OT? Welding, Soldering May Be Obsolete

Doesn't look too promising for cost - on the bulk metals market gallium and indium are both more than 10x the cost of tin and 100x the cost of lead.

SMT soldering has the great effect of self-centering components too- so the pick and place and the paste printing don't have to be perfect.

--sp

f welded and soldered joints, but without heat:

e contains indium, the other gallium. Upon contact, with a little pressure applied, they melt together, then solidify. The joint is thermally and elec trically conductive and gas/liquid-tight. The article doesn't say just *how

• conductive, of course, or what metals it works on, but if it's cheap enou gh it could eliminate reflow soldering (and associated cleanup) in board pr oduction frinst. Pick-and-place would become pick, place, and push.

They say it's cheaper--

"'Hot' processes like sol-dering and welding can result in metallic con-nec-tions that are sim-ilar to those pro-duced with the metallic glue, but they cost much more."

They also say the glue comprises a sea of intermeshed / locking metallic nanorods, solid, with In and Ga-coated tips. The rods (& most of the mass) must be another metal, and cheaper than In / Ga.

It sounds like a metallic Velcro, gap-filled with molten Ga-In that is trapped by the sparse metallic matrix. Weird.

"These coated rods are arranged along a sub-strate like angled teeth on a comb: There is a bottom 'comb' and a top 'comb.' We then inter-lace the 'teeth.'"

Yep.

Cheers, James Arthur

Do such exotic structures come cheap? I certainly didn't think so.

NT

Beats me. Sounds like they're making them. Applying "coated rods" along an SMD part's leads "like angled teeth on a comb" sure doesn't sound easier (or cheaper) than soldering, though.

Cheers, James Arthur

Sounds like some kind of amalgam / liquid-phase sintering done at or near room temperature. I suppose they justify "low cost" by microscopic layers; but microscopic layers necessitate expensive flat surfaces. So, they're still trapped...

Tim

-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website:

It's kinda sketchy on details but AIUI it's a two-component system. One contains indium, the other gallium. Upon contact, with a little pressure applied, they melt together, then solidify. The joint is thermally and electrically conductive and gas/liquid-tight. The article doesn't say just

Mark L. Fergerson

I'd expect spot welding to be cheaper.

NT