Magnesium Powder Research Articles

Total Phenolic and Flavonoid Contents and Antioxidant Activity of Kembang Bulan Leaves (Tithonia diversifolia (Hemsley) A. Gray)

Many plants are used ethnomedicinally for the treatment of disease and restoration of health. One of these medicinal plants is Tithonia diversifolia . This study aims to determine the phenolic and flavonoid contents and antioxidant activity using the DPPH method from the leaves of T. diversifolia . Phenolic identification was carried out with FeCl 3 reagent; the blackish green color formed indicates the presence of phenolic compounds. Identification of flavonoid was carried out using a reagent between magnesium powder and concentrated HCl; the orange-red color formed indicated the presence of flavonoid. Determination of phenolic and flavonoid contents from extract of T. diversifolia leaves was carried out colorimetrically using a UV-Vis spectrophotometer. The results showed that the Total Phenolic Contents (TPCs) of the ethyl acetate and ethanolic extract of the T. diversifolia leaves was 1.28 and 1.37% GAE, respectively, while the Total Flavonoid Contents (TFCs) was 2.21 and 3.41 mgQE/g, respectively. Better antioxidant activity was shown by the ethanol extract with an IC 50 value of 84.018 µg/ml. Keywords : Antioxidant, flavonoid, phenolic, Tithonia diversifolia

Infiltration-controlled combustion of magnesium for power generation in space

Chemical heat integrated power systems can potentially provide high energy densities and long lifetimes compared to the best batteries. They are of interest for space missions where the use of solar or nuclear energy is impractical. In a new concept of such a system, a metal combustor is coupled with a chemical oxygen generator, and the metal powder bed inside the combustor burns with the infiltrated oxygen. However, the infiltration-controlled combustion of metal powders is not well understood. In the present work, a magnesium powder poured in a vertical quartz tube was ignited by a laser inside a chamber filled with oxygen at pressures of 44 – 90 kPa. The ignition resulted in the propagation of a thermal wave followed by a second ignition at the other end and propagation of a thermal wave backward. High-speed and infrared video recordings as well as thermocouple measurements were used for diagnostics. The results demonstrate that if a metal with a low Pilling-Bedworth ratio (0.81 for magnesium) is used, coflow combustion is possible. The coflow combustion wave propagates at incomplete conversion, with an axial velocity being as low as 0.1 mm/s and the zone of the highest temperature traveling along a helical path. An increase in the axial velocity of the combustion wave is accompanied by an increase in the flame thickness and a decrease in the extent of conversion.

The Effect of Local Application of Magnesium Oxide Powder on the Blood Parameters During Nerve Regeneration of Injured Sciatic Nerve in Rat

Peripheral nerves injuries are very common defects in animals which may lead to loss of sensory andmotor functions of the nerve. These defects are highly corrected using nanotechnology. This studyaimed to find out the effect of applying local application of magnesium Nano- and Microparticles onthe level of magnesium and rat nerve group factor in rat during the process of nerve regeneration. Thisstudy included sixty adult male apparently healthy Wistar rats had bodyweight average (M±SD: 230± 20) gram. Random division to three group was done as: Controlgroup (CG), Nanogroup (NG) andMicrogroup (MG) of (n=20) each after transecting the sciatic nerve and instant proximal and distal endof the sciatic nerve suturing. First group the (Controlgroup) which had no interferences after suturing;the second group (Nanogroup) had a local application of nanoparticles powder of MgO on sutured sitein addition to third group (Microgroup) had a local application of microparticles powder of MgO onthe sutured site. The results showed that a significant and continuous increase of rat growth factor to beseen in Nanogroup and Microgroup however, Microgroup had the highest level to the end of the study,while no significant correlation between the three groups and level of Mg during the study was seen. Itis concluded that MgO forms of Micro and Nano particles have a positive effect on nerve regenerationwhich can be determined by significant increase of NGF in Microgroup then Nanogroup but not inControlgroup. In addition to that using low dose of local application of Nano and Microparticle has nosystemic toxicity on body.

Fabrication of porous forsterite-spinel-periclase ceramics by transient liquid phase diffusion process for high-temperature thermal isolation

Porous forsterite-spinel-periclase ceramics with low thermal conductivity were synthesized via a transient liquid phase diffusion process by using pre-synthesized pellets and fused magnesia powder. The effects of sintering temperature on the pore formation, phase composition, sintering behavior, and properties of the resulting porous ceramics were investigated. The pre-synthesized pellets had a porous structure and contained a large amount of cordierite and enstatite. During the sintering progress, the pellets were converted into a transient liquid phase, which diffused into the solid MgO matrix. The liquid phase diffusion reaction promoted forsterite and spinel formation, which resulted in the in-situ formation of large pores. At elevated temperatures, the liquid phase disappeared and a large number of well-developed grains were simultaneously precipitated from the liquid phase. Porous ceramics with thermal conductivities of 0.42–0.48 W/(m·K) and refractoriness under load values of 1588 °C and 1624 °C were obtained after sintering at 1600 °C for 3 h.

Experimental Compressive Strength and Microstructure Analysis of Magnesium Fluxed Pellets

In this paper, Zhong Guan iron ore is used as raw material. By adjusting the content of lime, raw magnesium powder and bentonite, the effect law of different SiO₂, MgO content and alkalinity on the compressive strength of pellet ore under low silicon conditions was studied, And the pellet strength change law was systematically analyzed from the microscopic morphology and structure perspective. The results of the study show that increasing the roasting temperature and alkalinity can effectively improve the compressive strength of pellets. At low SiO₂ content, the pellet ore is mainly cemented by hematite continuous crystals and the change in strength is not obvious. With the increase of alkalinity, the amount of liquid phase of low silicon flux pellets increases during roasting, and the liquid phase of calcium ferrite system with strength higher than hematite eutectic appears, which improves the pellet strength; With the increase of MgO mass fraction, magnesium ferrite increases, which not only inhibits the formation of liquid phase in pellets, but also inhibits the oxidation of magnetite. Because the strength of magnesium ferrite system is greater than that of magnetite and hematite, the pellet strength increases, but too much magnesium ferrite will also affect the liquid phase bonding inside the pellet, lead to structural deterioration and reduce the pellet strength. Therefore, the compressive strength of pellet increases first and then decreases. The above study provides theoretical guidance and reference for the investigation of low-silica magnesia fluxed pellets.

Peculiar Reaction Characteristics on the Magnesium Powders Exposed to Hygrothermal Aging and Oxygen-Rich Conditions

Peculiar Reaction Characteristics on the Magnesium Powders Exposed to Hygrothermal Aging and Oxygen-Rich Conditions

Exothermic reaction of fine and coarse magnesium powders with water

Exothermic reaction of fine and coarse magnesium powders with water

Experimental Evaluation for the Catalytic Effect of Nickel in Micron Size on Magnesium Hydride

Magnesium hydride is well known as the ideal candidate for solid-state hydrogen storage and thermochemical thermal storage since both gravimetric and volumetric storage are considerably high. The main drawbacks of magnesium hydride are thermodynamic unfavorable and poor kinetic. Adding Nickel as a catalyst, which mainly incorporates mechanical modification (alloying or particle size reduction), can accelerate the reaction rate and decrease the enthalpy formation. It is hard to determine the catalytic of Nickel in magnesium hydride for the kinetic rate improvement. This study is focused on the observation of the effect of Nickel on magnesium hydride by using the market size availability of magnesium and nickel powder (74 μm for Mg and 63 μm for Ni). Mg and Ni are mixed by Ni variation (weight %) from 14%, 15%, and 16%. The characterization starts with initial hydrogenation and dehydrogenation, continues with activation and PCI measurement to obtain the kinetic characteristic of each sample. From this study, it is clear that the increase in nickel ratio will improve the rate of reaction for magnesium hydride, where the maximum storage for magnesium hydride is 4.2% by adding 16 wt% nickel.

Recovery of Magnesium from Ferronickel Slag to Prepare Magnesium Oxide by Sulfuric Acid Leaching

This paper provides a technical approach for efficiently recovering Mg from ferronickel slag to produce high-quality magnesium oxide (MgO) by using the sulfuric acid leaching method under atmospheric pressure. The leaching rate of magnesium is 84.97% after a typical one-step acid leaching process, which is because Mg in FNS mainly exists in the forsterite (Mg2SiO4) phase, which is chemically stable. In order to increase the leaching rate, a two-step acid leaching process was proposed in this work, and the overall leaching rate reached up to 95.82% under optimized conditions. The response surface methodology analysis for parameter optimization and Mg leaching rules revealed that temperature was the most critical factor affecting the Mg leaching rate when the sulfuric acid concentration was higher than 2 mol/L, followed by acid leaching time. Furthermore, interactive behavior also existed between the leaching temperature and leaching time. The leaching kinetics of magnesium from FNS followed a shrinkage-nuclear-reaction model with composite control, which were chemically controlled at lower temperatures and diffusion controlled at higher temperatures; the corresponding apparent activation energy was 19.57 kJ/mol. The leachate can be used to obtain spherical-like alkali magnesium carbonate particles with diameters of 5–10 μm at 97.62% purity. By using a further calcination process, the basic magnesium carbonate can be converted into a light magnesium oxide powder with a particle size of 2–5 μm (MgO content 94.85%), which can fulfill first-level quality standards for industrial magnesium oxide in China.

Экспериментальные и расчетно-аналитические исследования совместимости горючих веществ друг с другом и с окислителями

The danger of chemical reactions in the interaction of incompatible substances manifests itself in an increase in temperature and pressure, ignition, and finally, these reactions can be accompanied by an explosion. By the method of a constant volume bomb, the processes of interaction of mutually reacting substances are studied, as which mixtures of combustible substances (sodium, magnesium, sulfur, and an organic liquid — glycerin) with a changing mass of the oxidizer (ammonium nitrate, ammonium perchlorate, potassium permanganate, potassium bichromate) and in a mixture of these substances of stoichiometric composition are studied: a combustible component and an oxidizer. Analysis of the dependences of the coefficient of participation of a substance in an explosion on the coefficient of excess of an oxidizer of various interacting substances indicates that these dependences can be of two types: with an extremum and in the form of a direct dependence. Continuous increase in the coefficient of participation in the explosion with an increase in the coefficient of excess of the oxidizer indicates the ability to decompose and participate in the explosion of the oxidizer itself. This type of dependence established experimentally for the powders of combustible sulfur and magnesium with oxidizing agents-ammonium nitrate and ammonium perchlorate, shows that both combustible and decomposition products of a flammable oxidizing substance participate in the explosion. Other mixtures (magnesium, glycerin mixed with potassium permanganate, potassium bichromate) have an extremum, and the oxidizer does not participate in the pressure increase when the oxidizer content in the mixture increases. Calculation confirms the possibility of determining chemical compatibility (incompatibility) of substances using the standard Gibbs energy. Based on the example of the experimentally established incompatibility of mixtures of magnesium and sulfur with ammonium nitrate, the calculation also shows that these substances are incompatible with each other. In the absence of experimental data on the compatibility of substances, the input data for calculating the Gibbs energy, the information on the compatibility (incompatibility) of substances can be borrowed from tables 15–17 of GOST 12.1.004. Hazardous and especially hazardous substances indicated under numbers 3 and 4 in these tables are incompatible.

The Effect of Local Application of Magnesium Oxide Powder on the Blood Parameters During Nerve Regeneration of Injured Sciatic Nerve in Rat

Peripheral nerves injuries are very common defects in animals which may lead to loss of sensory andmotor functions of the nerve. These defects are highly corrected using nanotechnology. This studyaimed to find out the effect of applying local application of magnesium Nano- and Microparticles onthe level of magnesium and rat nerve group factor in rat during the process of nerve regeneration. Thisstudy included sixty adult male apparently healthy Wistar rats had bodyweight average (M±SD: 230± 20) gram. Random division to three group was done as: Controlgroup (CG), Nanogroup (NG) andMicrogroup (MG) of (n=20) each after transecting the sciatic nerve and instant proximal and distal endof the sciatic nerve suturing. First group the (Controlgroup) which had no interferences after suturing;the second group (Nanogroup) had a local application of nanoparticles powder of MgO on sutured sitein addition to third group (Microgroup) had a local application of microparticles powder of MgO onthe sutured site. The results showed that a significant and continuous increase of rat growth factor to beseen in Nanogroup and Microgroup however, Microgroup had the highest level to the end of the study,while no significant correlation between the three groups and level of Mg during the study was seen. Itis concluded that MgO forms of Micro and Nano particles have a positive effect on nerve regenerationwhich can be determined by significant increase of NGF in Microgroup then Nanogroup but not inControlgroup. In addition to that using low dose of local application of Nano and Microparticle has nosystemic toxicity on body.

Application of Nanosilicon to the Sintering of Mg-Mg2Si Interpenetrating Phases Composite.

The new in situ fabrication process for Mg-Mg2Si composites composed of interpenetrating metal/intermetallic phases via powder metallurgy was characterized. To obtain the designed composite microstructure, variable nanosilicon ((n)Si) (i.e., 2, 4, and 6 vol.% (n)Si) concentrations were mixed with magnesium powders. The mixture was ordered using a sonic method. The powder mixture morphologies were characterized using scanning electron microscopy (SEM), and heating and cooling-induced thermal effects were characterized using differential scanning calorimetry (DSC). Composite sinters were fabricated by hot-pressing the powders under a vacuum of 2.8 Pa. Shifts in the sintering temperature resulted in two observable microstructures: (1) the presence of Mg2Si and MgO intermetallic phases in α-Mg (580 °C); and (2) Mg2Si intermetallic phases in the α-Mg matrix enriched with bands of refined MgO (640 °C). Materials were characterized by light microscopy (LM) with quantitative metallography, X-ray diffraction (XRD), open porosity measurements, hardness testing, microhardness testing, and nanoindentation. The results revealed that (n)Si in applied sintering conditions ensured the formation of globular and very fine Mg2Si particles. The particles bonded with each other to form an intermetallic network. The volume fraction of this network increased with (n)Si concentration but was dependent on sintering temperature. Increasing sintering temperature intensified magnesium vaporization, affecting the composite formation mechanism and increasing the volume fraction of silicide.

Magnesium Nanoparticle Synthesis from Powders via Pulsed Laser Ablation in Liquid for Nanocolloid Production

Magnesium nanoparticles of various mean diameters (53–239 nm) were synthesised in this study via pulsed laser ablation in liquid (PLAL) from millimetre sized magnesium powders within isopropyl alcohol. It was observed via a 3 × 3 full factorial design of experiments that the processing parameters can control the nanoparticle distribution to produce three size-distribution types (bimodal, skewed and normal). Ablation times of 2, 5, and 25 min where investigated. An ablation time of 2 min produced a bimodal distribution with the other types seen at higher periods of processing. Mg nanoparticle Ultraviolet–Visible spectroscopy (UV–Vis) absorbance at 204 nm increased linearly with increasing ablation time, indicating an increase in nanoparticle count. The colloidal density (mg/mL) generally increased with increasing nanoparticle mean diameter as noted via increasing UV–Vis absorbance. High laser scan speeds (within the studied range of 3000–3500 mm/s) tend to increase the nanoparticle count/yield. For the first time, the effect of scan speed on colloidal density, UV–Vis absorbance and nanoparticle diameter from metallic powder ablation was investigated and is reported herein. The nanoparticles formed dendritic structures after being drop cast on aluminium foil as observed via field emission scanning electron microscope analysis. Dynamic light scattering was used to measure the size of the nanoparticles. Magnesium nanoparticle inks show promise for use in the fabrication conductive tracks or thermal insulation in electronics.

XRD and EDX Analyses on the Formation of MgTiO3 Phase in (Mg0.6Zn0.4)(Ti0.99Sn0.01)O3 Powders Due to Calcination Temperature Variations

MgTiO3-based dielectric ceramics have been recognized as functional materials in the microwave telecommunications industry. Research and development on MgTiO3 dielectric ceramics has therefore developed rapidly. This paper reports x-ray diffraction (XRD) and energy dispersive x-ray (EDX) analyses on the formation of MgTiO3 phase in (Mg0.6Zn0.4)(Ti0.99Sn0.01)O3 powder due to variations in calcination temperature from 550 to 700°C for 2 h. The powder was synthesized via the dissolved metal mixing course using magnesium, zinc, titanium and tin metal powders (Merck) as starting materials. The Rietveld refinement on the XRD patterns of the samples revealed that increasing the calcination temperature reduces the molar% content of MgTiO3 phase of from (97.91±1.51) at 550°C to (87.81±1.29) at 700 °C and causes a decrease in the diffraction peak intensity. The remaining % belongs to TiO2 rutile. The calcination temperature also enlarged the size of MgTiO3 unit cell volume. The EDX data on the atomic% ratio of the elements confirmed the presence of the phases. Discussion of these results is presented in detail in this paper.

Acquisition, Properties, and Application of Nanosized Magnesium Oxide Powders: An Overview

Acquisition, Properties, and Application of Nanosized Magnesium Oxide Powders: An Overview

Research on structure and technological parameters of multi-channel cold spraying nozzle

Cold spraying technology is a method to obtain coating by the high-speed collision of particles with the substrate through supersonic (300–1200 m/s) propulsion gas. The deposition process is mainly mechanical bonding, which has attracted more and more attention in engineering applications. The critical component of a cold spraying system is the nozzle. The performance of the nozzle directly affects the quality of the material surface coating. Therefore, the discussion of the nozzle is of great significance. At present, there are many examples of cold spraying single-channel nozzles in engineering, but there are few reports about multi-channel cold spraying nozzles. This paper explores and studies the multi-channel cold spraying nozzle, designs a special three internal channel nozzle, and adopts a 90° angle in the divergent section of the nozzle. When spraying in a small area, the nozzle with angle has apparent advantages for spraying more areas. The powder injection pressure, particle size, recovery coefficient, and internal channel position are analyzed, which affect the particle trajectory. Combined with these factors, the multi-channel nozzle is optimized and improved to solve the problem of particle collision with the inner wall of the nozzle. Finally, the technological parameters of aluminum, titanium, copper, nickel, magnesium, and zinc powders are preliminarily studied using the multi-channel nozzle. The results show that the multi-channel nozzle meets the critical velocity requirements of copper, magnesium, and zinc powder spraying in the homogeneous (powder and matrix are the same material) and aluminum powder spraying in the case of heterogeneous (powder and matrix are different materials), the multi-channel nozzle has a sound engineering application prospect and provides a specific reference for relevant technicians.

Mechanical properties and biomedical application characteristics of degradable polylactic acid–Mg–Ca3(PO4)2 three-phase composite

Polylactic acid (PLA), pure magnesium powder, and calcium phosphate powder were used to form a three-phase degradable biomedical composite. The effects of various powder proportions in polylactic acid–Mg–Ca3(PO4)2 composites were analyzed through mechanical and biological tests, which revealed that both the tensile and impact strength of the composite increased. Additionally, ductility presented only after a small proportion of powder was added. Hardness slightly increased because of dispersion strengthening. Furthermore, the addition of pure magnesium and calcium phosphate accelerated the degradation rate, and biocompatible salts were generated after degradation, which can improve healing and renewal in bone tissue. None of the composites exhibited cytotoxicity, meeting biological safety requirements. Overall, PLA10M10C (10 wt.% Mg, 10 wt.% Ca3(PO4)2) exhibited superior performance. Accordingly, PLA10M10C can serve as a reference for degradable biomedical material applications in orthopedic implants.

Influence of Rubber Powder Modification Methods on the Mechanical and Durability Properties of Rubberized Magnesium Oxychloride Cement

In the present study, three modification methods, including water washing, sodium hydroxide (NaOH), and styrene–acrylic emulsion, were used to modify waste rubber powders. The influence of rubber powders on the mechanical properties and frost resistance of magnesium oxychloride cement was examined, and the different modification mechanisms were also analyzed. Based on the analysis of hydrophilic properties after modification, styrene–acrylic emulsion achieved the best modification effect, while water washing produced the least modification effect; regarding mechanical properties, magnesium oxychloride cement mixed with NaOH modified rubber powders achieved the best modification effect, in which the 28 d flexural strength and compressive strength increased by 41.2% and 59.6%, respectively. During the freeze-thaw cycles, the mass loss of specimens was reduced with an increase in the content of rubber powders. In addition, after 300 cycles, the relative dynamic modulus of elasticity of the blank sample was about 28.12%, while that of the magnesium oxychloride cement mixed with NaOH modified rubber powders was approximately 42.38%. In general, the properties of the modified rubber powder–magnesium oxychloride cement composite material can meet the requirements for engineering materials, which provides a theoretical basis and technical support for the application of rubberized magnesium oxychloride cement.

Effect of Ball Size on the Microstructure and Morphology of Mg Powders Processed by High-Energy Ball Milling

Commercial powders of pure magnesium were processed by high-energy ball milling. The microstructural and morphological evolution of the powders was studied using scanning electron microscopy (SEM), energy dispersive spectrometry (EDX) and X-ray diffraction (XRD). From the results obtained, it was determined that the ball size is the most influential milling parameter. This was because balls of 1 mm diameter were used after a previous stage of milling with larger balls (i.e., 10 and 3 mm). The powder particles presented an unusual morphology with respect to those observed in the Mg-milling literature and recrystallization phenomena. Moreover, the result strongly varied depending on the ball-to-powder weight ratio (BPR) used during the milling process.

Экспериментальные исследования воспламенения нитрата аммония при взаимодействии с порошками магния и серы

Выполнены экспериментальные исследования взрывоопасности взаимореагирующих веществ: нитрата аммония (аммиачной селитры), который является сильным окислителем, относится к пожароопасным соединениям, в смеси с магнием и серой. Исследования свидетельствуют о взрывоопасности металлов и серы при их взаимодействии с пожароопасным веществом - окислителем (нитратом аммония). Эти особенности аммиачной селитры должны учитываться в процессе ее обращения (производство, хранение, транспортирование, применение, утилизация), при предотвращении и тушении пожаров. Ammonium nitrate (ammonia nitrate) is widely used in industry and in agriculture. The use of ammonium nitrate as a fertilizer gives this strong oxidizer a reputation of harmless agricultural chemical. At the same time, many cases of fires and explosions were registered during the storage, transportation and processing of saltpeter. Saltpeter decomposes with the release of highly toxic nitrogen oxides, which actively maintain combustion, and in case of fire also with release of oxygen. The analysis of statistical data on fires and explosions during the circulation of ammonium nitrate indicates serious problems in ensuring fire and explosion safety of buildings and structures in particular facilities of its storage. Clean and dry saltpeter explodes at normal temperature only in the presence of large volumes of the substance under the influence of a strong initiator, for example, a detonator. However, in the presence of some substances of both organic and inorganic origin the decomposition temperature of saltpeter decreases and this process of chemical spontaneous combustion can lead to an explosion. There are conducted experimental investigations by the method of constant volume bomb to determine the excess explosion pressure (ΔР) at interaction of ammonium nitrate with magnesium and sulfur powders and to compare these data with the calculated data of the excess explosion pressure (ΔР). It is established that the explosion pressure increases continuously with an increase in the concentration of the oxidant for mutually reactive substances consisting of combustible chemical element (magnesium, sulfur) and ammonium nitrate. This feature of the explosion of metals with an oxidizer - ammonium nitrate is a consequence of metal oxidation as well as the direct influence of decomposition products of the oxidizer in explosion. The growth of the overpressure of the explosion is also determined in the experiments when changing the volume of the reaction vessel (bomb camera) At the same specific weight of the mixture of mutually reactive substances (magnesium - ammonium nitrate) the explosion pressure increases with the volume of the bomb (the camera). The performed studies show that the contact of ammonium nitrate (ammonia nitrate) with foreign inclusions (additives) and, in particular, with metals and sulfur can lead to an explosion.