Mössbauer study of sediment alteration produced by heat treatment

1994 ◽  
Vol 83 (1) ◽  
pp. 437-441
Author(s):  
F. Labenski de Kanter ◽  
S. Duhalde ◽  
C. Saragovi ◽  
R. J. March
1975 ◽  
Vol 40 (309) ◽  
pp. 79-88 ◽  
Author(s):  
C. S. Hogg ◽  
R. E. Meads

SummaryThe effect of heat treatment in air at temperatures from 200°C to 1000°C of two Cornish biotites has been studied using the M6ssbauer effect in 57Fe. One of the micas was also studied after heating in vacuo.Progressive changes in the Mössbauer spectra of the materials after heat treatment can be correlated with the following processes: Oxidation of Fe2+ ions in isolated octahedral sites to give Fe3+ in the co-ordination Fe3+(OsOH); oxidation of Fe2+ ions in adjacent a-octahedral (cis OH−) sites to give Fe3+(O6); and oxidation of Fe z+ in adjacent a and b (trans OH−) sites to give either Fe3+(O5OH) or Fe3+(O6) depending on whether a shared hydroxyl group remains intact or otherwise (these processes occur at temperatures below 500°C Also, at higher temperatures, dehydroxylation of Fe3+(O5OH) to give more Fe3+ in the Fe3+(O6) configuration. Finally, in the temperature range 900 to 1000°C structural breakdown yielding α-Fe2O3 as the iron-containing phase.The results and interpretation are in good agreement with thermogravimetric data and with a previous infra-red study. The mechanism of charge diffusion in the lattice during oxidation is discussed in the light of the results.


1979 ◽  
Vol 40 (C2) ◽  
pp. C2-481-C2-482
Author(s):  
C. H.W. Jones ◽  
M. Dombsky ◽  
A. F. Skinner

2008 ◽  
Vol 185 (1-3) ◽  
pp. 115-121
Author(s):  
Shiro Kubuki ◽  
Hiroshi Sakka ◽  
Kanako Tsuge ◽  
Zoltán Homonnay ◽  
Katalin Sinkó ◽  
...  

ICAME 2007 ◽  
2008 ◽  
pp. 795-801
Author(s):  
Shiro Kubuki ◽  
Hiroshi Sakka ◽  
Kanako Tsuge ◽  
Zoltán Homonnay ◽  
Katalin Sinkó ◽  
...  

Author(s):  
R. M. Anderson

Aluminum-copper-silicon thin films have been considered as an interconnection metallurgy for integrated circuit applications. Various schemes have been proposed to incorporate small percent-ages of silicon into films that typically contain two to five percent copper. We undertook a study of the total effect of silicon on the aluminum copper film as revealed by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and ion microprobe techniques as a function of the various deposition methods.X-ray investigations noted a change in solid solution concentration as a function of Si content before and after heat-treatment. The amount of solid solution in the Al increased with heat-treatment for films with ≥2% silicon and decreased for films <2% silicon.


Author(s):  
E. Bischoff ◽  
O. Sbaizero

Fiber or whisker reinforced ceramics show improved toughness and strength. Bridging by intact fibers in the crack wake and fiber pull-out after failure contribute to the additional toughness. These processes are strongly influenced by the sliding and debonding resistance of the interfacial region. The present study examines the interface in a laminated 0/90 composite consisting of SiC (Nicalon) fibers in a lithium-aluminum-silicate (LAS) glass-ceramic matrix. The material shows systematic changes in sliding resistance upon heat treatment.As-processed samples were annealed in air at 800 °C for 2, 4, 8, 16 and 100 h, and for comparison, in helium at 800 °C for 4 h. TEM specimen preparation of as processed and annealed material was performed with special care by cutting along directions having the fibers normal and parallel to the section plane, ultrasonic drilling, dimpling to 100 pm and final ionthinning. The specimen were lightly coated with Carbon and examined in an analytical TEM operated at 200 kV.


Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D. Matlock

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.


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