INTERFACE PHYSICAL-CHEMISTRY OF ENAMELS ( PART 1) - EXAMINATION OF COBALT AND NICKEL BEHAVIOR AND ADHESION OF ENAMEL

Observation of the enamels interface with SEM, EPMA and ESCA, and meas urement of adhesive strength of the enamels were done. Simultaneously, cobalt and nickel in the enamel layer examined a given influence, at the interface and the adhesive strength. As a result, the relationship between iron-oxygen, cobalt-oxygen and nickel-oxygen, at the reaction of enamel process was explained by the interface thermodynamics. Furt hermore, characteristics and differences of reaction of cobalt and nic kel were clarified. (1) The adhesive ability of Co-enamel was larger t han that of Ni-enamel. (2) The adhesive behavior of cobalt changes at about 730 degrees, but that of nickel remains unchanges. Consequently, cobalt has an adhesion with the high temperature (over 730 degrees C) but nickel does not have am influence on the temperature. (3) At high firing temperature, the Co-enamel can create FeO easily compared with Ni-enamel, and dissolve Fe2O3 of steel surface into glass. (4) Cobalt spreads for a vertical direction of interface, but nickel tends depos ition an the interface surface. And the diffusion capability of cobalt into the steel was considerably greater than that, of nickel.