Pressureless Melt Infiltrated Non-Oxide Ceramic-Metal Composites

2008 ◽  
Vol 403 ◽  
pp. 251-252
Author(s):  
A. Kalemtas ◽  
Gürsoy Arslan ◽  
Ferhat Kara
Keyword(s):  
Oxide Ceramic ◽  
Light Weight ◽  
X Ray Diffraction ◽  
Infiltration Process ◽  
Metal Composites ◽  
X Ray ◽  
Melt Infiltration ◽  
In Situ Reactions ◽  
B4c Powder

In the present study highly dense (open porosity < 1 %), light-weight (d £ 2.85 g/cm3) and Al4C3-free non-oxide ceramic-metal composites were produced at comparatively low temperatures ( 1250°C) by pressurless melt infiltration. Phase analysis of the SiC-B4C-Al composites revealed that a significant amount of hygroscopic Al4SiC4 and Al4C3 phases were formed. Si3N4 powder was added in different amounts to the SiC-B4C powder batches to suppress formation of these phases via in-situ reactions during the infiltration process. X-ray diffraction results of the SiC-B4C-Si3N4-Al composites confirmed that the incorporation of Si3N4 to the SiC-B4C system reduced or eliminated the formation of the hygroscopic phases and resulted in in-situ formation of AlN, SiC and Si phases in the composite.

Effect of Al and ZrO2 on Sinterability and Mechanical Properties of B4C

2010 ◽  
Vol 160-162 ◽  
pp. 1494-1497
Author(s):  
Wen Song Lin ◽  
Liang He
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Single Phase ◽  
Sintering Process ◽  
Densification Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rich Solution ◽  
In Situ Reactions

Ceramics composites of B4C matrix with 5 wt% Al and various amount of ZrO2 additives were pressureless sintered under vacuum at 2250 °C for 60 min. Density, hardness, flexural strength and microstructure of the specimens were measured and characterized. Densities above 97% theoretical density (TD) were determined in the samples prepared with the addition of 8 wt% ZrO2 and 5 wt% Al, compared to 86% TD for single-phase B4C. X-ray diffraction analysis showed that B2O3 (impurity in B4C) was eliminated and new phases (ZrB2 and B4C1-x) were formed in the sintered samples, suggesting that in situ reactions between B4C/B2O3 and Al/ZrO2 happened during sintering process. It was showed that the elimination of B2O3 and the forming of boron rich solution of B4C1-x significantly improved the sinterability of B4C matrix ceramics, and consequently enhanced the densification rate greatly. The flexural strength and Vickers hardness of the sintered samples with addition of 8 wt% ZrO2 and 5 wt% Aluminum reached the value of 560 MPa and 30.2 GPa respectively, much higher than those of single-phase B4C ceramics.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

In-situ Investigation of Bainite Formation with fast X-Ray Diffraction (iXRD)

2017 ◽  
Vol 72 (6) ◽  
pp. 355-364
Author(s):  
A. Kopp ◽  
T. Bernthaler ◽  
D. Schmid ◽  
G. Ketzer-Raichle ◽  
G. Schneider
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Investigation

Texture Evolution Under Fast Heating and Cooling Rates of Zirconium Alloys Studied In-Situ by Synchrotron X-Ray Diffraction

2020 ◽  
Author(s):  
Chi-Toan Nguyen ◽  
Alistair Garner ◽  
Javier Romero ◽  
Antoine Ambard ◽  
Michael Preuss ◽  
...  
Keyword(s):  
Texture Evolution ◽  
Zirconium Alloys ◽  
X Ray Diffraction ◽  
Fast Heating ◽  
Cooling Rates ◽  
X Ray ◽  
Heating And Cooling

STRUCTURAL EVOLUTION OF EXCEPTIONALLY IRON-DEFICIENT HEMATITE NANOCRYSTALS AS OBSERVED BY IN SITU SYNCHROTRON X-RAY DIFFRACTION

2019 ◽  
Author(s):  
Si Athena Chen ◽  
◽  
Peter Heaney ◽  
Jeffrey E. Post ◽  
Peter J. Eng ◽  
...  
Keyword(s):  
Structural Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Deficient

In situ X-ray diffraction techniques as a powerful tool to study battery electrode materials

2002 ◽  
Vol 47 (19) ◽  
pp. 3137-3149 ◽  
Author(s):  
M. Morcrette ◽  
Y. Chabre ◽  
G. Vaughan ◽  
G. Amatucci ◽  
J.-B. Leriche ◽  
...  
Keyword(s):  
Electrode Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Battery Electrode

scholarly journals In-Situ Synchrotron X-ray Diffraction Investigation of Microstructural Evolutions During Low-Pressure Carburizing

2021 ◽  
Author(s):  
Ogün Baris Tapar ◽  
Jérémy Epp ◽  
Matthias Steinbacher ◽  
Jens Gibmeier
Keyword(s):  
Carbon Content ◽  
Carbon Diffusion ◽  
Low Pressure ◽  
Carbon Accumulation ◽  
Experimental Chamber ◽  
Carbide Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Supply

AbstractAn experimental heat treatment chamber and control system were developed to perform in-situ X-ray diffraction experiments during low-pressure carburizing (LPC) processes. Results from the experimental chamber and industrial furnace were compared, and it was proven that the built system is reliable for LPC experiments. In-situ X-ray diffraction investigations during LPC treatment were conducted at the German Electron Synchrotron Facility in Hamburg Germany. During the boost steps, carbon accumulation and carbide formation was observed at the surface. These accumulation and carbide formation decelerated the further carbon diffusion from atmosphere to the sample. In the early minutes of the diffusion steps, it is observed that cementite content continue to increase although there is no presence of gas. This effect is attributed to the high carbon accumulation at the surface during boost steps which acts as a carbon supply. During quenching, martensite at higher temperature had a lower c/a ratio than later formed ones. This difference is credited to the early transformation of austenite regions having lower carbon content. Also, it was noticed that the final carbon content dissolved in martensite reduced compared to carbon in austenite before quenching. This reduction was attributed to the auto-tempering effect.

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