B.J. Kestel

Non-acid electrolyte thins many materials for TEM without causing hydride formation

Abstract A new electropolishing solution for thinning metal TEM specimens has been developed. The solution, designated BK-2, consists of lithium chloride, magnesium perchlorate, butyl cellosolve, and methanol. It reduces the inventory of solutions needed in a lab, increases the quality and speed of specimen preparation, and is safer to use than most acidic electrolytes. In addition, it does not cause hydride formation in materials which are initially free of hydrogen.

Jet thinning of YBa2Cu3Ox high Tc superconductor and also gold for TEM with a non-acid electrolyte☆

Abstract Important new uses have been found for the electropolishing solution designated BK-2 which was published previously in Ultramicroscopy 19 (1986) 205–212. This solution allows electropolishing of non-porous YBa 2 Cu 3 O x superconductors. The production of clean, artifact-free specimens should prove valuable for the study of these superconductors. In addition, annealed bulk gold has been jet thinned with this solution without the use of hazardous solutions which contain cyanides.

Microstructural evolution and yield stress increase for ion-irradiated V15Cr5Ti alloy☆

The effect of 4-MeV 58Ni2+-ion irradiation on the microstructure of the V15Cr5Ti alloy was determined for irradiation temperatures ranging from 550 to 750°C and for damage levels of 50 to 260 dpa. The swelling of the alloy that could be attributed to voids was negligible ( < 0.1%). The principle effect of the irradiation was to induce the formation of disc-shape precipitates in the alloy microstructure. The increase of the yield stress for the alloy resulting from the irradiations was evaluated from the irradiation-produced dislocation density and the number density and size of irradiation-produced precipitates. These evaluations showed that the increase of yield stress for the alloy on ion irradiation had a maximum value at ~ 50 dpa and the increase of yield stress decreased for irradiation temperatures above 600°C.

Improved retention of precipitates in stainless steels during jet thinning for TEM

Abstract Difficulties are often encountered in the use of electrolytic jet polishing to produce TEM specimens from sensitized stainless steels because conventional electrolytes tend to preferentially attack the precipitate-laden grain boundaries. Some modified solutions have been developed which sucessfully solve the various thinning problems encountered with these materials.

Improved Methods and Novel Techniques for Jet Electropolishing of TEM Foils

Experience has shown that the difficulties encountered in jet polishing of TEM foils can be minimized by the selection of equipment and an electrolyte appropriate for each material. The use of a jet polishing instrument for more than one type of specimen preparation after minor modification will be presented. Some insights on the relationship and manipulation of the parameters involved in achieving well polished TEM foils having appropriate surface quality, thin area, and perforation size will be included. Methods used to develop new electrolytes for specific purposes and the results of their use on both conventional and superconducting materials will be shown. A technique to calibrate equipment for more reproducible specimen hole size, use of new electrolytes on various materials, the salvage of unsatisfactory foils, and thinning of undersized specimens will be reviewed.

Technique for preparation of TEM foils from two-phase uranium silicide

Abstract Thinning of U 3 Si containing a second phase of U 3 Si 2 for TEM is difficult because the precipitates are preferentially attacked by most electrolytes. The resulting foil contains several holes surrounded by inadequate thin areas. A solution has been developed which minimizes this problem and produces usable specimens.

Effect of helium on swelling and microstructural evolution in ion-irradiated V-15Cr-5Ti alloy☆

Abstract The effect of helium implantation on the swelling and microstructural evolution in the V-15Cr-5Ti alloy was determined from TEM observations of the alloy after either single-ion irradiation, dual-ion irradiation, or helium implantation followed by single-ion irradiation. In addition to the TEM observations of the irradiated alloy, the effect of helium implantation on the dependence of the RIS of solute atoms was determined by use of the AES, EDXS, and EELS techniques. The swelling of the alloy was negligible (

Preparation of damage-free glass TEM specimens

A jet polishing technique to chemically thin glass specimens for transmission electron microscopy (TEM) after a preliminary mechanical dimpling step has been developed. Slightly modified commercial equipment is used with automatic optical termination of the polishing process to produce foils exhibiting large, high quality, electron transparent regions.

Solute Segregation and Microstructural Evolution in Ion-Irradiated Vanadium-Base Alloys

The microstructural evolution in V + 14.7 Cr, V + 2.5 Mo, V + 2.5 W, V + 8.0 Ni, V + 5.3 Ti, V + 14.7 Cr + 5.2 Ti, V + 9.6 Cr + 3.1 Fe + 0.7 Zr, and V + 3.2 Ti + 1.8 Si alloys (concentrations in atomic percent), and unalloyed V was determined from observations of specimens by transmission electron microscopy (TEM) following 4.0-MeV 5 1 V + + ion irradiation at 900 to 970 K to 50 dpa. The radiation-induced segregation (RIS) of solutes in the ion-irradiated alloys was investigated by auger electron spectroscopy (AES), energy-dispersive X-ray spectroscopy (EDXS), and electron energy loss spectroscopy (EELS) analyses. The RIS of solutes and microstructural evolution in the irradiated alloys were correlated with the solute diffusivity and the relative chemical affinity of the substitutional solutes for oxygen.

In-Situ Irradiation Studies on the Effects of Helium on the Microstructural Evolution of V-3.8Cr-3.9Ti

Role of He in microstructural evolution of V-3.8Cr-3.9Ti was investigated by in-situ TEM of as-prepared and He implanted (<10 appM) samples subjected to 200 keV He irradiation at RT. Quantitative analysis showed an increase in defect density and size with irradiation in both. The unimplanted sample showed a defect density consistent with electron irradiation experiments. The He preimplanted sample had slightly larger defects and a substantially greater increase in number density of defects. This is consistent with a mechanism of He trapping by formation of He-vacancy-X (X=C,N,O) complexes.