Journal of the Australian Ceramic Society最新文献

The production of innovative ceramic powders through surface functionalization of grains, featuring a core–shell structure, accelerates mass diffusion and enhances sintering behavior. This approach significantly impacts the additive manufacturing field. In this study, a commercial SiC preceramic compound from the polycarbosilane family, specifically poly(silaethylene), was grafted onto the surface of Silicon Carbide (SiC) particles, forming a conformal molecular layer. Powder Bed Selective Laser Processing, also known as Selective Laser Sintering/Melting, was employed to fabricate 3D SiC and surface-modified SiC parts, enabling a comparative analysis of the efficiency and impact of surface modification in the manufacturing process. The surface functionalization increases densification by at least 5% without affecting the final phases of the manufactured parts. Additionally, Spark Plasma Sintering (SPS) was employe as a post-treatment to further densify the samples, increasing their final density and eliminating residual silicon and carbon, which are produced due to the undesired decomposition of SiC during the manufacturing process.

The materials sintered with FS are determined by considering temperature, time, energy, cost, environmental pollution, and human health. In this study, cast iron slag wastes (CISW) were utilized in powder form and sintered using flash sintering (FS). The outcomes of both FS and conventional sintering (CS) processes were assessed regarding their physical, chemical, and mechanical properties. The CS process was performed at 1000ºC for 4 h. FS experiments were conducted under 20, 25, and 30 V/mm electric fields. CISW was sintered using the FS method resulting in lower temperatures and shorter processing times, thus yielding energy savings. Through this method, it was observed that the interatomic spaces narrowed due to the electric field and temperature applied to the sample. Physical, chemical, and mechanical tests (3-point bending and hardness) were carried out on all sintered materials. Experimental results indicated that the sample sintered under the 20 V/mm electric field at 517ºC for 15 s exhibited better mechanical properties compared to CS. On the other hand, the sample flash sintered under 30 V/mm electric field had lower temperatures (478ºC) compared to all FS processes that were carried out with perfect intergranular interactions. However, the mechanical properties were lower than the others because the structures may have passed into the liquid phase. Consequently, it has been proven that this product obtained from CISWs can be used in floor and wall tiles according to ISO10545-4 and BS—EN14411:2016 standards. It has better mechanical strengths than all other sintering processes with FS under 20 V/mm electric field.

In this study, the workability, mechanical properties, failure mode, and microstructure of three types of fiber (steel fiber, basalt fiber, carbon fiber) modified concrete are characterized. The addition of steel fiber ≤ 40 kg/m³ or basalt fiber ≤ 6 kg/m³ shows little effect on the slump of concrete, there is an obvious decrease in slump as the carbon fiber addition exceeds 3 kg/m³. For steel fiber concrete, the relatively high 14-day mechanical properties belong to the 40 kg/m³ addition, with a compressive strength of 99.1 MPa and a bending strength of 18.5 MPa. The optimal addition of both basalt and carbon fibers is 3 kg/m³. For basalt fiber modified concrete, its 14-day compressive strength and bending strength are 111.1 MPa and 18.6 MPa respectively, and that for carbon fiber are 110.6 MPa and 18.2 MPa. Basalt fiber mainly reinforces concrete by its fracture energy, leading to brittle failure of specimens; whereas carbon fiber mainly relies on fiber pull-out to restrain the transverse expansion deformation of concrete, resulting in ductile failure of specimens. Consequently, the 3 kg/m³ carbon fiber-modified concrete with excellent mechanical strength and toughness is more suitable for building structures.

Cerium oxide, a popular ultraviolet screening agent in cosmetics, is hindered by its oxidation catalytic activity. Seeking an alternative to cerium phosphate, which increases particle size but lacks catalytic activity, we synthesized a novel cerium hydroxide-cerium oxide pigment by coprecipitating a small amount of phosphate. We chose a baseline Ce/P ratio of 10:1 based on preliminary tests showing that a moderate level of phosphate effectively reduces oxidation catalytic activity while still preserving key cerium oxide characteristics. We evaluated its composition, particle size, oxidation catalyst activity, and hue. Coprecipitation and subsequent heating yielded a yellowish pigment containing both cerium oxide and cerium phosphate. Compared to cerium oxide, our pigment exhibited superior smoothness. Additionally, samples prepared under low pH or high phosphate ratios demonstrated reduced oxidation catalytic activity. However, when applied as a pigment in oil paints, its hiding power was diminished. Our findings highlight a promising strategy for mitigating the catalytic drawbacks of cerium oxide while improving pigment properties, yet caution is warranted regarding its efficacy in paint applications. This study underscores the potential of cerium-based compounds in diverse fields, with room for optimization in specific applications. This study underscores the potential of systematically tuning cerium-based compounds for a range of applications, including cosmetics and paints, by exploring how pH and Ce/P ratio influence catalytic activity, coloration, and particle properties.

The tribocorrosion and electrochemical performances of laser cladded Co08 coating in 3.5% NaCl solution was improved by the addition of Ni60WC, which were carried out using a reciprocating wear tester and an electrochemical workstation. The results show that the Co08–xNi60WC coatings are composed of Co(Ni, Cr, W, Mo), Ni60WC, W₂C and WC phases, and their hardness is increased by the addition of Ni60WC. The coefficients of friction and wear rates of Co–xNi60WC coatings are decreased with the Ni60WC mass fraction, and the wear form is changed from fatigue wear to oxidation wear and adhesion wear, indicating that the wear resistance is enhanced by the addition of WC. The charge transfer resistance R_ct of Co08–xNi60WC coatings is increased with the Ni60WC mass fraction, and the corresponding n_ct is also increased, showing that the Co08–30%Ni60WC has the best corrosion resistance among the three kinds of coatings.

Hydroxyapatite (HA), a primary inorganic component of human bone, is highly regarded for its biocompatibility and osteoconductivity, making it an ideal material for orthopedic and dental applications. In this study, HA powders were synthesized using waste oyster shells as a calcium source via a hydrothermal reaction at temperatures ranging from 100 to 200 °C. The influence of these temperatures on the morphology, particle size, and crystallinity of the synthesized products was examined. The crystallinity of the HA increased from approximately 22% for the room-temperature precipitation method to 38%–64% for the hydrothermal method, reflecting enhanced crystallinity with increasing temperature. X-ray diffraction (XRD) confirmed that the product was a pure HA phase, with no residual raw materials. Scanning electron microscopy (SEM) revealed that the HA particles synthesized hydrothermally were larger than those obtained by precipitation, with lengths ranging from 165 to 212 nm, widths from 26 to 41 nm, and aspect ratios between 5.2 and 6.3, compared to precipitation method particles which had lengths of 156 nm, widths of 24 nm, and an average aspect ratio of 6.7. Energy-dispersive X-ray spectroscopy (EDS) analysis indicated that the Ca/P ratios of the HA synthesized through hydrothermal synthesis ranged from 1.94 to 2.12, suggesting a Ca-rich structure. After immersion in simulated body fluid (SBF), needle-like apatite deposits were observed on the HA surface, demonstrating good bioactivity. Furthermore, osteoblast culture experiments confirmed the HA’s non-toxic nature, with the cells showing excellent attachment and growth. These findings highlight the potential of HA synthesized from waste oyster shells for bone regeneration and dental applications.

Biosilicate^® is a strong, highly bioactive, bactericidal, machinable, (almost) fully crystalline glass–ceramic that has been successfully used in several in vivo and clinical trials. However, there is still scope to optimize its crystallization ability, resulting microstructure and properties. Here we tested 13 compounds, from which we choose six for more detailed screening (2% ZrO₂, 6% Fe₂O₃, 3% WO₃, 4% NaF, 3 and 20% TiO₂, 2, 4 and 8% Li₂O, and 4% TiO2 + 3% ZrO2, in wt.%) as potential nucleating agents. We used DSC analyses to estimate their tendency to boost internal nucleation. For some compositions, we also used optical microscopy. XRD was used to evaluate the crystalline phase, most of these modified BIOS glasses showed combeite as the main phase. To evaluate whether one of the key components of the formula, P₂O₅, significantly affects the nucleation process, a particular composition (25.97Na₂O-24.23CaO-49.8SiO₂, wt.%), named SS, had its P₂O₅ content replaced by Li₂O and Fe₂O₃. Among the additives tested, Li₂O significantly increased the internal nucleation rate. This study confirmed that DSC is a practical, fast tool to assess the suitability of prospective nucleating agents, and revealed a new, unexpected, nucleating agent (Li₂O) for this bioactive glass family.

This work presents a comprehensive investigation into the sustainable synthesis and extensive characterization of zirconium oxide (ZrO₂) nanopowder. The study examines the anticancer properties of the synthesized nanoparticles as well as their electrochemical behavior using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The fascinating attributes of ZrO₂ nanoparticles were elucidated through detailed analyses, including powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FT-IR), and UV–visible spectroscopy (UV–vis). PXRD analysis confirmed a monoclinic crystal structure with crystallite size within the range of 30–40 nm. FESEM reveals irregular shapes and agglomeration of particles, UV–vis showed absorption peak at 347 nm with an energy gap (Eg) of 3.16 eV and FT-IR studies reveals metal–oxygen bonds at 594 cm⁻¹. Additionally, electrochemical studies using PDP and EIS investigated the inhibition efficiency of nanoparticles dispersed in an acidic medium (1 M HCl). Anti-oncogenic studies conducted via MTT assay illustrated the efficacy of ZrO₂ NPs against the MDA-MB-231 cell line with an IC50 value of 22.56 µg/mL. Our findings underscore the versatile potential applications of ZrO₂ nanoparticles and provide significant new insights into their optical, structural, electrochemical, and anticancer properties.

TiC-10Mo-20Ni cermets with outstanding comprehensive properties were fabricated using Ni powder, self-synthesized ultrafine TiC and Mo powders. The effects of different liquid-phase sintering temperatures (1450–1525 °C) on the microstructure and mechanical properties of TiC-10Mo-20Ni cermets were investigated. The results demonstrated that all sintered samples exhibited a uniformly distributed core-rim structure. As the temperature increased, the degree of densification increased, and the number of gray coreless grains increased. The grain size of TiC-10Mo-20Ni cermets gradually increased with temperature, with the average grain size rising from 1.04 ± 0.29 μm to 1.43 ± 0.55 μm. The hardness of the sintered samples initially increased and then decreased with temperature, reaching a peak value of 1622 HV₃₀ at 1475 °C. The fracture toughness (K_IC) and transverse rupture strength (TRS) increased with temperature, and had the values of 15.02 MPa·m^1/2 and 1741 MPa at 1525 °C, respectively. The sintered samples were mainly dominated by a mixed fracture pattern of intergranular fracture and transgranular fracture, with transgranular fracture increasing as the temperature rose. Meanwhile, the crack extension and fracture morphology became more intricate, thus enhancing the K_IC and TRS.

The present research study focuses on optimizing the formulation of (PLA/PCL) polycaprolactone/polylactic acid biocomposite films for durable packaging applications by incorporating cardanol oil and nanosilica. The materials used include PLA pellets (Mw = 207,000 g/mol) and PCL polymer (Mn = 95 kDa). Cardanol oil were utilized as compatibilization and reinforcing agents. Composite films were prepared using a film casting method with varying concentrations of PCL (8, 10, 12 wt.%), cardanol oil (5, 10, 15 wt.%), and nanosilica (1, 3, 5 wt.%) based on the L9 orthogonal design. The produced films, with thicknesses ranging from 85 to 100 microns, were conditioned at 50% relative humidity and 25 °C to stabilize their properties. The key findings reveal that the optimal combination of process parameters, A2B1C3 (10 wt.% PCL, 5 wt.% cardanol oil, and 5 wt.% nanosilica), significantly enhanced the mechanical properties, achieving a tensile strength of 91.47 MPa and hydrophobicity of 95.25°, showing a 2.57% improvement in Grey Relational Grade (GRG). These results underscore the effectiveness of using cardanol oil and nanosilica to improve the compatibility and performance of PLA/PCL blends, providing valuable insights for developing sustainable biocomposite films for packaging applications. The FTIR analysis demonstrated effective compatibility between PLA/PCL and the added components, with distinctive peaks at 2900 cm⁻¹ and 3300 cm⁻¹ indicating CH alkyl bonds and OH phenolic groups, respectively. Morphological analysis using SEM images confirmed a uniform distribution of nanosilica and cardanol oil within the PLA/PCL matrix, which enhanced the composite’s properties, although minor submicron gaps and pits were observed. Unlike previous studies, this did not explore the ideal amounts or combined effects of these additives. This work employs a systematic approach using the Taguchi L9 orthogonal array to determine optimal input process parameters. However, this study has certain limitations like requirement of raw material for mass production of biosilica, and limited properties are studied under optimization in this study. This can be overcome by upcoming research study on this background and more properties studies on this research. Moreover, the natural material influenced biofilm composite can potentially be applied in areas such as food packaging industry, pharmaceutical, biomedical field, etc.