Morphological instabilities in argon ion sputtered CoSi binary mixtures

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.

Download Full-text

Transmission Electron Microscopy Studies of Aluminum Oxidation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118254 ◽

1985 ◽

Vol 43 ◽

pp. 268-269

Author(s):

J.Y. Lee

Keyword(s):

Nucleation And Growth ◽

Ion Milling ◽

Cross Sectional ◽

Polycrystalline Aluminum ◽

Axis Orientation ◽

Temperature Oxidation ◽

Aluminum Oxidation ◽

Transmission Electron ◽

High Resolution Images ◽

Argon Ion

In the oxidation of metals and alloys, microstructural features at the atomic level play an important role in the nucleation and growth of the oxide, but little is known about the atomic mechanisms of high temperature oxidation. The present paper describes current progress on crystallographic aspects of aluminum oxidation. The 99.999% pure, polycrystalline aluminum was chemically polished and oxidized in 1 atm air at either 550°C or 600°C for times from 0.5 hr to 4 weeks. Cross-sectional specimens were prepared by forming a sandwich with epoxy, followed by mechanical polishing and then argon ion milling. High resolution images were recorded in a <110>oxide zone-axis orientation with a JE0L JEM 200CX microscope operated at 200 keV.

Download Full-text

Ultrastructural Features of Normal and Diseased Hair Revealed by Ion Beam Etching and Freeze Fracture

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115419 ◽

1975 ◽

Vol 33 ◽

pp. 358-359

Author(s):

M. Spector ◽

A. C. Brown

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Ectodermal Dysplasia ◽

Ion Beam ◽

Freeze Fracture ◽

Ion Current ◽

Ion Beam Etching ◽

Pili Torti ◽

Argon Ion ◽

Scanning Electron

Ion beam etching and freeze fracture techniques were utilized in conjunction with scanning electron microscopy to study the ultrastructure of normal and diseased human hair. Topographical differences in the cuticular scale of normal and diseased hair were demonstrated in previous scanning electron microscope studies. In the present study, ion beam etching and freeze fracture techniques were utilized to reveal subsurface ultrastructural features of the cuticle and cortex.Samples of normal and diseased hair including monilethrix, pili torti, pili annulati, and hidrotic ectodermal dysplasia were cut from areas near the base of the hair. In preparation for ion beam etching, untreated hairs were mounted on conducting tape on a conducting silicon substrate. The hairs were ion beam etched by an 18 ky argon ion beam (5μA ion current) from an ETEC ion beam etching device. The ion beam was oriented perpendicular to the substrate. The specimen remained stationary in the beam for exposures of 6 to 8 minutes.

Download Full-text

High-resolution transmission electron microscopic study of highly oxygen doped silicon layer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155438 ◽

1989 ◽

Vol 47 ◽

pp. 692-693

Author(s):

H. Takaoka ◽

M. Tomita ◽

T. Hayashi

Keyword(s):

High Resolution ◽

Oxygen Concentration ◽

Silicon Layer ◽

Detailed Structure ◽

Electron Microscopic ◽

Cross Sectional ◽

Transmission Electron ◽

Doped Silicon ◽

Argon Ion

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.

Download Full-text

The microstructure of a TiB2/Ti-47 Al composite material

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155347 ◽

1989 ◽

Vol 47 ◽

pp. 674-675

Author(s):

O. Popoola ◽

A.H. Heuer ◽

P. Pirouz

Keyword(s):

Composite Material ◽

Ion Beam ◽

Chemical Properties ◽

Intermetallic Alloys ◽

Transmission Electron ◽

Diamond Polishing ◽

Al Composite ◽

The Matrix ◽

Argon Ion ◽

And Chemical Properties

The addition of fibres or particles (TiB2, SiC etc.) into TiAl intermetallic alloys could increase their toughness without compromising their good high temperature mechanical and chemical properties. This paper briefly discribes the microstructure developed by a TiAl/TiB2 composite material fabricated with the XD™ process and forged at 960°C.The specimens for transmission electron microscopy (TEM) were prepared in the usual way (i.e. diamond polishing and argon ion beam thinning) and examined on a JEOL 4000EX for microstucture and on a Philips 400T equipped with a SiLi detector for microanalyses.The matrix was predominantly γ (TiAl with L10 structure) and α2(TisAl with DO 19 structure) phases with various morphologies shown in figure 1.

Download Full-text