Ce Zr Research Articles

Ce–Zr–Mn Oxide Catalysts for Soot Combustion: The Role of Preparation Method

Ce–Zr–Mn Oxide Catalysts for Soot Combustion: The Role of Preparation Method

Magnetic field-assisted adsorption of phosphate on biochar loading amorphous Zr–Ce (carbonate) oxide composite

For metal-based phosphate adsorbents, the dispersity and utilization of surface metal active sites are crucial factors in their adsorption performance and synthesis cost. In this study, a biochar material modified with amorphous Zr–Ce (carbonate) oxides (BZCCO-13) was synthesized for the phosphate uptake, and the adsorption process was enhanced by magnetic field. The beside-magnetic field was shown to have a better influence than under-magnetic field on adsorption, with maximum adsorption capacities (123.67 mg P/g) 1.14-fold greater than that without magnetic field. The beside-magnetic field could also accelerate the adsorption rate, and the time to reach 90% maximum adsorption capacity decreased by 83%. BZCCO-13 has a wide range of application pHs from 5.0 to 10.0, with great selectivity and reusability. The results of XPS and ELNES showed that the "magnetophoresis" of Ce3+ under the magnetic field was the main reason for the enhanced adsorption performance. In addition, increased surface roughness, pore size and oxygen vacancies, enhanced mass transfer by Lorentz force under a magnetic field, all beneficially influenced the adsorption process. The mechanism of phosphate adsorption by BZCCO-13 could be attributed to electrostatic attraction and CO32–dominated ligand exchange. This study not only provided an effective strategy for designing highly effective phosphate adsorbents, but also provides a new light on the application of rare earth metal-based adsorbent in magnetic field.

Epoxy resin with both ultraviolet shielding and enhanced thermal mechanical properties: Study on synergistic modification of Ce–Zr–Si oxide nanoparticles and basalt fibers

AbstractComposites with good thermomechanical and UV‐shielding properties are essential in fiber‐reinforced composites. This paper focuses on composites' ultraviolet (UV) shielding efficiency with added Ce‐Zr‐Si oxide nanoparticles/epoxy resin. The Ce‐Zr oxide nanoparticles were first functionalized with a silicon coupling agent and ethyl silicate to improve their dispersion and surface activity. In this work, we prepared epoxy nanocomposites with the addition of Ce‐Zr ‐Si oxides(1,3,5,7 wt%) and found that the materials had good enhancement of the UV shielding properties of the epoxy resin matrix. Meanwhile, it was used in basalt fiber (BF)/epoxy composites prepared by the hot‐pressing method, and surface treatment of basalt fibers was carried out. The results showed that the modified fiber composites could effectively enhance the thermomechanical properties of epoxy resin composites. It is noteworthy that the tensile strength and flexural strength of the hybrid composites reached their peak when 5 wt% Ce‐Zr‐Si was added, increasing by 13.8% and 33.67% respectively. The modified (BF)/epoxy composites exhibited improved thermal stability compared to pure epoxy resin, with the maximum weight loss temperature of BF‐1/EP reaching 349°C. The T(UVA) decreased to 2.41%, while the T(UVB) decreased to 0.053%, and almost all the ultraviolet irradiation was blocked. These results show that our prepared composites have good thermomechanical and UV shielding properties.Highlights Ce‐Zr oxide nanoparticles were functionalized with a silicon coupling agent. Ce‐Zr‐Si oxide was added to enhance the ultraviolet shielding efficiency. Modified BFs were composited to improve thermomechanical properties.

Severe Plastic Deformation of Mg–Zn–Zr–Ce Alloys: Advancing Corrosion Resistance and Mechanical Strength for Medical Applications

Magnesium-based alloys hold potential for medical applications, but face challenges like rapid bioresorption and limited mechanical strength during early bone healing. In our study, we present a novel Mg–Zn–Zr–Ce alloy with low cerium content (up to 0.1 wt.% Ce) processed using two severe plastic deformation (SPD) techniques. Through an innovative combination of multiaxial forging and multipass rolling, we have achieved a fine-grained structure with an average grain size of the primary α-Mg phase of 1.0 μm. This refined microstructure exhibits improved mechanical properties, including a substantial increase in yield strength (σYS) from 130 to 240 MPa, while preserving ductility. The alloy’s composition includes α-Mg grains, cerium and zinc hydrides, and intermetallic phases with cerium and zinc elements. Tensile testing of the fine-grained alloy demonstrates an enhancement in yield strength (σYS) to 250 MPa, marking a 2.8-fold improvement over the conventional state (σYS = 90 MPa), with a modest 2-fold reduction in ductility. Crucially, electrochemical tests conducted in physiological solutions highlight substantial advancements in corrosion resistance. The corrosion current was reduced from 14 to 2 μA/cm2, while polarization resistance decreased from 3.1 to 8.1 kΩ∙cm2, underlining the alloy’s enhanced resistance to biodegradation. Our results show that the novel Mg–Zn–Zr–Ce alloy, after combined SPD, demonstrates mitigated bioresorption and enhanced mechanical properties. Our findings highlight the fact that the introduction of this innovative alloy and the application of SPD represent significant steps towards addressing the limitations of magnesium-based alloys for medical implants, offering potential improvements in safety and effectiveness.

Effects of the potassium incorporation in Fe–Ce–Zr based catalysts and activation condition in CO2 hydrogenation to C2/C3 olefins at atmospheric pressure

Fe–Ce–Zr-based catalysts (FCZ) were promoted with potassium and evaluated in the CO2 hydrogenation reaction, carried out at atmospheric pressure, to produce light olefins, as ethene and propene. The FCZ catalyst was prepared using the coprecipitation technique, followed by a hydrothermal step. Potassium was added to the catalyst considering four nominal weight contents (0.5, 1, 2, and 4% wt) through wet impregnation. They were characterized using the following techniques: XRF, XRD, XPS, TPR-H2, TPD-H2, TPD-CO2, and in situ DRIFTS along the CO2 desorption and CO2 hydrogenation reaction. Selectivity towards ethene and propene reached the highest values with catalysts containing 1% and 2% wt of K. With this last one, the selectivity towards CO was around 95%, as potassium promotes the reverse water-gas shift reaction. Nonetheless, with this catalyst, the selectivity towards CH4, on a CO-free basis, was lower than 40%, and the olefins’ concentration in the C2–C3 range was superior to 90%, which can facilitate the light olefins separation in downstream processes. The catalysts were also in situ activated using the same feed flow, i.e., H2 and CO2 simultaneous flow, with the H2: CO2 ratio of 3:1, at 550 °C, for 1 h. CO2 conversion showed opposite trends for the case of H2 and H2+CO2 activation. With the former condition, the CO2 conversion increased with the incorporation of potassium, and it decreased for the second case. As the capability of the H2 adsorption diminished with the potassium incorporation to the catalysts, there was not enough hydrogen available to react with the CO2. Hence, for the activation using H2+CO2 flow, CO2 conversion diminished with potassium incorporation.

Nickel Based Ni–Ce<sub>1–<i>x</i></sub>Zr<sub><i>x</i></sub>O<sub>2</sub> Catalysts Prepared by Pechini Method for CO<sub>2</sub> Methanation

Nickel-based Ni–Ce1 – xZrxO2 catalysts were prepared by Pechini method and their catalytic performance towards CO2 methanation reaction was studied. It was shown that the catalysts exhibit high catalytic activity comparable to the activity of industrial methanation catalyst NIAP-07-05. The catalysts were characterized using a complex of X-ray diffraction methods with experiments on synchrotron radiation, high-resolution electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. It is shown that the preparation method makes it possible to achieve a high dispersion of nickel-containing particles formed during the decomposition of the Ni–Ce–Zr–O substitutional solid solution obtained during the synthesis. However, due to the decorating effect, the surface of nickel-containing particles is poorly accessible to reagents. For this reason, the Ni–Ce1 – xZrxO2 catalysts obtained by the Pechini method are less active than the supported Ni/Ce1 – xZrxO2 catalysts.

Evolution of copper species during heat treatment and its effect on CO oxidation reaction on CuCeZrOy catalyst synthesized by a facile solvent-free route

Several ternary oxides CuCeZrOy (CCZ) were synthesized by a facile grinding method followed by calcination at high temperatures, and used as catalysts for CO oxidation at low temperatures. The influences of calcination temperature (400–600 °C) on the physicochemical properties of the as-synthesized ternary oxides were investigated by thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman, inductively coupled plasma-optical emission spectrometry (ICP-OES), N2 adsorption, H2-temperature programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) characterizations. The results show that the increase in calcination temperature from 400 to 500 °C is conducive to the high dispersion of CuOx on catalyst surface and the incorporation of Cu species into the support to form the Cu–Ce–Zr–O solid solution. Further raising of calcination temperature from 500 to 600 °C, however, leads to the segregation of Cu species from the solid solution to aggregate on support surface and growth of highly dispersed CuOx nanoparticles. The highest catalytic activity is acquired over the CCZ calcined at 500 °C, which can be ascribed to the largest contents of Cu+ species and oxygen vacancies owing to the formation of the maximum amount of Cu–Ce–Zr–O solid solution.

Kinetic Relevance of Surface Reactions and Lattice Diffusion in the Dynamics of Ce–Zr Oxides Reduction–Oxidation Cycles

Reduction–oxidation cycles in oxides are ubiquitous in oxygen storage and transport, chemical looping processes, and fuel cells. O-atom addition and removal are mediated by coupling reactions of oxidants and reductants at surfaces with diffusion of O-atoms within oxide crystals, with either or both processes as limiting steps. CeO2–ZrO2 solid solutions (CZO) are ubiquitous in practice. They are used here to illustrate general experimental strategies and reaction–diffusion formalisms for nonideal systems that enable assessments of the kinetic relevance of the steps that mediate O-atom addition and removal in these materials; these experiments are described within the context of models that describe the driving forces for reaction and diffusion rigorously in terms of oxygen chemical potentials (μO). These strategies assess the rate consequences of varying the fluid phase redox potential, through changes in the identity and pressures of the reactants and products used in redox cycles (O2; CO/CO2; H2/H2O; N2O/N2), of introducing dispersed metal nanoparticles that capture and react lattice O-atoms in CZO using CO or H2, and of imposing intervening dwells without reaction within redox cycles. O-removal rates depend on reductant pressures, even when CO/CO2 and H2/H2O ratios are chosen to maintain the same surface μO if surface reactions were quasi-equilibrated. These data, taken together with significant rate enhancements in O-removal when Pt nanoparticles are present at CZO crystal surfaces and with similar rates before and after inert dwells, demonstrate that reduction rates by both CO and H2 are limited by surface reactions without the presence of consequential spatial gradients in μO within CZO crystals. In contrast, O-addition rates to partially reduced CZO crystals are similar for N2O and O2 reactants and are not affected by the presence of Pt nanoparticles; O-addition rates are significantly higher after intervening inert dwells during CZO oxidation, indicative of spatial gradients in μO, which relax during nonreactive periods. These methods and models, illustrated here for CZO redox cycles at conditions relevant to oxygen storage practice, allow systematic assessments of the kinetic relevance of lattice diffusion and surface reactions for systems that use solids for the reversible storage and release of atoms, irrespective of the identity of the solids or the atoms (e.g., O, H, N, and S).

Syntheses and Redox Properties of Carboxylate-Ligated Hexanuclear Ce(IV) Clusters and Their Photoinduced Homolysis of the Ce(IV)–Ligand Covalent Bond

Oxo- and hydroxo-bridged hexanuclear Ce(IV) clusters surrounded by 12 carboxylate ligands, Ce6O4(OH)4(O2CR)12(L)n (R = 2,6-Me2-4-MeOC6H2 (1a), 2,6-Me2-4-tBuC6H2 (1b), 2,4,6-Me3C6H2 (1c), 2,6-Me2C6H3 (1d), 2,6-Me2-4-FC6H2 (1e), 2,6-Me2-4-ClC6H2 (1f), 9-anthracenyl (1g), and CH2tBu (1h), L = H2O or RCO2H), were synthesized by treating Ce(OtBu)4 with the corresponding carboxylic acids (2-3 equiv.) in acetone or toluene, and the molecular structures of 1d and 1g were clarified by X-ray diffraction studies. UV-vis analyses of the clusters showed broad absorption corresponding to the ligand-to-metal charge transfer (LMCT) in the ultraviolet A (315-400 nm) to blue light region; density functional theory (DFT) studies of the simplified Ce(IV) and related Zr(IV) clusters, M6O4(OH)4(O2CR)12 (M = Ce, Zr, R = Ph, Me), revealed that the low-lying vacant 4f-orbitals of the Ce(IV) were responsible for absorption in the ultraviolet A to blue light region. Irradiation of blue LED light to 1a-f under an argon atmosphere resulted in the formation of 7-methylisobenzofuran-1(3H)-one (2a-f), which involved the following four steps: photoinduced homolysis of the Ce(IV)-OCOR bond, intramolecular hydrogen atom transfer to generate the corresponding benzyl radical, oxidation to the benzyl cation, and intramolecular cyclization. Cyclic voltammetry of cerium clusters 1a-f having 2,6-dimethyl-4-substituted arylcarboxylate ligands showed electrochemically irreversible redox waves in the range of -0.79 to -0.38 V (vs [Cp2Fe]+/Cp2Fe for E1/2). The one-electron-reduced Ce(III)Ce(IV)5 clusters 3a-h were isolated by reducing 1a-h with Cp*2Co to give [Cp*2Co][Ce6O4(OH)4(O2CR)12(thf)n] (3a-h); cluster 3d was the first structurally determined hexanuclear cerium cluster containing a [Ce6O4(OH)4]11+ core.

Ni and Ni–Co Catalysts Based on Mixed Ce–Zr Oxides Synthesized in Isopropanol Medium for Dry Reforming of Methane

Ni and Ni–Co Catalysts Based on Mixed Ce–Zr Oxides Synthesized in Isopropanol Medium for Dry Reforming of Methane

High Catalytic Efficiency of a Nanosized Copper-Based Catalyst for Automotives: A Physicochemical Characterization.

The global trend in restrictions on pollutant emissions requires the use of catalytic converters in the automotive industry. Noble metals belonging to the platinum group metals (PGMs, platinum, palladium, and rhodium) are currently used for autocatalysts. However, recent efforts focus on the development of new catalytic converters that combine high activity and reduced cost, attracting the interest of the automotive industry. Among them, the partial substitution of PGMs by abundant non-PGMs (transition metals such as copper) seems to be a promising alternative. The PROMETHEUS catalyst (PROM100) is a polymetallic nanosized copper-based catalyst for automotives prepared by a wet impregnation method, using as a carrier an inorganic mixed oxide (CeO2-ZrO2) exhibiting elevated oxygen storage capacity. On the other hand, catalyst deactivation or ageing is defined as the process in which the structure and state of the catalyst change, leading to the loss of the catalyst's active sites with a subsequent decrease in the catalyst's performance, significantly affecting the emissions of the catalyst. The main scope of this research is to investigate in detail the effect of ageing on this low-cost, effective catalyst. To that end, a detailed characterization has been performed with a train of methods, such as SEM, Raman, XRD, XRF, BET and XPS, to both ceria-zirconia mixed inorganic oxide support (CZ-fresh and -aged) and to the copper-based catalyst (PROM100-fresh and -aged), revealing the impact of ageing on catalytic efficiency. It was found that ageing affects the Ce-Zr mixed oxide structure by initiating the formation of distinct ZrO2 and CeO2 structures monitored by Raman and XRD. In addition, it crucially affects the morphology of the sample by reducing the surface area by a factor of nearly two orders of magnitude and increasing particle size as indicated by BET and SEM due to sintering. Finally, the Pd concentration was found to be considerably reduced from the material's surface as suggested by XPS data. The above-mentioned alterations observed after ageing increased the light-off temperatures by more than 175 °C, compared to the fresh sample, without affecting the overall efficiency of the catalyst for CO and CH4 oxidation reactions. Metal particle and CeZr carrier sintering, washcoat loss as well as partial metal encapsulation by Cu and/or CeZrO4 are identified as the main causes for the deactivation after hydrothermal ageing.

Hydrogen production employing Cu/Zn-BTC metal-organic framework on cordierite honeycomb ceramic support in methanol steam reforming process within a microreactor

Three metal-organic frameworks Cu-BTC, Zn-BTC, and Cu/Zn-BTC were prepared and impregnated in nitrate solutions to obtain the precursors. After calcination, three metal-BTC-derived CuO/ZnO/CeO2/ZrO2 catalysts were obtained. The samples were characterized and the catalyst-coated cordierite honeycomb ceramics were used in a microreactor for methanol steam reforming at different reaction conditions. Results showed that the Cu/Zn-BTC-derived catalyst exhibited the most fine and uniform particles, the best reducibility, the largest specific surface area, and the optimal surface elemental state due to the difference in the formation mechanisms, resulting in its remarkable catalytic performance. The ceramic support coated with Cu/Zn-BTC-derived catalyst could achieve 100% methanol conversion rate and 0.336 mol/h H2 output at 260 °C in the microreactor. Stability tests demonstrated that the Cu/Zn-BTC-derived catalyst could maintain its excellent performance without deactivation within 30 h continuous reaction, which was connected with the Ce–Zr–O solid solution with high concentration of oxygen vacancies and surface oxygen.

Effect of Calcination Temperature on the Properties of Mn–Zr–Ce Catalysts in the Oxidation of Carbon Monoxide

Effect of Calcination Temperature on the Properties of Mn–Zr–Ce Catalysts in the Oxidation of Carbon Monoxide

The Effect of (Mg, Zn)12Ce Phase Content on the Microstructure and the Mechanical Properties of Mg-Zn-Ce-Zr Alloy.

The quantitative study of rare earth compounds is important for the improvement of existing magnesium alloy systems and the design of new magnesium alloys. In this paper, the effective separation of matrix and compound in Mg–Zn–Ce–Zr alloy was achieved by a low-temperature chemical phase separation technique. The mass fraction of the (Mg, Zn)12Ce compound was determined and the effect of the (Mg, Zn)12Ce phase content on the heat deformation organization and properties was investigated. The results show that the Mg–Zn–Ce compound in both the as-cast and the homogeneous alloys is (Mg, Zn)12Ce. (Mg, Zn)12Ce phase formation depends on the content and the ratio of Zn and Ce elements in the initial residual melt of the eutectic reaction. The Zn/Ce mass ratios below 2.5 give the highest compound contents for different Zn contents, 5.262 wt.% and 7.040 wt.%, respectively. The increase in the amount of the (Mg, Zn)12Ce phase can significantly reduce the critical conditions for dynamic recrystallization formation. Both the critical strain and the stress decrease with increasing rare earth content. The reduction of the critical conditions and the particle-promoted nucleation mechanism work together to increase the amount of dynamic recrystallization. In addition, it was found that alloys with 6 wt.% Zn elements tend to undergo a dynamic recrystallization softening mechanism, while alloys with 3 wt.% Zn elements tend to undergo a dynamic reversion softening mechanism.

Effect of ZrO2 on the performance of Co–CeO2 catalysts for hydrogen production from waste-derived synthesis gas using high-temperature water gas shift reaction

In this study, highly active and stable CeO 2 , ZrO 2 , and Zr (1- x ) Ce ( x ) O 2 -supported Co catalysts were prepared using the co-precipitation method for the high-temperature water gas shift reaction to produce hydrogen from waste-derived synthesis gas. The physicochemical properties of the catalysts were investigated by carrying out Brunauer-Emmet-Teller, X-ray diffraction, CO-chemisorption, Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and H 2 -temperature-programmed reduction measurements. With an increase in the ZrO 2 content, the surface area and reducibility of the catalysts increased, while the interaction between Co and the support and the dispersion of Co deteriorated. The Co–Zr 0.4 Ce 0·6 O 2 and Co–Zr 0.6 Ce 0·4 O 2 catalysts showed higher oxygen storage capacity than that of the others because of the distortion of the CeO 2 structure due to the substitution of Ce 4+ by Zr 4+ . The Co–Zr 0.6 Ce 0·4 O 2 catalyst with high reducibility and oxygen storage capacity exhibited the best catalytic performance and stability among all the catalysts investigated in this study. • CeO 2 , ZrO 2 , and Zr (1-x) Ce (x) O 2 -supported Co catalysts were prepared. • WGS reaction was carried out over the catalysts to produce hydrogen from syngas. • Oxygen storage capacity and reducibility were dependent on the ratio of Ce/Zr. • Co–Zr 0.4 Ce 0·6 O 2 showed the best performance among the prepared catalysts. • This performance was relating to its high oxygen storage capacity and reducibility.

Petrogenesis and implications of ∼2.1 Ga Jingqishan granites in the Jiaobei Terrane, North China Craton

Widely distributed 2.2–2.1 Ga A-type granites in the North China Craton (NCC) have not only a significant role in unveiling the regional Palaeoproterozoic tectonic evolution but also crucial implications for the spatial and temporal evolution of A-type granite. This paper presents zircon U-Pb dating, geochemistry and Nd and Hf isotopes of Jingqishan Palaeoproterozoic gneissic granites from the Jiao-Liao-Ji Belt (JLJB) of the eastern NCC. The Jingqishan granites are mainly monzogranites. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb analyses of three samples yield concordant ages of 2124 ± 7 Ma, 2089 ± 11 Ma and 2088 ± 10 Ma. The Jingqishan granites are ferroan, calc-alkalic to alkali-calcic, and metaluminous-peraluminous. The high Ga/Al ratios, Zr + Nb + Y + Ce contents and Zr saturation temperatures (861 °C on average) of these granites are consistent with the features of A-type granite. The granites have εNd(t) values of −5.7 to −0.8 with two-stage Nd model ages of 2.99–2.63 Ga and zircon εHf(t) values of −7.3 to −2.9 with two-stage Hf model ages (TDM2(Hf)) of 2.94–2.61 Ga. These TDM2(Hf) ages are similar to those of ∼ 2.5 Ga Jiaobei Tonalite-Trondhjemite-Granodiorite (TTG) gneisses. Based on petrology, geochemistry and isotopic characteristics, we infer that the Jingqishan A-type granites are mainly partial melts of the Jiaobei 2.5 Ga TTGs. Combining our data with those published for 2.2–2.1 Ga JLJB granites and extensive data, we discover that both 2.1 Ga and 2.18 Ga A-type granites of the JLJB have A2-type granite characteristics and formed in a back-arc basin but were generated from the partial melting of different sources at two magmatic stages. Most 2.2–2.1 Ga A-type granites of the NCC belong to A2-type that sourced from late Achaean crustal rocks in an extensional setting.

Hydrothermal Synthesis of a Ce–Zr–Ti Mixed Oxide Catalyst with Enhanced Catalytic Performance for a NH3-SCR Reaction

A series of mesoporous CeZrTiOx catalysts were prepared by a facile hydrothermal method. Compared with CeTiOx catalysts synthesized under the same conditions, the catalytic activity and anti-SO2 performance of the Ce1Zr1TiOx catalyst are greatly improved, and at the gas hourly space velocity (GHSV) of 60 000 h-1, the NOx removal efficiency is maintained at 90% in the temperature range of 290-500 °C. The catalytic effect of ZrO2 on the Ce-Ti catalyst NH3-SCR activity was elucidated through a series of characterizations. The results revealed that the doping of Zr could significantly improve and optimize the structure of Ce-Ti catalysts. At the same time, due to the doping of Zr, the synergistic effect between Ce and Zr in the CeZrTiOx catalyst can effectively increase oxygen mobility, total acid content, and surface adsorbed oxygen species and lead to a larger pore volume. In addition, the introduction of ZrO2 made the transformation of Ce4+ into Ce3+ more obvious, and the 2Ce4+ + Zr2+ ↔ 2Ce3+ + Zr4+ reaction greatly improved the reducibility of Ce1Zr1TiOx. Among them, the improvement of SCR performance and H2O/SO2 tolerance is due to the electronic interaction between Zr and Ce.

Fabrication of Zr–Ce Oxide Solid Solution Surrounded Cu-Based Catalyst Assisted by a Microliquid Film Reactor for Efficient CO2 Hydrogenation to Produce Methanol

Currently, supported copper-based catalysts have been regarded as one of the most promising catalysts for catalyzing the hydrogenation of CO2 to synthesize methanol, due to their good selectivity t...

A review on electromagnetic shielding magnesium alloys

Electromagnetic waves generated by electronic equipment are widely present in all living and working spaces because of the rapid development of electronic products and frequent use of digital systems. Electromagnetic shielding is an effective method of protection against these waves. Therefore, the demand for materials with high electromagnetic shielding properties has remarkably increased. Magnesium (Mg) alloys, as potential electromagnetic shielding materials, have sparked great interest worldwide. This review highlights the effects of grain size, texture, alloying elements and second phase on the shielding properties of Mg alloys. Recent progress on the shielding properties of Mg–Zn, Mg–Al, Mg–RE and other new shielding Mg alloys is then summarised, and the successful design of Mg alloys with superior electromagnetic shielding properties, such as Mg–Zn–Y–Ce–Zr, Mg–Sn–Zn–Ca–Ce, Mg–Gd–Y–Zn–Zr and Mg-based composite materials, is described. Finally, this review provides insights into the future development and applications of Mg alloys with superior shielding properties.

Internal friction and heat resistance of Al, Al–Ce, Al–Ce–Zr and Al–Ce–(Sc)–(Y) aluminum alloys with high strength and high electrical conductivity

To study the application performances of new aluminum alloy conductors, dynamic mechanical analysis and microstructure observation were used to characterize the heat resistance and internal friction. Severe recrystallization occurred in Al and Al–0.2Ce alloy above 320 °C. The hardness and electrical conductivity of Al decreased from 40.3 to 22.2 HV and 61.58 to 60.87 %IACS after temperature scanning from 50 to 500 °C, which was mainly attributed to the enhancement of electron scattering by recrystallized grain boundaries. The co-addition of Sc and Y element can obtain the best heat resistance. The diameter of Al3Sc precipitates enriched with Y atoms is lower than 40 nm under high temperature (400–500 °C) and the recrystallization behavior can be effectively inhibited by Al3Sc precipitates. The internal friction of Al, Al–0.2Ce and Al–0.2Ce–0.1Y alloys mainly originates from dislocation motion before PR peaks and the growth of recrystallization grains after PR peaks. The internal friction of Al–0.2Ce–0.2Sc and Al–0.2Ce–0.2Sc–0.1Y alloys increases evenly because of the strong pinning effect of Al3Sc precipitates on dislocations and boundaries. The internal friction is composed of weak dislocation motion and boundaries relaxation. Finally, the internal friction of Al–0.2Ce–0.12Zr alloy under high temperature is complicated and affected by the precipitation behavior of Al3Zr precipitates, dislocations motion, the interaction between Al3Zr precipitates and dislocations, recrystallization processes.