Dissolution of metals utilizing an aqueous H.sub.2 SO.sub.4 -H.sub.2 O.sub.2 -3-sulfopropyldithiocarbamate etchant
AssigneeDart Industries Inc.
InventorsSilvester P. Valayil, Moenes L. Elias
Life of this patent
Estimating the term…
Abstract
Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and a catalytic amount of 3-sulfopropyldithiocarbamate sodium salt having the general formula ##STR1## wherein R can be a C.sub.1 -C.sub.4 alkyl group, phenyl, a C.sub.7 -C.sub.10 alkaryl group or a C.sub.7 -C.sub.10 aralkyl group.
Claims19
A method of metal dissolution which comprises contacting a metal with an aqueous solution containing from about 0.2 to about 4.5 gram moles per liter of sulfuric acid, from about 0.25 to about 8 gram moles per liter of hydrogen peroxide and a catalytically effective amount of an additive of 3-sulfopropyldithiocarbamate sodium salt having the general formula ##STR3## wherein R is selected from the group consisting of C.sub.1 -C.sub.4 alkyl, phenyl, C.sub.7 -C.sub.10 alkaryl and C.sub.7 -C.sub.10 aralkyl.
A composition for metal dissolution comprising an aqueous solution of from about 2.0 to about 4.5 gram moles per liter of sulfuric acid, from about 0.25 to about 8 gram moles per liter of hydrogen peroxide and a catalytically effective amount of an additive of 3-sulfopropyldithiocarbamate sodium salt having the general formula ##STR4## wherein R is selected from the group consisting of C.sub.1 -C.sub.4 alkyl, phenyl, C.sub.7 -C.sub.10 alkaryl and C.sub.7 -C.sub.10 aralkyl.
Dependencies are inferred from the claim text.