Abstract: A flexible pH probe device is provided for use in hot water and other high temperature environments up to about 590° F. The pH probe includes a flexible, inert tubular probe member, an oxygen anion conducting, solid state electrolyte plug located at the distal end of the tubular member, oxide powder disposed at the distal end of the tubular member; a metal wire extending along the tubular member and having a distal end in contact with the oxide powder so as to form therewith an internal reference electrode; and a compression fitting forming a pressure boundary seal around a portion of the tubular member remote from the distal end thereof. Preferably, the tubular member is made of polytetrafluoroethylene, and the solid state electrolyte plug is made of stabilized zirconia. The flexibility of the probe member enables placement of the electrode into the area of interest, including around corners, into confined areas and the like.

Abstract: A composite beta, mainly beta"-alumina article is described which comprises a first layer of beta-alumina, a second layer of mainly beta"-alumina adhering securely to the first layer, and the first layer consisting of 1 to 15 percent thickness of the total thickness of the article. A method is also described for producing such composite articles.

Abstract: A composite beta, mainly beta"-alumina article is described which comprises a first layer of beta-alumina, a second layer of mainly beta"-alumina adhering securely to the first layer, and the first layer consisting of 1 to 15 percent thickness of the total thickness of the article. A method is also described for producing such composite articles.