Reaction Diffusion in Diffusion Couples Ni-Al SolidSolution/Intermetallic NiAl and Ni/Intermetallic NiAl

2007 ◽  
pp. 77-82
Author(s):  
Toshimi Yamane ◽  
Kazushi Katayama ◽  
Yoritoshi Minamino ◽  
Hideki Araki
Keyword(s):  
Reaction Diffusion ◽  
Diffusion Couples

Reaction Diffusion in Diffusion Couples Ni-Al SolidSolution/Intermetallic NiAl and Ni/Intermetallic NiAl

2007 ◽  
Vol 127 ◽  
pp. 77-82
Author(s):  
Toshimi Yamane ◽  
Kazushi Katayama ◽  
Yoritoshi Minamino ◽  
Hideki Araki
Keyword(s):  
Reaction Diffusion ◽  
Diffusion Couples

scholarly journals Microscopic and Quantitative Investigations on PST Ti-Al / Ti Reaction Diffusion Couples

2002 ◽  
Vol 753 ◽  
Author(s):  
Ling Pan ◽  
David E. Luzzi
Keyword(s):  
Reaction Diffusion ◽  
Lamellar Thickness ◽  
Concentration Profiles ◽  
Controlled Growth ◽  
Diffusion Couples ◽  
Direction Parallel ◽  
Transmission Electron ◽  
Diffusion Controlled ◽  
Major Factors ◽  
Multi Phase

ABSTRACTInterdiffusion in multi-phase diffusion couples of polycrystalline Ti and polysynthetically twinned (PST) Ti-49.3 at.% Al, with the diffusion direction parallel to the lamellar planes, is investigated in the temperature range 973 – 1173 K. A reaction zone (RZ) of the a2-Ti3Al phase forms between the end materials and exhibits deeper penetration in the a2 lamellae than in the primary g lamellae. The mass balance and the lamellar thickness across the RZ / PST interface are believed to be the major factors that lead to the different behaviors in the penetration depth of the RZ. Direct measurements of the RZ thickness reveal a parabolic growth of the RZ, indicating a diffusion-controlled growth macroscopically. Concentration profiles from the Ti, through the RZ, into the PST g and a2 lamellae are measured by x-ray spectroscopy in a transmission electron microscope. Deviations from a diffusion-controlled composition profile indicate some extent of interface-controlled growth. Plateaus are seen in the concentration profiles in the RZ adjacent to the RZ/PST interface, extending through most of the deeply penetrated well region. The interfacial energy and strain energy are possible reasons for the plateaus. The interdiffusion coefficients are found to be largely independent of composition with a temperature dependence that obeys the Arrhenius relationship.

Reaction diffusion in Ni–Al diffusion couples in steady magnetic fields

2015 ◽  
Vol 641 ◽  
pp. 7-13 ◽  
Author(s):  
Chuanjun Li ◽  
Zhaojing Yuan ◽  
Rui Guo ◽  
Weidong Xuan ◽  
Zhongming Ren ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Reaction Diffusion ◽  
Diffusion Couples

Oxidation Behavior of TiAl3 Formed in Ti/Al Diffusion Couple and Reaction Diffusion in Ti/TiAl3 Multi-Phase Diffusion Couple

2006 ◽  
Vol 258-260 ◽  
pp. 340-345 ◽  
Author(s):  
Toshitada Shimozaki ◽  
Kenichi Takasaki ◽  
Takahisa Okino ◽  
C.G. Lee
Keyword(s):  
Diffusion Couple ◽  
Reaction Diffusion ◽  
Growth Rate Constant ◽  
Diffusion Couples ◽  
Coating Materials ◽  
Phase Diffusion ◽  
Temperature Range ◽  
Naoh Solution ◽  
Multi Phase ◽  
Interdiffusion Coefficients

Oxidation resistance of TiAl3, one of the candidates of coating materials for high temperature structural materials such as Ti3Al and TiAl, has been studied. Specimens were prepared by forming TiAl3 in Al/Ti/Al reaction diffusion couples at 923 K and then TiAl3 layer was exposed to air by dissolving Al plate in a 1N NaOH solution. The obtained TiAl3/Ti/TiAl3 couples were annealed in air in the temperature range from 1173 K to 1468 K. The oxidation rate was compared with that determined by using bulk TiAl3. The present data show a bend on the Arrhenius plot of parabolic phase growth rate constant, k2, at 1323 K. Above 1323K, the constant coincides well with the extrapolated values of bulk data while the value in the lower temperature range is larger than that of bulk specimens. During the oxidation experiments, intermetallic compounds Ti3Al, TiAl and TiAl2 were formed between Ti and TiAl3. Interdiffusion coefficients in the Ti3Al, TiAl phases determined from these diffusion couples are more than one order of magnitude larger than the interdiffusion coefficients determined by previous investigators from single-phase diffusion couples but coincide with the coefficients determined from multi-phase diffusion couples. This difference between interdiffusion coefficients has been discussed and explained by the effect of boundary diffusion in the diffusion layers formed in the multi-phase diffusion couples.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

Reaction couples of ceramic thin films prepared by CVD

1988 ◽  
Vol 46 ◽  
pp. 798-799
Author(s):  
D.W. Susnitzky ◽  
S.R. Summerfelt ◽  
C.B. Carter
Keyword(s):  
Thin Film ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Solid State Reactions ◽  
Spatial Distributions ◽  
Diffusion Couples ◽  
Kinetics Studies ◽  
Ceramic Thin Films ◽  
Initial Stage

Solid-state reactions have traditionally been studied in the form of diffusion couples. This ‘bulk’ approach has been modified, for the specific case of the reaction between NiO and Al2O3, by growing NiAl2O4 (spinel) from electron-transparent Al2O3 TEM foils which had been exposed to NiO vapor at 1415°C. This latter ‘thin-film’ approach has been used to characterize the initial stage of spinel formation and to produce clean phase boundaries since further TEM preparation is not required after the reaction is completed. The present study demonstrates that chemical-vapor deposition (CVD) can be used to deposit NiO particles, with controlled size and spatial distributions, onto Al2O3 TEM specimens. Chemical reactions do not occur during the deposition process, since CVD is a relatively low-temperature technique, and thus the NiO-Al2O3 interface can be characterized. Moreover, a series of annealing treatments can be performed on the same sample which allows both Ni0-NiAl2O4 and NiAl2O4-Al2O3 interfaces to be characterized and which therefore makes this technique amenable to kinetics studies of thin-film reactions.

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