Abstract: A novel humidity sensor printed and fired on a dielectric substrate comprising an interdigitated pattern of a conductive precious metal with cobalt oxide as the only binder. Sensors according to the invention may be employed as hermeticity detectors in semiconductor packages.

Abstract: A high density precious metal powder that resists sintering at 600.degree. C. and contains a very small percentage of titania or zirconia is produced by co-nucleation and precipitation of gold and titania from an ammoniacal solution at pH 3-4 with a bisulfite.A nickel powder including a very small percentage of a refractory oxide such as zirconia is prepared by co-nucleation and precipitation from an alkaline solution with hydrazine.Materials so prepared have oxidation resistance and sintering temperatures superior to the pure metal, and find utility in microelectronics as air-fired thick films. Nickel powders so prepared are also useful as hydrogenation catalysts and in other applications.

Abstract: A thermistor material is deposited and fired on a substrate, and an interdigitated pair of electrodes is deposited and fired thereover. The device is removed from the substrate and a third electrode of low thermal mass is applied on the side opposite the electrode pair. The three electrodes may be connected in a bridge circuit to form a novel, AC-generating infrared detector. When encapsulated in a header-type enclosure including a slit parallel to the electrode pair the sensor functions as an intrusion detector for moving objects. The thermistor material is preferably cobalt oxide.

Abstract: A high density precious metal powder that resists sintering at 600.degree.C. and contains a very small percentage of titania or zirconia is produced by co-nucleation and precipitation of gold and titania from an ammoniacal solution at pH 3-4 with a bisulfite.A nickel powder including a very small percentage of a refractory oxide such as zirconia is prepared by co-nucleation and precipitation from an alkaline solution with hydrazine.Materials so prepared have oxidation resistance and sintering temperatures superior to the pure metal, and find utility in microelectronics as air-fired thick films. Nickel powders so prepared are also useful as hydrogenation catalysts and in other applications.

Abstract: The operation of relative humidity sensors made from cobalt oxide on a non-conductive ceramic substrate is improved by (1) providing a porous, sputtered overcoat of polytetrafluoroethylene which renders the sensor surface non-wettable without affecting other properties, and (2) providing a printed heating element on the back surface of the sensor, enabling in situ degassing of chemisorbed or adsorbed impurities and regeneration of a nascent sensor surface.

Abstract: The operation of relative humidity sensors made from cobalt oxide on a non-conductive ceramic substrate is improved by heating the sensor for a short period to a high temperature in a reducing atmosphere. This reduces the specific resistance of the device. With a lower resistivity, it is possible to reduce the size of the sensor to the point where it can be included along with a semiconductive device in standard hermetic packages. This makes possible the continuous, one-line monitoring of hermeticity for the life of the circuit without the necessity fo applying a load to the circuit.