PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 3246608

Technique for preparing cross-section transmission electron microscopy specimens from ceramic oxide braze joints.

M L Santella·A T Fisher·C P Haltom
View original source ↗Export metadata ↓

Abstract

A method for preparing cross-section transmission electron microscopy specimens from alumina and partially stabilized zirconia braze joints is described. The technique relies on masking a mechanically dimpled 3-mm disc in order to avoid preferential thinning of the metallic braze filler alloy during ion milling. The results presented show that specimens made by this technique are suitable for characterizing the fine microstructural details of interfacial reactions at oxide surfaces that occur during brazing.

Explore related subjects

CeramicsMicroscopy, ElectronJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M L Santella, A T Fisher, C P Haltom. 1988. Technique for preparing cross-section transmission electron microscopy specimens from ceramic oxide braze joints.. https://doi.org/10.1002/jemt.1060080208

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Bioactive glass as precursor of designed-architecture scaffolds for tissue engineering.

In this work, the conditions to obtain concentrated and fluid suspensions from a bioactive glass (55-SiO(2); 41-CaO; 4-P(2)O(5); mol %) were investigated. The influence of the heat treatment of the glass on the specific surface area, solubility, bioactivity, and finally on their dispersion characteristics was studied. Zeta potential and viscosity measurements were carried out, and based on the obtained results, the best dispersant was selected. The optimum concentration of dispersant, maximum content of solid and time of mixing were also investigated. Slurries containing 50 vol % could be obtained calcining the glass at 1100 degrees C and using Darvan 811 (sodium polyacrylate) as dispersant. Scaffolds with designed architecture were prepared from these suspensions combining the gelcasting method and the stereolithography technique. A polymeric negative (replica of the desired structure) was previously obtained by stereolithography. The slurry was cast into the molds and then polymerized (gelcasting method). The negative was eliminated by heat treatment. After sintering at 1300 degrees C, scaffolds with interconnected porosity and three-dimensional channels of 400-470 microm and macropores of 1.4 microm were obtained.

Ceramics↗
PubMed2007

Effect of crystallization heat treatment on the microstructure and biaxial strength of fluorrichterite glass-ceramics.

The purpose of this study was to evaluate the effect of crystallization heat treatment on the flexural strength of potassium fluorrichterite glass-ceramics for biomedical applications. After melting and casting, discs were sectioned from the glass ingots, randomly divided into 10 groups, and heat treated at various temperatures ranging between 890 degrees C and 925 degrees C for various durations. One group was air-abraded after heat treatment. XRD revealed the presence of fluorrichterite and fluormica for all heat-treated groups. SEM confirmed the presence of both fluorrichterite and fluormica crystals. Crystal size increased with temperature and duration of the heat treatment. The mean flexural strength after air abrasion was not significantly different than that of the other groups except the group heat treated at 925 degrees C. The mean flexural strength was maximum after heat treatment at 900 degrees C for 1 h (497.6 +/- 25.5 MPa) and decreased linearly with the longer durations of heat treatment at 900 degrees C.

Ceramics↗
PubMed2007

Influence of contamination on bonding to zirconia ceramic.

The purpose of this study was to investigate the influences of contaminations and cleaning methods on bonding to dental zirconia ceramic. After saliva immersion and using silicone disclosing agent, airborne-particle abraded ceramic specimens were cleaned with isopropanol (AL), acetone (AC), 37% phosphoric acid (PA), additional airborne-particle abrasion (AA), or only with water rinsing (SS). Airborne-particle abraded specimens without contaminations (CL) were used as control group. For chemical analysis specimens of all groups were examined with X-ray photoelectron spectroscopy (XPS). Plexiglas tubes filled with composite resin were bonded to ceramic specimens using a phosphate-monomer containing composite luting resin. After 3-day water storage, tensile bond strengths (TBS) were tested. XPS analysis of group SS showed the presence of saliva and silicone (Si) contamination on the surface. The ratios of carbon/zirconium and oxygen/zirconium for groups PA and AA were comparable to those ratios obtained for group CL, indicating the removal of the organic saliva contamination. Airborne-particle abrasion and acetone completely removed Si contamination from ceramic surfaces. Isopropanol had little cleaning effect on the two contaminants. TBS (median +/- standard deviation) in MPa of the groups SS (11.6 +/- 3.1), AL (10.0 +/- 2.9), and AC (13.0 +/- 2.8) were statistically lower than those of groups PA (33.6 +/- 5.5), AA (40.1 +/- 3.6), and CL (47.0 +/- 8.1) (p < 0.001), while no differences were found in TBS between groups AA and CL (p > 0.5). Contamination significantly reduced bond strengths to zirconia ceramic. Airborne-particle abrasion was the most effective cleaning method.

Ceramics↗