New
Applications
Determination of
the instability of disperse systems and its causes
The distribution of
dispersed phases in a matrix has a considerable influence on the functional
properties of all multi-phase products. Among these are emulsions, dispersions,
foams, and gels in products such as lacquers, paints, inks, cosmetics,
agrochemicals, pharmaceuticals, lubricants, foodstuffs, and a great number
of their raw materials. Both the particle diameter and the distribution
of the particles in a surrounding phase and their degree of agglomeration,
flocculation, gel formation or coalescence determine the product image
and its functional behavior.
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Determination of the surface free energy of electronic components. A method for evaluating their wetting and adhesive behavior with embedding compounds and adhesives.
Dispensing tasks in the electronics industry are increasing in their extent and complexity because of the use of new materials and technologies. A wide range of different boundaries is produced during the manufacture of single-chip circuits and multi-chip modules. This includes the individual steps involved in assembling the module whether in applying an electronic component to a PCB or other carrier construction or in applying a glob top to this component. Both the wetting and adhesive behavior of the individual components between themselves play an important role. The contact angle is an easily accessible and directly observable quantity which describes the wetting and dewetting behavior of a liquid on a solid surface. Not only the surface tension of the liquid influences the size of the contact angle but also the surface free energy of the solid and the interfacial tension which forms between the two phases. This paper provides a step-by-step description of the procedure for the determination of the surface free energy including the polar and disperse fractions of two different electronic components on a carrier. A knowledge of these quantities enables an estimation of the wetting and adhesive behavior with embedding compounds.
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