Study on Properties of Cupriferous and Boracic Iron Based Sintered Composites

2013 ◽  
Vol 756-759 ◽  
pp. 80-84
Author(s):  
Ming Hua Jiao ◽  
Bing Chao Wan ◽  
Bai Wan Su ◽  
Shao Bo Ma ◽  
Yan Guo Yin
Keyword(s):  
Powder Metallurgy ◽  
Synergistic Effect ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Sinter Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Based ◽  
Self Lubricating Composites

Pre-configured powders were mixed uniformly through bonding granulation method. The boracic iron based self-lubricating composites with copper of different mass were prepared by the powder metallurgy press-sinter process. The tribological properties under different conditions of load were investigated on HDM20 end-face tribometer. The composite structure, the wear mechanism which copper affect the friction and wear behaviors of boracic iron based composites were analyzed by using X-ray diffraction, EDS and metallographic microscope. The results show that elementary copper which forming alloy phase could strengthen the combination of each phase in composites, playing the role of binder, improve the tribological properties. The synergistic effect between the phases combination, hardness and strength of Cu-20w composite were observably, which lead to the excellent tribological properties synthetically.

Tribological Properties of Cu Based Friction Composites with In Situ Synthesized TiC Filler

2010 ◽  
Vol 160-162 ◽  
pp. 35-47 ◽  
Author(s):  
Bai Ming Chen ◽  
Zheng Yu Zhang ◽  
Ming Xu Wang ◽  
Guo Cai Han ◽  
Liang An
Keyword(s):  
Powder Metallurgy ◽  
Friction Coefficient ◽  
Tribological Properties ◽  
Solid Lubricant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wear Rates ◽  
Ti Content

The Cu based friction composites using graphite as solid lubricant with different weight rations of Ti, i.e. 8 wt.%, 12 wt.%, 16 wt.%, 20 wt.%, were sintered by powder metallurgy (P/M) method. The structure of the composites was characterized by X-ray diffraction (XRD) and the tribological properties was studied on block-on-ring tester. XRD results verified presence of TiC phase which was in-situ synthesized through reaction of Ti and graphite in the composites, and the content of TiC was increased with the increased Ti content. The in-situ synthesized TiC phase which was fine and distributed uniformly improved tribological properties of Cu based friction composites significantly. The hardness, wear rates and friction coefficient of composites were increased with increasing amount of in-situ synthesized TiC.

Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said
Keyword(s):  
Active Sites ◽  
Isopropyl Alcohol ◽  
Oxide Catalyst ◽  
Flow System ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalyst Composition ◽  
Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

scholarly journals Modeling of magneto-conductivity of bismuth selenide: a topological insulator

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystal ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Field Range ◽  
X Ray ◽  
Bulk Carriers ◽  
Different Temperatures

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

scholarly journals Crystallization and X-ray diffraction data analysis of human deoxyhaemoglobin A0 fully stripped of any anions

1999 ◽  
Vol 55 (11) ◽  
pp. 1914-1916 ◽  
Author(s):  
F. A. V. Seixas ◽  
W. F. de Azevedo ◽  
M. F. Colombo
Keyword(s):  
Diffraction Data ◽  
Oxygen Affinity ◽  
X Ray Diffraction ◽  
Structural Explanation ◽  
Human Haemoglobin ◽  
X Ray ◽  
High Resolution Structure ◽  
Allosteric Properties

In this work, initial crystallographic studies of human haemoglobin (Hb) crystallized in isoionic and oxygen-free PEG solution are presented. Under these conditions, functional measurements of the O2-linked binding of water molecules and release of protons have evidenced that Hb assumes an unforeseen new allosteric conformation. The determination of the high-resolution structure of the crystal of human deoxy-Hb fully stripped of anions may provide a structural explanation for the role of anions in the allosteric properties of Hb and, particularly, for the influence of chloride on the Bohr effect, the mechanism by which Hb oxygen affinity is regulated by pH. X-ray diffraction data were collected to 1.87 Å resolution using a synchrotron-radiation source. Crystals belong to the space group P21212 and preliminary analysis revealed the presence of one tetramer in the asymmetric unit. The structure is currently being refined using maximum-likelihood protocols.

Tribological Behavior of Mesophase Carbon Added with Titanium and Copper

2011 ◽  
Vol 80-81 ◽  
pp. 60-63
Author(s):  
Xue Qing Yue ◽  
Hua Wang ◽  
Shu Ying Wang
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Friction Coefficient ◽  
Ball Mill ◽  
Friction And Wear ◽  
Applied Load ◽  
Tribological Behavior ◽  
Metallic Elements ◽  
X Ray Diffraction ◽  
X Ray

Incorporation of metallic elements, titanium and copper, into carbonaceous mesophase (CM) was performed through mechanical alloying in a ball mill apparatus. The structures of the raw CM as well as the Ti/Cu-added CM were characterized by X-ray diffraction. The tribological behavior of the Ti/Cu-added CM used as lubricating additives was investigated by using a high temperature friction and wear tester. The results show that, compared with the raw CM, the Ti/Cu-added CM exhibits a drop in the crystallinity and a transition to the amorphous. The Ti/Cu-added CM used as lubricating additive displays an obvious high temperature anti-friction and wear resistance effect, and the lager the applied load, the lower the friction coefficient and the wear severity.

Role of water in the surface relaxation of the fluorapatite (100) surface by grazing incidence x-ray diffraction

2007 ◽  
Vol 75 (3) ◽  
Author(s):  
Aparna Pareek ◽  
Xavier Torrelles ◽  
Jordi Rius ◽  
Uta Magdans ◽  
Hermann Gies
Keyword(s):  
Grazing Incidence ◽  
Surface Relaxation ◽  
X Ray Diffraction ◽  
X Ray

Influence of soil organic matter on sulfate retention in two Podzols in Quebec, Canada

1999 ◽  
Vol 79 (1) ◽  
pp. 103-109 ◽  
Author(s):  
F. Courchesne ◽  
J.-F. Laberge ◽  
A. Dufresne
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Ammonium Oxalate ◽  
X Ray Diffraction ◽  
Weighted Mean ◽  
Fine Silt ◽  
Mineral Horizon ◽  
Organic C ◽  
X Ray

The role of soil organic matter (OM) on SO4 retention was investigated by comparing OM content, SO4 retention, and the distribution of Fe, Al and Si compounds in OM-poor (Grands-Jardins, PGJ) and OM-rich (Hermine, HER) Podzols from Québec, Canada. At both sites, four pedons were sampled by horizon; soil pH in H2O, organic C, phosphate-extractable SO4 and, sodium pyrophosphate, acid ammonium oxalate and dithionite-citrate-bicarbonate (DCB) extractable Fe, Al and Si were measured for each mineral horizon. The mineralogy of the clay (<2 µm) and fine silt (2–20 µm) fractions of selected horizons was determined by X-ray diffraction (XRD) and infrared spectroscopy (IR). Weighted mean organic C and pyrophosphate extractable Fe and Al contents were significantly higher in the HER than in the PGJ sola, while the PGJ soils were richer in amorphous inorganic Al. No trends were observed for inorganic Fe compounds. Chemical dissolution and IR allowed the identification of short-range ordered aluminosilicates, probably allophane, in the OM-poor and slightly acidic to neutral PGJ soils. These materials were absent from the OM-rich and acidic HER soils. Phosphate extractions showed that the weighted mean native SO4 content was five times higher in the PGJ than in the HER soil. Finally, native SO4 was strongly related to inorganic Fe, Al and Si (associated with allophane) at PGJ but only to inorganic Fe at HER. These results indicate that OM indirectly affects SO4 sorption through the influence organic substances exerts on the nature and distribution of pedogenic Fe, Al and Si compounds, such as allophane, in Podzolic profiles. Key words: Organic matter, sulfate, imogolite, allophane, silica, Podzol

Effects of dietary alteration of bicarbonate and magnesium on rat bone

1986 ◽  
Vol 250 (2) ◽  
pp. F302-F307 ◽  
Author(s):  
J. M. Burnell ◽  
C. Liu ◽  
A. G. Miller ◽  
E. Teubner
Keyword(s):  
Crystal Structure ◽  
Bone Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growing Rats ◽  
Final Composition ◽  
Rat Bone

To study the effects of bicarbonate and magnesium on bone, mild acidosis and/or hypermagnesemia were produced in growing rats by feeding ammonium chloride and/or magnesium sulfate. Bone composition, quantitative histomorphometry, and mineral x-ray diffraction (XRD) characteristics were measured after 6 wk of treatment. The results demonstrated that both acidosis (decreased HCO3) and hypermagnesemia inhibited periosteal bone formation, and, when combined, results were summative; and the previously observed in vitro role of HCO3- and Mg2+ as inhibitors of crystal growth were confirmed in vivo. XRD measurements demonstrated that decreased plasma HCO3 resulted in larger crystals and increased Mg resulted in smaller crystals. However, the combined XRD effects of acidosis and hypermagnesemia resembled acidosis alone. It is postulated that the final composition and crystal structure of bone are strongly influenced by HCO3- and Mg2+, and the effects are mediated by the combined influence on both osteoblastic bone formation and the growth of hydroxyapatite.

Microstructure and Tribological Properties of Cu-Fe Based Braking Materials

2014 ◽  
Vol 941-944 ◽  
pp. 280-283
Author(s):  
Xiao Yang Wang ◽  
Hong Qiang Ru
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tribological Properties ◽  
X Ray Diffraction ◽  
Pressing Method ◽  
X Ray ◽  
The Coefficient Of Friction ◽  
Worn Surface ◽  
Scanning Electron ◽  
Sic Particle

SiC particle-reinforced Cu-Fe based braking materials were fabricated by the P/M hot pressing method. The phase composition, microstructure and the worn surface of the composite were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).The tribological properties were evaluated using a disk-on-disk type laboratory scale dynamometer. Results indicate that the friction coefficient is 0.42 in 6800rpm, 0.7MPa. With the increase of rotation speeds the coefficient of friction and stable rate were decreased.

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