Oxygen Effects in Mechanically Alloyed Si80 Ge20 Doped with GaP and P

1991 ◽  
Vol 234 ◽  
Author(s):  
B. A. Cook ◽  
J. L. Harringa ◽  
B. J. Beaudry
Keyword(s):  
Thermal Conductivity ◽  
Oxygen Content ◽  
Carrier Mobility ◽  
High Mobility ◽  
Fused Silica ◽  
High Oxygen ◽  
Low Oxygen ◽  
Total Oxygen ◽  
Mechanically Alloyed ◽  
Oxygen Effects

ABSTRACTA neutron activation study was performed to follow the total oxygen content during the preparation sequence of mechanically alloyed Si-20 at.% Ge n-type alloys using both elemental powders and chunk starting materials. The Si-20 at. % Ge alloys were doped with 1.6 at. % GaP and 3.4.at. % P and the total oxygen concentration was measured in the starting materials, after six hours of mechanical alloying in a helium environment, after hot pressing, and after a short 1100°C soak in fused silica ampoules. The alloys containing high oxygen levels showed low carrier mobility and low thermal conductivity whereas those containing low oxygen showed high mobility and thermal conductivity. The microstructure, as observed by optical metallography and SEM, was found to differ greatly with oxygen content as the low oxygen alloys showed relatively large, well defined grains and the high oxygen alloys showed evidence of poor sintering and limited grain growth.

The Influence of Diamond Addition to Ni-Al Powder on Oxidation Behavior of Ni-Al During Plasma Spraying for High Performance Oxide-Free Ni-Al Intermetallic Coating

2021 ◽  
Author(s):  
Li Zhang ◽  
Di Wang ◽  
Xian-Jin Liao ◽  
Xiao-Tao Luo ◽  
Chang-Jiu Li
Keyword(s):  
Oxygen Content ◽  
High Performance ◽  
Thermal Spraying ◽  
Low Oxygen ◽  
Mechanically Alloyed ◽  
Intermetallic Coating ◽  
Novel Approach ◽  
Ultrahigh Temperature ◽  
Diamond Powders ◽  
Plasma Sprayed

Abstract Ni-Al intermetallics have excellent corrosion and oxidation resistance, but their use in thermal spraying has been limited due to issues with in-flight oxidation. In this study, a novel approach is proposed to remove oxide from Ni-Al droplets in-flight by adding a deoxidizer (diamond) to the feedstock powder. A mixture of nickel, aluminum, and diamond powders was mechanically alloyed using a combination of cryogenic and planetary ball milling. The resulting Ni/Al/diamond composite powder was then plasma sprayed via the APS process, forming Ni-Al coatings on Inconel 738 substrates. Phase composition, microstructure, porosity, and microhardness of the coatings were characterized by X-ray diffraction, scanning electron microscopy, image analysis, and hardness testing, respectively. Oxygen content measurements showed that the coatings contained significantly less oxygen than coatings made from ordinary Ni/Al powders. In-flight particle temperatures were also measured and found to be higher than 2300 °C. The low oxygen content in the coatings is attributed to the in-situ deoxidizing effect of ultrahigh temperature droplets which are also oxide-free.

scholarly journals Study on edge cracking of titanium cold rolled sheet

2020 ◽  
Vol 321 ◽  
pp. 11017
Author(s):  
Hyunseok lee ◽  
Miseon Choi
Keyword(s):  
Cold Rolling ◽  
Oxygen Content ◽  
High Oxygen ◽  
Rolled Sheet ◽  
Low Oxygen ◽  
Fine Grained ◽  
Slip Bands ◽  
Cold Rolled ◽  
Edge Cracking ◽  
Rolling Deformation

In this study, to understand oxygen effects on workability of titanium, edge cracking and microstructure changes with the oxygen content variations in the cold rolled sheets were observed carefully and discussed. The higher oxygen content of titanium sheet, the more the edge cracks occurred after cold rolling deformation. While the specimen containing low oxygen became fine grained structures after the cold rolling, the other high oxygen sheets consisted of relatively coarse and elongated grains. The fine-grained structures was assumed to come from an active twinning behavior, meanwhile the other’s elongated structures were due to the twinning suppression by increasing oxygen contents. In addition, distinct shear bands were appeared in the high oxygen sheets after cold rolling. The high oxygen contents may multiply dislocation density by suppression of twinning and promoting dislocation slips. The increased dislocations can also produce a concentration of strain, slip bands thus appears during the cold rolling deformation. These slip bands cause the edge cracking in the higher oxygen sheets.

scholarly journals Effect of Zr Purity and Oxygen Content on the Structure and Mechanical Properties of Melt-Spun and Suction-Cast Cu46Zr42Al7Y5 Alloy

2016 ◽  
Vol 61 (2) ◽  
pp. 1215-1219 ◽  
Author(s):  
T. Kozieł ◽  
J. Latuch ◽  
G. Cios ◽  
P. Bała
Keyword(s):  
Mechanical Properties ◽  
Oxygen Content ◽  
Melt Spinning ◽  
Amorphous Structure ◽  
High Oxygen ◽  
Low Oxygen ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Arc Melting ◽  
Melt Spun

AbstractThe effect of oxygen content in zirconium on the structure and mechanical properties of the Cu46Zr42Al7Y5alloy, in the form of melt-spun ribbons and suction-cast rods, was investigated. Two types of Zr, rod and crystal bar of different nominal purities and oxygen contents, were used to synthesize the alloy by arc melting. Rapidly solidified ribbons were produced by melt spinning and their amorphous structures were confirmed by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). Bulk samples in the form of rods were cast using a special water-cooled suction casting unit attached to the arc melting system. XRD and DSC studies proved the amorphous structure of the bulk alloy synthesized from low-oxygen Zr and partial crystallization of the same alloy for high-oxygen Zr. In both bulk samples, uniformly distributed crystalline particles were identified as yttrium oxides. Higher mean compressive strength of amorphous alloy was observed. The hardness of amorphous phase was close to 500 HV1 in both bulk alloys, while the hardness of crystalline dendritic areas, observed in the alloy synthesized from high oxygen Zr, was lower by about 50 HV1.

scholarly journals Reoxidation of Al-Killed Steel by Cr2O3 from Tundish Cover Flux

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 554 ◽  
Author(s):  
Feng Wang ◽  
Daoxu Liu ◽  
Wei Liu ◽  
Shufeng Yang ◽  
Jingshe Li
Keyword(s):  
Experimental Study ◽  
Oxygen Content ◽  
Liquid Steel ◽  
Controlled Experiments ◽  
Low Oxygen ◽  
Total Oxygen ◽  
Total Oxygen Content

Reoxidation has long been a problem when casting ultra-low oxygen liquid steel. An experimental study of the reoxidation phenomenon caused by Cr2O3-bearing cover flux of Al-killed steel is presented here. MgO-CaO-SiO2-Al2O3-Cr2O3 tundish cover flux with various Cr2O3 contents were used to study the effects of Cr2O3 on total oxygen content (T[O]) and alumina and silicone loss of Al-killed steel at 1923 K (1650 °C). It was found that Cr2O3 can be reduced by Al to cause reoxidation, and the reaction occurs mainly within 2 to 3 min after the addition of the tundish cover flux with 5% and 10% Cr2O3 concentration. T[O] and Al loss increase with higher Cr2O3 concentration flux. Two controlled experiments were also made to investigate the oxygen transported to the steel by the decomposition of Cr2O3. It was calculated that when Al is present in steel, more than 90% of the reoxidation of Cr2O3 is caused by Al, and the rest is caused by decomposition.

scholarly journals High carrier mobility and ultralow thermal conductivity in the synthetic layered superlattice Sn4Bi10Se19

2021 ◽  
Author(s):  
Ruiming Lu ◽  
Alan Olvera ◽  
Trevor Bailey ◽  
Jiefei Fu ◽  
Xianli Su ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Crystal Lattice ◽  
Carrier Mobility ◽  
Complex Materials ◽  
High Carrier Mobility ◽  
High Carrier

The integration within the same crystal lattice of two or more structurally and chemically distinct building units enables the design of complex materials featuring the coexistence of dissimilar functionalities. Here...

Effect of the Sintering Atmosphere on the Corrosion Resistance of Titanium for Application as Biomaterial

2012 ◽  
Vol 727-728 ◽  
pp. 85-89
Author(s):  
Luzinete P. Barbosa ◽  
Elki C. Souza ◽  
Lucio Salgado ◽  
I. Costa
Keyword(s):  
Corrosion Resistance ◽  
Oxygen Content ◽  
Passive Film ◽  
Titanium Surface ◽  
Sintered Titanium ◽  
Nacl Solution ◽  
Low Oxygen ◽  
Sintering Atmosphere ◽  
Corrosion Tests ◽  
Vacuum Atmosphere

In this work, the effect of sintering atmosphere on the corrosion resistance of sintered titanium has been evaluated in 0.9 % aqueous NaCl solution to simulate physiological environment. Corrosion tests were performed on titanium porous sintered under vacuum and vacuum plus dynamic argon. The results showed better passive properties associated to the titanium sintered under argon plus vacuum atmosphere than to the vacuum sintered titanium. The better corrosion resistance of the argon plus vacuum sintered titanium was attributed to the formation of a thin passive film on the titanium surface during sintering due the low oxygen content present in this atmosphere.

Annealing of defects in irradiated silicon detector materials with high oxygen content

2005 ◽  
Vol 17 (22) ◽  
pp. S2247-S2253 ◽  
Author(s):  
M Mikelsen ◽  
E V Monakhov ◽  
G Alfieri ◽  
B S Avset ◽  
J Härkönen ◽  
...  
Keyword(s):  
Oxygen Content ◽  
Silicon Detector ◽  
High Oxygen ◽  
High Oxygen Content ◽  
Detector Materials
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