Abstract
That glasses melted by passing electric current through their batches are colored black by the contamination of electrode-carbon and also that the discoloration can be avoided perfectly by introducting a few per cent of zinc oxide to the batches were described in the first report (this jour., 1932, 40, 72).
Then the authors made a study of the material of the electrodes with a result that Acheson graphite was most promising for the purpose.
In the present paper the results of experiments made of the reaction temperatures of zinc oxide and amorphous carbon or artificial graphite are given. The temperatures were determined by thermo-balance method and also by thermal analysis method.
Chemically pure zinc oxide, sugar carbon, and 99.5% pure artificial graphite were used. The samples were heated in a current of nitrogen in electric furnaces whose temperatures were raised with constant rates.
General conclusions are that the temperatures given by the thermal analysis method are higher than those given by the other and also that the amorphous carbon reacts with zinc oxide at a temperature about 50°C lower than the graphite, as shown in Table 1:
