Kinetics of solid-state reactions between zirconium thin film and silicon carbide at elevated temperatures

1983 ◽

Vol 41 ◽

pp. 54-55

Author(s):

K. M. Ostyn ◽

H. Schmalzried ◽

C. B. Carter

Keyword(s):

Solid Solution ◽

Solid State ◽

Solid State Reaction ◽

Elevated Temperatures ◽

Solid State Reactions ◽

Second Phase ◽

Oxide Interfaces ◽

Valence States ◽

Internal Reaction ◽

Kinetics Of

The usual method of forming the spinel AB2O4 by a solid-state reaction is to bring two oxides, AO and B2O3, into contact with one another at elevated temperatures, where diffusion is fast. The spinel then grows into both parent oxides; the kinetics of this solid-state reaction are well understood. Spinel can also be formed by exsoluting it as a second-phase in an oxide matrix. The two distinct internal reaction systems which have been used in this study are internal reduction and internal oxidation. Starting with an (Al-xBx)2O3 (x<1) solid solution, where one of the cations (B) can exist in at least two different valence states, it is possible to form spinel particles in an almost pure A2O3 matrix by internal reduction. Similarly, an (Al-xBX)O solid solution can be internally oxidized to form spinel in an almost pure AO matrix.

Download Full-text

Electron Microscopy Evidence of Interfacial Steps Controlling the Kinetics of NiSi2 Formation

MRS Proceedings ◽

10.1557/proc-320-221 ◽

1993 ◽

Vol 320 ◽

Cited By ~ 5

Author(s):

D. Hesse ◽

P. Werner ◽

J. Heydenreich ◽

R. Mattheis

Keyword(s):

Thin Film ◽

Electron Microscopy ◽

Relaxation Time ◽

Solid State ◽

Solid State Reactions ◽

Finite Rate ◽

Kinetic Reaction ◽

Reaction Barriers ◽

Kinetics Of ◽

Lateral Propagation

ABSTRACTThe kinetics and phase formation sequence of thin-film solid-state reactions, including silicide forming reactions, have frequently been considered to be controlled by interfacial kinetic reaction barriers. These are purely phenomenological quantities which describe the finite rate of the interfacial reaction in terms of limited particle fluxes crossing the respective interfaces. No atomic mechanisms that might be responsible for the action of such barriers have so far been indicated, with the exception of Schmalzried's formulation. The latter says that the interfacial barrier is due to the limited relaxation time needed by the particles to rearrange into the proper sublattice after having crossed the interface. We present correlated kinetic and structural observations during the 2Ni + Si → NiSi2 reaction on the Si(111) surface and discuss them with the help of a model involving the formation and lateral propagation of interfacial steps of different height. The model allows us to explain the kinetic observations by reaction barriers formed as a result of the crystallographic boundary conditions of the reaction.

Download Full-text

Reordering and Crystallization of Silicon Carbide Amorphized by Neutron Irradiation

MRS Proceedings ◽

10.1557/proc-650-r5.1 ◽

2000 ◽

Vol 650 ◽

Author(s):

Lance L. Snead ◽

Martin Balden

Keyword(s):

Thin Film ◽

Silicon Carbide ◽

Crystallization Kinetics ◽

Neutron Irradiation ◽

Onset Temperature ◽

Kinetics Of Crystallization ◽

Crystallization Onset Temperature ◽

Crystallization Onset ◽

Kinetics Of

ABSTRACTDensification and crystallization kinetics of bulk SiC amorphized by neutron irradiation is studied. The temperature of crystallization onset of this highly pure, fully amorphous bulk SiC was found to be between 875-885°C and crystallization is nearly complete by 950°C. In-situ TEM imaging confirms the onset of crystallization, though thin-film effects apparently alter the kinetics of crystallization above this temperature. It requires >1125°C for complete crystallization of the TEM foil. Annealing at temperatures between the irradiation and crystallization onset temperature is seen to cause significant densification attributed to a relaxation, or reordering, of the as-amorphized structure.

Download Full-text

Electric-Field Effects on Reactions Between Oxides

MRS Proceedings ◽

10.1557/proc-481-303 ◽

1997 ◽

Vol 481 ◽

Author(s):

Matthew T. Johnson ◽

Shelley R. Gilliss ◽

C. Barry Carter

Keyword(s):

Solid State ◽

Electric Field ◽

Elevated Temperatures ◽

Ionic Current ◽

Reaction Rates ◽

Solid State Reactions ◽

Interfacial Stability ◽

Electric Field Effects ◽

Thin Film Diffusion ◽

Microscopy Techniques

ABSTRACTThin films of In2O3 and Fe2O3 have been deposited on (001) MgO using pulsed-laser deposition (PLD). These thin-film diffusion couples were then reacted in an applied electric field at elevated temperatures. In this type of solid-state reaction, both the reaction rate and the interfacial stability are affected by the transport properties of the reacting ions. The electric field provides a very large external driving force that influences the diffusion of the cations in the constitutive layers. This induced ionic current causes changes in the reaction rates, interfacial stability and distribution of the phases. Through the use of electron microscopy techniques the reaction kinetics and interface morphology have been investigated in these spinel-forming systems, to gain a better understanding of the influence of an electric field on solid-state reactions.

Download Full-text