Observation of solid-state reaction between a thin yttria film and a (0001) α-alumina substrate

1994 ◽  
Vol 52 ◽  
pp. 644-645
Author(s):  
J. R. Heffelfinger ◽  
C. B. Carter
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Solid State Reaction ◽  
Yttrium Aluminum Garnet ◽  
Secondary Phase ◽  
Ceramic Composites ◽  
Alumina Substrate ◽  
Transmission Electron ◽  
Alumina Fibers ◽  
Optical Applications

Transmission-electron microscopy (TEM), scanning-electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were used to investigate the solid-state reaction between a thin yttria film and a (0001) α-alumina substrate. Systems containing Y2O3 (yttria) and Al2O3 (alumina) are seen in many technologically relevant applications. For example, yttria is being explored as a coating material for alumina fibers for metal-ceramic composites. The coating serves as a diffusion barrier and protects the alumina fiber from reacting with the metal matrix. With sufficient time and temperature, yttria in contact with alumina will react to form one or a combination of phases shown by the phase diagram in Figure l. Of the reaction phases, yttrium aluminum garnet (YAG) is used as a material for lasers and other optical applications. In a different application, YAG is formed as a secondary phase in the sintering of AIN. Yttria is added to AIN as a sintering aid and acts as an oxygen getter by reacting with the alumina in AIN to form YAG.

Evolution of Yttrium Aluminum Garnet Films by Solid-State Reaction

1993 ◽  
Vol 317 ◽  
Author(s):  
Jason R. Heffelfinger ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Reaction Temperature ◽  
Solid State Reaction ◽  
Yttrium Aluminum Garnet ◽  
Reaction Products ◽  
Cross Sectional ◽  
Garnet Films ◽  
Transmission Electron ◽  
Yttrium Aluminum

ABSTRACTYttrium aluminum garnet (YAG) films were produced by reacting thin Y2O3 layers with single-crystal Al2O3 substrates. Y2O3 films were deposited using pulsed-laser deposition (PLD), which produced smooth textured films on specially prepared (0001) α-Al2O3 substrates. Solid-state reaction of the Y2O3 with the Al2O3 was induced by specific heat treatments. Transmission-electron microscopy was used to characterize the reaction products of each heat treatment. For a reaction temperature of 1200°C, cross-sectional TEM specimens revealed the development of Monoclinic Y4Al2O9 at the interface between the Y2O3 and the Al2O3. Development of YAG was seen to occur at the interface between the Al2O3 and the Y4Al2O9 for a slightly higher reaction temperature of 1250°C. The Metastable Y4Al2O9 phase and the Y2O3 phase were found to be consumed at higher reaction temperatures to form the equilibrium Y3Al5O12 (YAG) phase. The Morphology of the YAG film was characterized by scanning-electron microscopy.

Solid-State Reactions in Fe/Si Multilayer Nanofilms

2014 ◽  
Vol 215 ◽  
pp. 144-149 ◽  
Author(s):  
Sergey M. Zharkov ◽  
Roman R. Altunin ◽  
Evgeny T. Moiseenko ◽  
Galina M. Zeer ◽  
Sergey N. Varnakov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Electron Diffraction ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Solid State Reactions ◽  
Transmission Electron ◽  
Reaction Processes

Solid-state reaction processes in Fe/Si multilayer nanofilms have been studied in situ by the methods of transmission electron microscopy and electron diffraction in the process of heating from room temperature up to 900ºС at a heating rate of 8-10ºС/min. The solid-state reaction between the nanolayers of iron and silicon has been established to begin at 350-450ºС increasing with the thickness of the iron layer.

Kinetics of the solid-state reaction for the formation of amorphous ZrCo studied by electrical conductance measurements

1988 ◽  
Vol 3 (3) ◽  
pp. 461-465 ◽  
Author(s):  
H. Schröder ◽  
K. Samwer
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Solid State ◽  
Solid State Reaction ◽  
Linear Time ◽  
Electrical Conductance ◽  
Reaction Times ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Kinetics Of

Thin-film reactions of Co with Zr have been studied in the temperature range between 473 and 523 K by electrical conductance measurements and cross-sectional transmission electron microscopy (CS-TEM). The reduction of the electrical conductance during the solid state reaction is explained by formation and growth of an amorphous phase at every Zr/Co interface. For long reaction times the growth of the layer thickness follows a shifted $\sqrt t$ law. For short reaction times the measurements show a linear time law, which is expected for an interface limited reaction.

scholarly journals In Situ Transmission Electron Microscopy Analysis of Copper–Germanium Nanowire Solid-State Reaction

Nano Letters ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 8365-8371 ◽  
Author(s):  
Khalil El hajraoui ◽  
Eric Robin ◽  
Clemens Zeiner ◽  
Alois Lugstein ◽  
Stéphanie Kodjikian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Solid State Reaction ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

Solid-state reaction mechanism for the formation of Ba6−xLn8+2 x/3Ti18O54 (Ln = Nd, Sm) solid solutions

2001 ◽  
Vol 16 (8) ◽  
pp. 2350-2356 ◽  
Author(s):  
Anatolii G Belous ◽  
Oleg V. Ovchar ◽  
Matjaz Valant ◽  
Danilo Suvorov
Keyword(s):  
Electron Microscopy ◽  
Reaction Mechanism ◽  
Solid State ◽  
Solid Solutions ◽  
Solid State Reaction ◽  
Thermal Analyses ◽  
Homogeneity Region ◽  
Structural Defects ◽  
X Ray ◽  
Transmission Electron

A solid-state reaction mechanism for the formation of Ba6−xLn8+2x /3Ti18O54 (Ln = Nd, Sm) solid solutions has been studied using x-ray powder diffraction, thermal analyses, and transmission electron microscopy (TEM). During the interaction of the starting reagents, Ln2Ti2O7, BaTi4O9, and BaTiO3 are formed. In the next sequence, these three phases react together to form a high-x end member of the Ba6−xLn8+2x /3Ti18O54 homogeneity region (Ba3.9Nd9.4Ti18O54 and Ba3.9Sm9.4Ti18O54). Subsequently, the reaction of Ba3.9Nd9.4Ti18O54 and Ba3.9Sm9.4Ti18O54 with the residual BaTiO3 takes place. TEM investigations revealed that compositional inhomogeneities and structural defects existed in the Ba4Sm9.33Ti18O54 sample heated at 1370 °C for 1 h. Sintering times, prolonged to ≥3 h, eliminated the structural defects and increased the homogeneity of the sample.

Transmission Electron Microscopy of an Aluminum-Silver-Stainless Steel Solid State Bond

1985 ◽  
Vol 43 ◽  
pp. 172-173
Author(s):  
M. J. Carr ◽  
J. F. Shewbridge ◽  
T. O. Wilford
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Specimen Preparation ◽  
Dimensional Control ◽  
Tem Analysis ◽  
Metal Parts ◽  
Dissimilar Metal ◽  
Transmission Electron ◽  
Short Time

Strong solid state bonds are routinely produced between physical vapor deposited (PVD) silver coatings deposited on sputter cleaned surfaces of two dissimilar metal parts. The low temperature (200°C) and short time (10 min) used in the bonding cycle are advantageous from the standpoint of productivity and dimensional control. These conditions unfortunately produce no microstructural changes at or near the interface that are detectable by optical, SEM, or microprobe examination. Microstructural problems arising at these interfaces could therefore easily go undetected by these techniques. TEM analysis has not been previously applied to this problem because of the difficulty in specimen preparation. The purpose of this paper is to describe our technique for preparing specimens from solid state bonds and to present our initial observations of the microstructural details of such bonds.

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