishing structure–property–processing relationships for LCM alumina is the fact that the current literature lacks consensus on heat treatments to achieve full densities. Treatment specifics that are recorded are frequently ambiguous and insufficiently detailed. In this work, temperatures and times for debinding and sintering schedules were varied to characterize the influence of heat treatment parameters on density, microstructure, and flexural strength of high‐purity, LCM‐formed alumina. Removing the bisque‐fire from debinding and fine‐tuning sintering parameters produced parts with full densities, high flexural strengths, and Weibull moduli that match or exceed the values documented in a round robin study of traditionally processed alumina.

An Approach for Designing an Optimal CNN Model Based on Auto-Tuning GA with 2D Chromosome for Defect Detection and Classification

Defect detection and classification on the final products are necessary for the manufacturers to ensure the quality of the final product before delivering it to the end customers. With rapid changes in manufacturing technologies, most of the companies have changed their operation methods toward industry 4.0. On this road, developing an automatic detection system based on the surface images can enhance the productivity and ensure the quality of the product. However, only a few studies have developed the models for solving this problem. Due to its complicated structure and parameters, designing an optimal convolution neural network (CNN) is still a challenge. Thus, this study aims to propose an autotuning genetic algorithm with two-dimension chromosomes for designing an optimal CNN model efficiently. In particular, a two-dimension chromosome is developed to represent a CNN’s structure and parameters. To enhance the searching process, the crossover rate and mutation rate are tuned automatically according to the generation. A two-dimension crossover method is proposed to create offspring for selecting the next population. In addition, a case of ceramic textile manufacturing is constructed to validate the proposed approach. The accuracy of the proposed approach is up to 95.5 percent on the testing dataset.

Plastic behaviour of clay materials for the manufacture of fast-drying red ceramics

AbstractFast drying (~60 min) is useful for optimizing production processes by increasing productivity and reducing costs and environmental impacts, especially in red ceramic industries in Brazil. However, suitable clays are necessary and, currently, studies focused on the plastic behaviour of clays with compositions suitable for extrusion, especially for fast drying, are scarce. Therefore, in this study, three different clays from the same mineral deposit were studied for producing clay-based structural products via fast drying. The clays were characterized according to their chemical, mineralogical and thermal properties, particle size, cation-exchange capacity, specific surface area and open pore volume distribution. Ten formulations were developed using a simplex-centroid mixture design of experiments and their plasticity index (PI) values were determined. The response surfaces of the formulations were evaluated according to their PI, while the formation characteristics were determined according to their extrusion workability factor values. Formulations F5 (50.0 wt.% yellow clay and 50.0 wt.% green clay) and F8 (66.6 wt.% yellow clay, 16.7 wt.% grey clay and 16.7 wt.% green clay; PI = 15.5–16.6%) displayed optimal extrusion properties, followed by formulations F7 (33.3 wt.% yellow clay, 33.3 wt.% grey clay and 33.3 wt.% green clay) and F10 (16.7 wt.% yellow clay, 16.7 wt.% grey clay and 66.6 wt.% green clay; PI = 13.8–14.2%), which are within acceptable extrusion index values. Thus, the chosen formulations have significant potential for use in the manufacture of fast-drying red ceramics.

The design and evaluation of additively manufactured piezoelectric acoustic transducers

Ceramic additive manufacturing (AM) has been demonstrated as a capable method to fabricate piezocomposite acoustic transducers that exhibit augmented sensitivity, increased bandwidth, and controlled directivity by virtue of geometry. These improvements are intrinsic to the novel piezoelectric ceramic structure, which may be printed in forms that cannot be fabricated through conventional manufacturing methods. The AM process allows for functionally-graded apertures, 3-3 piezocomposite structures, and auxetic lattices which have been simulated, printed, and measured with compelling results. This presentation expands upon previous work completed through a collaboration between Lithoz America, LLC (Lithoz), MSI Transducers Corp. (MSI), and the MITRE Corporation (MITRE) to produce novel piezoelectric structures and validate acoustic and hydrostatic pressure performance of 1-3 piezocomposite structures under operationally relevant conditions. The presentation will encompass a discussion of Finite Element Analysis (FEA) of piezoelectric metamaterials conducted at MITRE, the lithography-based ceramic manufacturing (LCM) process of said structures at Lithoz, and empirical measurements of piezoelectric and acoustical specifications of the printed structures conducted at MSI. Finally, test data recorded at Woods Hole Oceanographic Institute (WHOI) will be shown, demonstrating the resilience of AM 1-3 piezocomposite under 10 000 PSI of hydrostatic pressure derived by means of in-situ electrical impedance measurements.

Inka and Local ceramic production and distribution networks: A view from the Chinchaysuyo and Colesuyo

This paper uses multiple geochemical ceramic datasets generated using Laser Ablation Inductively Coupled Plasma Mass-Spectrometry (LA-ICP-MS) to reconstruct patterns in the manufacture of ceramics in four locales of the Inka realm. Specifically, we compare local and Inka Polychrome styles in different regions of the empire. Collectively, these data reveal that local systems of production were not greatly transformed by imperial expansion. However, our results suggest that potters continued to produce their earlier styles and added Inka styles manufactured with similar raw materials to their repertoire. This indicates that they actively made use of newly introduced craft concepts during political shifts. These results show the adaptability of local ceramicists in experimenting and/or learning paste recipes to manufacture Inka forms and design canons. Additionally, the data highlight the role of potters as participants in Inka imperialism through their manufacture of both foreign pottery and local ceramic styles.

Functionally graded ceramics by lithography-based ceramic manufacturing (LCM)

Functionally graded ceramics by lithography-based ceramic manufacturing (LCM)

Additive manufacturing of Al2O3 ceramics with MgO/SiC contents by laser powder bed fusion process.

Laser powder bed fusion is a laser-based additive manufacturing technique that uses a high-energy laser beam to interact directly with powder feedstock. LPBF of oxide ceramics is highly desirable for aerospace, biomedical and high-tech industries. However, the LPBF of ceramics remains a challenging area to address. In this work, a new slurry-based approach for LPBF of ceramic was studied, which has some significant advantages compared to indirect selective laser sintering of ceramic powders. LPBF of Al2O3 was fabricated at different MgO loads up to 80wt%. Several specimens on different laser powers (70W-120W) were printed. The addition of magnesia influenced the microstructure of the alumina ceramic significantly. The findings show that when the laser power is high and the magnesia load is low, the surface quality of the printing parts improves. It is feasible to produce slurry ceramic parts without binders through LPBF. Furthermore, the effects of SiC and MgO loads on the microstructure and surface morphology of alumina are compared and analysed.

Formation mechanism and quantitative analysis of pores in Al2O3–ZrO2 ceramic different structures by laser additive manufacturing

Pores is one of the most defects during laser additive manufacturing of ceramic material. In this paper, different structures of Al2O3–ZrO2 ceramics are deposited by using powder-feeding laser additive manufacturing. The ceramic structures can be simplified into three typical structures: linear-type, face-type and body-type structure. The formation mechanism and quantitative analysis of pores in different ceramic structures are studied. The pores of ceramic structure is mainly divided into four types: intercrystalline pore, interlayer pore, intralayer pore and shrinkage pore. In the linear-type structure, the number of pores with the interval 0–1000 μm2 accounts for 98.8%, while the area of pores with the interval above 104 μm2 accounts for 58.33%. The remelting rate of deposition layer has great influence on the pores. The Marangoni convection changed from inflow mode to outflow mode, which leads to that bubbles have easily escape from molten pool. In the face-type structure, the number and area of pores at the interval 0–1000 μm2 account for 98.96% and 51.62%, respectively. Overlap ratio is the key factor affecting pore. Under the effects of the Marangoni convection and the overlap of deposition layer, the irregular pores are easily formed in the bottom of overlap region of deposition layer. The pores characteristic in the body-type structure is similar to that in linear-type structure. Due to the laser remelting and overlap phenomenon, the thermal accumulation effect is more obvious in the short time interval and continuous deposition process of body-type structure. Thus, the gas of molten pool can be easily escaped. This study can provide the theoretical basis for the suppression of pores in ceramic laser additive manufacturing.

Geochemical and Geological Characterization of Clay in the Eastern Part of Hawal Massif Around Mubi and Environs, Northeastern Nigeria

The geochemical and geological characterization of clay is an important approach to determining the quality and productivity of clay for industrial use. This paper is aimed at providing detailed geochemistry, distribution, and utilization of clay from the eastern part of Hawal massif. The field study revealed that clay occurs in Bagira, Vimtim, Didif, Bulamary, Ngavahi, Dou-Gada, Madanya, TudunWada, Moda, and Kwabapale. The clays are residual deposits formed by weathering of feldspars from the granitic rocks, the clay deposits are restricted to the basal parts of highly weathered granite. The depth to which the samples were collected ranged from 0.6-1 meter. The clay was analyzed using the Xray Fluorescence (XRF) machine. The average concentration of the major oxides shows that SiO2 is 38.7%, Al2O3 is 9.62%, Fe2O3 is 5.48%, TiO2 is 0.69% and CaO is 0.598% while MnO, ZrO2, ZnO, V2O5, CdO, Cr2O3, SnO2 and Sb2O5 all have lower than 0.07%. This result shows that the clay in the study area can serve as a good raw material for the manufacture of traditional ceramics, refractories, and structural clay products especially burnt bricks.

Affects of Working Capital Management on Firm’s Performance: Evidence from Bangladesh

Working capital is a proportion of an organization's liquidity and monetary wellbeing which assesses the performance and profitability of an organization inside a limited period. The ceramic business is one the most troublesome and lengthy process industry comparing other industries. This industry is immense and includes bigger cycle which makes challenges to present the performance with genuine information. This paper is an attempt to investigate the affects of working capital management on firm’s performance of ceramic industries in Bangladesh. For this intent, ceramic corporations enrolled in Dhaka Stock Exchange (DSE) & Chittagong Stock Exchange (CSE) have been chosen and the investigation covers a period from year 2016 to 2021. Accordingly, secondary data from reputed ceramic manufacturers listed on DSE & CSE have been chosen to outline the measurable impacts of working capital management, also execution of firms by utilizing dynamic board information investigation. The results demonstrates that, inventory and cash conversion cycle periods are longer than expected. Also the industry is highly dependent on accrued sales and receiving cash from the sales are longer comparing other industry. The study clearly defines the significant level of relationship between the firm’s performances which is affected by different components of working capital management.

Micromechanical properties and microstructures of AC and DC flash-sintered alumina

Alumina (α-Al2O3), one of the most widely used structural ceramics for industrial applications, requires high temperature and long sintering time to achieve a fully dense structure through conventional pressureless consolidation and sintering methods. Recently, several attempts have been made to reduce sintering time and temperature of Al2O3 through the application of electric field with limited success. In this study, alternating current (AC) and direct current (DC) flash sintering techniques were employed to obtain high-density Al2O3 within 10 min. The density of flash-sintered (FS) specimens was greater than the specimens prepared by the pressureless sintering technique (hereinafter designated as conventional sintering) at the same temperature for 10 h. Furthermore, AC technique can reduce the electric field necessary for flash sintering substantially comparing to the DC flash sintering. The microindentation measurements reveal that the AC-FS Al2O3 provides the highest fracture toughness and a high hardness among all sintered specimens. The improved mechanical properties of AC-FS Al2O3 are attributed to defects, such as dislocations as well as stacking faults observed in the FS specimens. This study provides a fresh perspective on the low-energy manufacturing of structural ceramics with improved properties.

Mechanism of ceramic slurry light scattering affecting contour accuracy and method of projection plane correction

Digital light processing (DLP) is a relatively mature ceramic additive manufacturing technology widely applied in medical bone implantation, electronic communication, and other fields. However, the size error caused by the light scattering from the complex contour can seriously affect the precision and forming quality of the printed green body. This paper studied the scattering behavior of complex structure ceramics under different exposure energies through two structural parameters: exposure width and contour shape. A formula for excess cure width is presented. The formula will be then applied to simplify the machine learning algorithms. Finally, by inverse compensation for the complex contour, we optimized some pore structures and complex shapes to greatly improve the fidelity of the structure.

Evaluation insight into Abu Zenima clay deposits as a prospective raw material source for ceramics industry: Remote Sensing and Characterization

The rapid development and mutations have heightened ceramic industrialization to supply the countries' requirements worldwide. Therefore, the continuous exploration for new reserves of possible ceramic-raw materials is needed to overwhelm the increased demand for ceramic industries. In this study, the suitability assessment of potential applications for Upper Cretaceous (Santonian) clay deposits at Abu Zenima area, as raw materials in ceramic industries, was extensively performed. Remote sensing data were employed to map the Kaolinite-bearing formation as well as determine the additional occurrences of clay reserves in the studied area. In this context, ten representative clayey materials from the Matulla Formation were sampled and examined for their mineralogical, geochemical, morphological, physical, thermal, and plasticity characteristics. The mineralogical and chemical compositions of starting clay materials were examined. The physicochemical surface properties of the studied clay were studied utilizing SEM–EDX and TEM. The particle-size analysis confirmed the adequate characteristics of samples for white ceramic stoneware and ceramic tiles manufacturing. The technological and suitability properties of investigated clay deposits proved the industrial appropriateness of Abu Zenima clay as a potential ceramic raw material for various ceramic products. The existence of high kaolin reserves in the studied area with reasonable quality and quantity has regional significance. It would significantly help reduce the manufacturing cost and overwhelm the high consumption rate. The ceramic manufacturers in the investigated areas are expected to bring steady producers into the industry in the long term to gain the advantage of low-cost raw materials, labor, and factory construction.