Sintered alloy

In order that the possibility of contamination of catalysts with traces of oxides could be eliminated Campbell and Emmett (51) studied the catalytic activity of metallic films of nickel and its alloys with copper or gold. They were deposited under a high vacuum and then sintered (alloys also homogenized) in hydrogen at 5 cm Hg pressure at 350°C or 500°C. The films were subsequently allowed to cool to room temperature and only... 

In earlier work with pure metals, it was generally accepted that the area of films deposited at, say, 0°C was proportional to their weight (with the exception of group IB and low melting-point metals). Information was available on the surface areas of films of Ni, Pt, Pd, Rh, etc. (71), and hence absolute reaction rates could be calculated. It would be a considerable undertaking to establish similar data for alloy systems, bearing in mind that various compositions would have to be examined and also a method for preparing exact compositions would be required. However, for sintered alloy films, approximate methods can be proposed. 

Sintered alloy films of reasonable thickness, e.g., opaque, mirrorlike films, can provide an adequate number of diffraction peaks for the determination of a lattice constant of adequate accuracy for present purposes. Thus, the apparent lattice constants calculated from the centroids of individual diffraction peaks, observed with a counter-diffractometer, may be extrapolated to 0 = 90°, using the Nelson-Riley function to give a value of a0. There has been some discussion about differences in lattice constants for thin films compared with bulk metals values of ao for pure silver films ( 1000 A nominal thickness) were found (74) to be consistently small compared with bulk silver but only by 0.05%. For alloy films a similar deviation would correspond to a variation of 1% in the composition of the alloy. Larger deviations have been reported for very thin films, e.g., —0.2% in copper films of 100 A nominal thickness (75).]... 

J. Huot, H. Hayakawa, E. Akiba, Preparation of the hydrides Mg2FeH6 and Mg2CoH3 by mechanical alloying followed by sintering, ./. Alloys Compd. 248 (1997) 164-167. 

Cemented carbides are sintered alloys with one or more hard material phases... 

Effects of plasma treatment on thermoelectric properties of SigoGe2o sintered alloys... 

Fig.2. Temperature dependence of the electrical conductivity of GeH4-plasma-treated SiGe sintered alloys.

Ge concentration of the sintered alloys was obtained by XRD peak position of SiGe(lll)[7]. Figure 1 shows increases in the Ge concentration by the plasma treatment measured by EPMA and XRD. The half widths of XRD peaks of SiGe(lll) are also plotted in the figure. The increase in Ge concentration obtained by EPMA are larger than that obtained by XRD. A difference between the two values increases with increasing the... 

Figure 4 shows the room temperature thermal conductivity of the SiGe sintered alloys as a function of the treatment time. The thermal conductivity is reduced by the plasma treatment monotonously with increasing the treatment time. The reduction of the thermal conductivity may be attributed to presence of Ge-rich layers around grain... 

Gal] Galimberti, P, Antoni-Zdziobek, A., Mechanical Properties and Microstmcture of Fe-Co-W Sintered Alloys after Heat Treatment in ""Powder Metallurgy World Congress and Exhibition (PM2004) , European Powder Metallurgy Assoc., Shrewsbury, UK, 6 (2004) (Phase Relations, Experimental, Meehan. Prop., 13)... 

FIGURE 7 SEM images of the Ti-6A1-4V sintered alloy after electrochemical etching in IM H3P04 + 2% HF electrolyte at 10 V for 30 min (a) and (b) - surface morphology (different magnifications), (c) and (d) - cross section of the surface (different magnifications). 

FIGURE 8 SEM images of the Ti-6A1-4V sintered alloy after electrochemical etching in IM... 

Wright, C.S., Youseffi, M., Wronski, A.S., Ansara, L, Durand-Charre, M., Mascarenhas, J., Oliveira, M.M., Lemoisson, F., Bienvenu, Y., Supersohdus Liquid Phase Sintering of High Speed Steels. Part 3 Computer Aided Desing of Sinterable Alloys , Powder Met, 42(2), 131-146 (1999) (Calculation, Experimental, Phase Relations, Thermodyn., 32)... 

Fine flakes of A1 immediately form an oxide layer (AI2O3). When this powder is used to make sintered alloys, the oxide is retained as a dispersoid. This oxide prevents grain growth as well as dislocation motion, thus producing a high strength, high creep resistant sintered aluminum powder (SAP) alloy. 

Ger] German, R.M., Hwang, K.-S., Madan, D.S., Analysis of Fe-Mo-B Sintered Alloys , Powder Metallurgy International, 19(2), 15-18 (1987) (Crys. Stracture, Morphology, Experimental, Phys. Prop., 18)... 

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