ChemInform Abstract: High-Temperature Electrochemical Synthesis of Tungsten and Molybdenum Boride Phases in Chloride-Cryolite-Oxide Melts.

ChemInform ◽  
2010 ◽  
Vol 29 (36) ◽  
pp. no-no
Author(s):  
V. V. MALYSHEV
Keyword(s):  
High Temperature ◽  
Electrochemical Synthesis ◽  
Molybdenum Boride ◽  
Boride Phases ◽  
Oxide Melts

ChemInform Abstract: High-Temperature Electrochemical Synthesis of Group VIa Metal Silicides in Halogenide-Oxide Melts

ChemInform ◽  
2010 ◽  
Vol 28 (21) ◽  
pp. no-no
Author(s):  
V. V. MALYSHEV ◽  
R. V. KUPRINA ◽  
I. A. NOVOSELOVA ◽  
T. V. VERKHOVLYUK
Keyword(s):  
High Temperature ◽  
Electrochemical Synthesis ◽  
Metal Silicides ◽  
Oxide Melts

scholarly journals Properties of high-temperature melts using levitation

2000 ◽  
Vol 72 (11) ◽  
pp. 2127-2136 ◽  
Author(s):  
Paul C. Nordine ◽  
J. K. Richard Weber ◽  
Johan G. Abadie
Keyword(s):  
High Temperature ◽  
Aluminum Oxide ◽  
High Temperatures ◽  
Yttrium Aluminum Oxide ◽  
Yttrium Aluminum ◽  
And Behavior ◽  
Oxide Melts

Containerless conditions allow well-controlled investigation of liquids at high temperatures. Levitation methods used for this purpose are reviewed, and their application is illustrated by discussion of the properties and behavior of deeply undercooled yttrium-aluminum-oxide melts.

Effect of Ruthenium, Rhenium and Yttria Additions on the Microstructure of Wide Gap Brazing of IN738

2007 ◽  
Author(s):  
Xiao Huang ◽  
Scott Yandt ◽  
Doug Nagy ◽  
Matthew Yao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Life Cycle Cost ◽  
Filler Metal ◽  
Braze Alloy ◽  
Cost Effective ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Wide Gap ◽  
Boride Phases

Modern gas and steam turbine components are subject to severe thermomechanical loads and extremely high temperature in order to provide increased performance and efficiency. Most high temperature turbine components are made of superalloys specifically developed for high temperature and high mechanical stress applications but at considerable cost. Defects may occur during manufacturing of superalloy castings as well as after service. Repair of these components, rather than replacement, helps to reduce the life cycle cost. Wide gap brazing is a cost effective and reliable means to repair gas turbine hot section components with defect sizes exceeding 0.3 mm. With proper control of the braze alloy and brazing cycle, the repaired region has been reported to posses mechanical properties approaching that of the parent materials. In order to further improve the mechanical properties of the repaired region and to explore the possibility of employing the wide gap brazing method to repair single crystal components in the future, three alloying additions, Ruthenium (Ru), Rhenium (Re) and yttria (Y2O3), were incorporated into the braze filler metal by mechanical alloying. The microstructures of the wide gap brazed joints with Ru, Re and yttria additions were studied and compared to a braze joint with standard wide gap braze alloys of IN738 and AWS BNi-9. It has been found that two types of borides formed in all braze alloys, namely eutectic γ-Ni-rich and boride phases and discrete boride containing primarily Cr and W (or Ru). The addition of Ru to the filler metal did not seem to modify the microstructural constituents after brazing. However, Ru partitioned strongly to the discrete borides. No isolated elemental Ru region was observed. On the other hand, Re addition was found to change the occurrence and distribution of both types of borides. The eutectic boride constituent was significantly reduced and finer discrete boride particles were observed. The addition of yttria did not change the boride formation but led to the generation of more voids in the brazed joint.

scholarly journals Recent developments in the structure of high temperature oxide melts

2014 ◽  
Vol 70 (a1) ◽  
pp. C1332-C1332
Author(s):  
Chris Benmore ◽  
Lawrie Skinner ◽  
Oliver Alderman ◽  
Anthony Tamalonis ◽  
J.K. Weber ◽  
...  
Keyword(s):  
High Temperature ◽  
Interatomic Potential ◽  
Standard Technique ◽  
High Energy ◽  
Oxidation Reactions ◽  
Recent Developments ◽  
High Temperature Oxide ◽  
Temperature Oxide ◽  
Dynamics Simulations ◽  
Oxide Melts

Aerodynamic levitation with laser heating has now become a standard technique for studying the structure of oxide melts on synchrotron and neutron beamlines. Here we summarize the results of a growing number of findings that show a distinct decrease in the local cation-oxygen coordination number, for liquid state single and binary oxides, compared to their crystalline forms. This phenomenon is often correlated with a significant decrease in density upon melting and diffraction measurements show a distribution of lower coordinated polyhedra. The diffraction data allow us to refine interatomic potential parameters within molecular dynamics simulations to obtain very good agreement between the structural models and experiments. The feasibility of very high temperature experiments around and above 3000 degrees Celsius, as well as the safety aspects associated with measuring radioactive samples will be discussed. Future prospects on changing the oxidation state of high temperature oxide melts through reduction-oxidation reactions will also be considered. The photograph below shows a Uranium dioxide pellet being loaded into the aerodynamic levitator on a high energy x-ray beam line at the APS prior to melting.

Sign in / Sign up

Export Citation Format

Share Document