Abstract: At least a portion of an oxygen sensor element support to which portion an oxygen sensor element directly contacts is constructed of an heat insulating material having very low thermal conductivity, so that the heat release from the oxygen sensor element is minimized.

Abstract: Disclosed is a paste containing an electrically conducting powder, which is a mixture of a platinum powder and a ceramic material powder in a proportion in the range from 51:49 to 78:22 by volume and has a specific surface area of 1.0 to 10.0 m.sup.2 /g, uniformly dispersed in an organic liquid vehicle in a proportion in the range from 70:30 to 50:50 by weight. A cavity in a ceramic substrate of an electric device having two, or more, conducting parts separately fixed to the substrate is filled up with this paste, and subsequently the substrate is fired to sinter the paste in the cavity into a conducting solid filler which provides electrical connection between the two conducting parts with low resistance and close and firm contact with the conducting parts and wall surfaces defining the cavity.

Abstract: In an oxygen sensor comprising an oxygen ion conductive solid electrolyte, an electronically conductive reference electrode layer formed on one side of the electrolyte layer, an electronically conductive measurement electrode layer formed on the other side of the electrolyte layer, and a partition layer of an electrochemically inactive material formed on the outer side of the reference electrode layer, at least one of the reference and measurement electrode layers has a plurality of openings through which two layers which put therebetween the one of the electrode layers are united with each other.

Abstract: A method of producing a large-sized body of a ceramic honeycomb structure, comprising the steps of integrating unfired unit blocks each having a prismatic shape and a honeycomb structure with axial gas passages into a large-sized body by bonding the unit blocks to one another with a bonding agent and firing this body. The unit blocks are formed of a ceramic composition consisting of a powdered ceramic material and completely gasifiable substances, and essential components of the bonding agent are also completely gasifiable substances such as a combination of an organic binder material used in the ceramic composition and a solvent for this binder material. The gasifiable substances present in the large-sized body are completely dissipated by heating before the occurrence of sintering of the ceramic material by firing, so that the fired product is a wholly and homogeneously ceramic body of a honeycomb structure highly resistant to thermal shocks.

Abstract: In an oxygen sensor comprising an oxygen ion conductive solid electrolyte, an electronically conductive reference electrode layer formed on one side of the electrolyte layer, an electronically conductive measurement electrode layer formed on the other side of the electrolyte layer, and a partition layer of an electrochemically inactive material formed on the outer side of the reference electrode layer, at least one of the reference and measurement electrode layers has a plurality of openings through which two layers which put therebetween the one of the electrode layers are united with each other.

Abstract: A method of producing a flat solid electrolyte layer of a flat film type oxygen sensor is disclosed. The method comprises in steps, (a) preparing first and second electrolyte pastes each containing stabilizer, the content of stabilizer in the first electrolyte paste being smaller than that in the second electrolyte paste, (b) applying the first electrolyte paste onto an electrode layer and then applying the second electrolyte paste onto the outer face of the first electrolyte paste to form a layered paste heap on the electrode layer, and (c) firing the layered paste heap to form a solid electrolyte layer on the electrode layer. With this production method, the stabilizer is uniformly and homogeneously distributed into the body of the fired electrolyte layer.