Hi,

Anyone who's guru at this? Lids=nickel plated 0.5 mm thick Kovar.
Package= goldplated over nickel plated Kovar.

 We have He leakage problems due to porous and brittle welds. I suspect
that

 a)the 3-4um gold plating on the package is not metallurgically correct,
at least, ought to be much thinner, let's say like flash gold. 

b)too thin nickel on the package, just 1 um, should be 5um or more. 

 c)package shouldn't have electrolytic nickel, but electroless nickel,
because the later has 300 Centigrade lower melting point, and moreover,
is not so brittle (HV300, while EN can be HV1000)

Qs :

what nickel plating do you prefer?

What nickel plate thickness? (Welding, or rather brazing, is
nickel-to-nickel, Kovar should not be involved)

What wheel angle? 9, 12, 15 or what degrees?

Thanks in advance

Inge

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