Ceramic Metal Research Articles

Ultrasonic-based surface patterning and interfacial reaction of ZrO2 ceramics

We demonstrate a process to achieve selective surface metallization of ZrO2 ceramics using ultrasound technology in atmospheric environments at 350 °C, which bestows good weldability of ZrO2 to achieve rapid and reliable connections with other metals as well as ceramic materials. The challenge is that brazing or diffusion welding processes to accomplish metallurgical connections for ZrO2 typically require holding at elevated temperatures for minutes to hours, while the selective ultrasonic metallization process requires only a few seconds of processing without the application of covering films or solder resists. In this study, the selected Sn-2Ti alloy could effectively wet and spread on ZrO2 substrate under ultrasonication, and continuous interphase layers were rapidly formed in situ between ZrO2 and Sn-2Ti. The bonding strength for the ZrO2/Sn-2Ti interface was well established with the highest shear strength of 37.1 MPa, and the fracture location occurred at the filler metal. The interfacial reaction layer thickened remarkably with the prolongation of sonication, accompanied by the partial crystallization of amorphous TiO and the formation of irregularly striped Ti11.31Sn3O10 nanocrystals.

3D phase-field simulations to machine-learn 3D information from 2D micrographs

A novel approach is developed to support retrieval of 3D information from 2D experimental micrographs. The approach utilizes 3D phase-field simulations to train an artificial intelligence machine. In a first step, the phase-field simulations have to be validated to reproduce microstructural features which characterize elementary processes which govern processing and high temperature service exposure. The qualified 3D simulation setup is then applied to produce a high number of 2D simulated micrographs by automated sectioning. These simulated micrographs are then used to train a gradient boosting regression model together with the 3D information from the simulations. In the final step, the model is applied to 2D experimental micrographs to retrieve the hidden 3D features. The approach is generally applicable to all kinds of metallic materials, minerals or ceramics which can be treated quantitatively by phase-field simulations. In this paper we concentrate on the process of directional coarsening, referred to as ‘rafting’, in the field of creep of single crystal Ni-base superalloys. The experimental and modeling aspects of the evolution of the volume fraction of the phase during long term creep are discussed.

Sintering behavior of 8YSZ‐Ni cermet: Comparison between conventional, FST/SPS, and flash sintering

AbstractCermets are ceramic metal composites. The metallic phase in the cermet typically undergoes oxidation during sintering in air. Electric field‐assisted sintering processes such as field‐assisted sintering technology/spark plasma sintering (FAST/SPS) and flash involves very high heating rates, short processing time and low processing temperature. The main aim of this work was to see if field‐assisted sintering techniques can prevent the oxidation of the metallic phase in the cermet. Sintering behavior of 8YSZ‐5 wt.% Ni cermet was studied by three different techniques namely; conventional sintering, FAST/SPS and flash sintering. Phases and microstructure were analyzed through X‐ray diffraction and scanning electron microscopy, respectively. Temperature and time required for sintering the samples via FAST/SPS and flash sintering was significantly lower than that during conventional sintering. In addition, we found limited grain growth during FAST/SPS and flash sintering. During conventional sintering in reducing atmosphere (Ar and vacuum), Ni particles retained their elemental state, however the extent of densification was poor in the cermet. FAST/SPS in argon and vacuum resulted in almost complete densification (relative density > 97%) and Ni particles were retained in their elemental state in the cermet. During flash sintering in air, the samples sintered to a high densification (relative density ∼98%), however, Ni particles were completely oxidized.

Synthesis and evaluation of rocksalt structure (Mo, W) carbides via vanadium additions

The mechanical properties of rocksalt (B1) binary, ternary, and high entropy transition metal ceramics exhibit strong correlation with their valence electron concentration (VEC). With respect to maximizing ductility and hardness, it has been proposed that materials with VEC values between 9 and 10 will generally possess superior performance. While many of the transition metal cations inherently crystallize in the B1 structure, the VEC=10 Group-VIB elements don't form room temperature stable B1 carbides. This work demonstrates the ability to stabilize bulk, spark plasma sintered samples of the Group-VIB containing carbides with VEC values in this range. The stabilization of molybdenum and tungsten carbide as room-temperature B1 structures via the addition of different amounts of vanadium and nanoindentation measurements correlated with VEC are the primary goals of this work. The minimum atom percent vanadium to form a single-phase B1 carbide is thoroughly explored and verified via a combination of XRD, EDS, and EBSD.

Effect of Surface Dispersion of Fe Nanoparticles on the Room-Temperature Flash Sintering Behavior of 3YSZ

Arc floating in surface flashover can be controlled by reducing the interfacial charge-transfer resistance of ceramics. However, thus far, only a few studies have been conducted on methods of treating ceramic surfaces directly to reduce the interfacial charge-transfer resistance. Herein, we explore the flash sintering behavior of a ceramic surface (3 mol% yttria-stabilized zirconia (3YSZ)) onto which loose metal (iron) powder was spread prior to flash sintering at room temperature (25 °C). The iron powder acts as a conductive phase that accelerates the start of flash sintering while also doping the ceramic phase during the sintering process. Notably, the iron powder substantially reduces the transition time from the arc stage to the flash stage from 13.50 to 8.22 s. The surface temperature (~1600 °C) of the ceramic substrate is sufficiently high to melt the iron powder. The molten metal then reacts with the ceramic surface, causing iron ions to substitute Zr4+ ions and promoting rapid densification. The YSZ grains in the metal-infiltrated area grow exceptionally fast. The results demonstrate that spreading metal powder onto a ceramic surface prior to flash sintering can enable the metal to enter the ceramic pores, which will be of significance in developing and enhancing ceramic-metal powder processing techniques.

Numerical modeling of shaped charge jet penetration into ceramic–metal double-layered medium using smoothed particle hydrodynamics

The prediction of the damage effects of shaped charge projectile to ceramic–metal multi-layered target is a challenging task to address. In this paper, the smoothed particle hydrodynamics (SPH) method is applied to simulate the penetration of the metal jet generated by the shaped charge detonation into ceramic–metal double-layered plates. The presented SPH model incorporates different equations of states. Moreover, the elastic-perfectly plastic constitutive model and the Johnson–Holmquist-II material constitutive model were employed for modeling the mechanical behaviors of the solid materials in this study. Firstly, simulation of the high velocity impact process of a ceramic ball on a ceramic–metal double-layered plate was conducted to validate the presented constitutive model. After the validation of the numerical model, simulations of penetration of a shaped charge into a double-layered ceramic–metal plate by using millions of SPH particles were conducted. The simulation results (perforation diameter and debris cloud) are in good agreement with the available experimental data, which shows that our in-house SPH solver is capable of tackling the shaped charge detonation and its penetration into multi-layered structures very well. Furthermore, the presented SPH model can reproduce different types of fracture patterns observed in experiments and their dynamic formation processes.

Chalcolithic copper production and use in the western end of the Iberian Peninsula: The testimony of Castro de Chibanes (Portugal)

Recent archaeological excavations identified a prehistoric occupation at Castro de Chibanes (Setúbal Peninsula, Portugal) displaying ceramic crucibles and metal artefacts in stratigraphic levels assigned to 2500–1900 cal BC. Apart from basic tools such as flat axes and awls, the collection includes ceramic crucibles, with emphasis to an uncommon example with a pouring lip and four feet. The studied set was completed with metal prills and artefacts from neighbouring Chalcolithic settlements of Rotura and Pedrão. The studied collection was characterised by chemical and microstructural techniques (p-EDXRF, micro-PIXE, optical microscopy and SEM-EDS). Overall, the results point to a local production of copper with variable arsenic contents, agreeing with the composition of artefacts (Cu with 0.14 to 4.4 wt% As), whose post-casting manufacture included hammering and annealing (recrystallized grains and annealing twins), although with incipient conditions that prevented a full compositional homogenisation. These results were compared with the Chalcolithic metallurgy of southwestern Iberian Peninsula, allowing to integrate the Setúbal Peninsula region into a wider context of metal production and use during the 3rd millennium BC. Finally, a supposed Bell Beaker “tanged dagger” was found to be composed by a leaded bronze alloy with a worked microstructure exhibiting Cu-Fe sulphides with high Se contents. The contradiction between analytical features and ancient chronology led to a revision of the typology and chronology of this bronze, showing the importance of the integration of analytical and archaeological research.

Ballistic Impact Analysis of the Ceramic Metal Target

Ballistic Impact Analysis of the Ceramic Metal Target

Light Spectra Have Minimal Effects on Rooting and Vegetative Growth Responses of Clonal Cannabis Cuttings

Until recently, most clonal cannabis (Cannabis sativa) has been propagated using fluorescent lights. Transitioning to light-emitting diodes (LEDs) may be a viable alternative to fluorescent lighting, enabling cultivators to provide specific spectrum treatments to enhance rooting while also saving energy. Vegetative stem cuttings of ‘Gelato-27’, ‘Grace’, and ‘Meridian’ were rooted for 15 days under various combinations of blue (B), red (R), ultraviolet-A (UVA) LEDs, phosphor-converted white (W) LEDs, and a fluorescent (F) control treatment, each with a canopy-level photosynthetic photon flux density (PPFD) of 200 µmol·m−2·s−1 and 16-hour photoperiod. The photon flux ratios of blue (B; 400–500 nm) and red (R; 600–700 nm) narrowband LED treatment combinations were (1) BR, fixed spectrum of B15:R85; (2) B, B75:R25 on day 0–2 followed by B15:R85 on day 2–14; (3) B+UVA, B75:R25 on day 0–2 followed by B15:R85 on day 2–14 plus 15 µmol·m−2·s−1 of UVA on day 7–14; (4) B50, B15:R85 on day 0–7 followed by B50:R50 on day 7–14. The W and F treatments both had static spectra. After the propagation period (i.e., plug stage), a portion of the cuttings under each treatment × cultivar combination were destructively harvested and the remainder were transplanted and grown vegetatively for an additional 21 days (i.e., transplant stage) under a PPFD of ≈275 µmol·m−2·s−1 from ceramic metal halide fixtures and then destructively harvested. Although there were no spectrum treatment effects on the percentage of cuttings that rooted, root index values were higher in cuttings grown under B+UVA vs. F. Further, relative root dry weights of plugs from the B, B+UVA, B50, and F treatments were higher than the W treatment. At the end of the plug stage, there were no spectrum treatment effects on the chlorophyll content index, cuttings grown under the B treatment had thicker stems compared with BR and W treatments, and cuttings grown under the F treatment exhibited the lowest percentage of new aboveground growth. None of the aforementioned spectrum treatment effects from the propagation stage persisted post-transplant. The use of LEDs is a promising, energy-efficient alternative to fluorescent lighting for cannabis propagation and B-enhanced spectrum treatments appear to enhance the rooting performance of clonal cannabis cuttings.

Evaluation of the Failure Rate and Clinical Efficacy of Orthodontic Brackets Indirect Bonding with Computer-Aided Transfer Jig System: An In Vivo Study

This study aimed to evaluate the failure rates and relevant factors of bonded orthodontic brackets with a computer-aided design and manufacturing (CAD/CAM)-based 3D-printed indirect bonding jig system (IDBS) using 2531 natural teeth selected from 99 orthodontic patients. Ceramic self-ligating brackets and metal tubes were used in this study. Proportion analysis was used to calculate the total bracket re-bonding rate and respective proportions of bonding failure and position error. Crossover frequency analysis was used to analyze the total bracket re-bonding, bonding failure, and position error rates in different tooth positions of the maxilla and mandible. Multiple linear regression analysis was used to evaluate the association between dependent variables (age, sex, treatment stage, skeletal divergence, and tooth position) and the bracket bonding failure rate. Pearson’s Chi-square test was used to test the difference between the maxilla and mandible for each variable. The total bracket re-bonding rate was 22.64%, and the bonding failure rate and position error rates accounted for 15.09% and 7.55%, respectively. The bonding failure rate was higher in the mandibular teeth than in the maxillary teeth (p < 0.05). Anterior teeth had a higher position error rate, and mandibular anterior teeth had a higher bonding failure rate. The accuracy of IDBS was higher in the premolars and molars. Sex, age, and treatment stage were affected by IDBS. Patients with hyperdivergent skeletal patterns had higher rates of bracket bonding failure. The results of this study can provide practical guidelines for placing brackets with 3D-printed IDBS on the entire dentition to ensure the precision and accuracy of their use during orthodontic treatments.

Electrospinning spinneret: A bridge between the visible world and the invisible nanostructures

Electrospinning spinneret: A bridge between the visible world and the invisible nanostructures

Fabrication and tribo characteristics of in-situ polymer-derived nano-ceramic composites of Al-Mg-Si alloy

Polymer-derived nano ceramic metal matrix composites (PDC-MMC) have potential as wear-resistant materials. PDC-MMC are obtained from preceramic polymers after pyrolysis. To develop in-situ PDC-MMC, ball-milled Polymethylhydrosiloxane polymer particles were dispersed in an industrial-grade Al-Mg-Si matrix by Friction Stir Processing (FSP). Tribological properties were evaluated at variable loads using a reciprocating ball-on-flat method. PDC-MMC showed 67.2% reduction in wear volume loss. Improved resistance to abrasion and delamination could be reasoned for excellent wear resistance. Under the severe plastic deformation during FSP, the uniform ceramic distribution resulted in compact bonding with the metal matrix and yielded better wear properties. The dominant wear mechanism of PDC-MMC changed from abrasive to adhesive.

Effect of Vacancy Defect Content on the Interdiffusion of Cubic and Hexagonal SiC/Al Interfaces: A Molecular Dynamics Study.

The mechanical properties of ceramic-metal nanocomposites are greatly affected by the equivalent properties of the interface of materials. In this study, the effect of vacancy in SiC on the interdiffusion of SiC/Al interfaces is investigated using the molecular dynamics method. The SiC reinforcements exist in the whisker and particulate forms. To this end, cubic and hexagonal SiC lattice polytypes with the Si- and C-terminated interfaces with Al are considered as two samples of metal matrix nanocomposites. The average main and cross-interdiffusion coefficients are determined using a single diffusion couple for each system. The interdiffusion coefficients of the defective SiC/Al are compared with the defect-free SiC/Al system. The effects of temperature, annealing time, and vacancy on the self- and interdiffusion coefficients are investigated. It is found that the interdiffusion of Al in SiC increases with the increase in temperature, annealing time, and vacancy.

METAL ION RELEASE ACCORDING TO LEG LENGTH DISCREPANCY IN CERAMIC-ON-METAL HIP ARTHROPLASTY.

The ceramic-on-metal (CoM) bearing has the theoretical advantages over ceramic-on-ceramic (CoC) and metal-on-metal bearings. This study aimed to analyze factors affecting the metal ion release of CoM bearings and compare clinical performance with CoC bearings. The 147 patients were divided into 96 patients in group 1 (CoM group) and 51 patients in group 2 (CoC group). Additionally, within group1, 48 patients and 30 patients were sub-categorized into group 1-A with leg length discrepancy (LLD) less than 1cm and group 1-B greater than 1 cm. The level of serum metal ions, functional scores and plain radiographs were obtained for the analysis. The level of cobalt (Co) 2-years after surgery and chromium (Cr) 1-year after surgery showed significantly higher in the group1 than the group2. LLD indicated statistically significant positive correlation between serum metal ion levels among CoM bearing THAs. In comparison of the average metal ions level changes, group 1-B showed higher level of metal ion than group 1-A. In patients underwent THA with CoM bearings, large LLD have a higher risk of complications associated to metal ions. Therefore, it is critical to reduce the LLD to 1 cm or less in using CoM bearing. Level of Evidence III; Case Control Study.

Six-year clinical performance of lithium disilicate glass-ceramic CAD-CAM versus metal-ceramic crowns.

To assess the clinical performance of monolithic CAD-CAM lithium disilicate glass-ceramic (LDGC) crowns and metal-ceramic (MC) crowns provided by predoctoral students. This study also assessed the effects of patient and provider-related factors on their clinical performance as well as patient preference for these types of crowns. Twenty-five patients who received 50 crowns (25 LDGC CAD-CAM and 25 MC) provided by predoctoral students were retrospectively examined. LDGC CAD-CAM crowns were milled in-house using the CEREC Bluecam system and cemented with either RelyX Unicem or Calibra Esthetic resin cements. MC crowns were cemented with RelyX Unicem cement. Clinical assessment of the crowns and the supporting periodontal structures were performed following the modified California Dental Association (CDA) criteria. Patients' preference was recorded using a visual analog scale (VAS). The results were statistically analyzed using log-rank test, Pearson Chi-squared test and Kaplan-Meier survival analysis. Twelve complications were observed in the MC crown group (9-esthetic, 2-technical and 1-biological). In comparison, 2 complications in the LDGC CAD-CAM crown group were observed (1-technical and 1-esthetic). The 6-year cumulative survival rates for MC crowns and LDGC CAD-CAM were 90.8% and 96%, respectively, whereas the success rates were 83.4% and 96%, respectively. Overall, patients preferred the esthetic outcomes of LDGC CAD-CAM crowns over MC crowns. The high survival and success rates, low number of complications, and the high level of patients' acceptance of monolithic LDGC CAD-CAM crowns lend them well as predictable and viable alternatives to the "gold standard" MC crowns.

Indirect restorative systems-A narrative review.

The background and clinical understanding of the properties of currently available indirect restorative systems and fabrication methods is, along with manufacturer and evidence-based literature, an important starting point to guide the clinical selection of materials for tooth and/or implant supported reconstructions. Therefore, this review explores most indirect restorative systems available in the market, especially all-ceramic, along with aspects of manufacturing process, clinical survival rates, and esthetic outcomes. Progressive incorporation of new technologies in the dental field and advancements in materials science have enabled the development/improvement of indirect restorative systems and treatment concepts in oral rehabilitation, resulting in reliable and predictable workflows and successful esthetic and functional outcomes. Indirect restorative systems have evolved from metal ceramics and polymers to glass ceramics, polycrystalline ceramics, and resin-matrix ceramics, aiming to improve not only biological and mechanical properties, but especially the optical properties and esthetic quality of the reconstructions, in attempt to mimic natural teeth. Based on several clinical research, materials, and patient-related parameters, a decision tree for the selection of indirect restorative materials was suggested to guide clinicians in the rehabilitation process. The pace of materials development is faster than that of clinical research aimed to support their use. Since no single material provides an ideal solution to every case, professionals must continuously seek information from well designed, long-term clinical trials in order to incorporate or not new materials and technological advancements.

Experimental analysis of Al composites toughened by aluminium oxide and graphite using stir casting progression

Aluminum-Alloy Reinforced among ceramic particles Composites (AMCs) or Hybrid Metal Composites (HMC) is a class of compact, higher production compositions which are aluminum-centric. Due to their superior physcio-mechanical characteristics when compared to their base Al alloy. Aluminum MMCs are extensively utilized in a mixed range of applications. The present work is aimed to study the mechanical properties of composite Al alloy (A356/LM25) reinforced with micro-sized ceramic particles (Al2O3 and graphite) by means of stir casting process. Different sets of composites with invariable 1% weight fraction of graphite and 1, 3, 5 % weight of ceramic particle size of 100–200 μm (Al2O3) and un-reinforced A356/ LM25 samples are prepared by variable speeds of stirring likely be 200 rpm, 300 rpm and 400 rpm sustaining constant temperature. Tensile strength and hardness tests were performed to study the optimum composition.

PEMILIHAN GENTENG RUMAH MENGGUNAKAN METODE MULTIDIMENSIONAL SCALING

Tile is one of the most important building materials. Tile has the main function as a roof covering. Tile is more often used in the construction of houses. The tile protects the occupants of the house from the hot sun and rain. Selection of the right tile needs to be considered for the comfort of the occupants of the house. In this study, the determining factors in the selection of roof tiles are price, product quality, and product availability. The types of tiles used in this research are ceramic tiles, clay tiles, Alderon tiles, asbestos tiles, zinc tiles, and metal roof tiles. The method used in this study is the multidimensional scaling method. The multidimensional scaling method is one of the multivariate analysis methods used to determine the similarity value based on the proximity seen on the perceptual map. Based on the calculation results, it is determined that the types of tiles that have similarities are ceramic tiles and Alderon tiles with a distance value of 0.2062. Furthermore, the best roof tiles based on respondents' perceptions are Asbestos tiles because the variables of product quality and product availability have advantages

MYCOTECHNOLOGY FOR VALORISATION OF FRUIT TREE WASTES AS ECO-FRIENDLY AND USEFUL PRODUCTS

The main aim of this work was to set up the optimal mycotechnology for valorisation of fruit tree wastes by using them as growing sources for Basidiomycetes mushrooms, in order to get eco-friendly and useful products. In vitro experiments were carried out through controlled cultivation of two mushroom species, Ganoderma applanatum and Ganoderma lucidum, on substrates made of fruit tree wastes. There were set up three variants of substrates consisting of lignocellulosic wastes belonging to apple, plum and cherry trees, mixed with cereal grain wastes, such as wheat and barley bran, which were placed in ceramic trays and metal pots. After thermal sterilization and inoculation with the pure mushroom cultures, the substrates were placed inside growth chambers at the temperature of 23 °, the air flow volume exchanges 3-5 m3/h and the relative humidity content 90-95%, RU. The mushroom growth inside the substrates made of lignocellulosic wastes has followed the controlled biotechnological aiming to minimize the duration of cultivation and maximize the final production eco-friendly materials and biodegradable products.

Numerical investigation of ballistic impact on multilayered ceramic/metal target plate with or without air gap

The present work is based on numerical simulations of the ballistic behavior of multilayered alumina/aluminum armor plates of varying thicknesses against normal impacts of ogive-nosed steel projectiles. The numerical simulation and the associated models have been validated against published experimental results. A total of nine distinct combinations of ceramic–metal armor plates are impacted normally at different strike velocities, ranging from 200 to 1200 m/sec to determine the residual velocities and ballistic limit velocities of the projectile for each combination of target plate. In a few circumstances, a small air gap has been considered in a combination to compare its ballistic performance to that of a target without an air gap. The optimal ratio of ceramic in a ceramic metal bilayered target plate is determined numerically. This article visualizes the progressive damage of target plates and projectiles at various strike velocities to explore the effects of thicknesses and relative positions of ceramic layers in ceramic/metal armors of a given total thickness in terms of ballistic limit velocity, deformation, and damage of the projectile and target plate.