Oxide adherence of Fe-20Cr-4Al alloys with small amounts of sulfur and reactive elements (Y,Hf)

2000 ◽  
Vol 17 (1) ◽  
pp. 117-124 ◽  
Author(s):  
T. Amano ◽  
A. Hara ◽  
N. Sakai ◽  
K. Sasaki
Keyword(s):  
Reactive Elements ◽  
Oxide Adherence

High spatial resolution AEM observations of yttrium segregation in chromia scales grown on Co-45%Cr

1986 ◽  
Vol 44 ◽  
pp. 518-519
Author(s):  
K. Przybylski ◽  
A. J. Garratt-Reed ◽  
G. J. Yurek
Keyword(s):  
Spatial Resolution ◽  
Outer Surface ◽  
Maximum Concentration ◽  
High Spatial Resolution ◽  
Reactive Elements ◽  
Chromia Scales

The addition of so-called “reactive” elements such as yttrium to alloys is known to enhance the protective nature of Cr2O3 or Al2O3 scales. However, the mechanism by which this enhancement is achieved remains unclear. An A.E.M. study has been performed of scales grown at 1000°C for 25 hr. in pure O2 on Co-45%Cr implanted at 70 keV with 2x1016 atoms/cm2 of yttrium. In the unoxidized alloys it was calculated that the maximum concentration of Y was 13.9 wt% at a depth of about 17 nm. SIMS results showed that in the scale the yttrium remained near the outer surface.

scholarly journals Control of Valve Converters with Natural Current Characteristics

2018 ◽  
Vol 155 ◽  
pp. 01047 ◽  
Author(s):  
Sergazy Mendybayev ◽  
Yermek Sarsikeyev ◽  
Dameli Kapanova
Keyword(s):  
Reactive Elements ◽  
Electric Force ◽  
Current Characteristic ◽  
Current Converter ◽  
Characteristic Features ◽  
Current Characteristics ◽  
Valve Converter ◽  
Modulating Functions ◽  
Parametric Source

The article considers the valve converter with a natural current characteristic, which is called the current of parametric, for which the primary is not the source of the electric force but a parametric source of current, to the output of which connected to the counter-parallel thyristor sets assembled on the bridge scheme. The control of thyristors in the current converter is carried out taking into account the characteristic features of the parametric source, to avoid overvoltage on its reactive elements, analyzed algorithmic and modulating functions of the system borne temporary diagrams.

scholarly journals Cylindrical Dielectric Resonator Antennas with Harmonic Control as an Active Antenna Radiator

2009 ◽  
Vol 2009 ◽  
pp. 1-7
Author(s):  
L. Lucci ◽  
G. Manara ◽  
P. Nepa ◽  
G. Pelosi ◽  
S. Selleri
Keyword(s):  
Dielectric Resonator ◽  
Shape Factor ◽  
Satellite Communications ◽  
Reactive Elements ◽  
Active Antenna ◽  
Dielectric Resonator Antenna ◽  
Feed System ◽  
Dielectric Resonator Antennas ◽  
Harmonic Control ◽  
Integrated Antenna

A cylindrical dielectric resonator antenna is proposed as a radiator for an active integrated antenna. Harmonic tuning, which is the key step in designing active antenna radiators, is achieved via a combination of shape factor control over the resonator and insertion of reactive elements in the feed system. Numerical simulations are carried out in a finite elements framework and a layout for the complete antenna is proposed, aimed at compactness for subsequent utilization of the radiator as an element in an active array for satellite communications.

Analysis of Bulk Negative Differential Mobility Element in a Circuit Containing Reactive Elements

1972 ◽  
Vol 43 (1) ◽  
pp. 159-172 ◽  
Author(s):  
P. R. Solomon ◽  
M. P. Shaw ◽  
H. L. Grubin
Keyword(s):  
Reactive Elements ◽  
Differential Mobility

Interfacial Segregation in Oxide Scales on Nicrai-Based Alloys

1997 ◽  
Vol 3 (S2) ◽  
pp. 785-786
Author(s):  
K. Prüβner ◽  
K. B. Alexander ◽  
B. A. Pint ◽  
P. F. Tortorelli ◽  
I. G. Wright
Keyword(s):  
Cyclic Oxidation ◽  
Oxidation Behaviour ◽  
Reactive Elements ◽  
Oxide Scales ◽  
Protective Oxide ◽  
Form Complex ◽  
Scale Adhesion ◽  
Alumina Formers ◽  
Interfacial Segregation ◽  
Nicral Alloys

Previous studies addressing the segregation of reactive elements in protective oxide scales and their beneficial effect on scale adhesion have primarily concentrated on primary alumina-formers (e.g. β-NiAl + FeCrAl).In our study the oxidation behaviour of three NiCrAl alloys, which form complex scales was studied in air at 1423 K and at 1473 K, both in isothermal (100 h) and in cyclic oxidation (100 x lh). The composition (in at.-%) of these alloys is the following: General Electric alloy René N5 (64.9 Ni, 7.8 Cr, 13.9 Al, 0.1 Fe, 2.1 Ta, 0.05 Hf, 1.6 W, 1.0 Re, 0.15 Si, 7.3 Co, 0.9 Mo, 0.003 Y, 0.003 Zr, 4 ppm S, 0.25 C), Ni-7Cr-6.5Al+Y (80.1 Ni, 7.2 Cr, 12.5 Al, 0.01 Fe, 0.14 Si, 0.012 Y, 18 ppm S, 0.05 C) and Ni-10Cr-10Al+Y (71.2 Ni, 9.9 Cr, 18.8 Al, 0.01 Fe, 0.02 Si, 0.041 Y, 16 ppm S, 0.04 C).

scholarly journals Time-Varying Reactive Elements for Extreme Accumulation of Electromagnetic Energy

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
M.S. Mirmoosa ◽  
G.A. Ptitcyn ◽  
V.S. Asadchy ◽  
S.A. Tretyakov
Keyword(s):  
Electromagnetic Energy ◽  
Time Varying ◽  
Reactive Elements

Confined Gas Atomization: The Role of the Melt Delivery Tube in Particle Size Control

1986 ◽  
Vol 80 ◽  
Author(s):  
R. V. Raman
Keyword(s):  
Unique Feature ◽  
Size Control ◽  
Lower Surface ◽  
Spherical Particles ◽  
Gas Atomization ◽  
Reactive Elements ◽  
Delivery Tube ◽  
Atomization Process ◽  
Rapidly Solidified

AbstractGas atomization is one of the key processes used for the production of rapidly solidified materials. The unique feature of the gas atomization process is its capability to form spherical powders of multicomponent alloys containing reactive elements. Spherically shaped powder is specified in the secondary processing operations used in a number of applications. This requirement has resulted from the higher flow rate, better packing density, and lower surface area obtained in spherical particles compared to irregularly shaped particles.

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