Microstructural changes due to anodic polarisation of palladium and silver films on YSZ

Evidence for ordering (1-6) of interstitial impurities (O and C) has been obtained in b.c.c. metals, such as niobium and tantalum. In this paper we report the atomic and microstructural changes in an oxygenated c.p.h. metal (alpha titanium) as observed by transmission electron microscopy and diffraction.Oxygen was introduced into zone-refined iodide titanium sheets of 0.005 in. thickness in an atmosphere of oxygen and argon at 650°C, homogenized at 800°C and furnace-cooled in argon. Subsequently, thin foils were prepared by electrolytic polishing and examined in a JEM-7 electron microscope, operated at 100 KV.

Download Full-text

“Preparation of Single Crystalline Gold Films for ED Studies”

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096424 ◽

1972 ◽

Vol 30 ◽

pp. 634-635

Author(s):

Joseph D. C. Peng

Keyword(s):

Crystal Morphology ◽

Diffraction Theory ◽

Scattering Matrix ◽

Vacuum Evaporation ◽

Gold Films ◽

Matrix Formulation ◽

Silver Films ◽

Single Crystalline ◽

Grating Pattern ◽

Stacking Disorder

The relative intensities of the ED spots in a cross-grating pattern can be calculated using N-beam electron diffraction theory. The scattering matrix formulation of N-beam ED theory has been previously applied to imperfect microcrystals of gold containing stacking disorder (coherent twinning) in the (111) crystal plane. In the present experiment an effort has been made to grow single-crystalline, defect-free (111) gold films of a uniform and accurately know thickness using vacuum evaporation techniques. These represent stringent conditions to be met experimentally; however, if a meaningful comparison is to be made between theory and experiment, these factors must be carefully controlled. It is well-known that crystal morphology, perfection, and orientation each have pronounced effects on relative intensities in single crystals.The double evaporation method first suggested by Pashley was employed with some modifications. Oriented silver films of a thickness of about 1500Å were first grown by vacuum evaporation on freshly cleaved mica, with the substrate temperature at 285° C during evaporation with the deposition rate at 500-800Å/sec.

Download Full-text

Tensile Creep of Y-Si3N4: II. Cavitation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089172 ◽

1991 ◽

Vol 49 ◽

pp. 972-973 ◽

Cited By ~ 1

Author(s):

B. J. Hockey ◽

S. M. Wiederhorn

Keyword(s):

Silicon Nitride ◽

Creep Rupture ◽

Tensile Creep ◽

Sintering Aids ◽

Microstructural Changes

ATEM has been used to characterize three different silicon nitride materials after tensile creep in air at 1200 to 1400° C. In Part I, the microstructures and microstructural changes that occur during testing were described, and consistent with that description the designations and sintering aids for these materials were: W/YAS, a SiC whisker reinforced Si3N4 processed with yttria (6w/o) and alumina (1.5w/o); YAS, Si3N4 processed with yttria (6 w/o) and alumina (1.5w/o); and YS, Si3N4 processed with yttria (4.0 w/o). This paper, Part II, addresses the interfacial cavitation processes that occur in these materials and which are ultimately responsible for creep rupture.

Download Full-text