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Showing papers on "Iron oxide published in 1978"


Journal ArticleDOI
TL;DR: In this article, the Raman spectra of FeO, Fe3O4, α-Fe2O3, α -FeOOH, and γ-FeOH, the common products of iron oxidation have been measured.
Abstract: Raman spectra of FeO, Fe3O4, α-Fe2O3, α-FeOOH, and γ-FeOOH, the common products of iron oxidation, have been measured. The spectra of FeO and Fe3O4 appear to be identical. Armco iron oxidized in air at 250°C was examined by Raman spectroscopy after varying periods of exposure and the surface film was found to contain Fe3O4 and α-Fe2O3.

286 citations


Journal ArticleDOI
TL;DR: The distribution of dissolved iron, ferrous iron and acid-reducing agent soluble iron has been investigated in the main basin of Puget Sound and its tributaries as discussed by the authors.

149 citations



Journal ArticleDOI
TL;DR: In this article, radio frequency sputtering was used to deposit refractory carbide, silicide, and boride coatings on 440-C steel substrates and the films were deposited with and without a substrate bias.
Abstract: Radio frequency sputtering was used to deposit refractory carbide, silicide, and boride coatings on 440-C steel substrates. Both sputter etched and pre-oxidized substrates were used and the films were deposited with and without a substrate bias. The composition of the coatings was determined as a function of depth by X-ray photoelectron spectroscopy combined with argon ion etching. Friction and wear tests were conducted to evaluate coating adherence. In the interfacial region there was evidence that bias may produce a graded interface for some compounds. Biasing, while generally improving bulk film stoichiometry, can adversely affect adherence by removing interfacial oxide layers. Oxides of all film constituents except carbon and iron were present in all cases but the iron oxide coverage was only complete on the preoxidized substrates. The film and iron oxides were mixed in the MoSi2 and Mo2C films but layered in the Mo2B5 films. In the case of mixed oxides, preoxidation enhanced film adherence. In the layered case it did not.

94 citations



Journal ArticleDOI
TL;DR: In this paper, the results of two rice soils of south-eastern Australia were flooded for 146 days to simulate part of a rice-upland crop rotation, and the effects of additional organic matter (rice straw) and the growing of rice plants were examined.
Abstract: Intact cores of two rice soils of south-eastern Australia were flooded for 146 days to simulate part of a rice-upland crop rotation. The phosphorus sorptivity, and acetate (pH 4.8) and oxalate (pH 3.0) extractable iron levels were monitored for 210 days, before, during and after flooding. The effects of additional organic matter (rice straw) and the growing of rice plants were examined. In non-flooded soils phosphorus sorptivity was mainly influenced by clay content; there were no relationships between extractable iron and phosphorus sorbed. On flooding there were large increases in acetate and oxalate extractable iron and phosphorus sorptivity. Additional organic matter initially increased the rates of formation of extractable iron, and phosphorus sorptivity increased accordingly. However, with prolonged waterlogging, levels of oxalate iron and phosphorus sorptivity reached values dependent on the free iron oxide content of the soils. The growth of rice plants had no significant effects on phosphorus sorptivity or extractable iron at any time of sampling. During oxidation of previously flooded soils, levels of phosphorus sorptivity and oxalate iron decreased rapidly, but did not return to levels occurring before reduction. The results are consistent with domination of phosphorus sorption processes by ferrous hydrous oxides during the flooded (reduced) phase and by poorly crystalline ferric hydrous oxides during the post-flooding reoxidation phase. Agronomic implications of the results are mentioned.

83 citations


Journal ArticleDOI
TL;DR: The different types of iron oxide phases associated with the surfaces of two suites of kaolins from Georgia, U.S.A., and from the Southwest Peninsula of England, have been identified using electron spin resonance (ESR) spectroscopy combined with magnetic-filtration, thermal, and chemical treatments as discussed by the authors.
Abstract: The different types of iron oxide phases associated with the surfaces of two suites of kaolins from Georgia, U.S.A., and from the Southwest Peninsula of England, have been identified using electron spin resonance (ESR) spectroscopy combined with magnetic-filtration, thermal, and chemical treatments. It has been shown that the English kaolins are coated with a lepidocrocitelike phase, which is readily removed by de Endredy’s method of deferrification, while the Georgia kaolins are coated with a hematite- or goethitelike phase, which is not removed by this treatment. Throughout the course of this study, the effects of the various physical and chemical treatments on the brightness values of the kaolins were examined.

81 citations


Journal ArticleDOI
TL;DR: In this paper, a model based on the microlayer evaporation and drying out phenomena that occur in the nucleate boiling bubble is proposed for an interpretation of the deposition rate of suspended iron oxide in boiling water.
Abstract: The deposition of suspended iron oxide in boiling water at atmospheric pressure on a heated Zircaloy surface has been studied. The effects of various factors, including heat flux of the heated surface, concentration of iron oxide, and flow rate of boiling water, on the deposition rate during the initial period have been investigated.A model based on the microlayer evaporation and drying out phenomena that occur in the nucleate boiling bubble is proposed for an interpretation of the deposition rate. Close agreement is obtained between calculations using that model and the experimental results.

56 citations


Journal ArticleDOI
TL;DR: In this paper, a new magnetic material, cobalt adsorbed iron oxide (COME), was developed for high density magnetic recording media. But the structure of this material is quite different from the others, i.e., the inner part is pure iron oxide and the surface part is a high cobalt content structure formed by adsor-bed cobalt ion.
Abstract: The new magnetic material, "cobalt adsorbed" iron oxide, is an acicular single domain particle developed for high density magnetic recording media. The several magnetic instabilities of conventional cobalt doped or modified iron oxide are improved in this material. The structure of this material is quite different from the others. Generally, the particle for magnetic recording media is uniform in its structure from the surface to the inner part but this is a heterogeneous one, i.e, the inner part is pure iron oxide and the surface part is a high cobalt content structure formed by adsorbed cobalt ion. The surface anisotropy due to the adsorbed cobalt ion is in the order of 106erg/cm3. This surface anisotropy is uniaxial and its direction coinsides with that of the shape anisotropy of the acicular particle. The temperature coefficient of coercivity is as small as that of pure gamma ferric oxide. The new magnetic recording tapes are developed using this cobalt adsorbed iron oxide particles for both the home video tape and the audio cassette tape used in the high bias position. The home video tape is superior in color S/N and maximum output level than conventional one. The audio cassette tape is superior in sensitivity, in maximum output level, and in frequency response at high input level than conventional tapes.

52 citations


Patent
27 Apr 1978
TL;DR: In this paper, a thin layer of titanium dioxide or aluminum oxide was added between the iron oxide and the mica to improve the pigmentation of mica nacreous pigments.
Abstract: Iron oxide coated mica nacreous pigments are improved by interposing a thin layer of titanium dioxide or aluminum oxide between the iron oxide and the mica.

49 citations


Patent
14 Sep 1978
TL;DR: In this article, an ammonium, amine, or hydroxyalkylamine salt of nitrilotriacetic acid, N-2, -hydroxyethylaminodiacetic acid or alkylenepolyamine polycarboxylic acid at a pH of 8 to 11 was used to remove an iron oxide scale from a metal surface.
Abstract: .Iadd.Removing iron oxide scale or a mixture of iron oxide scale and hardness scale from a metal surface by contacting said scale with an aqueous solution containing at least one of an ammonium, amine, or hydroxyalkylamine salt of nitrilotriacetic acid, N-2, -hydroxyethylaminodiacetic acid, or alkylenepolyamine polycarboxylic acid at a pH of 8 to 11. .Iaddend.

Journal ArticleDOI
TL;DR: In this article, the formation range of iron oxides was determined as functions of the substrate temperature and the deposition rate at an oxygen pressure of 4×10-4 Torr.
Abstract: Films of iron oxides such α-Fe3O3 and Fe3O4 were prepared by evaporating iron in a low pressure atmosphere of oxygen gas and investigated by X-ray and electron diffraction and Mossbauer effect measurements. The formation range of iron oxides was determined as functions of the substrate temperature and the deposition rate at an oxygen pressure of 4×10-4 Torr. The oxide film consisted of fine grains, and the grain size of Fe3O4 increased with increase of the film thickness and the substrate temperature. Magnetic properties were investigated. The coercivity was found to increase up to 1000 Oe with the oxidation of the as-deposited Fe3O4 films. The origin of such high coercivity was briefly discussed.

Patent
23 Jun 1978
TL;DR: In this paper, the impregnation of porous lime particulates with iron oxide is used to improve lime utilization for sulfurous oxides adsorption in fluidized combustion of carbonaceous fuels.
Abstract: Lime utilization for sulfurous oxides adsorption in fluidized combustion of carbonaceous fuels is improved by impregnation of porous lime particulates with iron oxide. The impregnation is achieved by spraying an aqueous solution of mixed iron sulfate and sulfite on the limestone before transfer to the fluidized bed combustor, whereby the iron compounds react with the limestone substrate to form iron oxide at the limestone surface. The iron oxide present in the spent limestone is found to catalyze the regeneration rate of the spent limestone in a reducing environment. Thus both the calcium and iron components may be recycled.

Journal ArticleDOI
01 Sep 1978-Wear
TL;DR: In this paper, wear of plasma-sprayed TiO 2 coatings against cast iron was found to be low for both loads below 300 N at 12 kilocycles (kc) and higher loads up to 5 kc. Wear of cast iron is interpreted in terms of delamination, the formation of prows and loose wear debris.

Journal ArticleDOI
TL;DR: In this paper, an energy focused time-of-flight atom-probe field-ion microscope has been successfully employed to investigate the composition depth profile and the oxides species of metal oxide layers.
Abstract: An energy‐focused time‐of‐flight atom‐probe field‐ion microscope has been successfully employed to investigate the composition depth profile and the oxides species of metal oxide layers. Depth profiles of p‐type semiconducting thin films formed by i n s i t uoxidation of materials of three different crystal structures (bcc iron, hcp cobalt, and fcc nickel) showed, without exception, a metal‐rich near surface. After iron has been oxidized in pure research‐grade oxygen, iron oxide layers field evaporate mostly as FeO+, Fe2+, Fe+, O+, and O+ 2. A small number of FeO2+, FeO+ 2, and FeO+ 3 have also been observed. However, iron oxide layers formed by oxidation in air field evaporate exclusively as FeH2+ 2 and Fe(OH2)2+ 2. No Fe3O4 or Fe2O3 have been detected in both cases. No hydroxides and very few hydrides are found for nickel and cobalt when they are oxidized in air. Cobalt oxide layers field evaporate as CoO+, Co2+, O+ 2, and O+ as well as a small number of Co+, CoO2+, and CoH+. Although we also expected Co3O4 ions, none was found. Nickel oxide layers field evaporate mainly as NiO+, Ni2+, O+ 2, O+, and Ni+. In addition to these, some NiO+ 2 and masses which can be assigned as Ni2O3+ 3 and Ni2O4+ 3 are detected. We have also discovered that the oxygen content in the thick oxide layer does not, in general, vary uniformly, possibly due to oxygen diffusion along grain boundaries. The oxide films are polycrystalline in nature, and the adhesive strength of the oxide to the metal is found to be weakest at the oxide/metal interface.

Patent
06 Mar 1978
TL;DR: The red mud byproduct of the Bayer process by which aluminum oxide is reed from bauxite as an aluminate, is digested with concentrated sulfuric acid or with sulfur trioxide gas to produce sulfates that can be leached out to the resulting mass with water.
Abstract: The red mud by-product of the Bayer process by which aluminum oxide is reed from bauxite as an aluminate, is digested with concentrated sulfuric acid or with sulfur trioxide gas to produce sulfates that can be leached out to the resulting mass with water. The solution is then heated at a pH of 1 to precipitate titanium oxide hydrate by hydrolysis. The remaining sulfates of the solution are then obtained in solid form by evaporation, or by precipitation with acetone, and the solid is then roasted to convert the aluminum and iron to the oxide. After leaching out the sodium sulfate with water, the aluminum and iron oxide are separated by the Bayer process, which works in this case even though x-ray diffusion patterns show that the aluminum oxide is mainly αAl 2 O 3 .

Patent
05 Jun 1978
TL;DR: In this paper, the authors describe a refining process of coal gas containing hydrogen sulfide and ammonia, where the hot gas is first contacted with a first catalyst comprising iron oxide to remove hydrogen sulfides and then a second catalyst comprising reduced iron made by reducing iron oxide prior to introducing hot gas into the catalyst to remove ammonia.
Abstract: A refining process of a hot gas such as coal gas containing hydrogen sulfide and ammonia comprises steps of contacting the hot gas with a first catalyst comprising iron oxide to remove hydrogen sulfide, and then contacting the hot gas with a second catalyst comprising reduced iron made by reducing iron oxide prior to introducing the hot gas into the catalyst to remove ammonia. The refining process further includes steps of temperature adjustment of the gas directing to the first and second catalyst and the removal of hydrogen sulfide remaining in the hot gas after the removal of the ammonia with a third catalyst comprising iron oxide.

Patent
15 Sep 1978
TL;DR: In this paper, a process for the manufacture of acicular ferromagnetic metal particles which essentially consist of iron and carry, on their surface, from 0.02 to 0.6% by weight of boron in the form of a borate, by reducing an acicular iron oxide with a gaseous reducing agent at from 250° to 500° C.
Abstract: A process for the manufacture of acicular ferromagnetic metal particles which essentially consist of iron and carry, on their surface, from 0.02 to 0.6% by weight of boron in the form of a borate, by reducing an acicular iron oxide with a gaseous reducing agent at from 250° to 500° C., wherein a compound selected from the group comprising boron oxyacids and their inorganic salts is precipitated on the said iron oxide before reduction.

Journal ArticleDOI
Half Zantop1
TL;DR: The San Francisco manganese deposit as discussed by the authors is a well-stratified mass of manganes oxides and iron oxides enclosed in a continental sequence of Tertiary volcanic rocks.
Abstract: The San Francisco manganese deposit is a well-stratified mass of manganese oxides and iron oxides enclosed in a continental sequence of Tertiary volcanic rocks. The two oxides form irregular layers and lenses within the deposit and are clearly separated from each other: iron oxide layers predominate to the northwest, and manganese oxide layers and lenses to the southeast.The deposit's conformity with the surrounding tuffs and its textural and compositional stratification point to a syngenetic sedimentary origin. Ripple marks and cross-bedding in underlying sandstones and shales and an abundance of iron oxides in the adjacent tuffs indicate deposition in shallow water under oxidizing conditions. Empirical data from present-day environments and the mineralogic composition of the deposit give a probable range of Eh-pH for its formation and point to the mechanisms involved in the separation of iron and manganese in the depositional basin.The purity of the oxides, the large enrichment of manganese relative to iron as compared to crustal averages, and the trace element composition of the oxides suggest volcanic solutions as a source of the two metals.

Journal ArticleDOI
S. Uchida1, Makoto Kikuchi1, Yamato Asakura1, Hideo Yusa1, Katsumi Ohsumi1 
TL;DR: In this paper, a model was developed to predict the shutdown dose rate around the recirculation pipes and their components in boiling water reactors (BWRs) by simulating the corrosion product transport in primary cooling water.
Abstract: A calculation model was developed to predict the shutdown dose rate around the recirculation pipes and their components in boiling water reactors (BWRs) by simulating the corrosion product transport in primary cooling water. The model is characterized by separating cobalt species in the water into soluble and insoluble materials and then calculating each concentration using the following considerations: (1) Insoluble cobalt (designated as crud cobalt is deposited directly on the fuel surface, while soluble cobalt (designated as ionic cobalt) is adsorbed on iron oxide deposits on the fuel surface. (2) Cobalt-60 activated on the fuel surface is dissolved in the water in an ionic form, and some is released with iron oxide as crud. The model can follow the reduction of /sup 60/Co in the primary cooling water caused by the control of the iron feed rate into the reactor, which decreases the iron oxide deposits on the fuel surface and then reduces the cobalt adsorption rate. The calculated results agree satisfactorily with the measurements in several BWR plants.

Journal ArticleDOI
TL;DR: In this paper, the effects of a combination of an iron sulfide surface and surfactants on wear were examined in air and argon atmospheres using a ball-on-dish friction machine.
Abstract: The adsorption of organic polar compounds onto iron sulfide and onto iron oxide was investigated using a flow microcalorimeter. The effects of a combination of an iron sulfide surface and surfactants on wear were examined in air and argon atmospheres using a ball-on-dish friction machine. The polar interaction and reactivity between organic polar compounds and iron sulfide are important functions for wear reduction. This was shown from the results obtained in the measurement of the heat of adsorption, amount of adsorption, heat of desorption and iron content in the desorption solution. The adsorption of stearic acid on the steel ball sulfidized in H2S reduced wear significantly in the air atmosphere. Surfactants contribute considerably to wear reduction when used with sulfur EP additives which form an iron sulfide film.

Patent
20 Oct 1978
TL;DR: In this article, the authors proposed a method to obtain ferromagnetic powder of high coercive force useful as the recording element of a magnetic recording medium by treating a dispersion contg. magnetic powder, a cobalt salt, a ferrous salt and an alkali.
Abstract: PURPOSE: To obtain ferromagnetic powder of high coercive force useful as the recording element of a magnetic recording medium by treating a dispersion contg. magnetic powder, a cobalt salt, a ferrous salt and an alkali to form a cobalt-contg. iron oxide layer on the magnetic powder. CONSTITUTION: Fe 2 O 3 powder or iron oxide magnetic powder, e.g. obtd. by partially reducing the Fe 2 O 3 powder in a reducing gas such as hydrogen is dispersed in a mixed aq. soln. of a cobalt salt and a ferrous salt. To the dispersion is added an alkali such as sodium hydroxide in an amt. of one equivalent or more to the total amt. of the salts in the dispersion. The alkali-added dispersion is then treated at 50°C or below, pref. 30°C or below to form 2wt% or less of a cobalt-contg. iron oxide layer on the magnetic powder. COPYRIGHT: (C)1980,JPO&Japio

Patent
31 Jul 1978
TL;DR: In this paper, a reductive roast is used to reduce the source to a desired particle size and then the reduced source is leached by treatment with a halogen-containing compound to form soluble titanium halides and iron halides.
Abstract: Titanium metal values may be recovered from iron and titanium bearing sources such as an ilmenite ore by subjecting the source to a reductive roast after having crushed the source to a desired particle size. The reduced source is then leached by treatment with a halogen-containing compound to form soluble titanium halides and iron halides. Thereafter, the soluble titanium halide is precipitated as titanium dioxide by treatment with an iron oxide such as ferric oxide. The desired titanium dioxide or rutile may be recovered without an appreciable loss by effecting the leach step of the process in such a manner so that the solution potential is not greater than about +150 millivolts.

Patent
27 Nov 1978
TL;DR: In this article, the authors used iron oxide for scavenging hydrogen sulfide in steelmaking coal furnaces and found that the reaction yields unexpected products, namely, free sulfur and iron hydroxides.
Abstract: Iron rich dusts created during steelmaking, as in the basic oxygen and open hearth processes, are useful for scavenging hydrogen sulfide. For example, basic oxygen furnace dusts, which are in more abundant supply, are found to consist of fine, nearly spherical particles of iron oxide whose crystalline composition comprises Fe3 O4 (major portion) and Fe2 O3 (minor portion) as seen by X-ray diffraction. Their great surface area makes them highly reactive to hydrogen sulfide gas. Their reaction yields unexpected products, namely, free sulfur and iron hydroxides. According to the present invention such iron rich dusts are used in water slurries through which sour hydrocarbon gas is bubbled, and in water based drilling muds to scavenge hydrogen sulfide encountered in well drilling.

Journal ArticleDOI
TL;DR: In this paper, the first stage of oxidation leads to the formation of a covering layer constituted of silica plus iron oxide (mainly hematite). Solid state diffusion of oxygen then takes place through this layer, which progressively evolves with the crystallization of the silica and a relaxation of stress due to fracture.
Abstract: The oxidation of fayalite to hematite and silica by oxygen and oxygen-nitrogen or oxygen-water vapour mixtures has been studied by TGA, SEM and X-ray diffraction. In the temperature range 690 to 950° C, the isotherms of oxidation are pseudo-parabolic. The Arrhenius plot shows a break near 840° C, related to the quartz-cristobalite transformation, the activation energy being about 230 kJ mol−1. The first stage of oxidation leads to the formation of a covering layer constituted of silica plus iron oxide (mainly hematite). Solid state diffusion of oxygen then takes place through this layer, which progressively evolves with the crystallization of silica and a relaxation of stress due to fracture. After the fracture of the covering layer, whiskers of hematite grow, usually on a silica substrate, and align themselves along linear defects. Under specific conditions, their growth is periodic.

Patent
27 Oct 1978
TL;DR: In this paper, it was shown that it is possible to make it possible to manufacture magnetic powder for use in a high powered magnetic toner by employing ferrite of iron saturated and spinel structure that has a particular component and composition.
Abstract: PURPOSE: To make it possible to manufacture magnetic powder for use in a high- powered magnetic toner by employing ferrite of iron saturated and spinel structure that has a particular component and composition. CONSTITUTION: The ferrite powder for a magnetic toner is formed, using a iron saturated ferrite pulverulent body of spinel structure built by 99.9W51mol% of iron oxide calculated in terms of Fe 2 O 3 and at least one of the 0.1W49mol% of manganese oxide, nickel oxide, cobalt oxide, magnesium oxide, copper oxide, zinc oxide and cadmium oxide calculated in terms of MO (M means one of Mn, Ni, Co, Mg, Cu, Zn and Cd). When the pulverulent body is formed, the iron oxide is mixed with one of the metal oxides above, and it is granulated, before being calcined in such a atmosphere that the partial oxygen pressure has been adjusted. Then the granule is pulverized mechanically, and it is made into magnetic powder for use in a high-powered magnetic toner of spinel structure built by 99.9W51mol% of iron oxide calculated in terms of Fe 2 O 3 and at least one of the 0.1W49mol% of the metal oxides mentioned above calculated in terms of MO. COPYRIGHT: (C)1980,JPO&Japio

Journal ArticleDOI
G. Bate1
TL;DR: In this article, the authors reviewed improvements which have been made within the last nine years in the properties of particles for magnetic recording applications and discusses how the improvements were effected and how the improved were effected.
Abstract: Magnetic recording coatings are still made predominantly of iron oxide particles but the newer particles are significantly better in magnetic properties, dispersibility and orientability than the particles used, say, ten years ago. Chromium dioxide particles show excellent recording performance (particularly at densities above 1000 flux changes per millimeter) but they are presently being challenged by the new cobalt-modified iron oxides. These are formed by diffusing cobalt into the surface of acicular iron oxide particles and it is claimed that the particles prepared in this way are much more stable with respect to temperature and stress than the older cobalt-substituted iron oxides. Metal particles, by virtue of their high moment density and high coercivity, would be ideal for high density recording if they could be passivated permanently. The paper reviews improvements which have been made within the last nine years in the properties of particles for magnetic recording applications and discusses how the improvements were effected.

Journal ArticleDOI
TL;DR: In this paper, the stoichiometric differences among iron oxides were investigated by successive coulometric determinations on 10 − 1 mg samples, using graphite-felt electrodes.

Journal ArticleDOI
TL;DR: In this paper, a chemical dissolution investigation of baseline aerosols has demonstrated that much of the 55 Fe associated with aerosols input to the oceans is present as either an amorphous iron oxide or as extremely small particulate species attached to the surfaces of the large aerosol particles.

Patent
Akira Okazoe1
24 Oct 1978
TL;DR: Ferro-magnetic, acicular particles for a recording medium prepared by treating metal hydroxides, the metal component mainly consisting of iron and cobalt, with an oxidative gas in an aqueous alkaline medium where magnetic, magnetic, acicle particles of iron oxide are present and crystallizing metal oxides resulting from the oxidation of the metal hyroxides on the surface of the magnetized particles of the iron oxide as discussed by the authors.
Abstract: Ferro-magnetic, acicular particles for a recording medium prepared by treating metal hydroxides, the metal component mainly consisting of iron and cobalt, with an oxidative gas in an aqueous alkaline medium wherein magnetic, acicular particles of iron oxide are present and crystallizing metal oxides resulting from the oxidation of the metal hydroxides on the surface of the magnetic, acicular particles of iron oxide.