In an article in PCB Design, former HP engineer Clyde Coombs looks at how the industry has coped with RoHS. One point he makes is that the list of alternatives to tin/lead solder has just grown longer over the years rather than consolidating on a standard or two. He also notes that new alloys are still being developed.
He notes that the lack of emerging standards is in some degree due to the information provided regarding the research and testing of alternatives. “The testing behind (the alternatives) is not necessarily performed in a uniform and comparable manner that would allow comparison between them and their relation to standards - or needs of the product for which an alloy is intended,” says Coombs.