Biodegradable Mg–Ca–Sr alloys are promising candidates for temporary implant applications, but their degradation behavior is strongly influenced by alloy composition and electrolyte chemistry. This comparative short-term study investigated how increasing the Sr content from 0.5 to 1.5 wt.% influences the electrochemical response and surface characteristics of cast Mg–0.5Ca–xSr alloys in 0.9% NaCl and calcium- and magnesium-free Dulbecco’s phosphate-buffered saline (DPBS). Potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy, quantitative image analysis, and energy-dispersive X-ray spectroscopy were used. Increasing the Sr content reduced the corrosion-current density from 0.0110 to 0.0039 mA/cm2 in NaCl and from 0.297 to 0.169 mA/cm2 in DPBS, while the corresponding calculated corrosion rates decreased from 2.51 to 0.886 mm/year and from 6.66 to 3.79 mm/year, respectively. Replicated EIS measurements of both alloys showed that Mg–0.5Ca–1.5Sr exhibited higher charge-transfer resistance than Mg–0.5Ca–0.5Sr in both NaCl (253 ± 15 versus 184 ± 14 Ω·cm2) and DPBS (853 ± 48 versus 615 ± 42 Ω·cm2). NaCl-exposed surfaces showed more porous and discontinuous deposits and a greater number of visible pit-like defects, whereas DPBS produced comparatively continuous P-containing deposits. Overall, increasing the Sr content to 1.5 wt.% was associated with lower polarization-derived global corrosion kinetics and a more resistive interfacial response, whereas electrolyte composition strongly influenced both interfacial impedance and surface-deposit morphology. These findings represent comparative short-term electrochemical and surface-characterization data obtained at 23 ± 1 °C and should not be interpreted as measures of long-term physiological degradation or in vivo performance.
La efectuarea lucrărilor din cadrul tehnologiilor moderne de cultivare a culturilor agricole pe larg se folosesc grapele cu discuri. Coroziunea componentelor utilajelor agricole cauzată de umiditate, sol și resturi vegetale accelerează uzura și reduce durata de viață a organelor de lucru de la interacțiunea discurilor cu solul. În lucrare sunt prezentate investigații privind rezistența la coroziune a discurilor cu și fără acoperi termice în jet de plasmă aplicate pe suprafețele de lucru a acestora în funcție de mediul de interacțiune și compoziția solului. Eficacitatea anticorozivă a trei sisteme de acoperire investigate a fost evaluată cantitativ prin analiza curbelor de polarizare potențiodinamică, obținând parametrii electrochimici extrași prin extrapolarea pantelor Tafel. Studiul micrografiilor pentru proba Initial (substratul martor) relevă un atac coroziv sever, caracterizat prin formarea unor produse de coroziune cu o morfologie neregulată și extrem de poroasă. Toate acoperirile investigate au îmbunătățit rezistența la coroziune a substratului, însă acoperirea P2 (Metco 136F) a demonstrat cea mai înaltă performanță, reducând viteza de coroziune de la 339,77 µm/an până la 41,07 µm/an comparativ cu oțelul Inițial fără acoperire, ceea ce reprezentă o scădere de peste 8 ori a vitezei de coroziune.
Cr2O3-based ceramic coatings are widely used in wear-critical applications; however, their tribological performance under dry sliding conditions can be limited by brittleness and frictional instability. In heavy-duty vehicles, the king pin–bushing contact operates under severe dry sliding conditions, motivating the investigation of composite Cr2O3–nTiO2 coatings as a potential surface engineering solution. In this study, Cr2O3–TiO2 coatings containing 0, 10, 20, 30, and 40 wt% TiO2 were deposited by atmospheric plasma spraying (APS) from mechanically mixed powders. Phase composition was analyzed by X-ray diffraction using an X’Pert PRO MRD diffractometer, while microstructure and elemental distribution were examined by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) on a FEG Quattro C microscope. Mechanical properties were evaluated by Vickers microhardness, instrumented indentation and scratch testing, while dry sliding wear behavior was assessed by pin-on-disc tests performed on a CETR UMT-2 tribometer against a bronze counterbody, with continuous monitoring of the coefficient of friction (COF). The results show that plasma spraying produces lamellar composite coatings with intrinsic porosity and locally modified phase composition. Cr2O3-rich coatings exhibit higher hardness (1198 HV2 compared with 877 HV2 for Cr2O3–40TiO2 corresponding to an increase of approximately 36%) and improved resistance to indentation, reflected by lower penetration depths and higher elastic modulus values (134 GPa for S0 compared with 77 GPa for S2). These coatings also exhibit a more stable friction response and reduced material transfer from the bronze counterbody, as confirmed by the lower mass loss of the pins (0.0295 g for S0 compared with 0.0473 g for S4, corresponding to a reduction of about 38%). Increasing TiO2 content leads to changes in friction stability and wear behavior associated with microstructural heterogeneity. These findings indicate that the sliding wear performance of Cr2O3–nTiO2 coatings is governed by elastic–plastic stability under localized contact loading and support their applicability for dry sliding king pin–bushing systems in heavy-duty vehicles.
Atmospheric plasma spraying (APS) represents a critical solution for enhancing the durability of agricultural components, such as harrow discs, which are subjected to synergistic wear and corrosion during soil cultivation. This study presents experimental results evaluating the electrochemical corrosion behavior and thermal shock resistance of discs coated via atmospheric plasma thermal spraying. Both metallic and ceramic materials, in powder form, from established manufacturers were used to produce the coatings, and the three types of coatings (two metallic and one ceramic) have the following chemical compositions and trade names: W2C/WC12Co (Metco71NS), Cr2O3-4SiO2-3TiO (Metco136F) and Co25.5Cr10.5Ni7.5W0.5C (Metco45C-NS). The coatings were analyzed using electron microscopy to evaluate the surfaces following corrosion testing. The ceramic coating based on the Cr2O3-4SiO2-3TiO demonstrated the highest protective efficiency by increasing the charge transfer resistance from 307 ohm/cm2 to 2213 ohm/cm2 for the ceramic coating. It provided a superior physical barrier, reducing the corrosion current density from 0.140 mA/cm2 for unprotected substrate to 0.004 mA/cm2, representing an improvement of nearly two orders of magnitude. These findings demonstrate that implementing Cr2O3-4SiO2-3TiO ceramic systems can significantly extend the operational lifespan of soil-engaging components, providing a cost-effective strategy for reducing maintenance intervals and material loss in aggressive agricultural environments.
Magnesium alloys are considered to be the third generation of biomaterials used in biomedical applications to promote bone tissue regeneration. Due to their Young’s modulus being similar to that of human bone and their release of magnesium ions that are antimicrobial and osteoinductive, these biomaterials not only promote bone regeneration, minimize the effects of stress shielding and reduce the risk of infection, but also their exceptional biocompatibility and bioresorbability eliminate the need for a second surgery to remove the implant. However, because magnesium has poor corrosion resistance, without different coatings and surface treatments, the implant can be compromised before the bone is fully healed. With additive manufacturing (AM) as a revolutionary technology, the one-size-fits-all approach can be replaced by fully personalized medicine, in which complex shapes can be created, designed, and processed with unique parameters for each patient. However, 3D printing of Mg-based devices remains particularly challenging due to magnesium’s high chemical reactivity, combustion risk, and low vaporization temperature, challenges that are further compounded when alloying elements are introduced. This review addresses this gap by critically examining the properties, corrosion behavior, and bio-medical performance of Mg and its alloys, with a focused analysis of selective laser melting (SLM) and wire arc additive manufacturing (WAAM) as key fabrication methods. The influence of processing parameters, microstructural defects, and alloy composition on the final properties of AM-fabricated Mg components is systematically discussed, alongside current limitations and prospective strategies toward their clinical translation.
This article presents an in-depth analysis of the application of thermal deposition techniques, in particular thermal spraying, to improve the properties of materials used in agricultural components that work the soil, such as agricultural plows (mainshare and foreshare). Due to the difficult operating conditions, characterized by abrasive wear, mechanical shocks, and chemical exposure from various soils, these surface coatings aim to increase the durability and corrosion resistance of the materials of components intended for working with the soil. The study investigates thermal deposition methods and their effects on the microstructure, hardness, and friction resistance of the obtained layers. The study highlights experiments that reveal significant improvements in mechanical properties, highlighting superior behavior in real conditions of agricultural use. Nevertheless, soil types significantly influence the abrasive wear rate of the components and also their corrosion, which depends on the soil pH. The results confirm that the use of thermal deposition represents a sustainable and effective solution for extending the life of plows, thus reducing maintenance costs and increasing the efficiency of agricultural processes. This research contributes to the optimization of agricultural equipment, providing an innovative approach for adapting plows to the increasing demands of agricultural exploitation.
Low-emissivity (low-E) coatings are among the most effective thin-film technologies for reducing radiative heat losses and controlling solar heat gain in buildings, which account for approximately 30–40% of global primary energy consumption. This expanded review follows the technological evolution of low-E glazing from early transparent-conductor “heat mirrors” to modern multi-silver dielectric/metal/dielectric (D/M/D) architectures and emerging functional coatings. Four complementary perspectives are addressed: (i) the materials employed, from silver-based multilayers and transparent conducting oxides (ITO, FTO, AZO, GZO) to seed, blocker, and protective dielectric layers; (ii) the deposition systems, contrasting on-line pyrolytic/CVD “hard” coatings with off-line magnetron-sputtered “soft” coatings, together with ALD, sol–gel, and evaporation routes; (iii) the methods of analysis used to correlate microstructure, composition. and interfaces with optical, electrical, and thermal behaviour (XRD, XRR, SEM/TEM, AFM, XPS, SIMS, spectrophotometry, ellipsometry, emissivity, and U-value metrology according to EN 410/EN 673 and ISO 9050); and (iv) the functional performance of low-E stacks in insulating glass units, vacuum glazing, retrofit films, and smart-window systems across climate zones. Persistent research gaps are identified in long-term durability and ageing, indium-free scalable materials, standardized accelerated testing, and multi-objective design of thinner, more selective, and more robust stacks.
This paper presents experimental investigations carried out on components belonging to agricultural plough assemblies, which undergo significant mechanical loading during soil tillage operations. Due to severe operating conditions, ploughs are subjected to abrasive wear and impact stresses, so that enhancing these properties translates into improved performance, accompanied by a lower failure rate and, consequently, reduced downtime in agricultural activity. In order to upgrade the material properties of the active parts that come into direct and sustained contact with the soil—and which are therefore most vulnerable to degradation—surface thermal coatings were applied by means of Atmospheric Plasma Spray (APS) deposition, with the aim of extending service performance and component lifespan. The mechanical properties of the deposited coatings were assessed through hardness testing (approx. 204 HV) and microscratch behaviour evaluation (COF > 1). In addition, microstructural examinations were conducted using scanning electron microscopy to characterise the surface condition following the thermal deposition process. The findings confirm that thermal coatings represent a viable technical solution, enabling not only the improvement of plough component properties, but also the possibility of reconditioning worn parts by compensating, through thermal deposition, for the material loss caused by soil-induced wear during field operation.
Background: Biodegradable magnesium-based alloys are increasingly explored as emerging biomaterials for dental and maxillofacial applications due to their osteoconductive properties and potential to reduce long-term implant-related complications. However, early-stage evaluation requires predictive diagnostic screening methods capable of assessing cytocompatibility and cellular response under clinically relevant extract conditions. Objectives: In this study, Mg-0.5Ca alloys modified with increasing strontium concentrations (0.5-3 wt.%) were investigated through an in vitro diagnostic framework using MG-63 osteoblast-like cells. Methods: Cell viability was quantitatively assessed via MTT assays after 24 and 72 h of exposure, while fluorescence-based live-cell imaging provided complementary morphological insights. Results: demonstrated a composition-associated cytocompatibility profile, with Sr-enriched compositions showing improved cellular metabolic activity and adhesion patterns compared to lower-Sr compositions. Conclusions: These findings support the role of strontium as a functional alloying element and highlight the importance of standardized diagnostic screening workflows for emerging dental biomaterials. Overall, this study proposes a simplified predictive platform for early biocompatibility diagnostics, contributing to the integration of biomaterial evaluation into future digitalized dental regeneration workflows.
The wear performance of coated and uncoated harrow discs was evaluated under real agricultural field conditions in order to assess the long-term effectiveness of three atmospheric plasma spraying (APS) systems: a Cr2O3–SiO2–TiO2 ceramic coating, a WC/W2C–Co carbide coating, and a Co–Cr–Ni–W–C alloy coating. In contrast to most previous studies focused on laboratory testing or short-term trials, the present work provides a comparative long-term field evaluation over 50 ha per disc (1000 ha total) under identical operating conditions in quartz-rich Argic Luvisol soil. Disc wear was quantified through periodic mass-loss and diameter measurements, complemented by microstructural and SEM analyses. The uncoated disc exhibited the most severe degradation, with a total mass loss of approximately 700 g and rapid acceleration of wear after the first 5–10 ha. The ceramic-coated disc showed the highest durability, limiting mass loss to approximately 390 g, corresponding to a reduction of about 44%, and maintaining the largest residual diameter after field operation. The Co-based alloy provided intermediate performance (~16% mass-loss reduction), while the carbide coating showed limited improvement (~7% reduction) due to microcracking and weak carbide–binder interfaces. The results demonstrate that, under real field conditions, coating microstructural integrity is more critical than nominal hardness, and highlight the superior effectiveness of ceramic APS coatings for extending disc service life in abrasive agricultural soils.
Background/Objectives: Dental caries remains one of the most prevalent chronic diseases worldwide, making enamel remineralization a key objective in minimally invasive dentistry. This in vitro study compared the remineralization efficacy of five therapeutic toothpastes containing fluoride, NovaMin, CPP-ACP, nano-hydroxyapatite, arginine, and xylitol. Methods: Sixty enamel specimens were prepared from extracted human posterior teeth and artificially demineralized. Samples were randomly allocated into six groups (n = 10): one negative control (C1) stored in artificial saliva and five treatment groups (P1–P5). A 28-day remineralization protocol with twice-daily applications was performed. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to assess surface morphology and elemental composition (Ca, P, F, Na, O, Ca/P ratio) at days 1, 14, and 28. Vickers microhardness testing was used to evaluate changes in mechanical properties. Statistical analysis included one-way ANOVA, repeated measures ANOVA, Tukey’s post hoc test, and Kruskal–Wallis where appropriate (α = 0.05). Results: All therapeutic toothpastes produced some increase in mineral content compared to the demineralized control. At day 28, significant intergroup differences were observed for calcium, phosphorus, and fluoride (p < 0.001). The arginine–fluoride formulation (P4) and the NovaMin-based formulation (P3) showed the most consistent increases in Ca and P, with SEM revealing the formation of a continuous, compact surface layer and marked reduction in prismatic porosities. Fluoride-containing toothpastes (P1, P3, P4) showed significant fluoride incorporation (p < 0.001 vs. control). The nano-hydroxyapatite/xylitol prototype (P5) produced a delayed but progressive increase in Ca and P, with partial filling of prismatic spaces. The CPP-ACP-based toothpaste (P2) led to limited changes, with only slight differences vs. control at day 28. Vickers microhardness values increased significantly in groups P1, P3, P4, and P5 (p < 0.05), in agreement with the higher mineral levels found in these samples. Conclusions: Under the present in vitro conditions, toothpastes containing fluoride in combination with NovaMin or arginine, as well as nano-hydroxyapatite/xylitol, demonstrated the highest remineralization potential under the present in vitro conditions, both chemically and mechanically. Xylitol-based formulations without a direct mineral supply showed limited effects. The pH and active composition of the toothpaste strongly influenced enamel remineralization outcomes.
The present work develops an explicit dynamic finite element model of soil–disc interaction for a notched harrow disc, aiming to quantify how APS coatings, soil type and disc–soil friction influence stresses in the disc and surrounding soil. The model reproduces a four-gang offset harrow operating at 7 km/h, 0.15 m working depth, with 18°disc angle and 15° tilt angle, and compares an uncoated steel disc with three APS-coated variants (P1 Metco 71NS, P2 Metco 136F, P3 Metco 45C-NS). Mechanical properties of the substrate and coatings are obtained from micro-indentation tests and introduced via a bilinear steel model and Johnson–Cook plasticity for the coatings, while disc–soil friction coefficients are calibrated from microscratch measurements. Soil behaviour is described using the AUTODYN Granular model for four representative agricultural soils, spanning sandy loam to saturated heavy clay. Results show that the uncoated disc develops von Mises stresses in the disc–soil contact region of ≈150–220 MPa, with intermediate-stiffness soils being most critical. APS coatings significantly alter both the level and distribution of stresses: P2, the stiffest ceramic, yields the highest stresses (≈421–448 MPa), P1 keeps stresses near the baseline while shielding the substrate through extended plastic zones, and P3 provides an intermediate, more uniformly distributed stress regime. Increasing disc–soil friction systematically amplifies von Mises stresses in the contact region, especially for P2. Overall, the calibrated explicit model captures the coupled influence of soil properties, coating stiffness and friction, and indicates that P1 is better suited for light-to-medium soils, P3 offers the most balanced response in medium-to-stiff soils, whereas P2 should be reserved for highly abrasive conditions and used with caution in cohesive soils.
Due to the high number of traumas and the increase in patients with osteoporosis/arthrosis, the biomaterials and implants market is growing rapidly. Consequently, bioactive phosphate coatings utilizing zinc and non-toxic metal ions have garnered increased interest in the surface modification of metallic implants. The primary focus remains on enhancing the body's biological response or reducing the adverse effects on the human body. Herein, two novel composite coatings based on Mg-Zn phosphate and Zr-Zn phosphate, respectively, have been developed on the surface of Ti6Al4V via the phosphate chemical conversion process. The effect of Mg and Zr ions on the morphology and the characteristics of the phosphate layers deposited on the Ti alloy substrate were analyzed. Studying the morphology of the layers, it was observed that the Zr ions promote the formation of a more compact structure while Mg ions will mainly create structures with acicular crystals and visible intercrystalline zones. The XRD results confirmed that both coatings contain hopeite (Zn3(PO4)2 center dot 4H2O) and phosphophyllite (Zn2Fe(PO4)2 center dot 4H2O) phases. Additionally, each coating includes phases specific to the metal ions added in each solution. In the coating with Mg addition, the specific phase identified are MgZn2(PO4)2 and reaphookhillite (MgZn2(PO4)2 center dot 4H2O). In contrast, the coating with Zr addition contains phases such as (ZnZr (PO4)2 center dot 2H2O, Zr(HPO4)2, (ZrP2O7). The results show that the coatings obtained with Zr-Zn compounds exhibited up to 9 times higher corrosion resistance in both Ringer and Dulbecco solutions. In addition, wettability tests demonstrated favorable cellular adhesion, while vitro cytotoxicity tests showed increased viability in the case of mouse fibroblasts L929 cells. Overall, this study elucidates the Zr and Mg ions-induced effects on the morphology and properties of the Zn-based phosphate coatings, promoting increased corrosion resistance and cell viability.
This study explores the adsorption and catalytic degradation of 2,4,6-trinitrotoluene (TNT) from aqueous solutions, using montmorillonite-based catalysts. Commercially, montmorillonite K10 was modified through aluminum pillaring (K10-Al-PILC), followed by vanadium intercalation (K10-Al-PILC-V) and ozone activation. A novel aspect of this work is the use of naturally contaminated water as the TNT source. The selected sample, collected from the Plaiul Arșiței–Cireșu–Leșunț region (Oituz, Bacau, Romania), originated from an area historically exposed to explosive residues, where TNT traces were previously identified. The adsorption performance of the materials was evaluated by varying adsorbent dosage, contact time, and solution pH. Catalytic ozonation experiments were conducted under different catalyst masses, ozone concentrations, and reaction times to assess degradation efficiency. The results demonstrated that aluminum pillaring significantly enhanced the adsorption capacity of the clay, while vanadium incorporation further improved both adsorption and catalytic activity. The vanadium-modified material exhibited superior performance in TNT removal, both through adsorption and oxidative degradation. Additionally, the catalytic ozonation process led to the formation of degradation products with reduced toxicity, confirming the potential of these materials for environmental remediation of nitroaromatic pollutants in real water systems.
The research of biomaterials is an area of significant interest in the biomedical field, and the present study investigates how the strontium (Sr) concentration influences the microstructure, corrosion resistance, and both in vitro and in vivo behavior of alloys in the ternary Mg-Ca-Sr system. Using an induction furnace with a controlled atmosphere (argon as the shielding gas), Mg-0.5Ca-xSr alloys (x = 0.5; 1; 1.5; 2; 3 at.%) were synthesized. Microstructural analyses, performed using optical microscopy and scanning electron microscopy (SEM), revealed a uniform and refined structure. Corrosion behavior assessments, carried out using linear and cyclic potentiometry, demonstrated favorable corrosion resistance for all samples. However, for the system containing 0.5% Sr, the corrosion rate values were lower compared to the other systems, and this alloy also exhibited the lowest corrosion current density. Cytocompatibility assay indicated the cytocompatible behavior of all the studied alloys, with favorable influence on cell viability and a stimulatory effect on the osteoblastic cell proliferation. In vivo biocompatibility assessments of the alloys showed that, for alloys containing 0.5% and 1% Sr, a more rapid degradation occurred in comparison with the other alloys (1.5, 2 and 3% Sr), which still persisted at the tissue level even after 12 weeks post-implantation. In all the batches examined, the inflammatory reaction was directly proportional and persistent in relation to the presence of the material in the tissue. In regions where the material was resorbed/degraded, the local inflammatory response was reduced or absent, and the fibrous tissue was denser and better organized. The field of biomaterials is in continuous development, and this study highlighted the applicability of these five alloy systems for dental and maxillofacial applications such as implants, plates, and related devices.
Background and Objectives: Magnesium (Mg)-based materials, such as the WE43 alloy, show potential in biomedical applications owing to their advantageous mechanical properties and biodegradability; however, their quick corrosion rate and hydrogen release restrict their general clinical utilization. This study aimed to develop a novel Mg-Zn-Ca alloy system based on WE43 alloy, evaluating the influence of Zn and Ca additions on microstructure, mechanical properties, cytocompatibility, and electrochemical behavior for potential use in biodegradable orthopedic applications. Materials and Methods: The WE43-Zn-Ca alloy system was developed by alloying standard WE43 (Mg–Y–Zr–RE) with 1.5% Zn and Ca concentrations of 0.2% (WE43_0.2Ca alloy) and 0.3% (WE43_0.3Ca alloy). Microstructural analysis was performed utilizing scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDS), while the chemical composition was validated through optical emission spectroscopy and X-ray diffraction (XRD). Mechanical properties were assessed through tribological tests. Electrochemical corrosion behavior was evaluated using potentiodynamic polarization in a 3.5% NaCl solution. Cytocompatibility was assessed in vitro on MG63 cells using cell viability assays (MTT). Results: Alloys WE43_0.2Ca and WE43_0.3Ca exhibited refined, homogeneous microstructures with grain sizes between 70 and 100 µm, without significant structural defects. Mechanical testing indicated reduced stiffness and an elastic modulus similar to human bone (19.2–20.3 GPa), lowering the risk of stress shielding. Cytocompatibility tests confirmed non-cytotoxic behavior for alloys WE43_0.2Ca and WE43_0.3Ca, with increased cell viability and unaffected cellular morphology. Conclusions: The study validates the potential of Mg-Zn-Ca alloys (especially WE43_0.3Ca) as biodegradable biomaterials for orthopedic implants due to their favorable combination of mechanical properties, corrosion resistance, and cytocompatibility. The optimization of these alloys contributed to obtaining an improved microstructure with a reduced degradation rate and a non-cytotoxic in vitro outcome, which supports efficient bone tissue regeneration and its integration into the body for complex biomedical applications.
By decreasing manufacturing costs for different civic purposes, glass recycling is an economically significant technology that also helps conserve natural resources and mitigates environmental problems. Throughout the recycling process, this study used recycled domestic glass in compliance with European guidelines for recycling of household garbage. The purpose of this research is to examine the chemical and mechanical properties of recycled and crushed glass with particle sizes varying from 0.1 mm to 2 mm as a function of various treatment temperatures. This might pave the way for novel building materials, artwork, and interior design components, among other potential uses. “Silica glass,” the most common and ancient kind of glass, which includes SiOₖ, NaₖO, CaO, and small amounts of other elements, was utilized in the investigation. Several materials can be successfully modified or altered using step heat treatment. The mechanical and chemical properties of recycled and shattered glass were assessed using microhardness, compressive, and chemical testing. These samples were then compared to mosaics from Murano, Italy, and Dynasty Smalti, China. The recycled and heat-treated glass produced microhardness values of 550.6 HV and 555.0 HV, respectively, when tested with forces of 0.981 N and 2.942 N. These values were higher than those of Murano (Italy) and were comparable to those of Dynasty Smalti mosaic (China). Furthermore, compression testing demonstrated that tempered and heat-tempered glass, which might include up to 5 g of TiO2, could endure compressive strains of up to 16 MPa. This is in sharp contrast to Dynasty Smalti, which could only withstand tensions of 6–8 MPa, and Murano, which could only withstand stresses of 3–4 MPa. Tests conducted chemically over a seven-day period using KOH at 30 g/L and 100 g/L, along with HCl at 3% and 18%, showed that the samples did not alter in any way; their surface, color, and weight were untouched. Crushing and heating recycled glass makes it a viable alternative to using new glass in civil engineering projects. This helps make material reuse more efficient, which in turn helps the environment. Sturdy and resilient in a variety of contexts, the material shares mechanical and chemical properties with standard mosaics.
Background: This study examined how the concentration of calcium (Ca) influences the microstructure, mechanical characteristics, and tribological attributes of Mg–Ca–Zn–RE–Zr alloys for orthopedic medicine. Materials and methods: Experimental alloys with 0.1 and 0.5 wt% Ca were prepared in a controlled atmosphere induction furnace. The microstructure of the alloys was investigated by scanning electron microscopy, the chemical composition by X-ray fluorescence and energy-dispersive spectroscopy, the mechanical properties by indentation and scratching, and the corrosion resistance by linear and cyclic potentiometry. Results: The alloy with 0.1% Ca exhibited greater fluctuations in the coefficient of friction, while the sample with 0.5% Ca showed a higher susceptibility to cracking. Regarding corrosion resistance, both samples exhibited a generalized corrosion trend with similar corrosion currents. At lower Ca concentrations (0.1%), the refined microstructure of the alloys provided an elastic modulus closer to that of human bone, minimizing the risk of excessive local stress and promoting uniform load distribution at the bone-implant interface. Conclusion: The 0.5% Ca alloy offered superior tribological stability and better shock absorption, making it suitable for applications requiring long-term stability. The study highlighted the potential of both compositions based on the specific requirements of biodegradable orthopedic implants.
This paper presents the characterization of ceramic thermal barrier coatings (TBCs) obtained by atmospheric plasma spraying (APS), focusing on their functional, structural, and chemical performance under extreme thermal conditions. The study highlights the critical requirements of TBC systems, including low thermal conductivity, high phase stability above 1200 °C, resistance to thermal shock, and strong adhesion between the ceramic top coat, bond coat, and metallic substrate. Special attention is given to YSZ (zirconia stabilized with yttria) coatings with a high yttria content (38 wt% Y₂O₃), which ensure cubic phase stabilization and enhanced durability at elevated temperatures. Recent advances in TBC design are discussed, such as optimized ceramic compositions, controlled microstructures, and multifunctional architectures that integrate chemical protection and sensing capabilities. The advantages of ceramic TBCs compared to massive or non-ceramic barriers are also outlined, emphasizing their reduced weight, improved thermal insulation, chemical stability, and thermomechanical compatibility. These results confirm the potential of advanced YSZ-based coatings to provide reliable thermal protection in aerospace and energy applications, contributing to increased efficiency and reduced environmental impact.
This paper presents a comprehensive analysis of recent advancements in the application of thermal spraying techniques to enhance the durability and wear resistance of agricultural machinery components, with a particular focus on disc harrow assemblies. Given the harsh conditions under which tillage tools operate—characterized by abrasive wear, impact stresses, and chemical exposure from various soil types—thermal sprayed coatings have emerged as a viable solution to extend the service life of these components. The study discusses various deposition methods, particularly Atmospheric Plasma Spraying (APS), and evaluates their effectiveness in creating high-performance surface layers that resist wear, corrosion, and mechanical degradation. The review also summarizes experimental and field test results for coatings based on materials such as NiCrBSi, WC-Co-Cr, TiO2, Al2O3, Cr2O3, and ceramic–metal composites, highlighting their significant improvements in hardness, friction reduction, and resistance to delamination and oxidation. The paper highlights research using thermal spraying techniques, especially APS for agricultural applications, with emphasis mostly on components intended for soil processing and requiring good resistance to abrasive wear.