Copper acid is a sulfuric acid base plating process that produces low stressed,ductile,and very bright copper deposits.The additives are designed to operate at the bath with temperatures up to 28C without any noticeable loss in quality.It can be used on both properly prepared metals and plastic substrates.The outstanding characteristics of this bright acid copper process are;
* High deposit brightness with superior speed of brightening and leveling with no loss of ductility
* Easily buffable surface
* Ease of bath maintenance and control under production conditions
* Addition agents are dosed on a ampere-hour basis.
Alkaline copper solutions have better throwing power (uniform deposit thickness) than acid copper solution.However,they cannot be used as high a current density as acid copper.They also relatively more difficult to control than acid sulfate solution.Also,Cyanide involves special handling and treatment procedures because of its acute health hazards and waste disposal requirements. But, the procedures are well understood, and, with care,cyanide can be handled safely.The plating process can be generally classified as low- efficiency or strike processes.A cyanide copper strike bath is typically used to deposit a thin,adherent layer that can completely cover an active metal surface such as zinc or steel prior to further plating operations.Because of the bath’s low plating efficiency,plating time,and thus the deposit’s thickness,is often determined by the time needed to just obtain complete coverage.The maximum practical thickness is typically in the range of 1.2-2.5 micron (0.05-0.10 mil).The copper strike serves only as a protective layer for further plating,typically with copper or nickel.It also improves adhesion and,in some cases,acts as insurance in the prep late cycle to obtain adhesion cyanide can function as cleaner/ activator.The low-metal and high- cyanide levels in the copper strike are responsible for the low efficiency,but these same properties ensure against a non-adhering immersion layer of copper forming on the surface being plated.This formulation also produces the desired excellent covering and throwing powers.The trend is to use cyanide copper baths just for strikes and use other processes such as copper acid to increase deposit thickness.