The influence of annealing conditions on Ca/P ratio and phase transformations in bulk calcium phosphates

CrystEngComm ◽  
2022 ◽  
Author(s):  
Diana Griesiute ◽  
Eva Raudonyte-Svirbutaviciene ◽  
Aivaras Kareiva ◽  
Aleksej Zarkov

The present study investigates the influence of annealing conditions on phase transformations in calcium phosphates. Synthetic brushite (CaHPO4∙2H2O) with Ca/P ratio 1:1 was taken as a starting material and annealed...

2016 ◽  
Vol 52 (11) ◽  
pp. 1121-1125 ◽  
Author(s):  
M. A. Goldberg ◽  
V. V. Smirnov ◽  
O. S. Antonova ◽  
L. I. Shvorneva ◽  
S. V. Smirnov ◽  
...  

2007 ◽  
Vol 42 (19) ◽  
pp. 8357-8362 ◽  
Author(s):  
O. M. Clarkin ◽  
M. R. Towler ◽  
G. M. Insley ◽  
M. E. Murphy

Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.


Author(s):  
K. Barmak

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.


Author(s):  
P. Moine ◽  
G. M. Michal ◽  
R. Sinclair

Premartensitic effects in near equiatomic TiNi have been pointed out by several authors(1-5). These include anomalous contrast in electron microscopy images (mottling, striations, etc. ),diffraction effects(diffuse streaks, extra reflections, etc.), a resistivity peak above Ms (temperature at which a perceptible amount of martensite is formed without applied stress). However the structural changes occuring in this temperature range are not well understood. The purpose of this study is to clarify these phenomena.


2003 ◽  
Vol 112 ◽  
pp. 1043-1046 ◽  
Author(s):  
M. Nagasako ◽  
M. Nishida

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