EFFECT OF SOME ADDITIVES AND ULTRASONIC-F IELD OF PROTECTIVE PROPERTIES OF ZINC COATINGS MADE IN LOW-CYANIDE BATHS

Results of studies on the effect of addition of polyvinyl alcohol and its mixtures with four other organic additives to low-cyanide bath con taining 18 g/cu.dm of NaCN - in the presence of ultrasonic field and w ithout it - on the appearance and corrosion resistance of obtained zin c coatings are presented. The same tests were performed to the coating s made in laboratory and semi-technological conditions in medium-cyani de bath applied in the Car Factory in Lublin. It has been found out th at zinc coatings made in the low-cyanide baths with polyvinyl alcohol addition revealed comparable or slightly better corosion resistance th en those made in the industrial medium cyanide bath. The application o f ultrasonic field makes possible to obtain almost twice faster deposi tion of zinc coatings on steel with no negative impact on their protec tive properties.