Ceramic Technique Research Articles

Interface adhesion on layered zirconia: Effects of the veneering ceramic material and veneering technique.

To evaluate the effect of different veneering ceramics and veneering techniques on the bond strength to zirconia. 3Y-TZP zirconia blocks were sliced into 60 slabs, polished, and sintered. Each slab received one ceramic cylinder (Ø = 3.4mm, 5mm-high), according to the veneering ceramic type (feldspathic-FEL or lithium disilicate-based-LD) and the veneering technique (file-splitting with resin-based luting agent-RC, file-splitting with fusion ceramic-FC, or heat-pressing-HT), which resulted in six groups: FEL-RC, FEL-FC, FEL-HT, LD-RC, LD-FC, LD-HT. After preparation, the samples were immersed in distilled water for 24h before the shear bond strength (SBS) test. The failure modes were classified as adhesive, predominantly adhesive, or cohesive. Representative failure mode images were taken in a Scanning Electron Microscope. The SBS data were analyzed by two-way ANOVA and Tukey's test. Both type of veneering ceramic and technique affected the bond strength. FC led to the highest SBS values. RC and HP provided similar results when compared within each veneering ceramic. Lithium disilicate achieved lower bond strength than feldspathic ceramic when the heat-pressing technique was applied. The most frequent failure modes were predominantly adhesive and adhesive for FEL and LD, respectively. File-splitting with fusion ceramic provided the highest adhesion to zirconia when feldspathic or lithium disilicate-based ceramics were used. The heat-pressing technique for veneering with lithium disilicate significantly decreased the bond strength when compared to the feldspathic ceramic.

About the problems and results of obtaining products from technical ceramics for metallurgical production. Message 2

The article presents the results of research in the field of synthesis of multifunctional ceramic materials for metallurgical, machine‑tool and other industries related to the processing of metals, their alloys and products from them; current trends and trends associated with the production of products from such materials; provides information on expanding the domestic raw material base for the production of ceramics with the involvement of domestic enterprises, and also, the prospects for the development of industrial potential for the organization of the production of such products.

Laser-Based Manufacturing of Ceramics: A Review.

Ceramics are widely used in microelectronics, semiconductor manufacturing, medical devices, aerospace, and aviation, cutting tools, precision optics, MEMS and NEMS devices, insulating components, and ceramic molds. But the fabrication and machining of the ceramic-based materials by conventional processes are always difficult due to their higher hardness and mechanical properties. Therefore, advanced manufacturing techniques are being preferred for these advanced materials, and out of that, laser-based processes are widely used. The benefits of laser fabrication and machining of ceramics include high precision, reduced thermal damage, non-contact processing, and the ability to work with complex geometries. Laser technology continues to advance, enabling even more intricate and diverse applications for ceramics in a wide range of industries. This paper explains various laser based ceramic processing techniques, such as selective laser sintering and melting, and laser machining techniques, such as laser drilling, etc. Identifying and optimizing the process parameters that influence the output quality of laser processed parts is the key technique to improving the quality, which is also focused on in this paper. It aims to facilitate the researchers by providing knowledge on laser-based manufacturing of ceramics and their composites to establish the field further.

A Systematic Review on Virtual Reality Technology for Ancient Ceramic Restoration

The protection of intangible cultural heritage has received much attention, among which the “ancient ceramic restoration technique” was included in The National List of Intangible Cultural Heritage of China (the fourth batch) in 2014. In preserving and restoring ancient ceramics, virtual reality (VR) technology has been widely applied, as it provides a new way to showcase the appearance and structure of ancient ceramics in a VR environment. This paper provides a systematic review of the application of VR reality technology in the conservation and restoration of ancient ceramics. The methodology comprises four steps: research problem formulation, literature search, study selection and data extraction. A total of 30 articles out of 1479 peer-reviewed database articles from six databases (Web of Science, SpringerLink, IEEE Xplore, Scopus, CNKI, Google Scholar) were extracted and screened, which covers the application of VR technology or VR-based devices in ceramic conservation. It has been found that the existing VR application on ceramic restoration is hardly systematic or user-oriented. Thus, we develop a VR-based Platform on ceramic restoration utilized with Unity and 3DS Max, ensuring authenticity, minimal intervention, and promising reversible repair within the VR environment. The findings show that VR technology applied to ancient ceramic restoration has contributed to the learning efficiency and learning willingness of users.

Glass with a low-melting temperature belonging to the P2O5–CaO–Na2O system, applied as a coating on technical ceramics (alumina, zirconia) and traditional ceramics (porcelain stoneware)

This article investigates the development and potential applications of low-melting point lead-free glasses. Their importance is due to strong market demands to comply with the strict international regulations against the use of lead. In this work, a preliminary study of the existing interactions of a low-melting-temperature glass belonging to the P2O5–CaO–Na2O system when it is deposited on different ceramic substrates, both traditional (porcelain stoneware) and technical (alumina and zirconia), has been carried out. The ionic diffusion through the studied interfaces, the phases present, the composition of the glassy phase and the surface morphology of the coating have been studied by Field Emission Scanning Electron Microscopy (FESEM), with coupled EDX microanalysis. The chemical resistance of the different glassy coatings obtained is also evaluated. The results showed that these new lead-free low-melting-temperature glassy coatings are chemically and mechanically compatible, and promising candidates for applications and markets in a broad range of fields.

Archaeological science, globalisation, and local agency: gold in Great Zimbabwe

Great Zimbabwe (CE1000–1600) is world famous for outstanding cultural innovations and localised and globalised entanglement with trans-Africa and trans-Indian Ocean exchange. New excavations yielded fragments of over a hundred gold processing vessels comprising reused pottery and purpose-made crucibles from stratified contexts in the Eastern Ridge Ruins and adjacent areas. Selected samples were studied using archaeological, microscopic, and compositional (SEM–EDS) techniques. All ceramics were made of alumina-rich clays and contain minerals common to granite-derived lithologies typical of the area, although it is possible that particularly refractory clays were selected to make crucibles locally. These technical ceramics were used for refining and collecting gold at high temperature, most likely producing not only relatively standardised ingots but also finished objects. The composition of the gold prills set in crucible slag is consistent with that of natural, unalloyed gold, while the variability in silver levels and minor impurities point to heterogeneous sources of the gold. Considering these finds in their multiple site and regional contexts, and together with complementary threads of information from early reports of antiquarians and looters, we argue that local agency and gold consumption were much more significant than generally assumed. The conclusion to the paper is that Great Zimbabwe’s famous participation in local and global exchanges was backed by internally driven but improvisation laden production and consumption occurring in homesteads located throughout its various settlements. We end by raising a word of caution about oversimplified narratives of globalisation and their archaeological expressions (see Supplementary Material S0 for the abstract in Shona).

THE INFLUENCE OF MECHANO ACTIVATION ON THE STRUCTURE AND ELECTRICAL CONDUCTIVITY IN THE SYSTEM KNO3-Al2O3

In this paper, the effect of mechanical activation on the structure and electrical conductivity of the KNO3-Al2O3 composite was studied. Based on the analysis of DSC curves measured during heating and cooling of the sample, it was found that the enthalpy of phase transitions decreases with increasing time of mechanical activation of the 0.5KNO3-0.5Al2O3 composite. X-ray diffraction analysis shows that mechanical activation leads to a decrease in the grain dimension and an increase in the defectiveness. Based on the electrochemical impedance spectroscopy data, it was determined that for the KNO3-Al2O3 system subjected to mechanical activation, the values of specific ionic conductivity are 3.8×10-5 S/cm at T = 373 K and 2×10-3 S/cm at T = 473 K and the energy value activations of 0.19 eV are comparable with the parameters of a composite of the same chemical composition obtained by the ceramic technique. Raman spectroscopy revealed the formation of a metastable γ-phase KNO3during the mechanoactivation of the composite, which is stable at temperatures above 397 K. It is proposed that an increase in electrical conductivity in the KNO3-Al2O3 composite at 373-403 K is due to the presence in the composite of an additional metastable γ-phase KNO3.

Synthesis of Technical Ceramics in a Beam of Fast Electrons

Synthesis of Technical Ceramics in a Beam of Fast Electrons

Three-dimensional piezoceramic sheets via mold-assisted sintering as 3D energy transducers

Bulk piezoceramics are widely used and functional materials, but they are hard to be shaped to adapt to complex 3D surfaces. Most existing ceramic shaping techniques, like 3D printing, come at the cost of physical properties such as piezoelectricity and thermal stability. Here to fabricate 3D piezoceramic sheets, we report a mold-assisted sintering (MAS) method that can replicate 3D surfaces with nonzero Gaussian curvatures while maintaining the intrinsic properties. Assisted with supporting molds, the MAS exploits elastic-to-viscous transition of piezoceramic powder compacts during sintering, bypassing the boundaries of deformation and surface development in an elastic continuum. We successfully replicate shapes to sintered lead zirconate titanate (PZT) ceramics from designed molds with saddle, sine and spherical surfaces, respectively. The PZT ceramic replicas show high piezoelectricity and excellent conformability towards nonplanar surfaces (maximum deviation 90 μm). We further demonstrate the advantage of the conformal curved piezoceramics by using them for wirelessly transferring power over a pipeline. The MAS method is low-cost, simple, scalable and applicable to various 3D energy transducers.

İNGİRGEN (REDÜKSİYON) ORTAMDA SIRSIZ SERAMİK PİŞİRİM TEKNİKLERİ VE UYGULAMA YÖNTEMLERİ

İndirgen (redüksiyon) ortam seramik pişirim yöntemi, yükselten (oksidatif) ortamdan daha az tercih edilen bir pişirim yöntemidir. İndirgen ortamın sağladığı coşkulu sonuçlar, çoğu seramik sanatçısının ilgisinin bu yönteme yoğunlaşmasını sağlamıştır. İndirgen ortam pişirim yöntem çeşitleri benzerlikler gösterse de, kendi aralarında uygulama farklılıkları bulundurmaktadır. Genellikle bu pişirim yöntemlerinde ilk uygulama amaçlarından uzaklaşılmış, yeni uygulama alanlarına dönüşmüşlerdir. İndirgen ortamda seramik pişirmek, yükselten ortamda pişirmekten çok daha zor bir uygulama yöntemidir. Bu yöntemde, kontrollü bir pişirim genellikle olmaz, her açıdan zayiat yüksek olabilmektedir. Bu şekildeki olumsuzlukların olmasına rağmen, yapılan uygulamalar sonucunda ortaya çıkan etkili sonuçlarla birlikte büyülü görsellikler birçok sanatçıyı etkilemektedir. Son yıllarda çoğu seramik sanatçısının bu uygulama yöntemi üzerine değişik denemeler yaptığı görülmektedir. Bu değişken etkilerden dolayı her dönem popülaritesini korumuş olmakla birlikte, etkin bir şekilde bu uygulama yöntemine olan ilgi artmaktadır İndirgen pişirim yöntemlerinin diğer etkin bir özelliği ise, iş birliği içinde çalışmayı genellikle zorunlu kılmasıdır. Bu pozitif özelliği ile, çok iyi bir sosyal etkileşim ve öğrenme yöntemi olarak da karşımıza çıkmakta olup, bu yönünden dolayı eğitimde etkili bir araç olarak kullanılmaktadır. Makale, bir ölçüde bu amaç doğrultusunda yapılmış uygulamalarımızın sunumu niteliğinde de görülebilir. 1989 yılından günümüze kadar birçok indirgen ortam denemelerinde edinilmiş tecrübelerle birlikte, ilgili literatürlerden de faydalanılarak, güncel analizler yapılmıştır. Makalede, ilk olarak indirgenme kavramı el alınmış, daha sonra indirgen ortamda öne çıkmış yöntemler gruplandırılmıştır. İndirgen ortam seramik pişirim tekniklerinin sayısı çok fazla olması sebebiyle, sadece sırsız bünyelerle yapılan uygulama yöntemleri üzerinde durulmuş ve bu yöndeki bilgi ve tecrübeler aktarılmıştır.

The Glass Produced from Recycled Soda-Lime Glass Cullet by Slip Casting

Slip casting is a ceramic processing technique which can be used to produce complex-shape ceramic object. In the present work, slip casting was applied to produce the 70 mm × 10 mm × 15 mm green samples from recycled soda-lime glass. The slip with 60% solid loading was prepared from 100 g of recycled cullet, 1 g of sodium silicate as a binder, 50 ml of DI water, and 16.7 ml of deflocculant. The deflocculant for slip casting was 0.1 wt% sodium tripolyphosphate solution. After slip casting, the samples were dried at room temperature for 3 days. Then the samples were sintered at 680, 700, and 720 °C with the soaking time of 1 and 2 hrs with 5 °C/min heating rate. The results from statistical analysis showed that there was a high variation on flexural strength which should be from the high closed porosity and high pore-size variation of the samples. Therefore, our glass produced from slip casting is not suitable for load bearing applications. However, this technique still can be used to produce other art products such as Buddha amulets.

Effects of platelet addition and loading direction on the mechanical properties of textured alumina fabricated by ceramic mask stereolithography

In order to simultaneously enhance the bending strength and fracture toughness of alumina, this research incorporated different amounts of alumina platelets into the ceramic slurry. Based on the shear force generated by the slurry flow during platform positioning, the platelets in the slurry were aligned. The green bodies were then sintered to prepare textured alumina. The results showed that the addition of 5 vol% alumina platelets in the slurry yielded the highest mechanical performance for the textured alumina. When the load was perpendicular to the printing direction, the bending strength and fracture toughness were measured to be 272 MPa and 4.41 MPam1/2, respectively, demonstrating an increase of 132 MPa and 1.25 MPam1/2 compared to non-textured alumina ceramics. Similarly, When the load was parallel to the printing direction, the bending strength and fracture toughness were 318 MPa and 3.4 MPam1/2, respectively, displaying improvements of 149 MPa and 0.65 MPam1/2 compared to non-textured alumina ceramics. The combination of ceramic mask stereolithography additive manufacturing technology and ceramic texturing techniques in alumina fabrication not only shortened the preparation cycle but also improved the bending strength and fracture toughness of alumina, thus expanding their potential applications.

Selected technical ceramics as nanoreinforcement for polyvinyl butyral/epoxy polymer composites

In this study, various technical ceramics in the form of nanostructures, known for their exceptional mechanical properties and thermal resistance, were analysed as potential reinforcement of a polymer matrix system. A combined, hybrid composite matrix was considered, consisting of epoxy resin and polyvinyl butyral. The following nanostructures were incorporated into the polymer matrix by ultrasonication and solvent-casting technique: B4C, TiB2, CNT and INT-WS2. Polymer composites were prepared by solvent-casting of neat hybrid polymer matrix and polymer matrix reinforcing with each chosen individual nanostructure from a temporary solvent – ethanol. The characterisation of the obtained polymer composite samples encompassed Fourier transform infrared spectroscopy analysis, differential scanning calorimetry, tensile test, hardness measurement and examination of resistance to cavitation wear.

Tribo-Mechanical Investigation of Glass Fiber Reinforced Polymer Composites under Dry Conditions.

Tribo-mechanical experiments were performed on Glass Fiber Reinforced Polymer (GRFP) composites against different engineering materials, and the tribological behavior of these materials under dry conditions was investigated. The novelty of this study consists of the investigation of the tribomechanical properties of a customized GFRP/epoxy composite, different from those identified in the literature. The investigated material in the work is composed of 270 g/m2 fiberglass twill fabric/epoxy matrix. It was manufactured by the vacuum bag method and autoclave curing procedure. The goal was to define the tribo-mechanical characteristics of a 68.5% weight fraction ratio (wf) of GFRP composites in relation to the different categories of plastic materials, alloyed steel, and technical ceramics. The properties of the material, including ultimate tensile strength, Young's modulus of elasticity, elastic strain, and impact strength of the GFPR, were determined through standard tests. The friction coefficients were obtained using a modified pin-on-disc tribometer using sliding speeds ranging from 0.1 to 0.36 m s-1, load 20 N, and different counter face balls from Polytetrafluoroethylene (PTFE), Polyamide (Torlon), 52,100 Chrome Alloy Steel, 440 Stainless Steel, and Ceramic Al2O3, with 12.7 mm in diameter, in dry conditions. These are commonly used as ball and roller bearings in industry and for a variety of automotive applications. To evaluate the wear mechanisms, the worm surfaces were examined and investigated by a Nano Focus-Optical 3D Microscopy, which uses cutting-edge μsurf technology to provide highly accurate 3D measurements of surfaces. The obtained results constitute an important database for the tribo-mechanical behavior of this engineering GFRP composite material.

African Vernacular Symbols of Black Intersex Children in Sinethemba Ngubane's Installations (2007-2016)

African Vernacular Symbols of Black Intersex Children in Sinethemba Ngubane's Installations (2007-2016)

Lead free glass-ceramic dielectrics: A highly potential material for energy storage, photonics and memory applications

To maintain a modern livelihood, huge amount of energy is needed which are primarily sourced from fossil fuels that causes global warming and has become an environmental concern. The use of renewable and sustainable green energy has been increasing day by day which needs efficient devices for storage and supply of energy on demand. Among the energy storage devices, batteries have a high energy storage density and low power output, while capacitors possess relatively lower energy density but are capable of exhibiting a high-power output. Dielectric capacitors show high-power density, ultra-fast charge-discharge rates and higher efficiency which make them indispensable for application in electronic devices. Dielectric materials used in the commercially available capacitors are mostly lead based ferroelectric and anti-ferroelectric ceramics. As lead is toxic and causes havoc environmental concerns, the usage of lead/heavy metal containing materials is being gradually phased out and alternate lead-free high-performance materials are sought after. Due to difficulties in ceramic synthesis technique, uncontrolled grain growth and other defects are created resulting in poor dielectric properties. This article tries to present lead-free anti-ferroelectric glass-ceramics based dielectrics as an emerging material for catering to the future green energy demands. Lead free glass-ceramics based dielectrics are multifunctional materials with huge potentials for ferroelectric random access memory (FRAM) and photonic applications, besides their prospects as a future energy storage material.

Next generation of advanced ceramic 3D printers

Ceramic on-demand extrusion (CODE) is a novel slurry-based additive manufacturing (AM) process for technical ceramics. Extensive characterization studies have shown that this process produces dense ceramic specimens with relatively improved mechanical properties such as flexural strength, fracture toughness, hardness, etc. The objective of the current study was to develop the next generation of CODE. The CODE printer created consists of an aluminum extrusion frame, a three-axis gantry system, an extruder, and a heat lamp. The ceramic slurry is fed to an extruder that prints parts onto a bedplate. The green body parts are then subject to postprocessing, including drying, debinding, and sintering. Ceramic composites and functionally graded materials are created using CODE to further study the process. Furthermore, a real-time deep learning defect detection protocol to identify common defects of CODE while printing, as well as a control feedback system to implement corrective action based on the defect detected, is being developed.

Multiscale modelling of the thermoelastic properties of alumina-zirconia ceramics for 3D printing

Additive manufacturing appears to facilitate the accurate manufacturing of alumina-zirconia technical ceramics. Nevertheless, the fine tuning of the manufacturing of these components by 3D printing requires an analysis of the parameters that influence their final thermoelastic properties. In this context, this work presents the application of (finite element-based) numerical procedures that aim at the prediction of the effective thermoelastic properties of 3D-printed alumina-zirconia ceramics. The numerical modelling considers three different scales: micro-, meso- and macroscale. The microscale corresponds to the microstructural level of, sintered at 1500 °C, slip-casted samples with different compositions of alumina-zirconia. On the other hand, the macroscale corresponds to the macrostructural level of porous lattice of 3D-printed ceramics, being defined at the mesoscale level by a periodic unit cell. Thus, an initial microstructural analysis (at microscale level) provides the influence of the alumina/zirconia ratio on the (macroscopically homogeneous and isotropic) material thermoelastic properties, which together with the definition of the geometry of a periodic unit cell (at mesoscale level), provides, by a second analysis (at both the meso- and macroscale levels), the coupled influence of material and geometry of the macrostructural lattice on the structural (macroscopically heterogeneous and anisotropic) thermoelastic properties. Moreover, experimental thermoelastic properties of the sintered slip-casted specimens were obtained for several alumina/zirconia ratios and analysed together with microstructure patterns. Prediction of the microstructural effective thermoelastic properties was also made using micromechanics and composite theory (analytical) models. All the numerical, experimental and analytical results for the microstructural level are presented and compared. Numerical results for the meso- and macrostructural levels are also presented.

In-Vitro Effect of Effectively of G-Bond and Z-Prime Plus in Prevention of Fracture of Prefabricated Zirconia Posts Bonded to Root Canal Walls

Background and Aim: The purpose of this research was to examine the influence of Z-Prime Plus and G-Bond on zirconia posts fracture resistance affixed to the walls of root canals. Place of Study: Avicenna Medical College Lahore Study Duration: March 2021 to April 2022 Materials and Methods: In this in-vitro experimental study, the diameter and length of each of the 20 mandibular premolars used were identical. This assured that the study's findings were comparable. Once a cut was made at the cementoenamel junction (CEJ) to prepare the teeth for root canal therapy, the teeth were randomly assigned to one of two groups (n=11) with the same number of teeth in each group. In the experiment, a single tooth from each group was chosen at random to serve as the control. A post space of approximately 10 millimeters in length was established in the remaining teeth. The following process involved etching the intracanal dentin, followed by rinsing and drying the material. The technique involved filling the canal with Panavia F2 resin cement. After applying G-Bond and Z-Prime Plus to the zirconia posts in respectively, groups 1 and 2, the placement of post was done in the canals and subsequently cemented. The photo core resin composite material was utilized in the fabrication of the cores. The longitudinal axis of the teeth was compressed by a force application to the core of central fossa o at a crosshead speed of 0.5 millimeters per minute. This was accomplished with a crosshead speed of 0.5 mm/min. The load that caused the fracture was measured and documented. To analyze the data, a t-test was conducted, and a normal distribution was also taken into account. Result: The results indicated that the average fracture resistance of G-Bond was 1088.1±330 while the average fracture resistance of Z-Prime Plus was 898.4±369 however, the difference was not statistically significant (P=0.3). Practical Implication: The influence of Z-Prime Plus and G-Bond on zirconia posts fracture resistance affixed to the walls of root canals Conclusion: There was no significant difference between the fracture resistance of zirconia posts bound with G-Bond and Z-Prime Plus to root canal walls. In contrast, G-Bond is highly advised for usage in this application due to its decreased coefficient of variation (CV) and significantly increased fracture resistance. This makes it a great option for the current endeavor. Keywords: Primer; resin composite; shear bond strength; zirconia ceramic, G-Bond, Post and Core Technique, Z-Prime Plus

Copper technology at the Early Iron Age fortified settlements near Lakes Itkul and Irtyash, middle Trans-Urals

During the EIA (7th-3rd c. BCE), the middle Trans-Urals were populated by the Itkul culture of metalworkers. Most of the Itkul sites were excavated in 1960-1980′s, and ever since then the copper smelting technology, and exploited ore sources remained limitedly understood. To provide insight into these questions, we consider the archaeological context of copper production and apply methods of OM, SEM-EDS and LA ICP-MS to analyse copper slag, technical ceramics and ores from the Itkul culture settlement of Dautovo-1 (Itkul-1). This data is considered against the analyses of ores from the EIA sites and the Gumeshevsky mine in the Polevskoy area located 35 km from Dautovo, and the formerly investigated copper slags (Stepanov et al., 2021) from the site of Irtyash-1 located 50 km apart. The obtained results confirm that secondary copper ores of the Gumeshevsky mine, long regarded as the main ore source of the Itkul culture, were smelted at the site of Dautovo-1. We also identify the plate slag as the residue attesting to the most frequently used smelting technique, which consisted of the smelting of secondary copper ores in shallow open furnaces or crucibles and under moderately reducing conditions. The smelt ended with the removal and fast-cooling of slag outside the furnace. In contrast to Dautovo-1, only slags from secondary metallurgical operations were found at the site of Irtyash-1, which aligns with the dominance of secondary copper-working remains at the latter site. The production probably was likely performed on a seasonal basis, the metalworking society was divided into smelters and copper-workers, and the copper supply was likely oriented at both domestic and external (nomadic) markets.