Indium based alloys typically solder very well and reliably to Au. The InPb
works very well for that application, as it doesn't seem to scavenge gold at
all. But you need to use nickel wires or you may have long term joint
issues.

When using In based alloys be aware that it tends to wet more materials than
Sn based alloys: For instance, they will typically wet alumina ceramic.
Normally not a major issue, but something to keep in mind.

Mike Fenner is our best expert in this area. I don't have the book Dave H.
is recommending, but all of his recommendations where I have taken his
advice have been good ones.

Wayne

-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]] 
Sent: Wednesday, June 03, 2015 7:38 PM
To: TechNet E-Mail Forum; Wayne Thayer
Subject: Re: [TN] Solder Alloy SnIn - Working Environmental Conditions:
-100°C to +100°C

you mean InAu?
          jk
> And don't forget about the potential for nasty InCu intermetallics! If 
> you go with indium, nickel plate everything first.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Fenner
> Sent: Wednesday, June 03, 2015 4:41 PM
> To: [log in to unmask]
> Subject: Re: [TN] Solder Alloy SnIn - Working Environmental Conditions:
> -100°C to +100°C
>
> In/Sn solidus of 118C is almost certainly too low for 100C working 
> environment and there is not much benefit in ductility from this alloy 
> at the other end.
> Probably Sn63 might cope in fact, but if you have large TEC mismatch, 
> or multiple cycles and other it depends stuff you might wish to look 
> at an In/Pb alloy. These are good for cryogenic apps so plenty in hand 
> and you have choice of MPs at other end of use scale.
> No benefit is without a cost though so you may have some surface 
> finish issues. To quote myself" it's never just the melting point" 
> when it comes to alloy choice. Discuss with your specialist supplier.
>
> --
> Regards
>
> Mike Fenner
> BS&P
> M: +44 [0] 7810 526 317
> T: +44 [0] 1865 522 663
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Ricardo 
> Moncaglieri
> Sent: Tuesday, June 02, 2015 10:18 PM
> To: [log in to unmask]
> Subject: [TN] Solder Alloy SnIn - Working Environmental Conditions: 
> -100°C to +100°C
>
> Dear Colleagues,
> Have to deploy a process and its qualification in order to perform 
> electrical connections which will be working under temperature 
> variations in the range of -100°C to +100°C (space application).
> We are pointing to SnIn solder alloy.
> We are just now starting  our investigation in our first steps.
> Will be invaluable some advise as per your background so as directing 
> me to some std and/or paper about best applicable solder alloy and its 
> qualification method.
> Being grateful in advance.
> brgds, Ricardo Moncaglieri
>
>
>
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