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Title: SI traceable calibration of an instrumented indentation sensor spring constant using electrostatic force

We present a measurement scheme for creating reference electrostatic forces that are traceable to the International System of Units. This scheme yields reference forces suitable for calibrating the force sensitivity of instrumented indentation machines and atomic force microscopes. Forces between 10 and 200 {mu}N were created and expressed in terms of the voltage, length, and capacitance between a pair of interacting electrodes. The electrodes comprised an electrically conductive sphere mounted as a tip on an instrumented indentation sensor, and a planar counterelectrode fixed to a sample stage in close proximity to the sphere. For comparison, we applied mechanical forces of similar magnitudes, first using deadweights and then using a reference force sensor. The deflection of the sensor due to the various applied forces was measured using an interferometer. A spring constant for the sensor was computed from the observed records of force versus displacement. Each procedure yielded a relative standard uncertainty of approximately 1%; however, the electrostatic technique is scalable and could provide traceable reference forces as small as a few hundred piconewtons, a range far below anything yet achieved using deadweights.
Authors:
; ; ; ;  [1]
  1. Manufacturing Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
Publication Date:
OSTI Identifier:
21266443
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 79; Journal Issue: 9; Other Information: DOI: 10.1063/1.2987695; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ATOMIC FORCE MICROSCOPY; CALIBRATION; CAPACITANCE; COMPARATIVE EVALUATIONS; ELECTRIC POTENTIAL; ELECTRODES; INTERFEROMETERS; LENGTH; SENSITIVITY; SENSORS; SPHERES; SPRINGS