Zincate zinc plating bath

Abstract

To provide a zincate zinc plating bath capable of efficiently forming a zinc plating film with high brightness and high qualities even at a low current density. The zincate zinc plating bath is used in electroplating for depositing a metal containing at least zinc and forming a zinc plating film. It contains a primary brightener having a function of reducing the size crystals of the metal to be deposited and a plating accelerator containing a heterocyclic compound having a predetermined structure such as 2,5-dimercapto-1,3,4-thiadiazole.

1 - 12 . (canceled) 
     
     
         13 . A zincate zinc plating bath for depositing a metal containing at least zinc to form a zinc plating film by using electroplating, comprising a primary brightener having a function of reducing the size of crystals of the metal thus deposited and a plating accelerator containing a heterocyclic compound represented by the following chemical formula (I): 
       
         
           
           
               
               
           
         
       
       (in the chemical formula (I), n stands for a natural number from 1 to 3, R 1  and R 2  may be same or different and each represents hydrogen, CH 2 COOH, CH 2 CH 2 OH, or CH 2 CH(OH)CH 2 Cl) and/or a derivative of the heterocyclic compound. 
     
     
         14 . The zincate zinc plating bath according to  claim 13 , wherein the heterocyclic compound and/or the derivative of the heterocyclic compound is contained in an amount of 0.01 g/L or greater but not greater than 1.0 g/L. 
     
     
         15 . The zincate zinc plating bath according to  claim 13 , wherein a water soluble cationic macromolecular compound is contained as the primary brightener. 
     
     
         16 . The zincate zinc plating bath according to  claim 14 , wherein a water soluble cationic macromolecular compound is contained as the primary brightener. 
     
     
         17 . The zincate zinc plating bath according to  claim 15 , wherein a compound represented by the following chemical formula (II): 
       
         
           
           
               
               
           
         
       
       (in the chemical formula (II), n stands for a natural number of 1 or greater, R 1 , R 2 , R 3 , and R 4  may be the same or different and each represents hydrogen, methyl, ethyl, isopropyl, 2-hydroxylethyl-CH 2 CH 2 (OCH 2 CH 2 ) x OH (X stands for a natural number from 0 to 6), or 2-hydroxyethyl-CH 2 CH 2 CH 2 (OCCH 2 CH 2 ) x OH (X stands for a natural number from 0 to 6), R 5  represents (CH 2 ) 2 —O—(CH 2 ) 2 , (CH 2 ) 2 —O—(CH 2 )—O—(CH 2 ) 2 , or CH 2 —CHOH—CH 2 —O—CH 2 —CHOH—CH 2 , and Y represents S or O) is contained as the water soluble cationic macromolecular compound. 
     
     
         18 . The zincate zinc plating bath according to  claim 16 , wherein a compound represented by the following chemical formula (II): 
       
         
           
           
               
               
           
         
       
       (in the chemical formula (II), n stands for a natural number of 1 or greater, R 1 , R 2 , R 3 , and R 4  may be the same or different and each represents hydrogen, methyl, ethyl, isopropyl, 2-hydroxylethyl-CH 2 CH 2 (OCH 2 CH 2 ) x OH (X stands for a natural number from 0 to 6), or 2-hydroxyethyl-CH 2 CH 2 (OCCH 2 CH 2 ) x OH (X stands for a natural number from 0 to 6), R 5  represents (CH 2 ) 2 —O—(CH 2 ) 2 , (CH 2 ) 2 —O—(CH 2 )—O—(CH 2 ) 2 , or CH 2 —CHOH—CH 2 —O—CH 2 —CHOH—CH 2 , and Y represents S or O) is contained as the water soluble cationic macromolecular compound. 
     
     
         19 . The zincate zinc plating bath according to  claim 13 , further comprising a secondary brightener having a function of planarizing the zinc plating film. 
     
     
         20 . The zincate zinc plating bath according to  claim 14 , further comprising a secondary brightener having a function of planarizing the zinc plating film. 
     
     
         21 . The zincate zinc plating bath according to  claim 15 , further comprising a secondary brightener having a function of planarizing the zinc plating film. 
     
     
         22 . The zincate zinc plating bath according to  claim 16 , further comprising a secondary brightener having a function of planarizing the zinc plating film. 
     
     
         23 . The zincate zinc plating bath according to  claim 17 , further comprising a secondary brightener having a function of planarizing the zinc plating film. 
     
     
         24 . The zincate zinc plating bath according to  claim 18 , further comprising a secondary brightener having a function of planarizing the zinc plating film. 
     
     
         25 . The zincate zinc plating bath according to  claim 19 , wherein at least one compound selected from the group consisting of organic aldehydes and heterocyclic compounds is contained as the secondary brightener. 
     
     
         26 . The zincate zinc plating bath according to  claim 25 , wherein at least either one of an aromatic aldehyde or a pyridinium compound is contained as the secondary brightener. 
     
     
         27 . The zincate zinc plating bath according to  claim 13 , comprising zinc ions in an amount of 5 g/L or greater but not greater than 20 g/L. 
     
     
         28 . The zincate zinc plating bath according to  claim 13 , comprising sodium hydroxide in an amount of 80 g/L or greater but not greater than 250 g/L. 
     
     
         29 . The zincate zinc plating bath according to  claim 13 , comprising at least either one of nickel ions or iron ions. 
     
     
         30 . The zincate zinc plating bath according to  claim 29 , wherein the nickel ions are contained in an amount of 100 mg/L or greater but not greater than 4000 mg/L. 
     
     
         31 . The zincate zinc plating bath according to  claim 29 , wherein the iron ions are contained in an amount of 10 mg/L or greater but not greater than 150 mg/L.