Gas Sensor Electrode Material for Temperature Control

The patent changes the material parameter of the electrode from noble metal to electrically conductive oxide, which fundamentally alters the temperature-resistance relationship. The electrically conductive oxide has a negative temperature coefficient, meaning its resistance decreases as temperature increases, opposite to the positive temperature coefficient of platinum. This parameter change enables accurate temperature control through internal resistance control while maintaining catalytic performance.

The patent uses composite material structure where electrically conductive oxide is combined with other materials to form the electrode. The electrically conductive oxide serves dual functions: providing catalytic activity similar to noble metals and providing a resistance-temperature relationship suitable for feedback control. This composite approach maintains durability and catalytic performance while enabling precise temperature control.

The patent replaces expensive noble metal with electrically conductive oxide, which is a cheaper material. Although the electrode material has different properties, it provides sufficient durability for the application. This substitution significantly reduces manufacturing cost while the negative temperature coefficient of the oxide actually improves temperature control accuracy, contrary to the problem with reduced noble metal content.

The patent changes the fundamental material parameter from noble metal to electrically conductive oxide, which has inherently different electrical properties. The electrically conductive oxide exhibits negative temperature coefficient behavior, which when used in feedback control, provides stable and accurate temperature control. This parameter change simultaneously achieves cost reduction and maintains or improves temperature control accuracy.