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To date, the application of additive manufacturing techniques in fabricating SiAlON ceramics with intricate geometries has been limited. This investigation demonstrates the synthesis of SiAlON ceramics by integrating silicon nitride (Si 3 N 4) powders with variable proportions of aluminum nitride (AlN) utilizing the vat photopolymerization (VPP) approach. The effects of AlN content on the properties of SiAlON ceramic slurries, green bodies, and sintered parts were systematically investigated. Notably, the slurry's viscosity decreases progressively with an increase in AlN, aligning with VPP printing prerequisites. Additionally, the curing depth of the slurry enhanced proportionally with AlN augmentation, elevating from 21 μm to 44 μm at an energy exposure of 800 mJ/cm2, with the pivotal addition being 15 vol% AlN, where optimal properties were achieved. The zeniths of flexural strength, bulk density, relative density, and thermal conductivity were recorded at 385.66 ± 22.63 MPa, 3.34 ± 0.09 g/cm3, 96.22 ± 2.55 %, and 37.4 ± 0.31 W m−1 K−1, respectively. The fabrication of SiAlON ceramics with complex configurations was successfully realized, heralding a novel methodology for future SiAlON ceramic production. [ABSTRACT FROM AUTHOR]

Porous Si 3 N 4 -based ceramics with different pore morphologies were prepared choosing Si 3 N 4 and Al 2 O 3 poly-hollow microspheres (PHMs) as pore-forming agents. The phase compositions, morphologies and mechanical properties of the samples were investigated. The SEM results show that the intact Si 3 N 4 and Al 2 O 3 PHMs distribute uniformly in the green body. However, after the sintering process, the basal body of the samples with Si 3 N 4 PHMs is fibrous and Si 3 N 4 PHMs still exist, while the basal body of the samples with Al 2 O 3 PHMs is dense and Al 2 O 3 PHMs disappear. In addition, the samples with Si 3 N 4 and Al 2 O 3 PHMs have different mechanical properties due to their different microstructures. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) is raised as one kind of additive manufacturing (AM) which is based on the discrete-stacking concept. This technique can fabricate advanced composites with desirable properties directly from 3D CAD data. In this research, 316L stainless steel (316L SS) and different fractions of calcium silicate (CaSiO 3 ) composites (weight fractions of calcium silicate are 0%, 5%,10% and 15%, respectively) were prepared by SLM technique with a purpose to develop biomedical metallic materials. The relative density, tensile, microhardness and elastic modulus of the composites were tested, their microstructures and fracture morphologies were observed using optical microscope (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the addition of CaSiO 3 particles influenced the microstructure and mechanical properties of specimens significantly. The CaSiO 3 precipitates from the overlap of adjacent tracks and became the origin of the defects. The tensile strength of specimens range 320–722 MPa. The microhardness and elastic modulus are around 250 HV and 215 GPa respectively. These composites were ductile materials and the fracture mode of the composites was mixed mode of ductile and brittle fracture. The 316L SS/CaSiO 3 composites can be a potential biomedical metallic materials in the medical field. [ABSTRACT FROM AUTHOR]

A novel way has been reported to fabricate porous silica ceramics, which is based on the in-situ foaming process of densely packed silica poly-hollow microspheres (SPHMs) at elevated temperature and inert atmosphere. The results show that sintering atmosphere and temperature have great effects on the formation and evolution of the porous structure. The original holes inside or between SPHMs could grow up to form uniform pores as the sintering temperature increases under inert atmosphere, and the optimal sintering temperature for well homogeneous microstructure could be 1575 °C. This novel method is facile and efficient, by which porous silica ceramics with the compressive strength ranging from 0.60±0.28 MPa to 29.77±2.28 MPa and the porosity of 39.0–77.2% have been prepared. [ABSTRACT FROM AUTHOR]