Influence of size and shape of metallic silver and palladium powders on the Ag70Pd30 solid solution formation by mechanical alloying

1996 ◽  
Vol 6 (9) ◽  
pp. 1543 ◽  
Author(s):  
Luc Aymard ◽  
Bernard Dumont ◽  
Bernard Beaudoin ◽  
Fran�ois Portemer
Author(s):  
T. R. Dinger

Zirconia (ZrO2) is often added to ceramic compacts to increase their toughness. The mechanisms by which this toughness increase occurs are generally accepted to be those of transformation toughening and microcracking. The mechanism of transformation toughening is based on the presence of metastable tetragonal ZrO2 which transforms to the monoclinic allotrope when stressed by a propagating crack. The decrease in volume which accompanies this transformation effectively relieves the applied stress at the crack tip and toughens the material; microcrack toughening arises from the deflection of a propagating crack around sharply angular inclusions.These mechanisms, however, do not explain the toughness increases associated with the class of composites investigated here. Analytical electron microscopy (AEM) has been used to determine whether solid solution effects could be the cause of this increased toughness. Specimens of a mullite (3Al2O3·2SiO2) + 15 vol. % ZrO2 were prepared by the usual technique of mechanical thinning followed by ion beam milling. All observations were made in a Philips EM400 TEM/STEM microscope fitted with EDXS and EELS spectrometers.


1986 ◽  
Vol 47 (C1) ◽  
pp. C1-441-C1-445
Author(s):  
E. KOSTIĆ ◽  
S. J. KISS ◽  
D. CEROVIĆ

2000 ◽  
Vol 11 (20) ◽  
pp. 4061-4070 ◽  
Author(s):  
Orsolya Barabás ◽  
Dóra K Menyhárd ◽  
Zsolt Böcskei ◽  
Kálmán Simon ◽  
Ilona Kiss-Ajzert ◽  
...  

2006 ◽  
Vol 980 ◽  
Author(s):  
Tatsuhiko Aizawa ◽  
Renbo Song

AbstractMagnesium binary and ternary alloy systems have been popular as a thermoelectric light-weight alloy to be working in the medium temperature range. The solid-state reactivity via the bulk mechanical alloying is applied to yield these types of alloys. The diffusion-controlled solid-state synthesis is first stated as a process to yield a binary compound, Mg2X (X = Ge, Sn and Pb). This processing is further applied to directly synthesize several ternary thermoelectric alloys Mg2Si1-xGex, Mg2Si1-ySny and Mg2Sn1-zPbz for 0.0 < x, y, z < 1.0 and to evaluate their thermoelectric properties. Hot pressing is used to make full-dense billets and samples for thermoelectric measurement. The effect of germanium and tin contents on their Seebeck coefficient and band-gap is investigated to describe the p-n transition behavior and to understand the change of electric structure with solid solution formation.


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