Abstract: Improved lead attachment method accommodates a situation wherein electrical signal leads must be connected to portions of a circuit operating at high temperatures such as 900.degree. F. or more and terminate in equipment operating at or near ambient temperatures. For example, in solid electrolyte oxygen sensors incorporating a tubular ceramic member, a connection wire which is sufficiently thick to resist wire breakage during normal handling has been found to be too thick to bond to a connection pad on the ceramic without having the bond crack during thermal cycling. With improved method, a thin wire is attached to a thicker one in a region where flexing cannot occur. At least the larger wire is shrunk-fit into a hole formed in the ceramic before firing, and then the thinner wire is bonded to the pad with a conductive paste which must also be fired.

Abstract: Improved lead attachment method accommodates a situation wherein electrical signal leads must be connected to portions of a circuit operating at high temperatures such as 900.degree. F. or more and terminate in equipment operating at or near ambient temperatures. For example, in solid electrolyte oxygen sensors incorporating a tubular ceramic member, a connection wire which is sufficiently thick to resist wire breakage during normal handling has been found to be too thick to bond to a connection pad on the ceramic without having the bond crack during thermal cycling. With improved method, a thin wire is attached to a thicker one in a region where flexing cannot occur. At least the larger wire is shrunk-fit into a hole formed in the ceramic before firing, and then the thinner wire is bonded to the pad with a conductive paste which must also be fired.

Abstract: Solid electrolyte oxygen sensor incorporates a sealed integral heater which is positioned internally of the tubular wall of the ceramic sensor body in the region radially adjacent the disc shaped solid electrolyte which is mounted transverse to the axis of the body. A plurality of small longitudinal apertures are formed in the body wall by extrusion. A groove formed in the external side wall of the body provides access so that a resistance heating wire can be threaded alternately in opposite directions through the small apertures. The wire bends are accommodated by the side wall groove and an end wall groove, each of which can be sealed with a castable ceramic after the wire is installed.

Abstract: Solid electrolyte oxygen sensor incorporates a sealed integral heater which is positioned internally of the tubular wall of the ceramic sensor body in the region radially adjacent the disc shaped solid electrolyte which is mounted transverse to the axis of the body. A plurality of small longitudinal apertures are formed in the body wall by extrusion. A groove formed in the external side wall of the body provides access so that a resistance heating wire can be threaded alternately in opposite directions through the small apertures. The wire bends are accommodated by the side wall groove and an end wall groove, each of which can be sealed with a castable ceramic after the wire is installed.

Abstract: Oxygen sensor with a disc type solid electrolyte has the disc sealed in a shrinkable ceramic tube by the pressure which is developed and the surface glazing which takes place as the tube is fired. The tube is preferably formed of forsterite which can shrink about 25% during firing, thus causing the tube to become slightly bulged out in the region of the disc due to the interference fit produced by the shrinkage. The porous electrodes on the top and bottom surfaces of the disc are preferably omitted from a small region near one edge of the top and bottom surfaces but are continued as a stripe or band down the edge from a diametrically opposite portion of each surface, the stripes and unelectroded areas associated with the respective surfaces being spaced to prevent electrical shorting. The disc stripes are pressure bonded during firing of the tube to a pair of spaced lead stripes on the inside tube surface.