The European WEEE has issued a new (5th) version of its recommendations. In it they say that , on January 1st, 2004, they will review the status of the Pb-Free issue. There is currently NO DEADLINE for implementation.
As far as a direct replacement for the currently-popular 63%Sn37%Pb, YES. The industry is accepting a SnAgCu alloy as the primary option. The approximate chemistry is 95.5%SN 3.8%Ag 0.7%Cu - or equivalent ternary eutectic alloy. It melts at ~217C and should be reflowed at ~240-245C.
As far as oven type - YES, the type DOES MATTER. Some current forced air convection ovens may not be able to reach suitably-high temperatures. And, since new fluxes will be working at higher temperatures, current ovens could cause troubles due to inadequate heating efficiencies. Results will vary from oven to oven. I do not consider this to be a major long-term issue.
Currently, an inert atmosphere IS ESSENTIAL. This may not be true in the future, but it is very important for current Pb-Free solder pastes.
Thank you for these great questions! Dr. Lee
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