Thick-film zirconium oxide oxygen

Principles and Development of a Thick-Film Zirconium Oxide Oxygen Sensor... 

Zirconium is a highly active metal which, like aluminum, seems quite passive because of its stable, cohesive, protective oxide film which is always present in air or water. Massive zirconium does not bum in air, but oxidizes rapidly above 600°C in air. Clean zirconium plate ignites spontaneously in oxygen of ca 2 MPa (300 psi) the autoignition pressure drops as the metal thickness decreases. Zirconium powder ignites quite easily. Powder (<44 fim or—325 mesh) prepared in an inert atmosphere by the hydride—dehydride process ignites spontaneously upon contact with air unless its surface has been conditioned, ie, preoxidized by slow addition of air to the inert atmosphere. Heated zirconium is readily oxidized by carbon dioxide, sulfur dioxide, or water vapor. 

An investigation of the stoichiometry of the ceramic films deposited for this project was conducted. Using an rf sputter unit, 1000 A-thick chromium oxide and zirconium oxide films were deposited on freestanding diamond film substrates. Rutherford Backscattering (RBS) measurements were performed on an unco.ated diamond film and on the coated films. The oxide films were found to be rich in oxygen. The chromium oxide is actually Cr2042, and the zirconium oxide is Zr02a. 

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