Resistance Measurement of Ceramic-Type Strain-Gage Cements
SourceThe resistivities of several commercial strain-gage cements and a number of experimental compositions were measured over the temperature range of 80 to 1800 F. Each cement specimen was placed between two cylindrical metal electrodes, allowed to air-dry, and then cured at 600 F. After curing, the specimen was heated to 1800 F at the rate of 15 F per min. Resistance measurements were made at 25 F intervals with a low-voltage d-c ohmmeter. After the specimen had cooled to room temperature, the breaking strength of the cement bond was evaluated in a bending test. The experimental cements were composed of high-purity, high-resistivity oxides as the bulk material, mixed with various reagents which appeared promising as bonding media. Several compositions were developed which had higher resistivities, in the 1200 to 1800 F temperatures range, than any of the commercial cements tested.