Determination of specific resistance during baking of electrode paste:
Place the corundum crucible containing the electrode paste sample in the silicon carbide rod electric furnace, raise the temperature at the rate of 100 ° C per hour, measure the resistance value of the electrode paste at the corresponding temperature through a pair of metal plates pre processed into the electrode paste with an electric bridge, and after calculation and correction with the container coefficient calibrated with 0.1N potassium chloride standard solution in advance, the specific resistance value of the electrode paste at this temperature can be obtained.
Through this test, we can see the following problems:
(1) In the past, although it was known that the electrode paste had poor conductivity before burning, it was still used to regard the electrode paste as a conductor. Conclusions can be drawn according to the measurement results; Electrode pastes before 400 ℃ are basically insulators. Taking standard pastes and special pastes for example, their specific resistance at low temperature is very large, and it is impossible for current to pass through under the working conditions of electric furnace.
In order to confirm this problem, we used to use a plastic pipe with a diameter of 100M / M and a length of 300m / m to put electrode pastes of different particle sizes, connect the power supply at both ends, control the voltage value with a voltage regulator, and record the voltage based on the current of 25mA passing through the line.
According to the different particle sizes, the electrode paste column with a diameter of 100 m / M and a length of 300 m / M needs a voltage of 140-260 V to start to pass current, which shows the poor conductivity.