CLEANING OF SILICON DENSITY STANDARDS

Horst Bettin, Detlef Schiel, Martin Vogtmann, Henning Niemann

Abstract

The cleaning of silicon density standards was investigated by mass comparison measurements. It was shown that even in clean laboratory air, the mass of silicon spheres increases considerably with time. On the other hand, after cleaning the sphere, mass stabilizes within only 8 hours and always yields the same mass within 10 µg. This is also true after using the spheres in liquids, e. g., for hydrostatic weighing. Additionally, an infrared absorption technique was used to identify hydrocarbons on silicon spheres and to estimate the layer thickness. A calibration of this method was possible with a mass determination of a paraffine layer deposited on a silicon sphere.

Keywords

cleaning, silicon density standard, mass comparison, carbonaceous layer, infrared absorption

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IMEKO-WC-2009-TC3-173.pdf

DOI

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IMEKO TC

TC3 - Measurement of Force, Mass, Torque, and Gravity

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