A novel micro glow plug fabricated from polymer-derived ceramics: in situ measurement of high-temperature properties and application to ultrahigh-temperature ignition

This work describes the design, fabrication, modeling, characterization and testing of a new class of MEMS: micro igniters for ultrahigh-temperature (exceeding 1000 degreesC) ignition applications. Micro glow plugs (MGPs) were fabricated from polymer-derived silicon carbon-nitride (Si-C-N). which is a recently-developed and highly refractory ceramic derived from a liquid polymer precursor. SiCN has been shown to possess outstanding mechanical robustness, corrosion resistance, and thermal shock resistance at ultrahigh-temperatures, making it an ideal material for harsh environment applications. The micro glow plug achieved temperatures of up to 1450 degreesC, with a response time of <1 s and power consumption of 3 W. Application as an ultrahigh-temperature igniter in both chip-scale and macro-scale reactions were demonstrated. Furthermore. polymer-derived ceramics (PDCs) being a relatively new class of materials, this work is the first to demonstrate the use of MEMS to obtain hip-h-temperature properties of these new materials in situ. The device was used to obtain the Mott variable range hopping (VRH) parameters for temperature-dependence of resistivity in SiCN, as well as the range for the oxidation activation energy. The micro glow plug thus demonstrates both a new class of harsh-environment M-EMS as well as a tool for in situ measurement of high-temperature properties in PDCs, (C) 2003 Elsevier Science B.V. All rights reserved.