Titanium Zirconium Research Articles

Numerical analysis of the powder mixed electrical discharge machining (PMEDM) process for TZM-molybdenum superalloy using finite element method

The powder mixed electrical discharge machining (PMEDM) process was simulated via finite element analysis in the current study to assess heat behavior and material removal rate. The goal of this paper is to conduct a thorough experimental and thermal examination of electrical discharge machining (EDM) in order to forecast its cutting characteristics and subsequently optimize the output variables using a response surface methodology for simulations and choosing the most suitable set of process variables related to the PMEDM process. This study’s objective is to design a 2D axisymmetrical transient thermal model that might also describe the physics of material removal in a single spark PMEDM operation on a Titanium Zirconium Molybdenum (TZM) superalloy. ANSYS (version 9.1) software is used to perform transient heat transfer simulations to determine the temperature profile with the amount of material removal at different current, pulse on and off times, gap voltages, and fraction of heat that enters the specimen. The PMEDM process produced craters with a lower diameter and depth, which increased the material removal rate and enhanced the surfacing quality. Compared to the conventional EDM process, the inclusion of powder raised the heat flux given to the work material by 10%–12%. It has been determined that with the single spark modeling technique, the temperature significantly dropped in both the radial and depth directions. The computational results are compared with experimental observations for similar machining conditions, and both results agree satisfactorily.

Experimental study on laser cutting process of titanium–zirconium amorphous alloy

This paper aims to assess the effects of various laser cutting parameters on the surface roughness of 2 mm thick titanium–zirconium amorphous alloy sheets. With multiple linear regression, a mathematical model was proposed to predict the maximum height of surface Sz as a function of two laser cutting parameters: cutting speed and assist gas pressure. The adequacy of the proposed model was evaluated using the analysis of variance method. Scanning electron microscopy was then used to observe the surface topography of the material following laser cutting under different conditions. It was found that for a fixed laser power, cutting speed dominates the parameter that determines the maximum height of surface roughness.

(Invited) Forming Multifunctional Ceramics with Different ZrO2 Polymorphs: Mixed Ion-Electron Conducting Properties of Zirconium Titanium Oxides

Infiltrating porous electrodes with solution phase precursors is a strategy employed to improve performance, catalytic activity and longevity in high temperature electrochemical devices. For example, traditional Ni yttria-stabilized zirconia (Ni-YSZ) cermet anodes used in solid oxide fuel cells (SOFCs) are susceptible to carbon accumulation and to sulfur poisoning. To counter the effects of degradation, anodes have been infiltrated with secondary materials containing Sn, Ba, Al and a host of other constituents, typically at levels of 1-5% (by mass). Processing and preparing infiltrated electrodes, however, can lead to formation of new material phases that affect surface chemistry and electrode microstructure in unexpected ways.In this work, XRD and Raman spectroscopy are used to investigate the formation of functional zirconium titanate secondary phases in Ti/Zr oxides. Different zirconia polymorphs (either pure or stabilized with small amounts of yttria (YSZ)) mechanically mixed with TiO2 and heated above 1000 ˚C in stagnant air react to form several secondary phases. For sintering temperatures > 1100 ˚C, mixtures of TiO2 and m-ZrO2 form a ZrTiO4 secondary phase while mixtures of TiO2 and 3YSZ or 8YSZ form Zr5Ti7O24. The extent of secondary phase formation is enhanced with both higher sintering temperature and yttria content. The Zr5Ti7O24 secondary phase formed from TiO2/8YSZ samples sintered at 1400 ˚C exhibits unexpected mixed ionic and electronic conductivity at 800 ˚C. These findings suggest that secondary phases intentionally integrated into electrode architectures can improve the performance of high temperature electrocatalyst systems.

Process optimisation and kinetic study for esterification of levulinic acid and n‐butanol using sulfonated titania–zirconia heterogeneous catalyst

AbstractBackgroundButyl levulinate (BL) was produced by the esterification of levulinic acid (LA) and n‐butanol (BOH) using a sulfonated nanocomposite of titania–zirconia as catalyst. A full factorial design was employed for studying the effects of reaction time, mole ratio and catalyst loading on LA conversion.ResultsThe synthesised catalyst was subjected to various characterisation techniques such as X‐ray diffraction, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller measurements, thermogravimetric analysis, temperature‐programmed desorption and scanning electron microscopy–energy dispersive X‐ray analysis indicating the presence of a nanocrystalline structure with good surface area and good stability at the operating temperature. The experimental data were analysed using the response surface method, and a complete quadratic regression model was built. The LA conversion was 85.37% for the optimised reaction conditions of 1:7 mole ratio, a catalyst loading of 1 wt% and a reaction time of 5 h at 110 °C. Based on the Langmuir–Hinshelwood–Hougen–Watson model, a kinetic model was developed. The activation energy was found to be 20.4 ± 0.8 kJ mol−1 from an Arrhenius plot. Reusability and leaching results are also reported.ConclusionThe catalyst exhibited good reusability and stability. Sulfonated TiO2–ZrO2 used to catalyse the reaction between LA and BOH to produce BL has proved to be a good candidate as a green catalyst. The results presented play an important part in directing subsequent research and commercialisation activities aimed at valorising LA to fuel additive. © 2023 Society of Chemical Industry (SCI).

Convective nanofluid flow subjected to variable porosity, inclined magnetic field, and thermal radiations

Nanofluids pique the attention of researchers and scientists because of their excellent thermal transfer rates. They have numerous technological and industrial implementations in daily life. Nonsimilar analysis in this research is performed to study the consequences of nonuniform porosity of a porous medium on the radiative flow of nanofluid across a vertically positioned stretching surface. Moreover, the effects of viscous dissipation and inclined magnetic field are also taken into account. Single phase nanofluid model with latest thermophysical features of nanofluid are considered to devise the physical problem. Hamilton–Crosser model is used to investigate the various shapes of nanoparticles. Titanium oxide (TiO 2), Zirconium dioxide (ZrO2 ), water and Borosilicate ceramic are regarded as nanoparticles, base fluid, and porous media, respectively. The Brinkman–Forchheimer-extended Darcy model is assumed to represent the flow through porous medium. The governing partial differential equations (PDEs) with accompanying boundary conditions are transformed into the dimensionless system by deploying the appropriate transformations. The local nonsimilarity (LNS) approach with MATLAB bvp4c algorithm is executed to solve the dimensionless nonlinear coupled differential system. Results demonstrate that the augmentation in Hartmann number and porosity parameter diminished the velocity profiles of the considered nanofluids. Moreover, maximum temperature profile is noticed for the lamina shaped nanoparticles. Local Nusselt number for considered cases diminishes against the augmented estimations of Richardson number, radiation parameter and nanoparticles shape factor. A comparative study between the current study and previously published results for a specific case is conducted to validate the results, and good agreement is found between them.

Identifying stir casting process parameters to maximize strength of LM13 with TiB2 and ZrC hybrid metal matrix composite

Abstract In this study, an LM13 metal-matrix composite was fabricated using two reinforcement particles (hard and soft) of titanium diboride and zirconium carbide. An experimental design was used to narrow down the trials. The significance of the model was tested using Student’s t-test and p values. The response surface statistical method was used to obtain the optimum process parameters for the high-strength hybrid metal matrix composite. From the experimental results, a maximum strength of 209 MPa was gained at a stirrer speed of 700 rpm, weight fraction of TiB2 and ZrC of 9 %, and casting temperature of 675 °C. The ANOVA results showed that TiB2 was the main influential process parameter, followed by the stirrer speed, casting temperature, and zirconium boride. The microstructure showed a fine and uniform distribution of reinforcement particles in the LM13 matrix. The fracture surface exhibited a mixed fracture pattern, which was due to the good bonding between the reinforcement and matrix at the interface.

Deposition of Ti[sbnd]Zr alloy films using Ti and Zr dual-cathode high-power impulse magnetron co-sputtering

In this study, titanium–zirconium binary alloy films were deposited using heterogeneous dual-cathode high-power impulse magnetron sputtering with a closed magnetron field. For both Ti and Zr cathodes, the discharge voltage pulses were synchronized with an equal pulse width. In addition, we investigated the effects of the average discharge power ratios of the two cathode materials, deposition pressure, and substrate bias voltage on the mechanical strength and microstructure of the deposited films. The results revealed that the film composition could be controlled by the average power ratio of the two cathodes at a constant deposition pressure; however, the deposition rate of each element varied with the deposition pressure. At a constant average power ratio at the two cathodes, the Zr content in the films decreased with decreasing the deposition pressure. Decreasing the deposition pressure can smoothen the film surface, but the dependence of the film composition on two cathode powers also changes. An adequate enhancement of the negative substrate bias can further increase the film hardness and reduce the film elastic modulus, yielding only a moderate loss in the film deposition rate and marginal variations in the film composition. However, the magnitudes of the increase in hardness and the decrease in elastic modulus brought by enhancing negative substrate bias varies with the film composition, and will be minimized when the atomic fractions of Ti and Zr are near equal. Notably, with adjusting the negative substrate bias, adding Zr can change the film hardness from 4.8 to 10.6 GPa, and the film elastic modulus from 100 to 162 GPa. Overall, the advantageous mechanical and structural properties of the TiZr alloy films deposited using HiPIMS might be useful in tools, biomedical devices, wearable equipment applications.

Desain dan Simulasi Dental Implant Resistens Menggunakan Finite Elemen Analysis

Tooth decay is a developmental disorder and trauma that causes tooth extraction. The solution is to make dental implants and dentures to restore normal contours, function, comfort, aesthetics, speech, and health. However, the problem of complications that arise is also a concern to be resolved; this occurs due to damage to the dental implant component itself. Based on these problems, it is necessary to conduct research to produce dental implants with good strength and service life by considering the value of stress and force distribution. This study discusses the differences in implant designs with different thread geometries: square, buttress, standard V-thread, and reverse buttress. This study used a static test in FEA (finite element analysis) SOLIDWORKS software using the ISO 14801 standard, using a loading of 100 N, the direction of vertical loading is 00, and using TiZr (Titanium Zirconium) material in the implant. The simulation results are validated by comparing the von Mises current study value with the existing research literature with a limit of ±5%. After the validation results are appropriate, the results are analyzed. The results of this study indicate that the buttress-type dental implant design is the most suitable dental implant to be applied. This is supported by the high value of the buttress type von Mises, which is 14.4 MPa. As for the square type, standard V-thread and reverse buttress type have a von Mises value of 13.8 MPa, 12.5 MPa, and 13.8 MPa. In addition, the profile of the buttress type is also very consistent, according to some literature, because it increases the transfer of stress to the surrounding bone according to the symmetrical profile.

The effects of diode and Er:YAG laser applications on the surface topography of titanium grade 4 and titanium zirconium discs with sand-blasted and acid-etched (SLA) surfaces

BackgroundLaser application for the treatment of peri‑implantitis provides a variety of advantages; however, depending on the laser type and parameters, it may also have adverse effects on the implant surface qualities. This study's objective is to assess the effects of laser type and parameters on the surface properties of two different titanium-based implant materials: titanium Grade 4 (Ti-Grade 4) and titanium zirconium (Ti-Zr) discs with sand-blasted and acid-etched (SLA) surfaces under in vitro conditions. Material & methodSand-blasted and acid-etched discs made of titanium grade 4 (Ti-Grade 4) and titanium zirconium (Ti-Zr) were treated using 808 nm AlGaAs (diode) and 2940 nm Er:YAG lasers with varying parameters (i.e., diode laser in continuous wave mode, Er:YAG in short pulse mode, and Er:YAG in variable square pulse mode with four different doses). Then, the surface morphology and topography of the treated discs were characterized using scanning electron microscopy and optical profilometry. ResultsThe 3D surface topographies of discs treated with a high power Er:YAG laser displayed irregular peaks and deep valleys, indicating surface deterioration. The average surface roughness values (Sa) of both discs varied with laser type and parameters (3.55–4.80 µm for Ti-Grade 4 versus 3.25–4.5 µm for Ti-Zr). With diode laser applications, the topography features of the discs were preserved despite a small number of irregular valleys and peaks. However, the surface morphologies of the discs were dramatically altered by erosion and local melting because of the Er:YAG laser treatment. ConclusionDiode laser application appears to be the most reliable method for treating peri‑implantitis, as diode laser-treated implants retained their overall surface quality despite a small number of irregular peaks and valleys.

Multi-method characterization of the recent sediment from the Dibi subsidence lake in the tropical Adamawa region (central Cameroon): Implications for the palaeoenvironmental reconstruction

The evolution and functioning of various tropical ecosystems is poorly understood due to a lack of quantitative techniques to characterize the physicochemical composition of soils and sediment. Here, a detailed multi-method study of lithological changes is provided from a core taken from the silted-up Dibi subsidence lake (central Cameroon). To unravel the provenance of sediment, mineral constituents, and organic matter sources, an array of tools are applied including a spectrophotometer, a laser particle sizer, Rock-Eval pyrolysis, X-ray diffractometer (XRD), a portable X-ray fluorescence (XRF) spectrometry, and an inductively coupled plasma-atomic emission spectroscopy (ICP-AES) instruments. The studied core consists of light-colored deposits at the base (Unit 1) overlain by dark humic deposits (Unit 2). The sediment is very well graded (grading index Sd < 0.35Ф), indicative of bottom suspended to rolling transport. Unit 1 is characterized by relatively low values of total organic carbon (TOC: 2%–5%) whereas the dark Unit 2 has high contents of TOC (10%–33%). The core shows a high oxygen index (OI) value (average = 207 mg carbon dioxide (CO2)/g TOC) and a low hydrogen index (HI) value (average = 107 mg hydrocarbon (HC)/g TOC). This indicates highly altered organic matter (OM), likely from decomposed terrestrial plants. The chlorophyll-α fingerprint (peak around 675 nm) also reveals an autochtonous primary production of organic matter. The mineralogical assemblage of Unit 2 comprises kaolinite, quartz, feldspars, montmorillonite, ilmenite, siderite, gibbsite, rutile, and anatase whereas that of Unit 1 is similar but differs with the presence of illite and the absence of gibbsite. The high titanium dioxide (TiO2) and zirconium (Zr) contents confirm that the source rocks also are comprised of granites, and gneiss without volcanic rocks, such as basalts and trachytes. The source rocks have been intensively weathered using some parameters such as ln(Al2O3/Na2O), K2O/Rb, K/Al, and weathering indices, where Al2O3 denotes aluminum oxide, Na2O denotes sodium oxide, K2O denotes potassium oxide, Rb denotes rubidium, K denotes potassium, and Al denotes aluminum. The enrichment factors (EF) of redox-sensitive trace elements and their relation with TOC, the negative values of manganese/iron ratio (Mn∗) associated to three elemental ratios (cupper/zinc (Cu/Zn), thorium/uranium (Th/U), and vanadium/chromium (V/Cr)) attest to the predominance of sub-oxic to anoxic bottom waters in Dibi lake during sediment deposition. The data also show low primary productivity at the base of the core, followed by an increase towards the top, linked to the intensification of weathering and facilitated by humid climatic conditions, usually increase terrestrial input and palaeoproductivity. The petrological data show a generally warm and humid palaeoclimate. This climatic variation has contributed to the large spread of the savannah and disappearance of the forest. This study sheds light on the late Pleistocene to Holocene palaeoenvironment evolution of the Adamawa region which could be integrated into the context of the Pleistocene to Present regional evolution of the tropical palaeoenvironment.

Selective Laser Melting and Spark Plasma Sintering: A Perspective on Functional Biomaterials.

Achieving lightweight, high-strength, and biocompatible composites is a crucial objective in the field of tissue engineering. Intricate porous metallic structures, such as lattices, scaffolds, or triply periodic minimal surfaces (TPMSs), created via the selective laser melting (SLM) technique, are utilized as load-bearing matrices for filled ceramics. The primary metal alloys in this category are titanium-based Ti6Al4V and iron-based 316L, which can have either a uniform cell or a gradient structure. Well-known ceramics used in biomaterial applications include titanium dioxide (TiO2), zirconium dioxide (ZrO2), aluminum oxide (Al2O3), hydroxyapatite (HA), wollastonite (W), and tricalcium phosphate (TCP). To fill the structures fabricated by SLM, an appropriate ceramic is employed through the spark plasma sintering (SPS) method, making them suitable for in vitro or in vivo applications following minor post-processing. The combined SLM-SPS approach offers advantages, such as rapid design and prototyping, as well as assured densification and consolidation, although challenges persist in terms of large-scale structure and molding design. The individual or combined application of SLM and SPS processes can be implemented based on the specific requirements for fabricated sample size, shape complexity, densification, and mass productivity. This flexibility is a notable advantage offered by the combined processes of SLM and SPS. The present article provides an overview of metal-ceramic composites produced through SLM-SPS techniques. Mg-W-HA demonstrates promise for load-bearing biomedical applications, while Cu-TiO2-Ag exhibits potential for virucidal activities. Moreover, a functionally graded lattice (FGL) structure, either in radial or longitudinal directions, offers enhanced advantages by allowing adjustability and control over porosity, roughness, strength, and material proportions within the composite.

Clinical Outcomes of Titanium Zirconium and Titanium Dental Implants under Immediate Functional Loading in Posterior Mandibular Region.

Studies comparing the clinical performance of titanium zirconium (Ti-Zr) and titanium (Ti) dental implants subjected to immediate loading in the posterior mandibular region where occlusal forces are higher are sparse in the current literature. Hence, the study aimed to evaluate and compare the clinical outcomes of Ti-Zr and Ti dental implants under immediate functional loading in the mandibular posterior region. Forty participants fulfilling the predetermined selection criteria were randomly grouped based on dental implant used; Titanium zirconium (Ti-Zr):20, and Titanium (Ti):20. Dental implants were placed through a standard full-thickness mucoperiosteal flap approach and loaded immediately fulfilling the principle of implant protective occlusion. Clinical parameters including crestal bone loss (CBL), modified plaque index (MPI), probing depth (PD) and modified sulcular bleeding index (MSBI) were measured at baseline and follow-up visits (4, 8, and 12 months). Obtained data were compared with standard tests such as the t-test, Chi-square test, and Mann-Whitney U test. On intergroup comparison, CBL was more in the Ti-Zr group as compared to the Ti group at 4 months (0.72 ± 0.16 mm versus 0.70 ± 0.13 mm), but it was less at 8 months (1.08 ± 0.16 mm versus 1.13 ± 0.13 mm) and 12 months (1.19 ± 0.17 mm versus 1.24 ± 0.12 mm) but the difference was not statistically significant (P > 0.05). Mann-Whitney test also revealed no statistically significant difference in MPI, PD and MSBI at 4 months, 8 months and 12 months recall (P > 0.05). CBL and periodontal parameters of Ti-Zr dental implants were found similar to Ti dental implants under immediate loading in the posterior mandibular region. However, further studies are needed to determine its long-term efficacy and cost-effectiveness.

Packed in-tube solid-phase microextraction with mesoporous zirconium titanium oxides for highly efficient phosphopeptide enrichment and analysis

Phosphorylated peptides are crucial for understanding biological regulation processes. However, the detection of phosphorylated peptides remains challenging in mass spectrometry (MS) due to their high hydration, low abundance, and the significant signal suppression caused by non-phosphorylated peptides. It is essential to enhance the efficiency of phosphopeptide enrichment from complex biological samples to achieve comprehensive analysis and identification of phosphopeptides. Herein, a packed in-tube solid-phase microextraction (IT-SPME) method was developed based on mesoporous zirconium titanium oxides for the selective enrichment and analysis of phosphopeptides. The IT-SPME system achieved the efficient capture of phosphopeptides from complex biological samples followed by high-sensitivity detection (5 fmol). This exceptional performance can be attributed to the high surface area (289.77 m2/g) of mesoporous zirconium titanium oxides, which provided abundant active sites for a high loading capacity. The zirconium titanium oxides with a mesoporous structure (∼4.5 nm) was prepared through a sol–gel and solvothermal process. Importantly, this method proved effective in enriching phosphopeptides from practical samples such as non-fat milk and egg white. It is the first attempt to employ a mesoporous packed IT-SPME approach for phosphopeptide enrichment. These results demonstrate the significant application potential of mesoporous zirconium titanium oxides in phosphoproteomics.

Taguchi optimizations on friction stir welding of nitinol alloy

The welding strength plays a vital role in all manufacturing sectors in welding proces. At the same time, advanced materials with reinforced particles offers good welding strength. The admirable weldability characteristics are attained by friction stir welding process (FSW). Cubic Boron Nitride - CBN, Titanium Zirconium Molybdenum - TZM acts as a tool material in FSW process which gives good welding strength when compared to other tool material. Silicon carbide based nitinol composite is manufactured by stir casting route which provides admirable substance properties. Scanning Electron Microscope (SEM) was used to analyze the material characteristics. The welding strength obtained from two tool materials were compared. The optimal strength of the joint is attained by Taguchi optimization. The objective of the research work is to increase the welding strength using TZM tool. Optimal strength of welding was obtained at rotational speed of tool: 1499.9 rpm, speed of welding at 49.9 mm/min, feed: 9.9 mm/min.

Biofilm formation on metal alloys and coatings, zirconia, and hydroxyapatite as implant materials in vivo.

Composition of implant material and its surface structure is decisive for oral biofilm accumulation. This study investigated biofilm formation on eight different materials. Eighteen healthy subjects wore intraoral splints fitted with two sets of eight materials for 24 h: zirconia [ZrO2 ]; silver-gold-palladium [AgAuPd]; titanium zirconium [TiZr]; Pagalinor [PA]; hydroxyapatite [HA]; silver-platinum [AgPt]; titanium aluminum niobium [TAN]; titanium grade4 [TiGr4]. Total biomass was stained by safranin to assess plaque accumulation while conventional culturing (CFU) was conducted to investigate viable parts of the biofilm. Cell viability of human gingival fibroblasts (HGF-1) was assessed in vitro. Statistical evaluation was performed with linear mixed-effects models to compare materials (geometric mean ratios, 95% CI), with the level of significance set at ɑ = .05. Less biofilm mass and CFU were found on noble metal alloys (AgPt, AgAuPd, and PA). Compared to AgPt, PA had 2.7-times higher biofilm mass value, AgAuPd was 3.9-times, TiGr4 was 4.1-times, TiZr was 5.9-times, TAN was 7.7-times, HA was 7.8-times, and ZrO2 was 9.1-times higher (each p < .001). Similarly, CFU data were significantly lower on AgPt, AgAuPd had 4.1-times higher CFU values, PA was 8.9-times, TiGr4 was 11.2-times, HA was 12.5-times, TiZr was 13.3-times, TAN was 16.9-times, and ZrO2 was 18.5-times higher (each p < .001). HGF-1 viability varied between 47 ± 24.5% (HA) and 94.4 ± 24.6% (PA). Noble alloys are considered as beneficial materials for the transmucosal part of oral implants, as less biofilm mass, lower bacterial counts, and greater cell viability were detected than on titanium- or zirconia-based materials.

Optimization of microreactor-assisted transesterification for biodiesel production using bimetal zirconium-titanium oxide doped magnetic graphene oxide heterogeneous nanocatalyst

The application of novel heterogeneous catalyst materials with unique physicochemical properties for the production of biodiesel can increase the sustainability of the process. In this study, a novel heterogeneous nanocatalyst (NCT) was developed and improved using a microreactor for biodiesel production from used cooking oil (UCO). The NCT was developed based on double-layered bimetal titanium-zirconium oxide nanoparticles (NPs) incorporated over magnetic graphene oxide (ZrO2-TiO2@MGO) using a simple hydrothermal method. The physiochemical morphology of newly developed NCT materials of ZrO2-TiO2 NPs and ZrO2-TiO2@MGO was investigated using FESEM, FTIR, VSM, XRD, and EDX. The effects of several independent variables, including residence duration (60–180 s), oil/methanol molar ratio (1–3), and catalyst concentration (1–5 wt.%) on biodiesel production yield were optimized. The optimum reaction conditions in the microreactor-intensified transesterification process were the ZrO2-TiO2@MGO concentration of 4.75 wt.% (oil-based), reaction duration of 180 s, and oil/ methanol ratio of 2.33. The designed microreactor-assisted ZrO2-TiO2@MGO provided a conversion rate of 99.32%. Consequently, the results revealed that the microreactor effectively shortens the transesterification time while producing a high rate of biodiesel.

The effect of secondary phase on corrosion behaviors of the titanium–zirconium–molybdenum alloy

The effect of secondary phase on corrosion behaviors of the titanium–zirconium–molybdenum alloy

Effect of Ti[sbnd]Cr filler on microstructure, mechanical properties, and thermal shock resistance of TZM/graphite brazed joints

The objective of this work was to braze titanium zirconium molybdenum(TZM) alloy and graphite with Ti40Cr filler in order to explore its practical application on computed tomography tube target. The brazed joints' microstructure, mechanical properties, and thermal shock properties were characterized by X-ray diffraction, scanning electron microscopy, and a 3D laser confocal measuring microscope. The results indicated that the interface microstructure of TZM/graphite brazed joints was graphite/Cr3C2/TiC/Ti-Cr(Mo)/Ti-Mo(Cr)/TZM, and the thickness of the brazing seam increases with increasing temperature. In contrast, the thickness of the carbide reaction layer near the graphite side gradually becomes thicker. The shear tests showed that the joint's strength increased with the temperature increase in a specific temperature range. Maximum shear strength of 26.5 MPa was reached when the joint with groove structure brazed at 1480 °C. The effect of holding time on the joints was similar to that of temperature, but the thickness of the carbide reaction layer did not change with holding time. The optimal brazing process for TZM/Ti-40Cr/graphite brazed joints was to hold for 20 min at 1480 °C. TZM/Ti-40Cr/graphite brazed joints were subjected to a laser thermal shock test. The results indicated that TZM/Ti-40Cr/ graphite brazed joints would not cause serious damage when subjected to 20A laser beam current. When the current rose to 40A, the joints will be broken down by the laser, and the damage depth reached −254.824 μm.

Shortening synthesis process of zirconium hydroxide as a hydrolysis product of sodium zirconate

This research was focusing on shortening the process of Zirconium hydroxide (Zr(OH)&lt;sub&gt;4&lt;/sub&gt;) synthesis to get a more efficient process. In the earlier method, Zr(OH)&lt;sub&gt;4&lt;/sub&gt; was produced through ZOC, which was the product of Na&lt;sub&gt;2&lt;/sub&gt;ZrO&lt;sub&gt;3&lt;/sub&gt; reacted with HCl. While this study offers a new method to synthesize Zr(OH)&lt;sub&gt;4&lt;/sub&gt; through the hydrolysis process of sodium zirconate (Na&lt;sub&gt;2&lt;/sub&gt;ZrO&lt;sub&gt;3&lt;/sub&gt;), removing the leaching step of Na&lt;sub&gt;2&lt;/sub&gt;ZrO&lt;sub&gt;3&lt;/sub&gt; with HCl. The hydrolysis process of Na&lt;sub&gt;2&lt;/sub&gt;ZrO&lt;sub&gt;3&lt;/sub&gt; was carried out in a multistage stirred reactor at 70 °C. The multistage hydrolysis process occurred in 13 stages with 4000 grams of feed and 890 liters of water. This process produced 2500 grams of Zr(OH)&lt;sub&gt;4&lt;/sub&gt;. Then the impurities analysis was done using UV-Vis and atomic absorption spectroscopy (SAA). The UV-Vis analysis was done to analyze Si concentration, while the atomic absorption spectroscopy (SAA) was done to analyze Na concentration. Si and Na concentrations could decrease to 23.98 µg/ml and 1.05 µg/ml, respectively. The Zr(OH)&lt;sub&gt;4&lt;/sub&gt; contained in the residue was characterized using X-Ray Diffractometer (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Then, the calcination process of Zr(OH)&lt;sub&gt;4&lt;/sub&gt; was done at 300 °C and 400 °C for 1 hour, and characterized using XRD. The XRD result shows crystals of zirconium titanium oxide or srilankite, and SiO&lt;sub&gt;2&lt;/sub&gt; crystals that are separated from ZrO&lt;sub&gt;2&lt;/sub&gt; or TiO&lt;sub&gt;2&lt;/sub&gt; crystals. Surface analysis was done using Scanning Electron Microscope – Energy Dispersive X-Ray (SEM-EDX), the result shows that the hydrolysis process at the 3&lt;sup&gt;rd&lt;/sup&gt;, 7&lt;sup&gt;th&lt;/sup&gt;, and 13&lt;sup&gt;th&lt;/sup&gt; stages have different amorphous crystals with bright colors. At the 13th hydrolysis stage, Zr concentration increased to 63.38%, and Si concentration decreased. Thus, the shorter process of Zr(OH)&lt;sub&gt;4&lt;/sub&gt; synthesis has been done successfully.

Atomically dispersed copper sites on titanium zirconium oxide accelerate the simultaneous oxidative removal of organic carbon and ammonia from landfill leachate

Landfill leachate is a refractory wastewater. Low-temperature catalytic air oxidation (LTCAO) has shown considerable potential for leachate treatment owing to its green and simple operation, but the simultaneous removal of chemical oxygen demand (COD) and ammonia from leachate remains challenging. Herein, TiZrO4 @CuSA hollow spheres with high-loading single-atom Cu were synthesized using isovolumic vacuum impregnation and co-calcination methods, and the catalyst was applied to the LTCAO treatment of real leachate. Consequently, the removal rate of UV254 reached 66% at 90 °C within 5 h, while that for COD was 88%. Simultaneously, the NH3/NH4+ (33.5 mg/L, 100 wt%) in the leachate was oxidized to N2 (88.2 wt%), NO2--N (11.0 wt%), and NO3--N (0.3 wt%) owing to the effect of free radicals. The single-atom Cu co-catalyst in TiZrO4 @CuSA exhibited a localized surface plasmon resonance effect at the active center, which could quickly transfer electrons to O2 in water to form O2.− with a high activation efficiency. The degradation products were determined and the deduced pathway was as follows: the bonds joining benzene rings were first broken, and then the ring structure was further opened to produce acetic acid and other simple organic macromolecules, which were finally mineralized to CO2 and H2O.