ぶりきのスズ結晶成長について

抄録

A study has been carried out to clarify the crystal growth mechanism of the tinplate during flow-brightening and quenching in electrolytic tinning. It was found that the “quench stain” -a ripple-like surface pattern, formed during quenching corresponds to the crystallization of the tin layer. The origin of the ripple pattern indicated the nucleation site and the crystal growth rate. At most of origins of the ripple pattern, the Fe-Sn intermetallic compound did not form on the substrate strip, indicating that the number of sites, where nucleation occurs depends on the surface cleanness of the substrate strip. It is suggested that surface contaminants introduce localized supercooling of the tin layer thereby controlling the grain size of the tinplate crystals, but because the degree of supercooling depends on cooling rate, grain size is also affected by the cooling rate of the steel strip. Actually, tin grain size increased when the amount of surface contaminants was reduced during pretreatment or annealing.