EFFECT OF MANGANESE, NICKEL, AND COBALT OXIDE UPON THE ADHERENCE AND REBOILING PROPERTIES OF A GROUND‐COAT ENAMEL*

A series of enamels was compounded in which small amounts of adherence-promoting oxides were varied and their effect upon the adherence and reboiling properties of a base enamel glass applied to steel was studied. Results indicated that cobalt oxide was necessary in producing adherence, whereas nickel and manganese oxides increased the firing range. Reboiling was found to be dependent upon adherence. Photomicrographs showed that different phases existed in the interfacial layer when the different metallic oxides were introduced into the enamel.