International Journal of Applied Ceramic Technology最新文献

To address the extreme service performance demands of aerospace heat-resistant components, wear-resistant tools, and marine corrosion-resistant structures, metal matrix ceramics have emerged as a major international research focus due to their stable crystal structures, high hardness, exceptional corrosion, and heat resistance. This study systematically analyzes the correlation between preparation processes and the formation mechanisms of interfacial compounds, interatomic bonding mechanisms, and resultant mechanical properties in TiB₂-reinforced ultrahigh strength steel matrix composites. It further reveals the regulatory effects of atomic-scale interfacial dislocation evolution and elemental segregation on toughening mechanisms. By establishing a cross-scale evolution model of the cast-infiltrated interface phase composition, the phase evolution behavior during the liquid–solid phase transition in TiB₂/steel composites is elucidated. Surface modification and gradient structure design as effective interfacial bonding enhancement strategies are critically assessed. Based on this comprehensive analysis, the paper concludes with perspectives on future research directions for TiB₂-reinforced steel matrix composites.

The waste glass, Bayer red mud, and marble were utilized as sintering raw materials (85: 5: 10 wt%) to prepare fully solid waste-based foam glass-ceramics (FGC) with excellent comprehensive properties at a relatively low sintering temperature range of 750–875°C. The impacts of sintering temperature and soaking time on the phase composition, microstructure, and physical-mechanical attributes of FGC were examined, and the optimal sintering process for producing these materials was also explored. The results suggested that the optimum sintering process of FGC is 825°C for 60 min. The bulk density, porosity, specific strength, and room-temperature thermal conductivity of the FGC were 0.26 g/cm³, 89.9%, 9.2 MPa·cm³·g⁻¹, and 0.091 W/(m·K), respectively. The uniformly distributed pore structure, with an average pore size of 3.18 mm, combined with relatively thin and dense pore walls (ranging from 50 to 100 µm), not only ensures high porosity in the FGC but also provides excellent specific strength and low thermal conductivity at room temperature. Furthermore, this process allows for the efficient and valuable utilization of multiple types of industrial solid waste.

Porous fibrous mullite ceramics have the characteristics of high-temperature resistance, lightweight, and thermal insulation, and have been widely used as the high-temperature thermal insulation materials in various thermal protection systems. In order to further improve the rebound-resilience property, a porous nanofibrous mullite ceramic with a lamellar structure was successfully fabricated by stacking electrospun mullite fiber membranes layer-by-layer. Results indicate that the introduction of zirconia into mullite fibers was able to inhibit the rapid growth of mullite grains. The porous nanofibrous mullite ceramics exhibited a lamellar structure, in which a large amount of space existed between adjacent fiber membrane layers, which provided enough space for the deformation of the mullite fibers. Therefore, the samples exhibited excellent compression resilience properties. Results show that the sample sintered at 1400°C still exhibited a high porosity (95.6%), low thermal conductivity (0.0399 W·m⁻¹·K⁻¹) and high compression resilience ratio (96.4%). This work provides an effective strategy for the fabrication of thermally insulating elastic porous fibrous ceramics, which can be widely used in the thermal protection systems of various aircraft and the thermal insulation layers of diverse industrial furnaces.

The influence of different processing parameters on the structure and dielectric behavior of the bismuth sodium titanate (BNT) multilayered thin films was investigated. Six-layered BNT thin films with a thickness of ∼300 nm were prepared using sol–gel method and deposited by spin coating. The selection of solvent ratios (acetic acid-to-water) in precursor sol preparation had a strong influence on the physical quality of layers and on the formation of a pure perovskite BNT phase. In addition, the influence of thermal treatment of both individual layers and multilayers on the structure and dielectric properties was also studied.

Development of geopolymer concrete (GPC) is vital for minimizing the environmental impact of conventional cement. This study evaluates the predictive capabilities of three machine learning models, response surface methodology (RSM), artificial neural network (ANN), and support vector machine (SVM) for estimating the 28-day compressive strength of GPC. A total of 22 mix combinations were prepared in two grades (G40 and G60) using fly ash and ground granulated blast-furnace slag as primary binders. To improve performance, fly ash was partially replaced with rice husk ash and silica fume at 5%, 10%, and 15%. Specimens were ambient-cured, and compressive strength was measured at 7, 14, and 28 days. Modeling focused on 28-day results. RSM showed the highest correlation (R² = 0.9805), followed by SVM (0.9656) and ANN (0.9444). However, SVM outperformed others in error metrics, achieving over 58% lower prediction error than ANN and over 10% better performance than RSM. SVM was further optimized using a fine Gaussian kernel and fivefold cross-validation. While RSM showed the best fit, SVM demonstrated superior generalization and accuracy, making it the most reliable model for predicting GPC compressive strength.

TiB₂/Ti(C,N) cermets were synthesized using Co-C-BN-Ti-Mo₂C-TaC powders. The influence of the TaC/(Mo₂C+TaC) mass ratio on the microstructures and performances was studied. Results indicated that Mo from Mo₂C primarily resided in the binder. As the TaC/(Mo₂C+TaC) mass ratio was within the range of 0−0.2, excess Mo combined with some Co to form Co₃Mo. Raising the ratio decreased the amount of metal liquid. This change shortened the diffusion distance of atoms toward Ti(C,N), thereby increasing the relative density of cermets. In contrast, Ta exhibited a faster diffusion rate. Increasing the TaC/(Mo₂C+TaC) ratio resulted in the formation of core/rim structured (Mo,Ta,Ti)(C,N) and coreless (Ta,Ti)(C,N) solid solution grains. The core/rim structure can prevent the coalescence and growth of Ti(C,N). Nevertheless, an excessive increase in the TaC/(Mo₂C+TaC) ratio hindered the rapid consumption of C. Consequently, as the mass ratio varied from 0.8 to 1.0, C atoms within the liquid reacted with some Ti to form TiC. At a 0.6-TaC/(Mo₂C+TaC) ratio, the cermet displays optimal hardness, K_IC, and wear depth, with values of 2145 HV, 9.22 MPa·m^1/2, and 43.01 µm. This work is beneficial for preparing TiB₂/Ti(C,N) cermets with a relatively high K_IC.

Ti-doped ZnO films were synthesized via the sol-gel dip-coating method with a fixed Ti:Zn molar ratio of 0.2:1 to investigate their structural, optical, and antimicrobial properties. X-ray diffraction analysis confirmed the hexagonal wurtzite ZnO structure with a (002) preferred orientation, while scanning electron microscopy (SEM) and atomic force microscopy revealed compact nanostructures with uniform grain distribution. Raman spectroscopy displayed the characteristic E₂(high) mode associated with crystal quality, along with red shifts in the A₁(longitudinal optical) and 2LA modes, indicating lattice deformation induced by Ti incorporation. The prism coupler yielded a film thickness of approximately 1 µm and a refractive index of 1.96. The porosity was estimated as 13.4% using optical data and 14.8% via SEM-based ImageJ analysis. Ultraviolet-visible (UV-Vis) spectroscopy revealed high transparency in the visible range (>95%) and strong UV absorption, with a reduced optical band gap of 3.17 eV, suggesting bandgap narrowing due to defect formation and lattice strain. Antimicrobial activity tests showed a reduction of up to 99.96% of Acinetobacter baumannii and remarkable activity against other strains, including Candida parapsilosis (96.8%) and Enterococcus faecalis (83%) after UV light exposure. Although Staphylococcus aureus showed lower sensitivity (∼43%), the overall results indicate that Ti-doped ZnO films are promising candidates for multifunctional applications requiring high optical quality and effective antimicrobial surface activity.

The bulk compaction of granular materials has been studied for decades to interpret and manage responses for soils and powder-based component fabrication, and geophysical, celestial, and ballistic impact. Their bulk or macroscopic compaction response is limited by what occurs at the granular or microstructural scale. Motivation existed to more closely examine that association specific to granular brittle materials (e.g., ceramics and glasses). That examination is offered in a series of three companion papers where Part I describes a new supplemental analysis adopted to bulk compaction response involving relatively high compaction stresses (4000 MPa). Bulk compactions of vitreous silicates and crystalline quartzes were interpreted in three ways, including that of a new analysis that considers the product of void ratio (e) and stress (S) as a function of S, hereafter referred to as “SeS analysis”. The SeS analysis was found to be an informative supplement to conventional bulk compaction analyses because it provides more consistent higher sensitivity for the identification of bulk density rate increase with increasing compaction (softening); a rate increase that arises from the cumulative effect of the onsets and progression of compaction-induced yielding, fracture or comminution, densification, phase change, or combinations thereof occurring at the granular or microstructural scale.

With the development of 5G and high-power electronic devices, the demand for high-performance alumina ceramic packaging substrates has grown significantly. However, traditional manufacturing processes face issues such as high energy consumption and limited shape complexity, while additive manufacturing technologies (DLP 3D printing) encounter challenges like weak interlayer bonding and insufficient mechanical properties. This study explores the development of low-viscosity alumina slurries by optimizing the ratio of photosensitive resin to dispersants (BYK-110 and KH-570). Through the synergistic effects of sintering additives (ZrO₂, SiO₂, Y₂O₃) and sintering processes, it systematically investigates the preparation and performance regulation mechanisms of high solid-loading alumina ceramics. The results demonstrate that, at a photosensitive resin: BYK-110:KH-570 ratio of 6:1:7, the slurry achieves the lowest viscosity (0.7377 Pa·s), enabling successful fabrication of alumina ceramics with a maximum solid loading of 88 wt%. Samples produced with 2 wt% Y₂O₃ as a sintering additive exhibit the highest flexural strength across all sintering processes. When both the maximum sintering and re-sintering temperatures reach 1650°C, the flexural strength peaks at 138.17 ± 17.89 MPa. The optimal overall performance of alumina ceramics occurs at a maximum sintering temperature of 1450°C. Silica as a sintering additive under this process provides the lowest shrinkage rates: X-direction: 3.84 ± 0.25%, Y-direction: 4.79 ± 1.33%, Z-direction: 4.17 ± 0.87%, along with the highest open porosity (21.95 ± 0.3%), bulk density (3.52 ± 0.07 g/cm³), and sufficient flexural strength (91.50 ± 7.94 MPa). This study provides theoretical support for the compositional design and process optimization of high solid-loading alumina slurries for the additive manufacturing of electronic packaging.

A new and simple method is presented that enables the estimation of the yield strength (σ_y) of brittle materials (e.g., ceramics, glasses). It results from the combination of sufficiently high-stress compaction of their granular form, postmortem analysis of the crushed particles to identify the critical particle size corresponding to their brittle-to-ductile transition, and the use of a developed and simple analytical expression. This method was an outcome from Part I of this three-paper series. To execute it, a granular brittle material is compacted to a sufficiently high stress, whereby the acting comminution produces both a fraction of particles having a sufficiently small size formed by ductile or plastic-like deformation and a remaining fraction of larger particles formed from brittle fracture. Postmortem microscopy is then used to identify the smallest particle size whose morphology indicates it formed from brittle fracture (d_B2D). The brittle material's σ_y can then be estimated using a combination of the d_B2D, Kendall's and Griffith's theories, a priori knowledge of the material's fracture toughness (K_Ic), and a fracture mechanics shape factor constant (Y) using σ_y = √((32 π K_Ic²)/(3 Y² d_B2D)). The method's development and its use to estimate σ_y for several vitreous silicates, α-quartzes, and NaCl are provided.