Lead-free Forum

Lead-Free Products in Power Electronics.

Background

The European Directives WEEE/RoHS became European law February 13, 2003; member states must implement the law by August 13, 2004. Member states must ensure that by July 1, 2006, new electrical and electronic equipment placed on the market does not contain lead or any of the restricted hazardous materials identified in the document. To achieve Compliance to lead-free product requirements, many companies are converting to the use of lead-free alloys using tin with 95% to 100% tin (Sn), tin-silver (Sn-Ag), and, tin-silver-copper (Sn-Ag-Cu) solder chemistries. Some are using gold palladium; however, the additional cost and continued source of supply of palladium may be of issue. In addition, this requires different product materials which must be upgraded in order for the product to sustain the higher melting temperatures of lead-free solder alloys. Depending on the product type and application, commonly companies have adopted solder alloys Sn3.9Ag0.6Cu, Sn3.5Ag, and Sn. certain types of components traditionally using high melting temperature solder containing more than 85% lead may be exempted per the WEEE/RoHS regulation because of the lack of viable lead-free replacement materials.

Since there is a continual world-wide environmental movement away from the use of lead toward 'non-toxic' products in all types of items, various alternatives have replaced the traditional use of lead in wine bottle caps, fishing weights, casting alloys for toys, as well as solders for certain plumbing applications. Once considered a joke, lead-free ammunition (bullets and shot) is now available and experiencing a significant growth in demand. This is particularly true in the USA, where the possibility of litigation against environmental contamination or employee exposure to hazardous materials is high.

Additionally, there is now a series of initiatives worldwide that outline targets for electronic equipment re-use and recycling. In such initiatives, the use of hazardous materials such as lead is often limited in order to improve the ease of recycling.

Legislation directly affecting the solder and electronic assembly industries has been passed by the European Commission in the WEEE and RoHS directives outlining targets for electronic equipment re-use and recycling. This legislation also limits the use of hazardous materials to improve the ease of recycling. It will impact not only solder alloys but also component finishes and temperature ratings, board finishes and flame redundancy issues.

The EC has also passed a directive on end-of-life vehicles which again is mainly aimed towards recycling and re-use targets with additional clauses affecting the use of hazardous materials. Lead-bearing solders for automotive applications have a temporary exemption from the lead ban. This directive pre-dates the similar WEEE proposals and can be used an indicator of likely legislative direction.

The Danish Environment Agency has also taken action against lead chemicals and metallic products in a number of areas.

The Japanese Ministry of Trade (MITI) has drafted a recycling law for electrical appliances with a 2001 deadline. This does not yet include lead phase-out but it is expected to come.

Although there is no federal legislation yet in the US, there are a number of State electronics recycling initiatives to consider. In addition, the EPA has recently proposed a crack-down on lead emissions from plants that may impact the soldering industry.