High Oxygen Partial Pressure Research Articles

Investigation of epitaxial growth of La2Zr2O7 thin films with different carbonaceous phases

During the metal–organic deposition (MOD) process, the carbon-rich impurities remaining in a film are harmful to the epitaxial growth of the oxide film. Thus, it is of great importance to investigate epitaxial growth of oxide films with different carbonaceous phases. To control the carbonaceous phases in the as-fabricated LZO film, different dopant concentrations and annealing atmospheres have been suggested during the MOD process. A characterization of specimens was performed using X-ray diffraction θ–2θ scans, out-of-plane and in-plane scans, X-ray photoelectron spectroscopy, electron backscattering diffraction, and atomic force microscopy. It was found that a small number of carbonaceous phases, regardless of their type, has no obvious negative influence on the growth orientation of the film. Moreover, because some bridge-pillar spots in the graphene layer enable the epitaxial growth of oxide film, the texture degree of LZO film doped with a high concentration of reduced graphene oxide (RGO) is even sharpened. With increasing doping RGO concentration, the surface roughness of the LZO film increases, which indicates an exaggerated impact of the surface defects on the metallic substrate on the grain size of the LZO film doped with RGO. Different oxygen partial pressures in the annealing atmosphere determine the type of carbonaceous phase in the as-prepared oxide film. The carbonate species formed in the film under high oxygen partial pressure have a negative influence on the texture degree and the surface flatness of LZO film, while low oxygen partial pressure favors the reduction of the residual carbon in the film. Therefore, oxide films with high performance can be achieved by controlling the presence of the positive carbonaceous phases in the film during the introduction of an appropriate artificial doping source and the selection of a suitable annealing atmosphere.

Transnasal high flow oxygen therapy combined with noninvasive positive pressure ventilation Chronic obstructive pulmonary disease with respiratory failure patient outcomes

Objective To investigate the effect of Nasal high-flow oxygen therapy combined with noninvasive positive pressure ventilation on COPD patients with respiratory failure and the effects on the levels of PaO2, PaCO2 and SaO2. Methods A total of 126 patients with COPD complicated with respiratory failure who were admitted from January 2017 to June 2019, including 69 males and 57 females, aged(58.94±5.89)years and ranging in age from 45 to 76 years, were randomly divided into NPPV group and HFNC group by random number table method, with 63 cases in each group.Patients in the NPPV group were given NPPV, while HFNC group was given HFNC on the basis of NPPV group.The clinical treatment effect and complications of the two groups were compared 48 h after treatment, and the changes in blood oxygen partial pressure, blood carbon dioxide partial pressure, blood oxygen saturation level, heart rate, respiratory rate and sputum viscosity of the two groups before and after treatment were compared. Results After treatment, the effective rate of HFNC group[95.2%(60/63)]was higher than that of NPPV group[82.6%(52/63)]. HFNC group had higher blood oxygen partial pressure[(87.87±9.45)mmHg, 1 mmHg=0.133 kPa]and blood oxygen saturation[(89.29±8.99)%]than NPPV group[(78.43±8.69)mmHg and(82.21±8.20)%], and lower blood carbon dioxide partial pressure[(47.95±4.85)mmHg]than NPPV group[(56.72±5.19)mmHg]. HFNC group had lower heart rate[(85.45±4.38)times/minute]and respiratory rate[(18.39±2.03)times/minute]than NPPV group[(92.87±4.72)times/minute, [22.49±2.52)times/minute]than NPPV group, with statistically significant differences(P<0.05). Conclusion HFNC combined with NPPV in the treatment of COPD patients with respiratory failure has a good clinical treatment effect, which can improve the levels of PaO2, PaCO2 and SaO2 and reduce the viscosity of sputum, which is worthy of clinical application. Key words: Nasal high-flow oxygen therapy; Noninvasive positive pressure ventilation; COPD combined with respiratory failure; PaO2; PaCO2; Oxygen saturation

Defect chemistry of highly defective La0.1Sr0.9Co0.8Fe0.2O3−δ by considering oxygen interstitials: Effect of hole degeneracy

A revisit to defect structure of La0.1Sr0.9Co0.8Fe0.2O3−δ (LSCF1982) by considering its molecular chemical form as La0.1Sr0.9Co0.8Fe0.2Ox+δ, with B-site cations having +2 valence as reference charge, and oxygen interstitials (Oi″) and localized holes as majority ionic and electronic defects, have shown agreement between experimentally measured defect-chemical-properties and those calculated using regular solution model. With respect to oxygen nonstoichiometry (δ), the defect structure showed a positive deviation from ideal solution behavior. However, this regular solution model fails to account for variations of electronic thermopower and electronic conductivity in high oxygen partial pressure regions. In this work, we have analyzed the defect structure in terms of the degeneracy of holes and reinterpreted the positive deviation in defect chemical properties in terms of the activity coefficient of delocalized holes (γh). It is observed that the positive deviation can be ascribed to hole degeneracy, which is quantified by using Joyce-Dixon approximation of Fermi-Dirac integral. The Fermi energy relative to the valence band edge has negative values, indicating that it overlaps with the upper edge of valence band and thus suggesting a strong possibility of band conduction. Variation of hole mobility with temperature indicated a metal-type conduction behavior, which can be accounted by the band conduction from degenerated holes.

Effect of Aluminum on Microstructure and High-Temperature Oxidation Resistance of Austenitic Heat-Resistant Steel

The ZG40Cr20Ni20Alx (x = 0, 1.76, 3.45, and 5.34) heat-resistant steel has been newly developed on the basis of HK40 steel for aggressive oxidizing environments. The results reveal that the Al greatly enhances the oxidation resistance of ZG40Cr20Ni20 steel at high temperatures. The mass gain of ZG40Cr20Ni20 upon oxidation at 1100 °C for 480 h is up to 103.6 mg/cm2, while the values for the steels containing 1.76 and 3.45 wt% Al are sharply decreased to 6.1 and 5.4 mg/cm2, respectively. Both of their matrix phases are still austenite, which is the same as that of ZG40Cr20Ni20. Their FeCr2O4 spinel oxide scales appear to be more stable under high oxygen partial pressure than that of ZG40Cr20Ni20, and the continuous Cr2O3 film appears between their matrix and spinel oxide. As for the steel with 5.34 wt% Al, the mass gain is only 1.1 mg/cm2. Its matrix is compared to those of austenite and ferrite, and the oxide scale is continuous Al2O3.

A- and B-site Codoped SrFeO3 Oxygen Sorbents for Enhanced Chemical Looping Air Separation.

Chemical-looping air separation has numerous potential benefits in terms of energy saving and emission reductions. The current study details a combination of density functional theory calculation and experimental efforts to design A- and B-site codoped SrFeO3 perovskites as "low-temperature" oxygen sorbents for chemical-looping air separation. Substitution of the SrFeO3 host structure with Ca and Co lowers oxygen vacancy formation energy by 0.24-0.46 eV and decreases the oxygen release temperature. As a result, Sr1-x Cax Fe1-y Coy O3 (SCFC; x=0.2, 0.0<y<1.0) spontaneously releases oxygen at 400-500 °C even under a relatively high oxygen partial pressure (e.g. P =0.05 atm). Sr0.8 Ca0.2 Fe0.4 Co0.6 O3 exhibits a significantly higher oxygen capacity of 1.2 wt % at 400 °C and under a P swing between 0.05 and 0.2 atm, when compared to the <0.2 wt % capacity for undoped a SrFeO3 (SF) and Ca-doped Sr0.8 Ca0.2 FeO3 (SCF). Electrical conductivity relaxation (ECR) study demonstrates that codoping of Ca and Co lowers the activation energy of oxygen diffusion and surface oxygen exchange by 26.6 or 137.9 kJ mol-1 , respectively, resulting in faster redox kinetics for SCFC than for SCF perovskite. The SCFC oxygen sorbent also exhibits excellent stability for 2000 redox cycles for air separation.

Exhaled Volatile Organic Compounds Precedes Pulmonary Injury in a Swine Pulmonary Oxygen Toxicity Model.

PurposeInspiring high partial pressure of oxygen (FiO2 > 0.6) for a prolonged duration can lead to lung damage termed pulmonary oxygen toxicity (PO2T). While current practice is to limit oxygen exposure, there are clinical and military scenarios where higher FiO2 levels and partial pressures of oxygen are required. The purpose of this study is to develop a non-invasive breath-based biomarker to detect PO2T prior to the onset of clinical symptoms.MethodsMale Yorkshire swine (20–30 kg) were placed into custom airtight runs and randomized to air (0.209 FiO2, n = 12) or oxygen (>0.95 FiO2, n = 10) for 72 h. Breath samples, arterial blood gases, and vital signs were assessed every 12 h. After 72 h of exposure, animals were euthanized and the lungs processed for histology and wet-dry ratios.ResultsSwine exposed to hyperoxia developed pulmonary injury consistent with PO2T. Histology of oxygen-exposed swine showed pulmonary lymphatic congestion, epithelial sloughing, and neutrophil transmigration. Pulmonary injury was also evidenced by increased interstitial edema and a decreased PaO2/FiO2 ratio in the oxygen group when compared to the air control group. Breath volatile organic compound (VOC) sample analysis identified six VOCs that were combined into an algorithm which generated a breath score predicting PO2T with a ROC/AUC curve of 0.72 defined as a of PaO2/FiO2 ratio less than 350 mmHg.ConclusionExposing swine to 72 h of hyperoxia induced a pulmonary injury consistent with human clinical endpoints of PO2T. VOC analysis identified six VOCs in exhaled breath that preceded PO2T. Results show promise that a simple, non-invasive breath test could potentially predict the risk of pulmonary injury in humans exposed to high partial pressures of oxygen.

Hydrogen Production During Ethylene Glycol Photoreactions Over Ag-Pd/TiO2 at Different Partial Pressures of Oxygen.

The reaction of ethylene glycol has been studied over Ag–Pd/TiO2 (anatase) under photo-irradiation while monitoring the reaction products (in the gas and liquid phases) as a function of time and at different partial pressures of molecular oxygen. The catalyst contained metal particles with a mean size of about 1 nm, most likely in the form of alloy (TEM, STEM, and XPS). The complex reaction network involves hydrogen abstraction, C-C bond dissociation, de-carbonylation and water gas shift ultimately yielding hydrogen and CO2. The two main competing reactions were found to be, photo reforming and photo-oxidation. Based on our previous study, Ag presence improves the reaction rate for hydrogen production, most likely via decreasing the adsorption energy of CO when compared to pure Pd. At high ethylene glycol concentrations, the rate of hydrogen produced decreased by a factor of two while changing O2 partial pressure from 0.001 to 0.2 atm. The rate was however very sensitive to oxygen partial pressures at low ethylene glycol concentrations, decreasing by about 50 times with increasing oxygen pressures to 1 atm. The order of reaction with respect to O2 changed from near zero at high oxygen partial pressure to ½ at low partial pressure (in 0.008–0.2 atm. range). Liquid phase analysis indicated that the main reaction product was formaldehyde, where its concentration was found to be higher than that of H2 and CO2. The mass balance approached near unity only upon the incorporation of formaldehyde and after a prolonged reaction time. This suggests that the photo-reforming reaction was not complete even at prolonged time, most likely due to kinetic limitations.

Is a 12-h Nitrox dive hazardous for pulmonary function?

Prolonged exposure to a high partial pressure of oxygen leads to inflammation of pulmonary tissue [pulmonary oxygen toxicity (POT)], which is associated with tracheobronchial irritation, retrosternal pain and coughing, and decreases in vital capacity (VC). The nitric oxide (NO) concentration in exhaled gas (FeNO) has been used as an indicator of POT, but the effect of SCUBA diving on FeNO has rarely been studied. The study presented here aimed to assess alterations to pulmonary function and FeNO following a 12-h dive using breathing apparatus with a relatively high partial pressure of oxygen. Six healthy, male, non-smoking military SCUBA divers were recruited (age 31.8 ± 2.7years, height 179 ± 0.09cm, and body weight 84.6 ± 14kg). Each diver completed a 12-h dive using a demand-controlled semi-closed-circuit rebreather. During the 12h of immersion, divers were subjected to 672 oxygen toxicity units (OTU). A complete pulmonary function test (PFT) was completed the day before and immediately after immersion. FeNO was measured using a Nobreath™ Quark (COSMED™, Rome, Italy), three times for each diver. The first datapoint was collected before the dive to establish the "basal state", a second was collected immediately after divers emerged from the water, and the final measurement was taken 24h after the dive. Despite prolonged inhalation of a hyperoxic hyperbaric gas mixture, no clinical pulmonary symptoms were observed, and no major changes in pulmonary function were detected. However, a major decrease in FeNO values was observed immediately after emersion [0-12ppb (median, 3.8ppb)], with a return to baseline [2-60ppb (median, 26ppb) 24h later (3-73ppb (median, 24.7ppb)]. These results suggest that if the OTU remain below the recommended limit values, but does alter FeNO, this type of dive does not persistently impair lung function.

Corrosion Performance of AISI 304 Stainless Steel in CO2-Saturated Brine Solution

Corrosion behavior of 304 stainless steel exposed to a NaCl (3.5 wt %) solution saturated with CO2 has been analyzed using electrochemical techniques including, potentiodynamic polarization, polarization resistance, and electrochemical impedance measurements. The stainless steel samples were evaluated having different surface and pre-oxidation treatments. The oxide scales formed on 304 stainless steel oxidized in different pO2 at 1100°C have also been studied and compared. Different morphologies and chemical composition of the oxide scales were observed after oxidation at low and high oxygen partial pressures. Oxide layers with high chromium content were formed on the ground sample pre-oxidized in Ar while iron-rich oxides were mainly formed under air atmosphere. The electrochemical corrosion results indicate that non-oxidized 304 SS exhibits the best corrosion performance followed by the ground sample heat-treated in argon. For the oxidized stainless steels, the differences in the electrochemical responses are associated to the morphological characteristics and composition of the oxide layer. Homogeneous and dense Cr-rich oxide scale provides protection to 304 SS during exposure to CO2-saturated solutions while the formation of Fe-oxides with porous morphology increases the corrosion rate of 304 stainless steel.

Beyond Ceria: Theoretical Investigation of Isothermal and Near-Isothermal Redox Cycling of Perovskites for Solar Thermochemical Fuel Production

Thermodynamic data for several LaMnO3-based perovskites indicates that in the high oxygen partial pressure (pO2) range (e.g., 10–7 to 10–3 atm), where isothermal thermochemical redox cycling is via...

Defect structure and transport properties of (Co,Cr,Fe,Mn,Ni)3O4 spinel-structured high entropy oxide

Defect structure and chemical diffusion in the (Co,Cr,Fe,Mn,Ni)3O4 high entropy oxide is investigated. The material is synthesized by means of a solid-state reaction, through sintering mixture of composing oxides at 1273 K for 20 h. Presence of the single-phase, spinel-structured high entropy solid solution is confirmed with the use of X-ray diffraction method and scanning electron microscopy. Good thermal stability of the material is documented up to 1273 K. Modified marker experiment allows concluding that defects form predominantly in the oxygen sublattice. Based on thermogravimetric studies, general formula of (Co,Cr,Fe,Mn,Ni)3O4±y is established, with the defect inversion phenomenon (i.e. change of the dominating type of defects from oxygen vacancies to interstitial oxygen) likely to occur at high oxygen partial pressures (pO2). Chemical diffusion coefficient is calculated, based on the measured reequilibration kinetics, showing a very strong dependence on pO2 and relatively small values under low oxygen pressures.

Controlling the oxygen deficiency for improving the insertion performance of the layered LiNi0.6Co0.2Mn0.2O2

Spherical Ni0·6Co0·2Mn0·2(OH)2 precursor was synthesized by a co-precipitation method, and then uniformly mixed with Li salts and calcined to obtain the layered Ni-rich LiNi0·6Co0·2Mn0·2O2 materials. The obtained layered product was further treated at 600 °C for 2 h in four different atmospheres (oxygen, air, argon, argon/hydrogen (95/5)), to explore the effect of oxygen deficiency on the lithium-insertion and storage performance. X-ray diffraction, scanning electron spectroscopy and X-ray photoelectron spectroscopy were used to characterize the phase composition and structure, and the electrochemical performances were evaluated. A well developed layered crystal structure is obtained and the cations arrange more regularly under a high oxygen partial pressure, which leading to the remarkable electrochemical performance of higher discharge specific capacity (176 mAh g−1 at 0.1 C), excellent rate performance and structural stability (67.17% in capacity retention after 300 cycles at 1.0 C). These results demonstrate the positive effects and the underlying mechanisms of the oxygen deficiency regulated lithium-insertion properties in the layered materials.

Structural and magnetic properties of Cu-doped ZnO epitaxial films at the coalescence limit—A superparamagnetic CuO-ZnO nanocomposite

A series of Cu-doped ZnO epitaxial films has been grown on sapphire substrates to investigate the possibilities of preparing a doped magnetic oxide at the coalescence limit. The growth was performed using reactive magnetron sputtering by varying the oxygen partial pressure to tune the incorporation of the Cu dopant and the resulting valence state. At low oxygen pressures, metallic Cu precipitates are formed, while at high oxygen partial pressures, the formation of CuO as a secondary phase could be evidenced. In-between, only a small fraction of the Cu can be substitutionally incorporated into the ZnO host matrix. The resulting magnetic properties are predominantly paramagnetic. However, the formation of the secondary CuO phase is accompanied by a small field imprinted magnetic component, which suggests that the CuO secondary phase consists of small and, thus, magnetically unblocked nanoprecipitates which are dispersed in the ZnO host matrix.

Metalorganic-aerosol-deposited Au nanoparticles for the characterization of ultrathin films by surface-enhanced Raman spectroscopy

An alternative approach for ultrathin film characterization by means of Surface-Enhanced Raman Spectroscopy was realized and applied to the characterization of nanocrystalline TiO2 films. The vacuum-free metalorganic aerosol deposition (MAD) technique was used to grow gold nanoparticles onto the surface of thin TiO2 films. An averaged enhancement factor of 107, as well as the characterization of a 3 nm thin film, was accomplished. Since the thin film acts as a substrate itself, this technique can be used for the characterization of a variety of solid thin film materials. Furthermore, MAD-based nanoparticle growth can be of special interest for oxide films due to the high oxygen partial pressure and the constant oxygen flow during the deposition.

Effects of Oxygen Partial Pressure on 4-Hydroxy-2-Nonenal Induced Oxymyoglobin Oxidation

4-hydroxyl-2-nonenal (HNE) is a lipid oxidation product that can increase oxymyoglobin oxidation. However, limited research has evaluated the role of oxygen partial pressure in HNE-induced metmyoglobin formation. Therefore, the objective of was to compare the effects of atmospheric and high-oxygen partial pressure on HNE-induced oxymyoglobin oxidation in vitro. Oxymyoglobin was incubated with or without HNE at atmospheric (20% O2) or high-oxygen (80% O2) partial pressure. Metmyoglobin formation was measured after 0, 48, and 96 h of incubation at 4°C, and mass spectrometry was utilized to characterize the covalent binding of HNE to myoglobin. High-oxygen condition (80% O2) increased (P &lt; 0.05) HNE-induced oxymyoglobin oxidation compared with the atmospheric partial pressure condition (20% O2). However, HNE was bound to myoglobin at both high-oxygen and atmospheric partial pressure conditions, with no differences (P &gt; 0.05) in the extent of adduct formation. These results suggest that high-oxygen conditions had no effect on extent of HNE-binding, but can increase oxymyoglobin oxidation.

Structural Stabilization of Mullite Films Exposed to Oxygen Potential Gradients at High Temperatures

The oxygen shielding properties of polycrystalline Al4+2xSi2−2xO10−x (mullite) films applied as environmental barrier coatings (EBCs) on SiC fiber-reinforced SiC matrix composites (SiC/SiC) are determined by the grain boundary (GB) diffusion of oxide ions in the films, from the higher oxygen partial pressure (PO₂) surface to the lower PO₂ surface, with simultaneous GB diffusion of Al ions in the opposite direction. Herein, strategies to improve the oxygen shielding and phase stability of these films when applied to SiC/SiC substrates through bond coats are proposed, based on oxygen permeation data for mullite at high temperatures. The validity of these strategies is verified using experimental trials at 1673 K with bilayer specimens consisting of mullite films and bond coat substrates, serving as model EBCs. The data show that employing a bond coat made of β’-SiAlON rather than Si provides a source of Al for the overlying mullite film that greatly improves the phase stability of the film in the vicinity of the junction interface. Because the minimum equilibrium PO₂ values required to form SiO2 due to oxidation of the β’-SiAlON on a thermodynamic basis are significantly larger than those for oxidation of Si, the inward GB diffusion of oxide ions is effectively retarded, resulting in excellent oxygen shielding characteristics.

Investigate the proton uptake process of proton/oxygen ion/hole triple conductor BaCo0.4Fe0.4Zr0.1Y0.1O3-δ by electrical conductivity relaxation

The proton surface uptake kinetics of proton, oxygen ion and hole triple conductor BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) is investigated by electrical conductivity relaxation method (ECR). The proton uptake process is controlled by changing the water partial pressure at constant temperature. And the proton concentration in BCFZY bulk could be calculated by the conductivity change value (Δσ: 0.063 Scm−1 at 500 °C) from 0% to 10% pH2O. The proton surface exchange coefficient, kδ is 3.85 × 10−6 cm−1 at 500 °C, derived from fitting the relaxation curve. It is also found the proton uptake reaction rate would be enhanced under higher oxygen partial pressure. And the kδ value could be greatly enhanced by one order of magnitude with doped ceria coated on BCFZY surface, which also proved that the proton uptake kinetics is limited by the surface exchange step. In all, this work provides an effective way to measure the proton surface exchange kinetic for proton conductive cathode.

Synergetic donor–donor codoping strategy for enhanced photoelectrochemical activity of hematite

Hematite is a promising semiconductor for photoelectrochemical water splitting owing to its ideal band gap, nontoxicity, abundance, and chemical stability. However, the conversion efficiency remains less than its theoretical limit, which is in part due to a low carrier density. Although efforts have been made to increase the carrier density by incorporating appropriate donor dopants, structural instability caused by high donor doping has restricted the enhancement achieved and the resulting photocatalytic performance. Herein, we used density functional theory calculations to show that an enhanced carrier density and photocatalytic performance can be achieved without causing structural instability by using a donor–donor codoping strategy to introduce a 3d transition metal (Ti/V) and Si into hematite. Despite the Coulombic repulsion among the electrons from donors, the Coulombic attraction between donors with an oxidation number of +4 (Ti4+/V4+) and negatively charged small polarons contribute to a strong binding energy. The compensatory binding energy stabilizes the crystal structure and thus increases the density of carriers, most of which are small polarons. We also suggest that the carrier density can be further enhanced by increasing the ratio of Si interstitial doping, which produces four times more polarons than Si substitutional doping under experimental conditions of high temperature and low oxygen partial pressure. Our findings pave a way for an environment-friendly and efficient photocatalysis toward improvement of hydrogen fuel generation.

Oxygen Adsorption on Graphene-Encapsulated Palladium Nanoparticles Imaged by Kelvin Probe Force Microscopy

Graphene-encapsulated metal nanoparticles (G@NPs) offer a possibility to observe confined reactions in the nanocontainer formed by the NP's facets and graphene. However, direct experimental detection of adsorbed atomic and molecular species under the graphene cover is still challenging, and the mechanisms of intercalation and adsorption are not well understood. Here, we show that Kelvin probe force microscopy can largely contribute to the understanding of adsorption and desorption at the single NP level, which we exemplify by comparing oxygen adsorption experiments obtained at as-prepared PdNPs and G@PdNPs, both supported on highly oriented pyrolytic graphite and studied under ultrahigh vacuum (UHV) conditions. We show that oxygen adsorption at room temperature occurs at a much higher partial oxygen pressure on G@PdNPs compared to as-prepared PdNPs. Similarly, the removal of oxygen via a reaction with the residual gas of the UHV is slower on the G@PdNPs compared to as-prepared PdNPs. The differences can be explained by a limited facility for reactant and product molecules to enter and desorb from the nanocontainer via the defects of the graphene. Experimental observations are supported by assisting density functional theory calculations.

Influence of the Al2O3/SiO2 mass ratio and gas composition on the viscous behavior and structure of Cr-containing stainless steel slags

This study investigated the effects of the Al2O3/SiO2 mass ratio and gas composition on the viscosity and structure of Cr-containing CaO-SiO2-MgO-Al2O3-CrOx stainless steel slags. The wet chemical analysis method was used to identify the Cr3+/Cr2+ ratio, and XPS (X-ray photoelectron spectroscopy) and 27Al MAS NMR (magic angle spinning nuclear magnetic resonance) were used to correlate the structural units comprising the melt to the viscosity measurements. The results showed that the break temperature (TBr) corresponded to the temperature when the crystallization fraction increased rapidly. When the Al2O3/SiO2 mass ratio was in the range between 0.125 and 1.0, the viscosity gradually increased as the Al2O3/SiO2 mass ratio increased. Similar viscosity trends were observed for gas compositions with higher oxygen partial pressures, which was correlated to an increased degree of polymerization (DOP) of the slag structure. In addition, the variation in the Cr3+/Cr2+ ratio, which decreased with increasing Al2O3/SiO2 mass ratios and increased with higher oxygen partial pressures, correlated well with the viscous behavior of the slags, the variation trends of [AlO4]- and [AlO5]-structural units, and the increased DOP of the slags.