Slip Casting Method Research Articles

Development of Ultrafiltration Kaolin Membranes over Sand and Zeolite Supports for the Treatment of Electroplating Wastewater.

A high cost of high-purity materials is one of the major factors that limit the application of ceramic membranes. Consequently, the focus was shifted to using natural and abundant low-cost materials such as zeolite, clay, sand, etc. as alternatives to well-known pure metallic oxides, such as alumina, silica, zirconia and titania, which are usually used for ceramic membrane fabrication. As a contribution to this area, the development and characterization of new low-cost ultrafiltration (UF) membranes made from natural Tunisian kaolin are presented in this work. The asymmetric ceramic membranes were developed via layer-by-layer and slip-casting methods by direct coating on tubular supports previously prepared from sand and zeolite via the extrusion process. Referring to the results, it was found that the UF kaolin top layer is homogenous and exhibits good adhesion to different supports. In addition, the kaolin/sand and kaolin/zeolite membranes present an average pore diameter in the range of 4-17 nm and 28 nm, and water permeability of 491 L/h·m2·bar and 182 L/h·m2·bar, respectively. Both membranes were evaluated in their treatment of electroplating wastewater. This was done by removing oil and heavy metals using a homemade crossflow UF pilot plant operated at a temperature of 60 °C to reduce the viscosity of the effluent, and the transmembrane pressure (TMP) of 1 and 3 bar for kaolin/sand and kaolin/zeolite, respectively. Under these conditions, our membranes exhibit high permeability in the range of 306-336 L/h·m2·bar, an almost total oil and lead retention, a retention up to 96% for chemical oxygen demand (COD), 96% for copper and 94% for zinc. The overall data suggest that the developed kaolin membranes have the potential for remediation of oily industrial effluents contaminated by oil and heavy metals.

Two-body wear resistance and fatigue survival of new Y-TZP and ATZ ceramics made with a new slip-casting method

BackgroundDental zirconium oxide restorations are milled from pre-sintered blocks or disks which are produced either with high isostatic pressure (HIP) or, simpler, a slurry technique. The objective was to perform a fatigue test and an in vitro wear simulation of two ceramics, yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) ceramic and a hybrid zirconium oxide-aluminum oxide ceramic, (ATZ) both produced either the classical way using high isostatic pressure (HIP, control) or with a slurry technique. Materials and methodsTen discs/group were subjected to a cyclic biaxial fatigue test using a staircase approach under water at 37 °C in a dynamic universal testing machine. The 2-body wear test was performed on eight lapped 12 mm thick cylindrical samples subjected to spherical (ø 6 mm) leucite ceramic antagonists in a CS-4 chewing simulator at 49 N force and 0.7 mm lateral movement for 600 k cycles and 4167 thermal cycles (5–55 °C). Volumetric wear was calculated based on laser-scanned surfaces. Selected samples of both tests were viewed in SEM. ResultsAll the ceramic specimens produced using the HIP method survived up to 1.2 M cycles with the maximum load of the equipment (1000 N) loading the specimens up to 1527 MPa. The fatigue limit stress at 1.2 M cycles for the Slurry ATZ samples was 946 MPa. For the Slurry Y-TZP samples the fatigue limit stress at 1.2 M cycles was 658 MPa. At 600 k cycles, all zirconium oxide ceramics showed no measurable wear and had a highly polished appearance. The leucite ceramic antagonists wear developed in a linear way. There was no difference between the materials produced with the slurry and the HIP process. ATZ ceramic produced significantly more wear than 3Y- TZP ceramic. ConclusionsThe HIP method provided higher fatigue strength than the Slurry manufacturing method. All HIP ceramics surpassed the limit threshold (1527 MPa) of the testing machine. The tested ceramics did not show any measurable wear but had worn the leucite reinforced glass ceramic antagonists for a considerable amount.

Photocatalytic Properties of Immobilised Graphitic Carbon Nitride on the Alumina Substrate

Textile industries significantly impact the contamination of wastewater. Conventional wastewater treatment methods consider the most common pollutants; however, they are very expensive and commonly produce toxic by-products. In the scientific community, advanced oxidation processes appear to be the most appealing, and a majority of the published work considers heterogeneous photocatalysis for the degradation of various toxic chemicals. For convenience, the reaction is performed directly in the water environment. In this work, a metal-free graphitic carbon nitride (g-C3N4) was prepared through a simple thermal method using urea as a precursor. Prepared g-C3N4 was deposited on the surface of the alumina ceramic ring by the dip-coating method using ethylene glycol as binder. The alumina ceramic ring, as substrate, was prepared by the slip casting method. Photocatalytic properties of immobilised graphitic carbon nitride were used for degradation of methylene blue as a model pollutant under simulated solar light irradiation. The photocatalyst was characterised by XRD, FTIR, UV-Vis DRS, TGA, BET and SEM/EDX analyses. The photocatalytic degradation of MB from an aqueous solution was found to increase with increasing irradiation time. It was found that the graphitic carbon nitride immobilised on alumina ceramic is convenient for largescale environmental applications because the whole setup is cheap, nontoxic, easy to operate and offers reusability with a high removal rate of MB after three consecutive cycles.

Application of β-Wollastonite on Bulk Density and Ignition Loss of Clay-Based Ceramic Materials

This work focuses on the effect of β-wollastonite percentage with different particle sizes on the bulk density and weight loss of clay-based ceramics. The ceramic bodies were prepared by mixing clay with a synthesized β-wollastonite (5%, 15%, and 25%) using a solid slip casting method. The clay (75 µm) and β-wollastonite (63, 75, and 125 µm) were mixed and fired at 950°C, 1000°C, and 1050°C of firing temperatures. The fabricated ceramic material exhibited a maximum bulk density of 2.35 g/cm3 on 25% content of β-wollastonite, 63 µm particle size of β-wollastonite, and 1050°C of firing temperature. However, a minimum bulk density of 1.87 g/cm3 was found on 25% content of β-wollastonite, 125 µm particle size of β-wollastonite, and 950°C firing temperature. A minimum of 2.32% ignition loss was recorded on a ceramic specimen that contained 25% of β-wollastonite with a particle size of 125 µm and fired at 950°C of firing temperature. In contrast, a maximum of 4.37% ignition loss was observed at a ceramic body made up of 5% of β-wollastonite content with 63 µm particle sizes and fired at 1050°C. In general, the result shows that the firing temperature, the particle size of β–wollastonite, and the addition of β–wollastonite have a great effect on the bulk density and ignition loss of the clay ceramic materials.

Properties of Al2O3/Ti/Ni Composite Obtained by Slip Casting with Different Metal Phase Content.

This work analyzed ceramic-metal composites from the Al2O3/Ti/Ni system produced by the slip casting method. As starting powders, nanometric Al2O3, Ni and Ti of submicron size were used. Three series of composites were obtained and tested with the same solid phase content (50% vol.) and different metallic phase content: 5, 10 and 15% vol. The influence of the metallic phase content on the basic properties of the proposed composites was examined by determining the phase composition of the produced samples using the XRD method, rheological measurements, and microstructural analysis (SEM/EDS). Additionally, before the sintering process, the slip stability was analyzed. A study of the fractography of samples after the sintering process was also carried out. It was shown that the appropriate manufacturing process allowed to obtain NiTi intermetallic phases in the structure of composites.

Comprehensive analysis of the microstructure, properties and environmental performance of Al2O3-ZrO2 composites obtained via centrifugal slip casting

This research investigates the possibility of preparing Al2O3-ZrO2 composites with different proportions of the Al2O3 and ZrO2 phases by centrifugal slip casting (CSC) method and the effect of the solid phase content (50 vol%, 45 vol%, 40 vol%) on the microstructure and selected properties of the produced materials. The hardness results showed that all the series produced were characterised by high hardness, in the range of 16–19 GPa. The results of the static compression test demonstrated that increasing the solid phase content of the slip in the samples promotes the formation of fewer cracks during the monotonic compression loading of the composites. The LCA results demonstrated that as the content of ZrO2 in the composites increase, their environmental footprint increases.

Castable polymer-infiltrated ceramic network composite for training model tooth with compatible machinability to human enamel.

This study aimed to develop a novel polymer-infiltrated ceramic network (PICN) composite fabricated via a slip-casting method for a dental training model tooth with machinability compatible to human enamel. A PICN model tooth comprised of silica/acrylic-resin was fabricated via the slip-casting method. A commercial resin-based model tooth and human enamel were used as the control sample. The samples were evaluated based on Vickers hardness, inorganic contents, density, and machinability. The machinability was characterized by a grinding amount obtained from the grinding test using a device equipped with a dental micromotor handpiece with a diamond bur. The properties of the PICN model tooth yielded a silica content of 84.7% and a density of 1.99 g/cm3, and its Vickers hardness (312) was comparable with that of enamel (348). The grinding amount was comparable with that of enamel. The castable PICN model tooth was compatible to enamel in terms of hardness and machinability.

Fabrication and characterization of Si 3 N 4 whisker‐reinforced SiO 2 ceramic for radome materials

Fused silica ceramic has become one of the most widely used radome materials in the world since the 1970s. But its poor mechanical properties restricted its application to some extent. To improve the mechanical properties of the fused silica ceramic and keep its characteristic for radome materials, silicon nitride (Si3N4) whisker-reinforced fused silica ceramics were prepared by a slip-casting method in the work. The influence of Si3N4 whisker contents on the properties of the slurry was studied, indicating that the preferable pH values of the slurry were 4–6 and whisker contents were 10 wt.%. The flexural strength of as-prepared Si3N4w/SiO2 ceramic was about 74.35 MPa, exhibiting an increase of 7.75% over that of the pure silica sample. Its dielectric constant in the range from 8 to 12 GHz and tanδ under 10 GHz were, respectively, 3.37 and .0011. It is of great interest to find that Si3N4w/SiO2 has excellent oxidization resistance and its mass maintains even at 1270°C.

Properties of Al2O3/Ti/Ni composites fabricated via centrifugal slip casting under environmentally assessed conditions as a step toward climate-neutral society

The paper concerns functionally graded composites obtained by centrifugal slip casting method. Al2O3, Ni, Ti, differed is size and morphology, were used as starting powders. The influence of metallic phase content (2 vol% and 20 vol%) and homogenisation process (planetary-ball milling) on suspension viscosity as well as density, phase composition, microstructure and mechanical properties of sintered bodies was investigated. Planetary-ball milling decrease the viscosity of suspensions of lower metallic content due to increase of their homogeneity. Slurries of higher metallic content, after homogenisation process, exhibit higher viscosity due to refinement of large metallic particles which leads to more intense surface interactions. CSC was applied to shape samples in form of thick-wall tubes with gradient microstructure across the wall thickness. Relative densities, after sintering, were about 10% higher for the samples containing 2 vol% of metallic phase (99.40% and 98.42%) compared to specimens of higher metallic content (90.57% and 86.86%), regardless of homogenisation process. Planetary ball milling had a positive effect on microstructure of obtained graded composites, leading to more homogeneous microstructure with well defined zones and lower number of defects, in both types of sample (2 vol% and 20 vol% of metallic content). Higher content of Ti and Ni caused that metal-rich zone was thicker, but microstructure was more defected. Hardness was higher for samples of more homogeneous microstructure. XRD confirmed the presence of Al2O3 and Ni, Ti phases but also evinced occurrence additional intermetallic phases form Ni–Ti system. The environmental impact accompanying fabrication of composites was evaluated using the LCA method. It was done in order to determine burdens caused at the early beginning of the research and development stage, creating a reliable basis for further development of an environmentally friendly industrial process, simultaneously being a step toward transition to a climate-neutral society which is one of the main objectives of European Green Deal.

Characterization of Al2O3 Matrix Composites Fabricated via the Slip Casting Method Using NiAl-Al2O3 Composite Powder.

This work aimed to characterize Al2O3 matrix composites fabricated by the slip casting method using NiAl-Al2O3 composite powder as the initial powder. The composite powder, consisting of NiAl + 30 wt.% Al2O3, was obtained by mechanical alloying of Al2O3, Al, and Ni powders. The composite powder was added to the Al2O3 powder to prepare the final powder for the slip casting method. The stained composite samples presented high density. EDX and XRD analyses showed that the sintering process of the samples in an air atmosphere caused the formation of the NiAl2O4 spinel phase. Finally, the phase composition of the composites changed from the initial phases of Al2O3 and NiAl to Al2O3, Ni, and NiAl2O4. However, in the area of Ni, fine Al2O3 particles remaining from the initial composite powder were visible. It can be concluded that after slip casting, after starting with Al2O3 and the composite powder (NiAl-Al2O3) and upon sintering in air, ceramic matrix composites with Ni and NiAl2O4 phases, complex structures, high-quality sintered samples, and favorable mechanical properties were obtained.

Fabrication and characterization of ceramic hollow shaped from the local kaolin intended for the filtration

ABSTRACT Ceramic membranes are one of the emerging separation technologies with extremely high separation factors. In this work, natural Kaolin clay collected from the western of Algeria was characterized in detail to see its feasibility in a ceramic membrane preparation. The ceramic membrane was prepared by solid-state reactive firing under the slip casting method. The aim is to favor the mullite phase, once the alumina is added a part will be dispersed in the mullite matrix to form a mullite-alumina composite. The mineralogical, morphological structure, particle size distribution, thermal stability, and chemical composition of prepared alumina oxide membrane were carried out using several techniques. They reveal the apparition of two main phases the mullite and the alumina. The kaolin provides the membrane with a well homogeneous morphology, good hydrophobicity, and thermal stability. The obtained membrane presented a mesoporous membrane character that can use successfully for ultrafiltration applications..

Thin layer of nano nomposite RGO COMOS as a counter electrode on Dye Sensitized Solar Cell (DSSC)

This research aims to synthesis of GO using the Hummer method and the effect of adding CoS(Cobalt Sulfide) and CoMoS(Cobalt Molybdenum Sulfide) Nano composites to RGO as a counter electrode of DSSC. RGO doped CoMoS and RGO doped CoMoS was synthesis using solvothermal method by adding nanocomposite CoS and CoMoS to GO by heating 200˚C. RGO CoMoS powder was formed into a paste by stirring and adding a polymer binder. The paste was deposited onto the FTO glass substrate by the slip casting method so that a thin sheet was obtained on the substrate and applied as a counter electrode on the DSSC. This composite will be measured and tested for the morphology of its layer using SEM and tested for electrical properties with Keithley I-V meter. The additional of CoS and CoMoS may cause the changes crystal size of RGO. RGO CoMoS has higher efficiency than GO and RGO. Thin film of RGO CoMoS can be used of counter electrode DSSC that has Voc= 0,39volt, fill factor (FF) 34,32% and η= 1,54%.

Sustainable ZTA composites produced by an advanced centrifugal slip casting method

The centrifugal slip casting method presented in the paper is used to form ceramic sleeves with a good shape representation, eliminating material losses in machining or other forms of mechanical treatment that could be necessary when other moulding methods with a poorer shape representation are used. Sleeves developed this way can be used as system components to transport aggressive substances under elevated pressure and temperature conditions. To confirm the functionality of the sleeves prepared with the method, Al2O3, ZrO2, and composite components of ZTA were characterised for acid-base behavior, phase composition, microstructure, and mechanical strength. The tests confirmed the formation of expected gradient structures for ZTA composites. It results in the generation of components with improved flexural and torsional strength compared to non-gradient ZTA composites with the same Al2O3 to ZrO2 ratio. Applying a smaller quantity of ZrO2 should bring a positive economic effect, considering its high price. The analysis of accompanying environmental impacts was carried out for developed materials along with the lifecycle analysis. The paper describes a reduced waste generation method for making components for aggressive substance transportation systems. The present paper presents characteristics of materials for their resistance to factors under working conditions, demonstrating their durability and potential to reduce waste related to the operation of such system types.

Design, finite element analysis, fabrication and electroacoustic characterization of transducer arrays from piezoceramics with hollow cylindrical shell form

Electroacoustic transducers arrays operating in the 50–100 kHz frequency range are currently being investigated for underwater applications such as target detection transducers installed on underwater autonomous vehicles (UAV) and detection of underwater intruders to protect and secure economically and strategically critical coastal areas and facilities. However, the frequency range is such that it prevents the use of monolithic piezoceramics operating in the thickness mode due to the unacceptably high voltages that are required to drive them. Whereas the alternative such as Langevin-type transducer solutions have certain other assembly difficulties that arise due to the size limitations imposed on the transducer from the half-wavelength (λ/2) arrangement requirement of the units. In our study, an entirely new alternative was proposed to overcome these difficulties. A piezoceramic transducer constructed from a hollow cylindrical shell form poled in the radial direction was designed and developed to operate at the longitudinal length extension mode. Since the hollow cylindrical piezoceramics were designed and produced with one end closed, this closed end was used as a passive cap with the transducer operating in a piston mode. ATILA finite element analysis code was used to design, analyze and fine-tune the dimensional requirements of the transducer. The center frequency of the transducer was fixed to 70 kHz. Commercial lead zirconate titanate (PZT) composition with hard piezoelectric character (PZT-4) was used as the starting powder. The slip casting method was used to obtain the cylindrical shell form. Single element transducers, as well as a hexagonal close-packed array consisting of seven units and arranged with a distance of half-wavelength (λ/2) to obtain constructive interference at 70 kHz were constructed and tested for underwater electroacoustic performance.

Two-Body Wear Resistance and Fatigue Survival of New Y-TZP and ATZ Ceramics Made with a New Slip-Casting Method

Two-Body Wear Resistance and Fatigue Survival of New Y-TZP and ATZ Ceramics Made with a New Slip-Casting Method

DEVELOPMENT OF TECHNOLOGICAL PARAMETERS FOR THE FORMATION OF FASTS BY THE SLIDING CASTING METHOD

The materials of the article consider the effectiveness of additives for stabilization and dilution of clay-free slippers. For theproduction of radio-transparent ceramic materials of Celsius-Willemite composition, the most efficient and energy-saving methodof production is the method of slip casting. According to the charge composition, this technology is complicated by the lack of claycomponents, which shows the need to use impurities to improve the rheology of such a slip. The main characteristics of aqueousceramic slippers are density, humidity, fluidity, viscosity, density factor, rate of mass accumulation. The slip must meet thefollowing requirements: be free from foam and gas inclusions, have satisfactory fluidity under low viscosity; be aggregativelystable (characterized by the absence of aggregation, coagulation and sedimentation of solid phase particles); have a high filteringcapacity to ensure fast and defect-free weight gain; to be chemically inert, to provide sufficient strength and low shrinkage of semifinished products, as well as the possibility of their easy release from the mold.

The Potential of Al2O3\u2013ZrO2-Based Composites, Formed via CSC Method, in Linear Infrastructure Applications Based on Their Mechanical, Thermal and Environmental performance

Ceramic-ceramic composites have been prepared using the centrifugal slip casting method (CSC). The method has so far been mainly utilized in making ceramic-metal composites. Al2O3–ZrO2 composites have been obtained with different shares of ZrO2, i.e., 15, 50 and 75 vol pct, respectively. Prior to sintering the composite samples, the rheological properties of the casting slips were investigated and thermogravimetric tests were performed. Upon sintering, all three series of the ceramic composites showed a density close to 100 pct and no microcracks or delamination. Phase, microstructural and mechanical investigations were carried out to determine what effect the share of ceramics has on the composites produced. An increase in the share of ZrO2 in the Al2O3–ZrO2 composite leads to a reduction in the growth of Al2O3 grains and a decrease in the average hardness. Cross-sectional hardness testing of the composites showed no evident gradient in any of the samples. Life cycle analysis (LCA) results indicate that the further optimization of the composite formation process, including up-scaling, allows to obtain Al2O3–ZrO2-based pipes possessing more favorable environmental characteristics compared with materials conventionally used for linear infrastructure, which is important in light of the global transformation toward sustainable construction and the circular economy.Graphical abstract

ZTA Pipes with a Gradient Structure-Effect of the Rheological the Behavior of Ceramic Suspensions on the Gradient Structure and Characterized of the Obtained Products.

This paper focuses on the verifying the possibility of producing Al2O3-ZrO2 composite pipes with a gradient structure using centrifugal slip casting method. The aim of the research is to define the correlation between the rheological properties of aqueous suspensions of ceramic powders with different solid loading and obtaining the ZrO2 phase gradient in the Al2O3 matrix. Such products, due to their unique properties, can be utilized in the transport of aggressive substances, even in extreme temperature or corrosive conditions. The suspensions and the sintered samples were characterized by: broad rheological analysis, scanning electron microscopy, X-ray diffraction, stereological analysis and Vickers hardness tests. The study reports on a series of samples produced of ceramic suspensions (70 vol.% Al2O3–30 vol.% ZrO2) differing in the total solid loading in the range of 30–55 vol.%. The results clearly indicate that obtaining the gradient structure of ceramic-ceramic composite pipes is closely related to the rheological properties of the suspensions from which the samples are cast. The phase gradient is obtainable from suspensions 30–40 vol.%, in which the possibility of moving ZrO2 particles relative to the Al2O3 is quite high—these suspensions are characterized by low viscosity and the dominance of viscous over elastic properties (G′ > G″).

WO3 mono-nanocrystals: Synthesis, characterization and evaluation of their electrical behavior in oxygen and acetone atmospheres

WO3 nanoparticles were synthesized using the modified polymer complex method. The synthesized powders were characterized using infrared and UV–Vis absorption spectroscopy, X-ray diffraction (XRD), photoluminescence (PL), scanning (SEM) and transmission (TEM) electron microscopies. Results revealed the synthesized WO3 particles are monocrystalline, with a monoclinic structure (space group P21/c) and a size of 30 nm, a gap of 2.8 eV with structural defects promoting gas sensing. Using these powders, ceramic pieces were formed by the slip casting method and the sintered pieces evaluated for their electrical behavior in the presence of oxygen and acetone vapors. The favorable ability of WO3 to sense these gases and its potential use by way of acetone sensing in the diagnosis of diseases such as diabetes mellitus were reiterated in light of the results obtained in this trial.

Effect of crystalline orientation on photocatalytic performance for Nb-doped TiO2 nanoparticles

Crystalline-oriented thick films have been fabricated with using plasma-synthesized (0–20.0 at.%) Nb-doped TiO2 powder by slip casting method in a strong magnetic field (12 T). Degree of c-axis orientation of the fabricated thick film was evaluated by Lotgering factor (f). The orientation degree along c-axis was improved by sintering at 600 °C, but was deteriorated at 700 °C. Photocatalytic performance under the UV light irradiation was conducted on the film surface and was determined by bleaching methyl orange aqueous solution. The improvement in the photocatalytic performance was greatly attributed to the dominated crystalline-orientation of the (001) plane for the Nb-doped TiO2.