There is a need for rugged, low-cost hydrogen sensors for a variety of environments where hydrogen is used or generated. Examples include hydrogen-fueled aerospace vehicles, battery charging stations, furnaces, and submarines. A palladium thin-film sensor was developed at ORNL (U.S. Patent 5,367,283) but it was recognized that a thick-film sensor would be more rugged and more easily mass produced. After preliminary experiments at ORNL identified design requirements, DuPont began the formulation of a special thick-film paste having the required composition, adhesion, and printing characteristics.

The DuPont thick-film composition (U.S. Patent 5,338,708) was used to manufacture the sensor shown above. The paste had excellent printability, enabling the design of sensors with sinuous resistive elements (L/D = 460 sq) to minimize power consumption. The fired metallizations are strongly adherent, eliminating problems with debonding at high ambient hydrogen concentrations. The paste composition is compatible with other thick-film compositions, so the entire assembly can be made by standard techniques.

Solid State Technology magazine ran an article on the thick film hydrogen sensor. The thick film paste was a finalist for the Milton S. Kiver Award for Excellence in Electronics Packaging and Production.