scholarly journals The transition from linear to-parabolic growth of Cu3Si phase in Cu/a-Si system

2018 ◽  
Vol 149 ◽  
pp. 36-39 ◽  
Author(s):  
Bence Parditka ◽  
Hanaa Zaka ◽  
Gábor Erdélyi ◽  
Gábor A. Langer ◽  
Mohammed Ibrahim ◽  
...  
Keyword(s):  
Parabolic Growth

An experimental confirmation of a parabolic growth relation

1986 ◽  
Vol 75 (3) ◽  
pp. 633-636 ◽  
Author(s):  
E. Schönherr ◽  
E. Winckler ◽  
R. Lauck
Keyword(s):  
Experimental Confirmation ◽  
Parabolic Growth

Tests on High-Pressure Water Rotational Jetting Ventilation Cooling Characteristic

2012 ◽  
Vol 594-597 ◽  
pp. 2073-2076
Author(s):  
Zhong Fei Ma ◽  
Li Chen ◽  
Fu Qin Wang
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
High Temperature ◽  
Cooling Rate ◽  
Temperature Difference ◽  
Water Pressure ◽  
Obvious Effect ◽  
Guide Vanes ◽  
Parabolic Growth ◽  
Pressure Water

In order to improve the cooling effect and practical applicability of falling temperature technique on high-temperature workplaces, the aeration and cooling principle of the high pressure water rotational jetting ventilation were analysed, and the experimental study was carried out. The results show that water pressure and cooling rate are an approximation of parabolic growth relationship, different structure of jet tube and temperature difference on water and gas also have an obvious effect on the cooling amplitude and air quantity. the guide vanes installed may improve effect of ventilation and cooling the capacity on high pressure water rotational jetting.

Analysis of the Rate of Oxidation of the Arema Steel at High-Temperature

2007 ◽  
Vol 263 ◽  
pp. 237-242
Author(s):  
Krzysztof Adamaszek ◽  
Zbigniew Jurasz
Keyword(s):  
High Temperature ◽  
Linear Dependence ◽  
Oxidation Time ◽  
Experimental Results ◽  
Silica Sand ◽  
Comparison Analysis ◽  
Chamber Furnace ◽  
Parabolic Growth

In this paper we give a presentation of the recently developed approaches concerned of the rate of oxidation the Arema steel at high-temperature in first stage of this process. The comparison analysis was performed on the basis of the experimental results of oxidation of cylindrical specimens made of above steel. The experiment was carried out in chamber furnace on series of specimen with dimension Φ = 20 , l=30 mm. The specimens were oxidized at 1000 °C for 10 - 2280 minutes in air and then quenched in silica sand, afterwards were measured and weighed both with and without of scale. The analysis reveals that for longer oxidation time than one hour influence of linear dependence on parabolic growth of scale can be neglected.

The Oxidation off Iron, Nickel and Cobalt-Base Alloys Containing Aluminum

CORROSION ◽  
1965 ◽  
Vol 21 (10) ◽  
pp. 316-326 ◽  
Author(s):  
W. C. HAGEL
Keyword(s):  
Weight Gain ◽  
Internal Oxidation ◽  
Outer Layer ◽  
Al Alloys ◽  
Reaction Products ◽  
Parabolic Growth ◽  
Iron Nickel ◽  
Α Al2o3 ◽  
Cobalt Base ◽  
Continuous Weight

Abstract By conducting continuous weight-gain measurements from 500 to 1300 C on a variety of Fe-Al, Fe-Cr-Al, Ni-Al and Co-Al alloys in oxygen at 100 torr and examining the reaction products which form, reasons for the enexpected ineffectiveness of preferential aluminum oxidation have been explored. With Fe-4.4 percent Al and Fe-12 percent Al, there are two different regions of parabolic growth- these are associated with the appearance of γ-A12O3 below 900 C and α-Al2O3 above. The latter is normally more protective but possesses a greater tendency for cracking and spalling; adding 24.6 percent chromium promotes its formation at lower temperatures. With Ni-5.0 percent Al, two displaced regions are also found; here, nickel penetrates alumina to provide intermediate NiO · Al2O3 and an outer layer of NiO. With Co-4 percent Al, somewhat less cobalt penetrates γ-Al2O3 to provide CoQ · Al2O3 and an outer layer of Co3O4. When both CoO and α-Al2O3 are stable phases, the latter grows mainly by internal oxidation and offers little protection.

Parabolic Growth Law for Coherent Oxides

1964 ◽  
Vol 41 (2) ◽  
pp. 509-514 ◽  
Author(s):  
A. T. Fromhold
Keyword(s):  
Parabolic Growth

Dependence between the Boron Surface Concentration and the Growth Kinetics of Boride Layers in AISI 4140 Steels

2010 ◽  
Vol 297-301 ◽  
pp. 294-299 ◽  
Author(s):  
M. Ortíz-Domínguez ◽  
Ivan Campos-Silva ◽  
José Martínez-Trinidad ◽  
Milton Elías-Espinosa ◽  
E. Hernández-Sánchez ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Thick Layer ◽  
Thermochemical Treatment ◽  
Surface Concentration ◽  
Material Surface ◽  
Growth Equation ◽  
Boron Diffusion ◽  
Parabolic Growth ◽  
Aisi 4140 ◽  
Kinetics Of

The present work estimated the growth kinetics of Fe2B layers formed at the surface of AISI 4140 steels. The thermochemical treatment was applied in order to produce the Fe2B phase, considering temperatures of 1123, 1173, 1223 and 1273 K with five exposure times (2, 4, 5, 6, and 8 h), using a 4 mm thick layer of boron carbide paste over the material surface. The growth of boride layers was described by the mass balance equation between phases in thermodynamic equilibrium, assuming that the growth of boride layers obeys the parabolic growth equation and the boron concentration at the interfaces remains constant. Also, the boron diffusion coefficient at the Fe2B ( ) was established as a function of boriding temperature. Likewise, the parabolic growth constant (k), the instantaneous velocity (v) of the Fe2B/substrate interface and the weight-gain of borided steels were established as a function of the parameters and , which are related to the boride incubation time ( ) and boron surface concentration ( ), respectively.

Modelling of the Growth of Fe2B Layers in AISI 1018 Steel

2012 ◽  
Vol 323-325 ◽  
pp. 401-406 ◽  
Author(s):  
Z. Nait Abdellah ◽  
Mourad Keddam ◽  
A. Elias
Keyword(s):  
Present Model ◽  
Mass Balance Equation ◽  
Growth Constant ◽  
Parabolic Growth ◽  
Solid Diffusion ◽  
Upper Limit ◽  
Growth Constants ◽  
Good Concordance ◽  
Parabolic Growth Constant ◽  
Kinetics Of

In this work, a simulation of the growth kinetics of layers on AISI 1018 steel was done by means of a kinetic model. This model considers a solid diffusion of boron into a semi-infinite medium where the boron solubility in the Fe phase depends on the process temperature. An expression of the parabolic growth constant was then obtained through an application of the mass balance equation at the (/substrate) interface. The present model was validated by the experimental data available in the reference work (I. Campos-Silva et al: Kovove Mater. Vol.47 (2009), p.1-9). A good concordance was observed between the experimental parabolic growth constants and the predicted ones by the model for an upper limit of boron in the phase equal to 8.91 wt.% ( as a fitting parameter of the model). In addition, the generated weight gain was estimated at the surface of the borided AISI 1018 steel as a function of the upper limit of boron in the phase and the temperature.

A Model for the Growth of Fe2B Layers on a Steel Substrate: Effect of the Surface Boron Concentration

2011 ◽  
Vol 170 ◽  
pp. 185-189 ◽  
Author(s):  
Mourad Keddam ◽  
Redoune Chegroune
Keyword(s):  
Boron Concentration ◽  
Steel Substrate ◽  
Material Surface ◽  
Substrate Interface ◽  
Parabolic Growth ◽  
Growth Constants ◽  
Good Concordance ◽  
Parabolic Growth Constant ◽  
Two Parameters ◽  
Relationship Of

The growth kinetics of Fe2B layers formed at the surface of AISI 1018 was simulated. The paste-boriding (with a paste thickness of 4 mm) was applied to produce the Fe2B phase at the material surface; considering four temperatures (1123, 1173, 1223 and 1273 K) for 2, 4, 5, 6 and 8 h. The suggested model was based on the mass balance equation at the (Fe2B /substrate) interface. As a fitting parameter of the model, the surface boron concentration (12.16 wt. %B) was obtained in order to predict with a good agreement the experimental parabolic growth constants at the (Fe2B /substrate) interface derived from the literature. An expression of the parabolic growth constant at the (Fe2B /substrate) interface was obtained as a function of the two parameters: and . In addition, a relationship of the Fe2B layer thickness was also deduced that showed a good concordance with the experimental results from the literature.

Study on the Growth of Nb3Sn Superconductor in Cu(Sn)/Nb Diffusion Couple

2010 ◽  
Vol 297-301 ◽  
pp. 467-471
Author(s):  
A.K. Kumar ◽  
T. Laurila ◽  
V. Vuorinen ◽  
Aloke Paul
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Diffusion Couple ◽  
Product Phase ◽  
Growth Constant ◽  
Bronze Alloy ◽  
Phase Layer ◽  
Parabolic Growth ◽  
Different Temperatures ◽  
Parabolic Growth Constant

Nb3Sn growth following the bronze technique, (i.e. by interdiffusion between Cu(Sn) alloy (bronze) and Nb) is one of the important methodologies to produce this superconductor. In this study, we have addressed the confusion over the growth rate of the Nb3Sn phase. Furthermore, a possible explanation for the corrugated layer in the multifilamentary structure is discussed. Kirkendall marker experiments were conducted to study the relative mobilities of the species, which also explained the reason for finding pores in the product phase layer. Based on the parabolic growth constant at different temperatures, the activation energy for the growth is determined. We have further explained the dramatic increase in the growth rate of the product phase by changing just one atomic percentage of Sn in the Cu-Sn bronze alloy.

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