Al Mixture Research Articles

Silica Nanoparticles from Melon Seed Husk Abrogated Binary Metal(loid) Mediated Cerebellar Dysfunction by Attenuation of Oxido-inflammatory Response and Upregulation of Neurotrophic Factors in Male Albino Rats.

Silica nanoparticles (SiNPs) have been touted for their role in the management of non-communicable diseases. Their neuroprotective benefits against heavy metal-induced neurotoxicity remain largely unexplored. This is a comparative evaluation of the oxido-inflammatory and neurotrophic effects of Ni, Al, and Ni/Al mixture on the cerebellum of male albino rats with or without treatment with SiNPs generated from melon seed husk. The study complied with the ARRIVE guidelines for reporting in vivo experiments. A total of 91, 7-9 week-old weight-matched male Sprague rats (to avoid sex bias) were randomly divided into 13 different dosing groups where Group 1 served as the control. Other groups received 0.2mg/kg Ni, 1mg/kg Al, and 0.2mg/kg Ni + 1mg/kg Al mixture with or without different doses of SiNP for 90 days. Rotarod performance was carried out. Oxidative stress markers, Ni, Al, Ca, Fe, Mg, neurotrophic factors, amyloid beta (Aβ-42), cyclooxygenase-2 (COX-2), and acetylcholinesterase (AChE) were determined in the cerebellum. SiNPs from melon seed husk caused a significant decrease in Aβ-42 level and activities of AChE and COX-2 and a significant increase in brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) mediated by Ni, Al, and Ni/Al mixture exposure in rats. Neurotoxicity of the Ni/Al mixture is via heightened neuronal lipoperoxidative damage, decreased Mg, and increased Fe, and co-administration of SiNPs from melon seed husk with the Ni/Al mixture attenuated some of these biochemical changes in the cerebellum.

Assessment of genotoxic damage induced by exposure to binary mixtures of polycyclic aromatic hydrocarbons and three heavy metals in male mice

Introduction Heavy metals (HM) and polycyclic aromatic hydrocarbons (PAHs) exposition has been associated with health problems. Therefore, this research evaluated genotoxicity induced in male mice strain CD-1 exposed to benzo[a]anthracene (B[a]A) and benzo[a]pyrene (B[a]P) and their interaction with Fe, Pb, and Al. Methods Groups of animals were exposed intraperitoneally to HM, PAHs, and mixtures of both. Peripheral blood samples were taken from 0 to 96 h at 24 h intervals; genotoxicity was determined by micronucleus tests and comet assay. Additionally, toxicity and viability were evaluated. Results HM and PAHs individually were genotoxic. About toxicity, only Al altered polychromatic erythrocytes number and did not change leukocytes viability. Concerning mixtures, Fe + B[a]P, Fe + B[a]A, Pb + B[a]P increased genotoxicity. There were no changes with Pb + B[a]A. Finally, Al mixtures with both PAHs damage was decreased. Conclusions Exposure to HM and PAH caused genetic damage. Fe, Al, and B[a]A, established a genotoxic potential. Every metal can interact with PAHs in different ways. Also, the micronucleus test and the comet assay demonstrated their high capacity and reliability to determine the genotoxic potential of the compounds evaluated in this work.

Production of iron triad-based colored spinels by the self-propagating high-temperature synthesis

Blue, green, and khaki spinels were produced by self-propagating high-temperature synthesis (SHS) using Co3O4–ZnO–Mg(NO3)2·6H2O–Al(OH)3–Al, Ni2O3–ZnO–Cr2O3–Al(OH)3–Al, and Co2O3–Fe2O3–Al(OH)3–Al mixtures. The composition of the synthesis products was characterized by X-ray diffraction and IR spectroscopy. The oxides Co3O4, Co2O3, ZnO, Ni2O3, Cr2O3, Fe2O3, and aluminum hydroxide Al(OH)3 were used for the synthesis. Fuel was provided by aluminum powder (ASD-4). The spinel-type ceramic pigments were synthesized using layer-by-layer combustion, which involves two parallel exothermic reactions: aluminum oxidation and aluminothermic reactions. The fast self-propagating reactions and high synthesis temperatures rapidly destroy the structure of Al(OH)3 hydroxide in the starting mixture, producing gaseous reaction products that prevent the sintering of the spinels. The surface morphology of pigment powders and their composition was studied using a Quanta 3D 200i, FEI Co. scanning electron microscope and a Philips SEM 515 scanning electron microscope equipped with a local energy dispersive X-ray analysis (EDAX). The particle size of the synthesized spinels was approximately 1–5 μm. Colored spinels powders obtained by the SHS process can be used as ceramic pigments.

Combustion features of dispersed aluminum and boron in high-energy composition

Combustion of dispersed metals in an oxidizing environment is of practical interest, which is related to the prediction of characteristics of high-energy compositions (HECs) containing metal powders, as well as the characteristics of various propulsion systems and gas generators. The research studies peculiarities of ignition and combustion of dispersed systems of Al, B and Al-B mixture in gas products formed during thermal decomposition and combustion of HEC components. In the study of the characteristics of ignition and combustion, the development of flame processes, a continuous CO2 laser (high-speed radiant heating) and a continuous-pressure flow bomb (stationary combustion), including the filter system for the capture of condensed combustion products (CCPs) were applied. It was found that the high reactivity of dispersed Al reduces the ignition time and increases the burning rate of HECs, and increases the volume fraction of fine condensed particles. The use of amorphous B or Al-B mixture (17.2/82.8 mass ratio) increases the ignition time (up to 62%) and significantly reduces the burning rate of HECs, at the same time, the volume share of large CCPs increases due to the melting of the oxide layer on the surface of B particles and their increased cohesion. Analysis of CCPs showed that fine and large agglomerate particles were formed on the surface of the reactive HEC layer, which contain oxides of the metals used. When Al particles are burned together with B particles, complex oxides (aluminum borates) can be formed.

The Interaction between Anesthetic Isoflurane and Model-Biomembrane Monolayer Using Simultaneous Quartz Crystal Microbalance (QCM) and Quartz Crystal Impedance (QCI) Methods.

The interaction between anesthetic Isoflurane (Iso) and model-biomembrane on the water surface has been investigated using quartz crystal microbalance (QCM) and quartz crystal impedance (QCI) methods. The model-biomembranes used were dipalmitoyl phosphatidyl choline (DPPC), DPPC-palmitic acid (PA) mixture (DPPC:PA = 8:2), DPPC-Alamethicin (Al) mixture (DPPC:Al = 39:1), and DPPC-β-Lactoglobulin (βLG) mixture (DPPC:βLG = 139:1) monolayers, respectively. The quartz crystal oscillator (QCO) was attached horizontally to each monolayer, and QCM and QCI measurements were performed simultaneously. It was found that Iso hydrate physisorbed on each monolayer/water interface from QCM and changed those interfacial viscosities from QCI. With an increase in Iso concentration, pure DPPC, DPPC-PA mixed, and DPPC-Al mixed monolayers showed a two-step process of Iso hydrate on both physisorption and viscosity, whereas it was a one-step for the DPPC-βLG mixed monolayer. The viscosity change in the DPPC-βLG mixed monolayer with the physisorption of Iso hydrate was much larger than that of other monolayers, in spite of the one-step process. From these results, the action mechanism of anesthetics and their relevance to the expression of anesthesia were discussed, based on the "release of interfacial hydrated water" hypothesis on the membrane/water interface.

Spark Plasma Sintering and Hot Pressing of Cu+Al Powder Mixtures and Pre-Deposited Cu/Al Layers

Reactive processing of metals is interesting for materials design and achieving new sets of properties. The transformation degree of the metals, the factor governing the properties of the material as a whole, depends on the sintering/heat treatment conditions. In the present investigation, the phase and microstructure formation of materials obtained by sintering of Cu-10 wt.% Al mixtures and layered Cu/Al structures under different modes of pressing/heating is presented. The samples were obtained via spark plasma sintering (SPS), hot pressing (HP) and pressureless sintering. The products of the interaction between the metals were Al2Cu and Cu9Al4 intermetallics and Cu(Al) solid solutions. The influence of the consolidation method on the phase composition of the sintered materials was studied. The hardness of the composites was analyzed in relation to their structural features. A model experiment has been conducted to trace the structural evolution at the Cu/Al interface caused by interdiffusion. The Cu/Al layered structures obtained by detonation spraying of the powders on a steel substrate were treated by SPS or HP. The effect of electric current, which is a feature of SPS processing, was in accelerating the reaction product formation in the layered structures still containing the starting metallic reactants.

Gram-scale synthesis of graphene quantum dots via energetic material deflagration for bioimaging application

Graphene quantum dots, which possesses unique photoluminescence property, have received enormous attention for bio-sensor, photovoltaic devices and bioimaging application. However, synthesizing high-quality of GQDs remains a formidable obstacle in terms of the two conventional methods since the “top-down” method usually requires expensive raw materials while the “bottom-up” method suffers from incompatibility between quality and production. Thus, developing new strategies to trade-off these issues is promising for GQDs production. Here, we reported an ultrafast deflagration strategy by igniting Al and pentafluoropyridine mixture to prepare high-quality of carbon nanomaterials (CNs) with high graphitization, reaching a high yield of ∼3 g. Combining with a subsequent Hummer's exfoliation and dialyze method, the CNs materials were successfully exfoliated into the uniform-dispersed graphene quantum dots (D-GQDs) with size of 1∼2 nm. The as-prepared D-GQDs derivatives shows remarkable optical properties and it is successfully applied in fluorescence imaging of HeLa cells. Our results in this study highlighted the high efficiency of deflagration technique to prepare functional carbon-based nanomaterials, and proposed a facile and fast strategy for gram-scale synthesis.

Ni and Al mixture amplifies cerebellar oxido-inflammatory responses, down regulates AChE and BDNF/NGF levels in motor impairment in male albino rats

BackgroundAluminum and nickel are potent neurotoxicants to which humans are constantly exposed. Previous studies have demonstrated that these two metals can affect the motor system, but their effects on the cerebellum, a central nervous system region with the highest number of neurons, have remained largely unexplored. Therefore, we conducted a study to investigate the adverse effects of Al, Ni, and Al+Ni in vivo. MethodsIn our study, seven male Sprague Dawley rats per group were orally exposed to deionized water, 0.2 mg/kg of Ni, 1 mg/kg of Al, and 0.2 mg/kg of Ni + 1 mg/kg of Al (as a binary heavy metals mixture; HMM), respectively. ResultsNi, Al, and HMM exposed rats accumulated higher levels of Al and Ni compared to controls, and HMM treated animals had higher levels of Ca and Fe in the cerebellum (p < 0.05). Malondialdehyde (MDA) levels were significantly (p < 0.05) higher in the HMM, Ni, and Al treated groups compared to the control group that received deionized water. Superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx) activities were significantly (p < 0.05) reduced in the HMM, Ni, and Al treated groups compared to the control group that received deionized water. Ni, Al, and HMM significantly (p < 0.05) shortened the length of time of the grip in comparison to the control.Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) levels were significantly decreased in the nickel, Al, and heavy metal mixture groups compared with the control group. Moreover, there was a significant decrease in the activity of acetylcholinesterase (AChE) and a increase in cyclooxygenase-2 (COX-2) activity in the Ni, Al, and HMM treated groups compared to the control group. ConclusionHMM exposed animals had significantly poorer performance in the Rotarod test (p < 0.05) than controls. Al and Ni induced impairment of cerebellar function at various levels.

Sintering of SiC/Ti3SiC2 composites with high SiC contents

The SPS reactive sintering of SiC/Ti3SiC2 composites with high SiC contents was studied by adding SiC to reactive (2TiC+1Ti+1.2Si+0.2Al) or (3TiC+2.2Si+0.2Al) mixtures. Four final volume percentages of SiC were targeted: 21 %, 50 %, 60 % and 70 % by adding the appropriate amounts of a micro-sized SiC powder to the reactive mixtures. The synthesis and the sintering of SiC/Ti3SiC2 composites were realized at 1500 °C/15 min/50 MPa from these mixtures. Due to liquid losses and SiO volatilization, the silicon lack was proven to be a significant limitation in the synthesis of Ti3SiC2 + nSiC composites. A deleterious effect of SiC additions was evidenced on both the reaction and the densification. Finally, Ti3SiC2 + nSiC composites were successfully obtained up to 50 vol% and 60 vol% of SiC from the (2TiC+1Ti+1.2Si+0.2Al) and (3TiC+2.2Si+0.2Al) mixtures, respectively. The thermodynamic calculations showed that the driving force of formation of SiC was very high which could disturb the syntheses from the (3TiC+2.2Si+0.2Al) mixture.

Legume addition to alfalfa‐based mixtures improves the forage energy to protein ratio

AbstractAlfalfa (Medicago sativa L., AL)‐based forage mixtures are a major constituent of ruminant rations, and optimizing their energy‐to‐protein ratio has been identified as a way to improve N use efficiency. This study aimed to determine whether the energy‐to‐protein ratio could be improved by adding red clover (Trifolium pratense L., RC) or birdsfoot trefoil (Lotus corniculatus L., BT) at different seeding proportions, and/or one grass species [timothy, Phleum pratense L., or tall fescue, Schedonorus arundinaceus (Schreb.) Dumort] to AL. Annual forage yield, species proportion in botanical composition, and nutritive value of forage were measured at three sites in Canada for 2 post‐seeding years. The addition of RC or BT did not affect the annual forage yield but it increased the concentration of forage nonfiber carbohydrates (NFCs), particularly of soluble sugars, and decreased concentrations of crude protein (CP), nonprotein nitrogen (NPN), and rapidly degradable protein (PB1) of AL‐based mixtures. The addition of one percentage unit of RC or BT to forage botanical composition improved the NFC/CP ratio by 0.005, and the NFC/(NPN + PB1) ratio by 0.024. The addition of either grass species to AL mixtures also increased the two ratios, but it was related to a CP decrease with no increase in NFC concentrations. Adding RC or BT to AL‐based mixtures is therefore a valuable strategy to increase the forage energy to protein ratio.

Performance of TKX‐50 in thermobaric explosives

AbstractIn this study, the behavior of the high‐nitrogen compound TKX‐50 in model thermobaric formulations was investigated. The addition of 10 % Al to TKX‐50 reduces the heat of detonation by approximately 90 J/g. Despite this, Al reacts with the detonation products of TKX‐50 in an exothermic manner, and the energy contribution was calculated to be approx. 375 J/g. In addition, the overpressure in the explosion chamber filled with argon after detonation of aluminized TKX‐50 charges containing 27 % Al is approx. 20 % higher than in the case of neat TKX‐50. Also the maximum temperature of the TKX‐50/Al explosion products in the argon filled chamber is higher by 370 K than that of measured after detonating TKX only. What is more aluminum oxynitride with a low nitrogen content has been identified in the solid detonation products of aluminized TKX‐50, but only for detonations in argon. Of course, charges made of TKX‐50/Al mixture generate significantly higher overpressure and radiant temperature values in a confined space when they are detonated in an air atmosphere. It all means that burning aluminum in nitrogen provides little energy, and even if the concentration of nitrogen in the post‐detonation products is much higher than that of oxygen, aluminum oxides are preferentially formed.

Nickel and aluminium mixture elicit memory impairment by activation of oxidative stress, COX-2, and diminution of AChE, BDNF and NGF levels in cerebral cortex and hippocampus of male albino rats

This study evaluated nickel and aluminium-induced neurotoxicity, as a binary metal mixture. Twenty-eight male Sprague Dawley albino rats were weight-matched and divided into four groups. Group 1 (control) received deionized water. Group 2 and 3 received Aluminium (1 mg/kg) and Nickel (0.2 mg/kg) respectively, while Group 4 received Ni and Al mixture HMM three times a week orally for 90 days. Barnes maze tests was performed. Rats were sacrificed under pentobarbital anaesthesia, cerebral cortex and hippocampus were separated, and metal levels were measured using Atomic Absorption Spectroscopy (AAS). Malondialdehyde (MDA), catalase (CAT), glutathione content (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), Brain Derived Neurotrophic Factor (BDNF), Nerve growth factor NGF, cyclo-oxygenase COX-2 and Acetylcholinesterase (AChE) were assayed using ELISA kits. Ni/Al binary mixture exposed rats showed a shorter latency period (though not significant) of 3.21 ± 1.40 s in comparison to 3.77 ± 1.11 (Ni only) and 3.99 ± 1.16(Al only). Ni/Al mixture gp had the lowest levels of Mg in both the hippocampus and frontal cortex when compared with the individual metals. In the hippocampus Al only exposed rats significantly showed p < 0.05 higher iron and Ca levels in comparison to Ni/Al mixture. Al alone significantly showed p < 0.05 lower levels of Fe but higher Ca than the Ni/Al mixture group. Exposure to Al only showed lower levels of BDNF in comparison to Ni/Al combination, whereas Ni/Al mixture gp had lower levels of NGF in comparison to the individual metals in the hippocampus. In the frontal cortex Ni only, group showed significantly lower BDNF in comparison to Ni/Al mixture whereas the mixture showed significantly lower NGF when compared with Al only group. There were higher levels of COX-2 in the Ni/Al mixture than individual metal treated rats in both hippocampus and frontal cortex. AChE levels in the Ni/Al mixture group was higher than Ni or Al only gps in the hippocampus whereas in the frontal cortex, Ni/Al exposed rats showed significantly lower AChE levels in comparison to Al only group. Ni, Al and Ni/Al mixture exhibited memory impairment by activation of oxidative stress, COX-2, and diminution of AChE, BDNF and NGF levels in cerebral cortex and hippocampus. The BDNF-COX-2 AChE signalling pathway may be involved in the neurotoxicity of Ni and Al.

Effect of Diluent Amount on Properties of Porous NiAl

Porous NiAl parts were formed by using Ni and Al elemental powders, preformed NiAl as diluent and NaCl particles as space holder (SH). The aim of utilizing preformed NiAl (30%-40%) as a diluent was to preserve the shape of the products. The amounts of the SH NaCl particles in NiAl were 25-50-75 vol.% and their sizes were in 300-500 µm range. Porous NiAl samples were prepared by volume combustion synthesis (VCS). The adiabatic temperatures of the Ni+Al mixtures having 30 and 40% diluent NiAl were calculated as 1638.9 and 1460.8°C, respectively. Formation of NiAl phase was verified by XRD analyses. In the green pellets, the total porosity amount was higher than the added NaCl amount. Also it was slightly higher in the product pellets than in the green pellets before VCS. Compressive strength and microhardness values of the samples which contained 30% diluent NiAl were higher than the samples which contained 40% diluent. Average compressive strength values of the products that were obtained by 25% NaCl and 30 and 40% diluent NiAl additions were 112.0±29.5 and 66.0±20.5 MPa, respectively.

High-temperature oxidation behavior and pore structure of porous TiAl3 intermetallics at 650 °C to 900 °C

Porous TiAl3 materials were prepared by a time- and energy-saving thermal explosion (TE) method with Ti-75 at% Al mixture powders. Cyclic oxidation tests were performed in air at 650 °C, 800 °C, and 900 °C. Only a weak peak of the oxide phase was detected by X-ray diffraction when the oxidation temperature was below 800 °C. The pore structures remained stable without pore blockage or collapse due to the thin protective oxide layer formed on the surface of the product skeleton at 650 °C, which was confirmed to be Al2O3. The thickness of the oxide scale increased with increasing the oxidation temperature from 800 °C to 900 °C. The compressive strength of the oxidized sample was inversely proportional to its corresponding porosity. Additionally, the antioxidant mechanism at high temperature was further investigated, indicating excellent oxidation resistance. Therefore, porous TiAl3 intermetallic can be considered as promising materials for applications such as filtration, separation, and catalysis at a high temperatures up to 800 °C.

Single and combined effects of Zn and Al on photosystem II of the green microalgae Raphidocelis subcapitata assessed by pulse-amplitude modulated (PAM) fluorometry

Increasing metal concentrations in aquatic environments are mainly due to anthropogenic actions, which is a matter of concern for the biodiversity of aquatic biota. It is known that metals coexist in environments, however environmental risk assessments do not usually take into account the effects of these mixtures. We aimed to test Zn and Al mixtures on the photosynthetic apparatus of a green microalga, for the first time, using PAM fluorometry. After 72 h exposure, single concentrations from 0.08 to 0.46 µM Zn and 22.24 to 37.06 µM Al affected the photosynthetic parameters of Raphidocelis subcapitata. Metals affected the efficiency of the oxygen-evolving complex - OEC (F0/Fv), increasing it by 25% at 0.46 µM Zn and by 82% at 37.06 µM Al – concentrations where, 57% and 78% of growth inhibition occurred, respectively. We observed that the algal growth was more sensitive to infer Zn toxicity, while F0/Fv was more affected by Al. Regarding quenching, there was an increase in passive energy dissipation ((Y(NO)) at 0.46 µM Zn, and we observed an increase in both regulated ((NPQ and Y(NPQ)) and non-regulated energy dissipation ((qN and (Y(NO)) at 37.06 µM Al. Our results showed synergism and antagonism at different concentrations in mixtures, the antagonism prevailing at higher metal concentrations and, in some cases, synergism at lower concentrations of Zn and Al. Since we observe more than additive and less than additive effects, it is of the utmost importance to take mixture toxicity tests into account when performing risk assessments on green algae.

Near‐Atomic‐Scale Evolution of the Surface Chemistry in Li[Ni,Mn,Co]O2 Cathode for Li‐Ion Batteries Stored in Air

Layered LiMO2 (M = Ni, Co, Mn, and Al mixture) cathode materials used for Li‐ion batteries are reputed to be highly reactive through their surface, where the chemistry changes rapidly when exposed to ambient air. However, conventional electron/spectroscopy‐based techniques or thermogravimetric analysis fails to capture the underlying atom‐scale chemistry of vulnerable Li species. To study the evolution of the surface composition at the atomic scale, cryogenic atom probe tomography is used herein and the surface species formed during exposure of a LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode material to air are probed. The compositional analysis evidences the formation of Li2CO3. Site‐specific examination from a cracked region of an NMC811 particle also reveals the predominant presence of Li2CO3. These insights will help to design improved protocols for cathode synthesis and cell assembly, as well as critical knowledge for cathode degradation.

The Formation of Thermal Stresses in the Products Synthesized by Thermal Explosion of a Ni–Al Mixture Considering the Changes in Its Phase Composition

The Formation of Thermal Stresses in the Products Synthesized by Thermal Explosion of a Ni–Al Mixture Considering the Changes in Its Phase Composition

Aluminide Diffusion Coatings on IN 718 by Pack Cementation.

This paper addressed the issues of both direct and indirect synthesis of Ni aluminides by pack cementation (pure Ni and IN 718 superalloy). On the Al-Ni diffusion twosome under pressure, at temperatures below and above the Al melting temperature, the appearance and evolution of diffusion porosity because of the Kirkendall–Frenkel effect manifestation was highlighted. It has been confirmed that, as the temperature rises above the Al melting temperature, the porosity decreases. Nickel-based superalloys, and in particular IN 718, significantly increase their performance by increasing the aluminides proportion in the top diffusion coating. This is made possible by changing the value of the Al and Ni weight percentage ratio in this area (noted as Al/Ni). In the case of the diffusion twosome between IN 718 and pack aluminizing mixtures, having in their composition as active components Al powder, Ferroaluminum (FeAl40) or mixtures of Al and Fe powders, at processing temperatures above the Al melting temperature, by modifying the active component of the mixture, substantial changes in the Al/Ni values were observed, as well as in the maximum %Al in the diffusion coating and of its thickness. It was found that, when switching from Al to FeAl40 or powder mixture (Al + Fe), the Al/Ni value changes between 3.43 and 1.01, from initial subunit values. The experiments confirmed that the highest %Al in the top aluminized diffusion coating, for IN 718, was obtained if the powder mixture contained 66.34 wt.% Al.

Microstructural characterizations of γ-TiAl alloy after high-temperature steam oxidations at 900, 1000, 1100 and 1200 °C

A microstructural characterization of the early-stage steam oxidation behaviors of a γ-TiAl alloy was performed. The γ-TiAl alloy samples were oxidized in water steam at 900, 1000, 1100, and 1200 °C for 1 h, and multilayered structures were observed. A compact Ti 3 Al layer was formed next to the TiAl substrate. An outer layer of TiO 2 and Al 2 O 3 mixed oxides was observed, where the oxide grains are transferred from long-columnar grains at 900 °C to the randomly scattered grains at 1200 °C. The ribbon shaped Al 2 O 3 grains extend inward into the Ti 3 Al layer at 1100 °C and above. An intermediate layer with dark speckles and bright background was formed at 1200 °C. Fine pores existed in the near-surface areas of the oxide scales for all specimens. • Multilayered structures were observed in γ-TiAl oxidized in water steam at 900–1200 °C. • Surface Rutile-TiO 2 oxides with polyhedron shapes were observed. • A compact Ti 3 Al layer and mixtures of TiO 2 and Al 2 O 3 oxides were identified. • A transformation of the Ti-, Al-oxide mixture morphologies happened from 900 to 1200 °C. • An interior H concentration peak was ascribed to the metal-water reaction.

Effect of Impurity Gases on the Combustion of a Mechanically Activated Ni + Al Mixture

Effect of Impurity Gases on the Combustion of a Mechanically Activated Ni + Al Mixture