DACE GIGA-S, Instruction Manual

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3601 E. 34th St. Tucson, AZ 85713 USA Tel. +1 - 520 - 882 - 6598 Fax +1 - 520 - 882 - 6599 email: pace@metallographic.com Web: https://www.metallographic.com
Please read this instruction manual carefully and follow all installation, operating and safety guidelines.
GIGA - S Vibratory Polisher
20
7.5 Final Polishing Abrasives
Final polishing abrasives include fine diamond, alumina, and colloidal silica. For
successful microstructural preparation, the polishing abrasive / cloth combination
must be appropriately matched to the specimen hardness, fracture toughness, and
corrosion properties of the specimen.
7.5.1 Colloidal Silica
Colloidal silica is a relatively soft abrasive with high chemical activity. It is an ideal
chemical - mechanical polishing (CMP) abrasive. The chemical activity of colloidal
silica results from the electrochemical balance (zeta potential) required to keep very
fine particles from aggregating. This chemical balance also produces a surface
phenomenon which makes the specimen surface more chemically active. This
produces a surface layer which can be mechanically removed by the colloidal silica
particles themselves, or by the mechanical scrubbing of the surface with the
polishing pad.
For ceramics, the combination of fine polycrystalline diamond and colloidal silica
improves surface finishes and increases polishing rates.