Theory, Fabrication and Characterization of Micromachined Electrolytic Solution Conductivity Sensors

Thin-film nickel RTD has a thickness dependent temperature coefficient that is lower than the bulk material due to free electron boundary scattering. Four-wire resistance measurements are used to eliminate the effect of lead resistance for the RTD fabricated on the probe tip. The RTD integrated on the probe tip achieved an accuracy of +/-0.5% from 0 to 100°C with a parabolic correlation. A 200 mum probe gave a thermal resistance of 553°C/W during self-heating in water. With a RTD integrated on the sensor tip, temperature correction for conductivity can be made so that concentration could be measured locally in media with non-uniform temperature and concentration distributions. Finally, challenges to reduce the microprobe tip size further are discussed with respect to fabrication, measurement, and the underlying physics.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• He, Dongming

Contributors dc:contributor

• Shannon, Mark A.

• Engineering, Mechanical

Language dc:language

eng

Identifier

(MiAaPQ)AAI3017094

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/83753