Electron Microscopy Study of Stoichiometric and Non-Stoichiometric Titania

1997 ◽  
Vol 3 (S2) ◽  
pp. 669-670
Author(s):  
Solórzano I.G. ◽  
Kotani T. ◽  
Tuller H.L. ◽  
Van der Sande J.B.
Keyword(s):  
Electron Microscopy ◽  
Electric Activity ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Boundary Structure ◽  
High Tc Superconductors ◽  
High Tc ◽  
Grain Boundary Structure ◽  
Transmission Electron ◽  
Crystallographic Shear

It is currently well recognized that oxides are able to accommodate deviations from stoichiometry (1) and great advances in this understanding have been achieved by using transmission electron microscopy (TEM), particularly through lattice imaging and electron diffraction techniques (2). The physical properties of non-stoichiometric oxides are strongly influenced by their exact composition and for this reason they represent a class of materials with increasing and novel properties that are put to use in, for example, oxygen sensors and high-Tc superconductors. On the other hand, in electroceramic materials, such as TiO2, grain boundary structure and chemistry are important to be characterized in detail since these variables are responsible for the electric activity.Rutile (TiO2) can accommodate relatively large deviations from stoichiometry (TiOx with 2.0≥x≤ 1.75) by the crystallographic shear (CS) mechanism (1). The formation of CS planes is effectively a two-step process which involves the ordering of oxygen vacancies on a crystallographic plane and on their elimination by a shear of the lattice.

Factors influencing adhesive bonding at the bone/implant interface

1992 ◽  
Vol 50 (2) ◽  
pp. 1114-1115
Author(s):  
Julie A. Martini ◽  
Robert H. Doremus
Keyword(s):  
Electron Microscopy ◽  
Adhesive Bonding ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Bone Implant ◽  
Factors Influencing ◽  
Lr White ◽  
Transmission Electron ◽  
New Zealand White Rabbits ◽  
Scanning Electron

Tracy and Doremus have demonstrated chemical bonding between bone and hydroxylapatite with transmission electron microscopy. Now researchers ponder how to improve upon this bond in turn improving the life expectancy and biocompatibility of implantable orthopedic devices.This report focuses on a study of the- chemical influences on the interfacial integrity and strength. Pure hydroxylapatite (HAP), magnesium doped HAP, strontium doped HAP, bioglass and medical grade titanium cylinders were implanted into the tibial cortices of New Zealand white rabbits. After 12 weeks, the implants were retrieved for a scanning electron microscopy study coupled with energy dispersive spectroscopy.Following sacrifice and careful retrieval, the samples were dehydrated through a graduated series starting with 50% ethanol and continuing through 60, 70, 80, 90, 95, and 100% ethanol over a period of two days. The samples were embedded in LR White. Again a graduated series was used with solutions of 50, 75 and 100% LR White diluted in ethanol.

Transmission Electron Microscopy study of Bi-based superconducting phases

1990 ◽  
Vol 48 (4) ◽  
pp. 50-51
Author(s):  
J.G. Wen ◽  
K.K. Fung
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystals ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Space Groups ◽  
Superconducting Phases ◽  
Ceramic Samples ◽  
Transmission Electron ◽  
Modulated Structures

Bi-based superconducting phases have been found to be members of a structural series represented by Bi2Sr2Can−1Cun−1On+4, n=1,2,3, and are referred to as 2201, 2212, 2223 phases. All these phases are incommensurate modulated structures. The super space groups are P2/b, NBbmb 2201, 2212 phases respectively. Pb-doped ceramic samples and single crystals and Y-doped single crystals have been studied by transmission electron microscopy.Modulated structures of all Bi-based superconducting phases are in b-c plane, therefore, it is the best way to determine modulated structure and c parameter in diffraction pattern. FIG. 1,2,3 show diffraction patterns of three kinds of modulations in Pb-doped ceramic samples. Energy dispersive X-ray analysis (EDAX) confirms the presence of Pb in the three modulated structures. Parameters c are 3 0.06, 38.29, 30.24Å, ie 2212, 2223, 2212 phases for FIG. 1,2,3 respectively. Their average space groups are all Bbmb.

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