Corrosion of Electronics: Lead‐Free Initiatives

Abstract

Lead, mercury, cadmium, hexavalent chromium, and polybrominated compounds [polybrominated biphenyls (PBB) and polybrominated diphenyl ether (PBDE)] and similar substances contained inmodern electronic compounds have been associated with many health risks. The primary health concern has been associated with the migration of lead and other chemicals contained in electronic products from landfill sites into the secondary water sources after disposal [1]. A number of legislative acts have been issued with the aim of reducing the environmental effects due to the use of hazardous substances in electronic equipment. The European Union has issued the most influential of these acts. The European Union adopted the first one, the directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment, 2002/95/EC, commonly referred to as the Restriction of Hazardous Substances Directive (RoHS), in February 2003 [2]. The RoHS directive, which took effect on July 1, 2006, restricts the use of the six hazardous materials indicated above in the manufacture of various types of electronic and electrical equipment. RoHS is closely linked with the Waste Electrical and Electronic Equipment Directive [3] (or WEEE), which aims to prevent the generation of electrical and electronic waste while promoting the reuse, recycling, and recovery of the hazardous substances by reducing the quantity of this type of waste sent to landfills. The critical substance in the RoHS directive is lead, mainly because the directive requires that the manufacturers of electronic and electrical equipment must replace solders and printed circuit board (PCB) surface finishes on all electronic products sold in the European economic region. Although some exemptions were made for specialized medical, automotive, and telecommunications equipment, those exemptions expire in 2010. Following the European Community directives, other countries, including China and South Korea, implemented their own versions of the RoHS and WEEE initiatives. Although other countries, such as United States and Japan, have not passed similar laws, most of the companies in the United States and Japan have been phasing out electronics that are noncompliant to RoHS and moving toward “environmentally green electronics,” mostly because of their exports overseas where RoHS and WEEE