Silicide Formation Reactions in a-Si/Co Multilayered Samples

2008 ◽  
Vol 277 ◽  
pp. 3-8
Author(s):  
Z. Balogh ◽  
Csaba Cserháti ◽  
Z. Erdélyi ◽  
A. Csik ◽  
G.A. Langer ◽  
...  
Keyword(s):  
Growth Rate ◽  
Solid State ◽  
Synchrotron Radiation ◽  
Magnetron Sputtering ◽  
Interface Reaction ◽  
Solid State Reactions ◽  
Silicide Formation ◽  
Parabolic Kinetics ◽  
Heat Treated ◽  
Interface Reaction Control

Solid state reactions between amorpous Si and crystalline Co have been investigated by synchrotron radiation at Bessy (Berlin, Germany). The multilayered samples (with 10 periods of a-Si(15 nm)/Co(15 nm) layers) were produced by magnetron sputtering and isothermally heat treated at temperatures between 523 and 593 K. From the time evolution of the XRD spectra first the growth rate of the CoSi phase as well as the decay rate of the Co layer we determined (at 523 and 543 K). The kinetics were described by a power law; tk, and for the growth of CoSi k=0.65 while for the loss of the Co the k=0.77 was obtained, respectively. At higher temperatures (at 573 and 593 K) the formation and growth of the Co2Si layer, at the expense of the Co and already existing CoSi layers, was observed with exponents of about 1 for all the above kinetics. These results, together with the results of resistance kinetics measurements, in similar multilayered as well as bi-layered samples at similar temperatures, providing similar exponents will be presented. Possibility of the interface reaction control and/or the effect of the diffusion asymmetry (which was recently published for the interpretation of solid state reactions with non-parabolic kinetics on the nanoscale) will be discussed.

Co Anomalous Growth Kinetics of the CoSi Reaction Layer in a Si/System

2008 ◽  
Vol 273-276 ◽  
pp. 99-104
Author(s):  
Csaba Cserháti ◽  
Györgyi Glodán ◽  
A. Csik ◽  
G.A. Langer ◽  
Z. Erdélyi ◽  
...  
Keyword(s):  
Solid State ◽  
Electrical Resistance ◽  
Interface Reaction ◽  
Solid State Reactions ◽  
Heat Treated ◽  
Different Temperatures ◽  
Amorphous Si ◽  
Kinetics Of ◽  
Interface Reaction Control ◽  
Anomalous Growth

Solid state reactions between amorphous Si and crystalline Co have been investigated by 4W electrical resistance and TEM. Multilayered (with 10 periods of 5nm a-Si/5nm Co and 10 nma- Si/10nm Co layers) as well as tri-layered samples (20nm a-Si/3nmCoSi/6nm Co) were produced by magnetron sputtering and isothermally heat treated at different temperatures between 473 and 523K. From the time evolution of the normalized resistance the kinetics of the process were determined by fitting a power law, tk, and k was between 0.8 and 1. Possibility of the interface reaction control and/or the effect of the diffusion asymmetry (which was recently published for the non-parabolic interface shifts on the nanoscale) will be discussed.

Non Parabolic Shift of Interfaces and Effect of Diffusion Asymmetry on Nanoscale Solid State Reactions

2009 ◽  
Vol 7 ◽  
pp. 43-49 ◽  
Author(s):  
Dezső L. Beke ◽  
Z. Erdélyi ◽  
Z. Balogh ◽  
Csaba Cserháti ◽  
G.L. Katona
Keyword(s):  
Experimental Data ◽  
Solid State ◽  
Interface Reaction ◽  
Diffuse Interface ◽  
Solid State Reactions ◽  
Diffusion Couples ◽  
Parent Materials ◽  
Parabolic Law ◽  
And Shifts ◽  
Interface Reaction Control

In a set of recent papers we have shown that the diffusion asymmetry in diffusion couples (the diffusion coefficient is orders of magnitude larger in one of the parent materials) leads to interesting phenomena: i) sharp interface remains sharp and shifts with non Fickian (anomalous) kinetics [1-5], ii) originally diffuse interface sharpens even in ideal (completely miscible) systems [6,7], iii) an initially existing thin AB phase in A/AB/B diffusion couple can be dissolved [8], iv) there exists a crossover thickness (typically between few nanometers and 1m) above which the interface shift turns back to the Fickian behaviour [9], v) the growth rate of a product of solid state reaction can be linear even if there is no any extra potential barrier present (which is the classical interpretation of the “interface reaction control” for linear kinetics) [10]. These latter results will be summarized and reformulated according to the usual expression for linear-parabolic law containing the interdiffusion coefficient, D, and interface transfer coefficient, K. Relation between the activation energies of D and K will be analyzed and compared with available experimental data.

Solid state reactions between Ni3Al and SiC

1990 ◽  
Vol 5 (9) ◽  
pp. 1985-1994 ◽  
Author(s):  
T. C. Chou ◽  
T. G. Nieh
Keyword(s):  
Growth Rate ◽  
Solid State ◽  
Solid State Reactions ◽  
Growth Rate Constant ◽  
Cross Sectional ◽  
Rate Limiting Step ◽  
Nial Phase ◽  
Reaction Zones ◽  
Carbon Precipitation ◽  
Terminal Component

Solid state reactions between SiC and Ni3Al were studied at 1000°C for different times. Multi-reaction-layers were generated in the interdiffusion zone. Cross-sectional views of the reaction zones show the presence of three distinguishable layers. The Ni3Al terminal component is followed by NiAl, Ni5.4Al1Si2, Ni(5.4−x)Al1Si2 + C layers, and the SiC terminal component. The Ni5.4Al1Si2 layer shows carbon precipitation free, while modulated carbon bands were formed in the Ni(5.4−x)Al1Si2 + C layer. The NiAl layer shows dramatic contrast difference with respect to the Ni3Al and Ni5.4Al1Si2 layers, and is bounded by the Ni3Al/NiAl and Ni5.4Al1Si2/NiAl phase boundaries. The kinetics of the NiAl formation is limited by diffusion, and the growth rate constant is measured to be 2 ⊠ 10−10 cm2/s. The thickness of the reaction zone on the SiC side is always thinner than that on the Ni3Al side and no parabolic growth rate is obeyed, suggesting that the decomposition of the SiC may be a rate limiting step for the SiC/Ni3Al reactions. The carbon precipitates were found to exist in either a disordered or partially ordered (graphitic) state, depending upon their locations from the SiC interface. The formation of NiAl phase is discussed based on an Al-rejection model, as a result of a prior formation of Ni–Al–Si ternary phase. A thermodynamic driving force for the SiC/Ni3Al reactions is suggested.

An Investigation on Solid State Reactions in Heat Treated Au/Pd Thin Films for Electrodes Applications

2010 ◽  
Vol 10 (4) ◽  
pp. 2635-2640 ◽  
Author(s):  
Soroush Nazarpour ◽  
Albert Cirera ◽  
Cèsar Ferrater ◽  
Jofre Ventura ◽  
Eric Langenberg ◽  
...  
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Solid State Reactions ◽  
Heat Treated

Isothermal study of rapid solid‐state reactions by synchrotron radiation

1985 ◽  
Vol 56 (5) ◽  
pp. 712-715 ◽  
Author(s):  
J. D. Ayers ◽  
W. T. Elam ◽  
C. L. Vold ◽  
S. B. Qadri ◽  
E. F. Skelton ◽  
...  
Keyword(s):  
Solid State ◽  
Synchrotron Radiation ◽  
Solid State Reactions

Fabrication of NiAl Intermetallic from Dense Elemental Powder Blends VIA Solid State Reactions

1996 ◽  
Vol 460 ◽  
Author(s):  
L. Farber ◽  
I. Gotman ◽  
E. Y. Gutmanas
Keyword(s):  
Solid State ◽  
Solid State Reactions ◽  
Full Density ◽  
Reaction Products ◽  
Liquid Phases ◽  
High Temperature Synthesis ◽  
Heat Treated ◽  
Micron Size ◽  
Different Temperatures ◽  
Two Stages

ABSTRACTDense NiAl intermetallic was synthesized from very fine elemental powders via solid state reactions. Homogeneous blends of micron size Ni and Al powders were consolidated to full density and heat treated in a 425–800°C temperature range. During heat treatment, formation of various intermediate intermetallics phases: NiAl3, Ni2A13, Ni3Al and NiAl was observed. The sequence and kinetics of these phase formations at different temperatures were studied employing X-ray diffraction analysis (XRD). A model for a description of synthesis reaction kinetics in Ni-Al blends was developed. Based on the obtained results, the synthesis of NiAl was performed in two stages : reactions in 425–550°C range with consumption of Al, followed by a reaction at up to 800°C. It allowed uncontrolled SHS (self propagating high temperature synthesis, resulting in the occurrence of liquid phases and in formation of reaction products in a very fast /explosive manner) to be avoid. The synthesis temperatures are considerably lower than those used currently in processing of NiAl.

Periodic Mesoporous SiCO Glasses with Cubic Symmetry Stable at 1000°C

2003 ◽  
Vol 775 ◽  
Author(s):  
Raphaël Blum ◽  
Valérie Goletto ◽  
Bérangére Toury ◽  
Florence Babonneau
Keyword(s):  
Solid State ◽  
Synchrotron Radiation ◽  
Solid State Nmr ◽  
X Ray Diffraction ◽  
Periodic Mesoporous Organosilica ◽  
Cubic Symmetry ◽  
X Ray ◽  
Mesoporous Organosilica ◽  
Heat Treated ◽  
Adsorption Desorption

AbstractA periodic mesoporous organosilica (PMO) with cubic Pm3n structure has been prepared from bis(trimethoxysilyl)ethane and cetytriethylammonium chloride. The sample has been heat treated under argon up to 1000°C, and the pyrolysis intermediates were analysed by X-ray diffraction using synchrotron radiation, multinuclear solid state NMR (29Si, 13C and 1H) and N2 adsorption-desorption experiments. The cubic Pm3n structure is retained after pyrolysis at 1000°C. The sample is a SiCO glass with mixed SiCxO4-x units (x = 0, 1, 2) and a very large surface area of 730 m2/g.

scholarly journals Structure evolution of h.c.p./c.c.p. metal oxide interfaces in solid-state reactions

2018 ◽  
Vol 74 (5) ◽  
pp. 466-480 ◽  
Author(s):  
C. Li ◽  
G. Habler ◽  
T. Griffiths ◽  
A. Rečnik ◽  
P. Jeřábek ◽  
...  
Keyword(s):  
Solid State ◽  
Interface Reaction ◽  
Solid State Reactions ◽  
Structure Evolution ◽  
Growth Stages ◽  
Partial Dislocations ◽  
Wide Range ◽  
Scanning Transmission ◽  
Growth Selection ◽  
Edge Dislocations

The structure of crystalline interfaces plays an important role in solid-state reactions. The Al2O3/MgAl2O4/MgO system provides an ideal model system for investigating the mechanisms underlying the migration of interfaces during interface reaction. MgAl2O4 layers have been grown between Al2O3 and MgO, and the atomic structure of Al2O3/MgAl2O4 interfaces at different growth stages was characterized using aberration-corrected scanning transmission electron microscopy. The oxygen sublattice transforms from hexagonal close-packed (h.c.p.) stacking in Al2O3 to cubic close-packed (c.c.p.) stacking in MgAl2O4. Partial dislocations associated with steps are observed at the interface. At the reaction-controlled early growth stages, such partial dislocations coexist with the edge dislocations. However, at the diffusion-controlled late growth stages, such partial dislocations are dominant. The observed structures indicate that progression of the Al2O3/MgAl2O4 interface into Al2O3 is accomplished by the glide of partial dislocations accompanied by the exchange of Al3+ and Mg2+ cations. The interface migration may be envisaged as a plane-by-plane zipper-like motion, which repeats along the interface facilitating its propagation. MgAl2O4 grains can adopt two crystallographic orientations with a twinning orientation relationship, and grow by dislocations gliding in opposite directions. Where the oppositely propagating partial dislocations and interface steps meet, interlinked twin boundaries and incoherent Σ3 grain boundaries form. The newly grown MgAl2O4 grains compete with each other, leading to a growth selection and successive coarsening of the MgAl2O4 grains. This understanding could help to interpret the interface reaction or phase transformation of a wide range of materials that exhibit a similar h.c.p./c.c.p. transition.

scholarly journals Overview of Cr2N And Cr2N/Ag Coatings On Cr-V Ledeburitic Steel: Mechanical Properties and Adhesion

2014 ◽  
Vol 22 (341) ◽  
pp. 125-130
Author(s):  
Pavel Bílek ◽  
Peter Jurči ◽  
Mária Hudáková ◽  
Ľubomír Čaplovič ◽  
Matej Pašák
Keyword(s):  
Mechanical Properties ◽  
Growth Rate ◽  
Magnetron Sputtering ◽  
Tool Steel ◽  
Low Pressure ◽  
Argon Atmosphere ◽  
Heat Treated ◽  
Matrix Influence

Abstract Samples made from Vanadis 6 PM ledeburitic tool steel were surface machined, ground and mirror polished. Prior the deposition, they were heat treated to a hardness of 60 HRC. Cr2N- and Cr2N/Ag-coatings were deposited by magnetron sputtering technique, using pure Cr and Ag targets, in a composite low pressure nitrogen/argon atmosphere and at a temperature of 500 °C. The contents of silver in Cr2N/Ag coatings were established 3, 7, 11 and 15 wt. %. Incorporation of silver in the Cr2N-matrix influence the growth rate, namely from the content of 11 wt. %. The nanohardness and Young´s modulus do not change until the content of 11 wt. % where slightly increased but further increasing of silver led to decreasing these values rapidly. The best adhesion was established for coatings with 3 and 7 wt. % of silver.

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