Electroplating is a process used to reduce the positively charged ions of a desired material, with the help of an electric current. The process also coats a conductive object with a thin layer of the material, such as a metal. Zinc electroplating is one of the most common forms of electroplating and popular because of its relatively low cost, protective nature and attractive appearance. The coating done through this process gives corrosion protection to ferrous components and it can give colors like gold, black or olive drab finish, by post treatment.
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Driven by the need for increased speed, portability and wiring density, the interconnect pitch on semiconductor packages, and the corresponding high density interconnect (HDI) substrates, continue to shrink. The combination of filled blind microvias and build-up technology provides a means to achieve the required wiring densities. With the rapid growth of this technology, the use of electrodeposited copper for filling blind microvias has become a widely adopted process for manufacture of both HDI printed circuit boards (PCBs) and also semiconductor package substrates.
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The development of modern continuous sheet galvanizing lines has led to the disappearance of most of the old manual mills for galvanizing cut sheets. There are however still some machines that galvanize cut-to-length sheets; they use chemical pretreatment sequence similar to those for wire or tube galvanizing.
At the beginning of the line, the end of one coil is welded to the start of the next coil. Then there are two basic methods for continuously galvanizing sheet which differ in the way that the strip is cleaned before galvanizing-chemically or by thermal treatments. Coils of annealed cold reduced sheet may be fed directly to the galvanizing line, or alternatively, coiled sheet is continuously heat treated in the pretreatment line. After leaving the galvanizing bath, in which strip only stays for a few seconds, the surface is wiped to remove excess zinc and may be further treated to after the surface appearance, composition, smoothness or mechanical properties.
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