EVOLUTION OF THE CHEMICAL COMPOSITION OF MINERALS IN METAPELITES DURING LOW-TEMPERATURE CONTACT METAMORPHISM AT THE KARATASH PLUTON

Chemical composition effect on the weld properties for low temperature steel was evaluated. The alloy elements of interest at the weld metal were Cr and Mo, which come from the steel plate and welding wire, respectively. Both side one run SAW process was carried out in a Ygroove butt joint. Microstructure of the weld metal is strongly dependent on the chemical composition of the steel plate and the welding wire, due to high dilution. The microstructure of the weld metal became fine acicular ferrite by increasing Cr and Mo content because of high hardenability effect. The weld metal having Cr and Mo possessed the highest impact toughness at low temperatures among the weld metals studied. Cr seems to have more effect than Mo on the toughness of the weld metal.

Download Full-text

Formation of Intermediate Phases and Supersaturated Solid Solution in Al-Cu System during Diffusion

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.383.31 ◽

2018 ◽

Vol 383 ◽

pp. 31-35 ◽

Cited By ~ 2

Author(s):

Alexey Rodin ◽

Nataliya Goreslavets

Keyword(s):

Phase Diagram ◽

Solid Solution ◽

High Temperature ◽

Chemical Composition ◽

Low Temperature ◽

Supersaturated Solid Solution ◽

Diffusion Processes ◽

Equilibrium Phase ◽

Equilibrium Phase Diagram ◽

Intermediate Phases

The study of diffusion processes in the aluminum - copper system was carried out at the temperature 350 and 520 °C. Special attention was paid on the chemical composition of the system near Al/Cu interface. It was determined that the intermediate phases in the system, corresponding to the equilibrium phase diagram, were not formed at low temperature. At high temperature the intermediate phases forms starting with Cu - rich phases. In both cases supersaturated solid solution of copper in aluminum could be observed near the interface.

Download Full-text

MINERAL CHEMISTRY AND GEOCHEMISTRY OF HYPERSTHENE-BEARING DIORITE FROM ERUSU AKOKO, SOUTHWESTERN NIGERIA

Malaysian Journal of Geosciences ◽

10.26480/mjg.01.2020.13.18 ◽

2020 ◽

Vol 4 (1) ◽

pp. 13-18

Author(s):

E. J. Oziegbe ◽

V. O. Olarewaju ◽

O. O. Ocan

Keyword(s):

Chemical Composition ◽

Chemical Properties ◽

Mineral Chemistry ◽

Accessory Mineral ◽

Southwestern Nigeria ◽

Hydrous Minerals ◽

Icp Ms ◽

Composition Of Minerals ◽

Textural Relationship ◽

Opaque Minerals

Samples of mafic intrusive rock were analyzed for their mineralogical and chemical properties. The textural relationship was studied using the petrographic microscope, elemental composition of minerals was determined using the Electron Microprobe and the whole rock chemical analysis was done using the XRF and ICP-MS. The following minerals were observed in order of abundance; pyroxene, amphibole, plagioclase, biotite, opaque minerals, quartz and chlorite, with apatite and zircon occurring as accessory mineral. Two types of pyroxenes were observed; orthopyroxene (hypersthene) and clinopyroxene. Texturally, amphiboles have inclusions of plagioclase and pyroxene. The plagioclase has undergone sericitization. The chemical composition of the pyroxene is En51.95Fs44.53Wo3.52, biotite has Fe/(Fe+Mg):0.42, Mg/(Fe+Mg):0.59, and plagioclase is Ab63.5An34.55Or1.95. Whole rock chemistry shows a chemical composition; SiO2: 45.15 %, Al2O3: 14.04 %, Fe2O3: 16.01 %, MgO: 5.65 %, CaO: 7.58 % and TiO2: 3.59 %. There is an enrichment of LREE and a depletion of HREE. Based on the minerals, mineral chemistry and the geochemistry of the studied rock, the rock is mafic and hydrous minerals formed by hydration recrystallization of pyroxene. The rock has extensively retrogressed but has not been affected by any form of deformation.

Download Full-text

Preparation of Thin Sections

Microscopy Today ◽

10.1017/s1551929500068590 ◽

1998 ◽

Vol 6 (7) ◽

pp. 8-9

Author(s):

Ian Chaplin

Keyword(s):

Chemical Composition ◽

Thin Section ◽

Microprobe Analysis ◽

Rock Sample ◽

Rock Type ◽

X Rays ◽

Thin Sections ◽

Economical Method ◽

Optical Examination ◽

Composition Of Minerals

The optical examination of a rock sample in thin section is the quickest and most economical method for classifying rock type and determining which analytical route to follow.Thin sections for transmitted light are the most common, but there are also:Polished Thin Sections • Polished sections are used for classification and identification of minerals that cannot be determined in standard thin sections. They are also essential for microprobe analysis. Minute mineral grains are analyzed by bombarding them with a focused bean of electrons, which generate x-rays, characteristic of the elements within the grains. X-rays are identified and quantified to determine the chemical composition of minerals.

Download Full-text

CRYOGENIC GREASE LUBRICANTS FOR ROCKET AND SPACE TECHNOLOGY

Space engineering and technology ◽

10.33950/spacetech-2308-7625-2021-4-31-41 ◽

2021 ◽

pp. 31-41

Author(s):

Andrey D. PLOTNIKOV ◽

Aleksandr V. VODOLAZHSKIY ◽

Natalya S. YAKUPOVA

Keyword(s):

Chemical Composition ◽

Low Temperature ◽

Key Words ◽

Ir Spectrum ◽

Practical Relevance ◽

Space Technology ◽

Potential Evaporation ◽

Testing Methods ◽

Solidification Temperature ◽

Temperature Characteristics

The paper represents requirements for cryogenic grease lubricants used in the rocket and space technology. Data on lubricants based on perfluoropolyether liquid FEN is provided. New lubricant testing methods enabling to analyze their chemical composition and low-temperature characteristics are proposed. Quoted are investigation results for the equivalents of previously used cryogenic lubricants NIKA, NIRA and «Ametist». A practical relevance of the paper has been proven by introduction of low-temperature lubricants «Sever» currently being used in rocket and space items, as well аs successful application of the developed lubricant incoming inspection procedures at RSC Energia. Key words: low-temperature lubricant, perfluoropolyether liquid FEN, viscosity, solidification temperature, IR spectrum, potential evaporation.

Download Full-text

Supergene alteration of metamorphic chlorite in an amphibolite from Massif Central, France

Clay Minerals ◽

10.1180/claymin.1982.017.2.01 ◽

1982 ◽

Vol 17 (2) ◽

pp. 159-173 ◽

Cited By ~ 10

Author(s):

D. Proust

Keyword(s):

Chemical Composition ◽

Low Temperature ◽

Grain Boundaries ◽

Mixed Layer ◽

Low Pressure ◽

Chemical Changes ◽

Massif Central ◽

Rock Structure ◽

Initial Rock

AbstractThe mineralogical and chemical changes of sheridanite were followed in different alteration horizons as weathering of its host amphibolite increased. Microscopic and microprobe analyses of phases produced in or around the chlorite allowed a classification of the different alteration stages relative to their position in the profile. In the unweathered rock, prehnite and a sericite—kaolinite assemblage appear to have formed at grain boundaries between chlorites and plagioclases. These represent low-pressure (PH2O < 2.5 ± 1 Kb) and low-temperature (320–360°C) metamorphic phases. In the saprock, where initial rock structure is still preserved, chlorites weather to a more or less regular mixed-layer chlorite-vermiculite. In the saprolite, large-grain (20 µm) vermiculite forms in the clayey zones (plasma) when rock structure is destroyed. The chemical composition of these newly-formed minerals is influenced by the original chlorites and mixed-layer minerals.

Download Full-text

Octahedral occupancy and the chemical composition of diagenetic (low-temperature) chlorites

Clay Minerals ◽

10.1180/claymin.1991.026.2.01 ◽

1991 ◽

Vol 26 (2) ◽

pp. 149-168 ◽

Cited By ~ 108

Author(s):

S. Hillier ◽

B. Velde

Keyword(s):

Chemical Composition ◽

Low Temperature ◽

Bulk Composition ◽

Compositional Variation ◽

Low Grade ◽

Chemical Analyses ◽

Method Of Calculation ◽

Sedimentary Sequences ◽

Wet Chemical ◽

Potential Use

AbstractThe chemical composition of about 500 diagenetic chlorites, determined by electron microprobe, has been studied in six different sedimentary sequences spanning conditions from early diagenesis to low-grade metamorphism, in the temperature range 40–330°C. The range of Fe/(Fe + Mg) is almost complete and is positively correlated with Al. Five sequences show the same compositional variation. In each, the most siliceous chlorites have the lowest R2+, substantially more octahedral than tetrahedral Al, and the lowest octahedral totals. Conversely, the least siliceous have the highest R2+, nearly equal octahedral and tetrahedral Al, and octahedral totals close to that for an ideal trioctahedral mineral. A dioctahedral substitution Si[]R2−2 (where [] represents a vacant octahedral site) which decreases with temperature, describes this variation. Low octahedral totals are, however, induced by the method of calculation and need not indicate vacancies; for published wet chemical analyses of metamorphic chlorites they may simply indicate oxidation of Fe. Intergrown dioctahedral phyllosilicates may partly account for apparent vacancies in diagenetic chlorites. Nevertheless, the correlation of composition with temperature and similarities to the temperature-related evolution of synthetic chlorites, suggest that diagenetic chlorites are compositionally distinct from, but metastable with respect to, fully trioctahedral metamorphic chlorites. Temperature-related trends are modified by bulk composition, complicating their potential use for low-temperature geothermometry.

Download Full-text