Thermomigration

The mechanisms operating during thermomigration in the presence of a surfactant have been evaluated experimentally [130]. The overall mechanism consists of four main processes ... 

In fact thermomigration readily takes place in the absence of surfactant, albeit usually to a lesser extent. In this case only the second of the above processes takes place. The term surfactant in this model can be interpreted broadly to include any residual surfactant, reduction clearing assistant or applied finish, such as an antistat, lubricant or softener. 

It is important to recognise that the degree of thermomigration in itself is not necessarily indicative of any practical implications that may show up in fastness tests [129]. For... 

Whereas the blue dyes 31 and 32 are claimed to have good thermomigration fastness, 33, 34, and 35 have superior pH stability and are proposed as substitutes for bright anthraquinone blues. 

Softeners and thermomigration of dyes Many hydrophobic softeners are... 

Softeners on dyed polyester often cause more disperse dye migration (especially thermomigration) and cause reduced crocking fastness. This is similar to softeners on the basis of fatty acids and azoic dyeings. 

Ichinokawa et al. [175] investigated the influence of electromigration and thermomigration. They found that with electron beam traversal, movement of metallic nanoislands can be controlled by the reversal of field direction. Saka et al. [176] applied electric field on material inside the trench in the presence of a thermal input, yielding metallic nanowires. They have explained the formation based on electromigration phenomena. 

In Section 6.7, the influence of electric current on surface stracture evolution and grain rotation in tin thin films is studied. PecuHarities of mass transfer in two-phase alloys at electro- and thermomigration are highlighted in Section 6.8. 

We discuss here thermomigration in eutectic two-phase structures, such as the SnPb solder. It is very different from the Soret effect. The change in concentration in the two-phase structure under a fixed temperature does not mean any change of... 

However, when the composite solder joints were subjected to thermomigration, a substantial segregation of Sn and Pb occurred in the joint A temperature gradient of about 1000 K cm , or a 10 °C difference across a flip-chip solder... 

When an electron microprobe was used to measure composition distribution across a polished cross section of the flip-chip sample after thermomigration, a... 

Figure 6.27 Image of cross sections of unpowered solder joints after thermomigration for (a) 30 min, (b) 2 h,...

Figure 6.28 For unpowered solder joints after thermomigration for 30 min.

Figure 6.29 Sn fraction distribution from the Si chip side to the basis side on the flip-chip solder joint before and after thermomigration.

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