Alloys viscosity

Composition Dependence of Alloy Viscosity. Attempts have been made to calcnlate the viscosity of a dilnte liquid alloy from a theoretical standpoint, but with little success. This is primarily due to the fact that little is known about the interaction of dissimilar atoms in the liquid state. Empirical relationships for the viscosity of dilute liquid alloys have been developed, but these are generally limited to specific alloy systems—for example, mercury alloys with less than 1% impurities. The viscosities of binary liquid alloys have been empirically described using a quantity called the excess viscosity, (not to be confused with the excess chemical potential), which is defined as the difference between the viscosity of the binary mixture (alloy), pa, and the weighted contributions of each component, xipi and X2P2-... 

Alloy Rayons. It is possible to produce a wide variety of different effects by adding materials to the viscose dope. The resulting fibers become mixtures or aUoys of ceUulose and the other material. The two most important types of aUoy arise when superabsorbent or flame retardant fibers are made. 

It follows that since the addition of metal oxides has such a profound effect on the properties of liquid silicates such as the viscosity, that the Reynolds number of liquid silicates in metal-silicate liquid two-phase systems will influence the boundary layer thickness to a greater extent than in the liquid metals and alloys, mainly because of the higher viscosity of the silicate. 

Temperature effects indicate an activation energy of 113 kJ/mol for Stage I and 16 kJ/mol for Stage II in 7079-T651 alloy. Crack velocity in Stage II is lowered as the solution viscosity is increased. 

The simplest and most thoroughly studied solutions are those based on phosphoric acid at low temperatures (<35°C) which alone can fulfil all three requirements of acid solvent, film former (as metal phosphate) and diffusion agent by virtue of its viscosity. Thus copper and its main alloys of brasses and bronzes can be very effectively electropolished in 60-70% orthophos-phoric acid with the temperature maintained below 35°C under other conditions copper passivates or dissolves freely under mass transfer controlled conditions, but by varying the conditions appropriately polishing can be continued under mild agitation. An annotated polarisation curve is given in Fig. 11.7 readers are referred to recent studies for more detailed 2ispects " . 

Because sodium, which is liquid between about 100°C and 881°C, has excellent properties as a heat-transfer medium, with a viscosity comparable with that of water and superior heat conductivity , much attention has been paid to liquid sodium corrosion testing of metal and alloys. Indeed, ASTM have issued a Standard Practice which can be used for determination... 

Solution treated copper alloys, 7 723t Solution turbidimetry, 20 439 Solution viscosity, 10 677, 678 of PVA, 25 595-597... 

Atomization of melts has been used in two principal areas, i.e., powder production 4] and spray forming, 3] as shown in Figs. 1.4 and 1.5, respectively. It is not until recent years that the technologies for the atomization of melts have advanced sufficiently to ensure good yields of usable products over sustained periods of plant operation. In these two areas, some aspects such as melting of metals or alloys, basic atomizer designs, and atomization mechanisms are the same or similar. Metals or alloys melt at high temperatures to produce low viscosity but usually... 

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