Powder Metallurgy and Metal Ceramics最新文献

{"title":"Vertical Sections of the Hf–Rh–Ir System","authors":"L. S. Kriklya,&nbsp;K. Ye. Korniyenko","doi":"10.1007/s11106-026-00518-3","DOIUrl":"10.1007/s11106-026-00518-3","url":null,"abstract":"<p>Alloys of hafnium with refractory platinum-group metals (in particular, rhodium and iridium) are of interest as high-temperature creep-resistant structural materials. The scientific basis for the design of new structural alloys with a tailored and controllable combination of properties is provided by phase diagrams of the respective multicomponent systems and related information on physicochemical interactions (crystal structure of solid phases and thermodynamic properties of solid and liquid phases). Information on phase equilibria in the Hf–Rh–Ir system was unavailable at the beginning of our research. Based on experimental findings, the solidus and liquidus surfaces, melting diagram, and Scheil diagram were constructed for the first time. The complexity of the phase equilibria required more detailed understanding of alloy formation processes. Therefore, vertical sections of the phase diagram were presented to illustrate phase transformations during alloy crystallization. Sixteen alloy compositions were prepared from iodide-refined hafnium (99.98%), rhodium wire (99.97%), and iridium powder (99.97%) by electric-arc melting. The alloys were annealed at subsolidus temperatures (20–50°C below the solidus). In as-cast and annealed states, the alloys were studied by microstructural analysis, differential thermal analysis, electron probe microanalysis, X-ray diffraction, and the Pirani–Alterthum technique. The experimental results were used to construct, for the first time, vertical sections of the ternary Hf–Rh–Ir phase diagram along the Ir : Rh = 1 : 1 line at the 15 at.% Ir, 10 and 42.5 at.% Rh, and 30, 33, and 62.5 at.% Hf isopleths. These sections demonstrate characteristic features of the phase equilibria in the system, particularly the alloy crystallization ranges and the nature of phase transformations.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 3-4","pages":"212 - 227"},"PeriodicalIF":0.6,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146045513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multilayer Coatings as a New Stage in the Development of Modern Highly Effective Thermal Barrier Coatings II. Two-Layer Gd2Zr2O7/YSZ Thermal Barrier Coatings","authors":"S. M. Lakiza,&nbsp;M. I. Hrechaniuk,&nbsp;A. O. Makudera,&nbsp;I. O. Marek,&nbsp;O. K. Ruban,&nbsp;V. P. Red’ko,&nbsp;V. B. Shmybelskii,&nbsp;O. V. Dudnik","doi":"10.1007/s11106-026-00517-4","DOIUrl":"10.1007/s11106-026-00517-4","url":null,"abstract":"<p>Gadolinium zirconate Gd₂Zr₂O₇ (GZ₂) has excellent thermal stability up to 1530°C, low thermal conductivity (1.1 W ∙ m^–1 ∙ K^–1), a low sintering rate, and a higher coefficient of thermal expansion (CTE) (10.4 ∙ 10^–6 K^–1, 293–1373 K) compared with LZ₂. Therefore, GZ₂ is a very promising candidate for new thermal barrier coatings (TBCs). However, the relatively low fracture toughness of GZ₂, which promotes crack propagation, limits its application as a TBC. In addition, GZ₂ tends to react with aluminum oxide to form the porous GdAlO₃ phase. For this reason, the implementation of the two-layer coating concept will retain the advantageous properties of GZ₂ and mitigate its weaknesses. Analysis of published sources on the production and properties of two- and multilayer GZ₂/YSZ TBCs shows that two-layer GZ₂/YSZ coatings can be successfully applied employing all established techniques: atmospheric plasma spraying (APS), electron-beam physical vapor deposition (EB–PVD), plasma spray–physical vapor deposition (PS–PVD), solution precursor plasma spray (SPPS), and suspension plasma spray (SPS). Such coatings endure a greater number of thermal cycles than the single-layer 8YSZ coating at 1550°C. Two-layer GZ₂/YSZ TBCs are capable of increasing the operating temperature up to 1400°C and have a longer service life than similar LZ₂/YSZ TBCs. Nevertheless, the CTE mismatch between the layers and the low fracture toughness remain a serious problem for such coatings. The interaction between the GZ₂ and YSZ layers does not critically affect the TBC properties. Reduction in Young’s modulus of TBCs appears promising to achieve excellent characteristics. Multilayer TBCs demonstrate significantly longer thermal shock lives at both 1100 and 1200°C. Doping the GZ₂ topcoat with Yb₂O₃ increases the thermal cyclic life and CTEs of two-layer TBCs. At 1050°C, GZ₂-based coatings are more thermally and chemically stable than YSZ and show better hot corrosion resistance. The key factors that influence the properties of the GZ₂ layer in the two-layer APS GZ₂/YSZ coatings include the specific microstructure of the GZ₂ topcoats, particularly a higher density of defects and a higher proportion of unmelted particles compared with conventional YSZ coatings. In the post-sprayed state, the roughness of GZ₂ coatings is lower than that of YSZ coatings with the same porosity. The GZ₂ layers examined do not show higher resistance to sintering at 1100°C.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 3-4","pages":"194 - 211"},"PeriodicalIF":0.6,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146045615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the Corrosion Process in Al/Al2O3 Composite Materials","authors":"Jiang Wang,&nbsp;Aman Shankhyan,&nbsp;Jasgurpreet Singh Chohan,&nbsp;Nagaraj Patil,&nbsp;Deepak Gupta,&nbsp;H. Rambod","doi":"10.1007/s11106-026-00520-9","DOIUrl":"10.1007/s11106-026-00520-9","url":null,"abstract":"<p>In this study, an accumulative press bonding process (APB) is used to manufacture an AA1100/Al₂O₃ composite. Initially, Al/Al₂O₃ composites were manufactured via powder metallurgy, followed by warm roll bonding in four steps. To obtain the composites, the starting components were ground in a stainless steel ball mill in nitrogen at a pressure of 0.7 MPa for 24 hours at a speed of 450 rpm. During grinding, Al₂O₃ was mixed with Al 1100 alloy powder obtained by atomization. After milling, the resulting mixture was cold-pressed to form compact samples. The compaction was performed using a steel die at 750 MPa. Subsequently, the compacts were extruded at 550°C for 50 min. Al/Al₂O₃ samples produced by hot extrusion were preheated to 250°C for 10 min and pressed with a 50% reduction in thickness. A 100-ton press was used for pressing. This cycle was repeated four times. The corrosion resistance of the samples was measured using electrochemical impedance spectroscopy and potential dynamic polarization tests. The corrosion current density (J_corr), corrosion potential (E_corr), polarization resistance (R_p), and corrosion rate (C.Rat, mm/year; V_corr, μm/year) are investigated. A considerable improvement in the main electrochemical parameters was achieved for composites fabricated with higher press bonding steps. It was found that the APB process had a positive effect on the corrosion improvement of composite samples. Additionally, the electrochemical experiments demonstrated the positive influence of the APB process on the corrosion behavior.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 3-4","pages":"243 - 251"},"PeriodicalIF":0.6,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146045580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of Rheological Parameters of Chitosan Hydrogel/Silicon Nitride Paste During 3D Printing by Robocasting for Biomedical Applications","authors":"O. V. Derevianko,&nbsp;S. E. Ivanchenko,&nbsp;V. Yu. Naumenko,&nbsp;O. B. Zgalat-Lozynskyy","doi":"10.1007/s11106-026-00519-2","DOIUrl":"10.1007/s11106-026-00519-2","url":null,"abstract":"<p>The evolution of rheological parameters of chitosan hydrogel/silicon nitride paste was studied during and after the application of mechanical shear at different rates using a Rheotest RN 4.1 rotational viscometer. The paste composition for 3D printing by robocasting included chitosan, food-grade gelatin, Si₃N₄ nanopowder, distilled water, and a 9% acetic acid solution. At a shear rate of 800 sec^–1 (the maximum value for Rheotest RN 4.1), the paste exhibited a sharp decrease in dynamic viscosity: about 99% relative to the initial value. After cessation of shear, the paste recovered 25–35% of its viscosity within a period referred to by the authors as ‘viscosity stabilization time’. Based on practical observations, this viscosity stabilization time was determined to be 18–19 sec. According to the authors, the pronounced decrease in dynamic viscosity and thixotropic behavior of the paste can be attributed to the inherent properties of gelatin. They also suggest that the abrupt change in viscosity proceeds through a threshold mechanism. Printed samples were produced using a Zmorph 2.0SX Full Set (FDM) 3D printer equipped with a direct piston extruder developed by the authors. It was experimentally established that, even at a shear rate of 200 sec^–1, the paste had 7000 mPa · sec viscosity, which is sufficient for printing. Analysis of the drying process for the printed samples indicated the need for careful humidity control in the room or within the drying chamber. Examination of the material’s structure demonstrated the benefits of using (or adding) nanosized components, primarily intended to reduce pore sizes in the products and facilitate the penetration of biomaterials during subsequent biomedical use.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 3-4","pages":"228 - 242"},"PeriodicalIF":0.6,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146045581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multilayer Coatings as a New Stage in the Development of Modern Highly Effective Thermal Barrier Coatings I. Two-Layer La2Zr2O7 (LZ2)/YSZ Thermal Barrier Coatings","authors":"S. M. Lakiza,&nbsp;M. I. Hrechaniuk,&nbsp;A. O. Makudera,&nbsp;I. O. Marek,&nbsp;O. K. Ruban,&nbsp;V. P. Red’ko,&nbsp;V. B. Shmybelskii,&nbsp;O. V. Dudnik","doi":"10.1007/s11106-025-00507-y","DOIUrl":"10.1007/s11106-025-00507-y","url":null,"abstract":"<p>At the beginning of the 21st century, the classical yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBCs) reached their maximum operating temperature (1200°C). A further increase in the operating temperature and associated gain in the efficiency of gas turbine engines became possible through the complex stabilization of ZrO₂; the use of other compounds (oxides with fluorite (La₂Ce₂O₇), pyrochlore (La₂Zr₂O₇, La₂Hf₂O₇), magnetoplumbite (LaMgAl₁₁O₁₉), perovskite (SrZO₃), and other structures); and the design of functionally graded and two-layer TBCs. In the latter case, the bottom layer is mainly YSZ, whose coefficient of thermal expansion (CTE) matches that of the bound coat. Various materials with low thermal conductivity are proposed as the topcoat (an overview of the efforts focusing on the development of La₂Zr₂O₇ (LZ₂)/YSZ TBCs is presented in the first paper of the series). Two-layer LZ₂/YSZ TBCs can be successfully produced by all available application methods: atmospheric plasma spraying (APS), electron-beam physical vapor deposition (EB-PVD), spark plasma sintering (SPS), etc. The LZ₂ and YSZ phases exhibit good chemical compatibility even after sintering at 1400°C for 24 h. The mismatch in the CTEs of the layers remains a serious problem. The LZ₂/YSZ coatings demonstrate better thermal shock resistance compared to nanostructured and conventional YSZ TBCs. To produce high-quality two-layer coatings with the LZ₂ topcoat, APS parameters should be lowered to avoid lanthanum losses. Reducing the elastic modulus of two-layer TBCs is useful for decreasing the crack propagation tendency. The LZ₂ phase reduces the oxygen permeability of the ceramic coat in two-layer TBCs, thus preventing the bond coat oxidation and the rapid growth of thermally grown oxides. The twolayer LZ₂/YSZ TBCs show higher resistance to hot corrosion caused by Ca–Mg–Al silicates (CMAS) and V₂O₅+Na₂SO₄ compared to their single-layer counterparts. The doping of LZ₂ with CeO₂ increases the CTE of two-layer APS coatings, improving their efficiency. The overview of two-layer La₂Zr₂O₇(LZ₂)/YSZ TBCs confirms their advantages over single-layer ones, because each layer contributes to improving the properties and mitigating the weaknesses of the coatings, ultimately enabling higher operating temperatures and longer service lives of power equipment.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 1-2","pages":"74 - 92"},"PeriodicalIF":0.6,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transformations Between Mn-Like Phases in the Fe–Mo–Cr–C System","authors":"T. A. Velikanova,&nbsp;A. V. Kotko,&nbsp;A. M. Zaslavskii,&nbsp;V. V. Kuprin,&nbsp;S. D. Kharchenko","doi":"10.1007/s11106-025-00508-x","DOIUrl":"10.1007/s11106-025-00508-x","url":null,"abstract":"&lt;p&gt;Transmission electron microscopy was employed to establish the nature of transformations between Mn-like phases in the Fe–Mo–Cr–C system illustrated by the example of structural and phase states of the rapidly solidified Fe&lt;sub&gt;51.9&lt;/sub&gt;Mo&lt;sub&gt;11.1&lt;/sub&gt;Cr&lt;sub&gt;26.3&lt;/sub&gt;C&lt;sub&gt;10.7&lt;/sub&gt; (at.%) alloy. The alloy was produced as ribbons by melt spinning at a cooling rate of 5 · 10&lt;sup&gt;6&lt;/sup&gt; K/sec using the planar flow casting technique. The alloy consisted of the π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; and χ&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; phases, corresponding to the β- and α-Mn-type polymorphs, respectively. The direct π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; → χ&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; transformation was established to occur in the alloy. This transition proceeded completely, without changes in the composition or in the specific volume of the unit cell, which is ~0.012 nm&lt;sup&gt;3&lt;/sup&gt;/atom for both phases. In electron microscopy images, the π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; → χ&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; transformation appears as a two-level nanoscale deformation contrast within the grains of the polygonal π &lt;sub&gt;F e,Mo,Cr,C&lt;/sub&gt; phase. Specifically, it is manifested as a conglomerate of lamellar packets that are perpendicular to the spinning ribbon surface (with lamellae 10–20 nm wide), containing a substructure of transverse fragments (~ 10 nm in width). It was concluded that the π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; → χFe,Mo,Cr,C phase transition displayed the features of a diffusionless martensitic-type transformation between coherent phases. The transformation occurs within 700–727°C, the same temperature range as in the decomposition of the π phase in rapidly solidified Fe–Mo–C alloys and in the β-Mn ⇄ α-Mn polymorphic transformation in elemental manganese. The quaternary π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; phase is manifested morphologically in two microstructural forms. One corresponds to the metastable state of the π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; phase: elongated crystallites without signs of solid-state transformation, ranging in size from 200 nm to several microns. This microstructure is preserved from the crystallization temperature of the π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; phase to the observation temperature in regions adjacent to the melt-spun ribbon surface. The other microstructural form consists of polyhedral crystallites shaped as regular pentagons and convex deltoids with an average linear size of 50–200 nm. This polyhedral microstructure of the π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; phase, characteristic of the annealed state, forms in the ‘thermal bath’ within the ribbon under nearequilibrium conditions. It persists from the π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; phase crystallization temperature to the π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; → χ &lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; transformation temperature. The χ &lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; solid solutions appear morphologically as nanoscale deformation substructures within the grains of the original polygonal π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; phase and are observed from the π&lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; → χ &lt;sub&gt;Fe,Mo,Cr,C&lt;/sub&gt; transformation temperature to room ","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 1-2","pages":"93 - 101"},"PeriodicalIF":0.6,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Analysis of the Properties of ASTM F75 Alloy Powders Atomized with Argon and Nitrogen: Numerical and Experimental Insights","authors":"Deniz Aktürk,&nbsp;Emre Yurtkuran","doi":"10.1007/s11106-025-00501-4","DOIUrl":"10.1007/s11106-025-00501-4","url":null,"abstract":"&lt;p&gt;ASTM F75 alloy powders are widely used in biomedical implants, aerospace, and turbine components and are often produced via additive manufacturing. However, the effects of process parameters on particle size distribution, microstructure, and cooling behavior, as well as the impact of gas heating, remain unexplored. This study investigates the differences in the production of ASTM F75 powders using the gas atomization method with argon and nitrogen gases through experimental and numerical analyses. The experimental study compared the powder particle distributions, surface micrographs, and microstructures of powders produced with argon and nitrogen gases at a temperature of 300 K and a pressure of 3.5 MPa. For the ASTM F75 powder in the 0–53 μm range, the &lt;i&gt;Dv&lt;/i&gt;(10), &lt;i&gt;Dv&lt;/i&gt;(50), and &lt;i&gt;Dv&lt;/i&gt;(90) values are 7.94, 18.2, and 39.4 μm for nitrogen gas, while for argon gas these values are 11.3, 23, and 41.8 μm, respectively. Thus, it was observed that smaller particle size distributions were achieved in the production carried out with nitrogen. When comparing the surface micrographs, dendrite formation was observed during production with both gases. Therefore, it was determined that the cooling rates at 300 K and 3.5 MPa were not sufficient, as indicated by the dendritic structures observed on the surface. In the scanning electron microscope (SEM) images of the produced powders, more satellite was observed in the production carried out with nitrogen. Since experimentally studying the gas atomization parameters would be costly, the effect of gas heating on gas flow dynamics was investigated numerically. The experimentally validated numerical analyses were conducted in ANSYS Fluent using the standard &lt;i&gt;k&lt;/i&gt;–ε turbulence model. The numerical simulations were performed at an inlet gas pressure of 3.5 MPa, ensuring consistency with the experimental conditions. As the gas temperatures increased to 300, 400, 500, and 600 K, the maximum velocities for argon gas are 399.45, 458.58, 509.59, and 555.32 m/s, while these values are 516.21, 592.31, 658.88, and 719.27 m/s for nitrogen gas, respectively. As the temperature of both gases increased, a decrease in mass flow rate was recorded. As the gas was heated, an increase in velocity and a decrease in mass flow rate were observed. Therefore, it was concluded that higher kinetic energy could be achieved with lower gas consumption. It leads to stronger aerodynamic forces acting on the molten metal, which enhances its fragmentation and promotes the formation of finer powder particles. As a result, compared to argon, powders atomized with nitrogen achieved a reduction of approximately 29.73% in &lt;i&gt;Dv&lt;/i&gt;(10), 20.87% in &lt;i&gt;Dv&lt;/i&gt;(50), and 5.74% in &lt;i&gt;Dv&lt;/i&gt;(90) values. Additionally, based on numerical calculations, gas heating resulted in an average reduction of approximately 10.96% in gas consumption for argon and 11.79% for nitrogen per 100 K increase in temperature, highlighting its potential for improving ","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 1-2","pages":"1 - 17"},"PeriodicalIF":0.6,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure and Tribological Properties of Wear-Resistant Composites Produced From Brass Waste for Screen Printing Machine Parts","authors":"T. A. Roik,&nbsp;O. A. Gavrysh,&nbsp;Iu. Iu. Maistrenko","doi":"10.1007/s11106-025-00503-2","DOIUrl":"10.1007/s11106-025-00503-2","url":null,"abstract":"<p>The effect of the fabrication process on the structure and tribological properties of a new antifriction composite produced from grinding waste of brass L63 with CaF₂ solid lubricant was studied. The material is intended to operate under loads up to 3.0 MPa and sliding speeds up to 2.0 m/sec in friction assemblies of screen printing machines. The fabrication process ensured the formation of a two-phase antifriction composite structure: a metallic α-brass matrix with uniformly distributed CaF₂ solid lubricant particles. Comparative tests of the new composite produced from brass L63 grinding waste with (6.0–9.0)% CaF₂ demonstrated its advantageous antifriction properties over cast brass L63. The latter corresponds to CuZn37/CW508L (EN standard) or C27200 (ASTM standard, USA) brasses, which are conventionally used in the friction assemblies of Sakurai MS-80AII, Sakurai MS-80/102SD, and Sakurai SC-72AII/102AII/112AII/142AII screen printing machines. The composite from regenerated brass L63 grinding waste containing CaF₂ solid lubricant forms an antiseizure protective film on the contact surfaces at sliding speeds up to 2.0 m/sec and loads up to 3.0 MPa through the mass transfer mechanism. The film uniformly covers the surfaces. It is smooth and continuous, and its wear and regeneration rates balance under defined speed–load conditions. This minimizes friction, resulting in the lowest friction coefficient and wear rate compared to cast brass. Analysis of the functional properties allows the antifriction composite produced from industrial grinding waste of brass L63 with CaF₂ solid lubricant admixtures to be recommended for parts of screen printing equipment assemblies operating at sliding speeds up to 2.0 m/sec and loads up to 3.0 MPa.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 1-2","pages":"27 - 35"},"PeriodicalIF":0.6,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Few-Layered Graphene on the Corrosion Behaviour of the Al–Cu Matrix Composites","authors":"Cantekin Kaykilarli,&nbsp;Taha Yasin Eken,&nbsp;Burak Küçükelyas,&nbsp;Deniz Uzunsoy","doi":"10.1007/s11106-025-00505-0","DOIUrl":"10.1007/s11106-025-00505-0","url":null,"abstract":"<p>In the transportation, maritime and aviation industries, aluminum alloys — particularly those in the 2xxx series (Al–Cu type) — are frequently used because they offer an ideal combination of properties, including toughness, a high strength-to-weight ratio and fatigue resistance. Graphene, a two-dimensional material with a single-atom thickness composed of carbon atoms arranged in a hexagonal lattice, attracts interest due to its remarkable properties and is commonly utilized as a reinforcement in composite materials. Few-layered graphene (FLG) reinforced Al–4 wt.% Cu matrix composites were prepared via mechanical alloying (MA, 500 rpm, ball-to-powder ratio 7 : 1), uniaxial pressing (300 MPa), and conventional sintering (59°C, 3 hours, argon gas flow). The present work investigates corrosion behaviors of FLG (0.25 and 0.5 wt.%) reinforced Al–4 wt.% Cu composites with different MA durations. Open-circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) measurements were carried out in a 3.5% NaCl solution to determine the corrosion behavior. Following the corrosion test, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analysis were performed on the specimen that exhibited the optimum results. The data obtained before and after the test were compared to investigate the structural changes that occurred as a result of the corrosion test. The analysis demonstrated that the sample reinforced with 0.5 wt.% FLG and subjected to 7 hours of MA had the highest corrosion resistance.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 1-2","pages":"52 - 65"},"PeriodicalIF":0.6,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Influence of Spraying Parameters and Production Features of Nickel–Graphite Composite Powders on the Structure and Chemical Composition of Plasma Coatings","authors":"O. V. Kushchev,&nbsp;O. Ye. Terentiev,&nbsp;V. P. Brazhevskyi,&nbsp;O. O. Chernyshov,&nbsp;O. O. Vasiliev,&nbsp;R. E. Kostiunik,&nbsp;I. S. Martseniuk,&nbsp;O. P. Umanskyi","doi":"10.1007/s11106-025-00506-z","DOIUrl":"10.1007/s11106-025-00506-z","url":null,"abstract":"<p>The paper examines the effect of spraying parameters and production features of the nickel-clad NPG-75 graphite powder on the structure and chemical composition of plasma coatings. The starting NPG-75 powder consisted of graphite (25 wt.%) and a nickel shell (75 wt.%). During plasma spraying of the NPG-75 powder, the graphite content of the resulting coatings significantly reduced and did not exceed 4 wt.%. Several possible reasons for the reduction in graphite content of the coatings were considered. The influence of spraying parameters was studied using powder produced by the rolling process. This powder consisted of conglomerated graphite particles coated with nickel. In the spraying of coatings from the clad conglomerated powder, variations in plasma torch power from 20 to 29 kW and spraying distance from 80 to 300 mm did not have a significant effect and did not increase the graphite content of the coating. At powers below 20.4 kW, NPG-75KP coatings could not be formed. The optimal spraying parameters were found to be a plasma torch power of 24–25 kW and a spraying distance of 160 mm. Under these parameters, the graphite content of the coating reached a maximum of 5.3 wt.%, which was still much lower than in the starting powder (25 wt.%). The best results were shown by plasma coatings from the NPG-75 composite powder material produced without rolling but by direct cladding of solid graphite grains. Even though the quality of the nickel shell produced via autoclave cladding was lower, the graphite content of the resulting coating reached approximately 24 wt.%. The optimal spraying parameters remained the same as for the conglomerated NPG-75 powder. The research confirmed the critical importance of the methods employed to prepare the starting material for preserving the graphite content of plasma-sprayed Ni–C composite coatings.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"64 1-2","pages":"66 - 73"},"PeriodicalIF":0.6,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}