brazing copper to nickel, high working temperature

Anyone know of a good filler for brazing copper to nickel alloys, to be
use at a high (eg 800C) working temperature?
Thx,
-- Peter Fairbrother
Today I saw a solar eclipse!!
AND:
Spring is sprung
The grass is riz
I wonder where
The birdies is?
I heard
"The bird is on the wing",
but that's absurd;
The wing is on the bird.
Reply to
Peter Fairbrother
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Greetings Peter, Just use pure silver as the solder. Go to the local jeweler and ask for a strip of fine silver flat or round wire. Sterling silver would work too but melts at 893 c, whereas pure silver melts at 961c. Copper melts at 1083 c. Use flux. You can also blend pure silver with sterling to get an alloy that melts somewhere between the two. Eric
Reply to
etpm
I have no actual experience, but I do not think Eric's advice is quite righ t.
If you use pure silver to braze copper, I would think the silver would comb ine with the copper to form an alloy that melts at a lower temp than the pu re silver.
Before spending the big bucks for silver, I would try using pure copper wir e. Not exactly brazing,but worth trying.
If you really need to braze, then you might try silicon Bronze which melts at
ply.
Dan
Reply to
dcaster
Greetings Dan, There is indeed the likelyhood that the copper/silver interface would result in an alloy of lower melting temp than pure silver. This is of no consequence as long as the amount of copper that alloys with the silver is less than 20%. It is unlikely that this would happen. And pure silver flows quite well, as does sterling, into very tight spaces through capillary action. I don't know how well silicon bronze flows into these tight spaces. One thing silicon bronze rod has going for it though is ready availability and low price compared to silver and its alloys. Eric
Reply to
etpm
Traditionally Monel 67 is used to join copper and nickle with TIG welding, as it is basically Nickel-Silver (copper/nickel)
Any silver solder will join them, but for high temp work, there are nickle solders used for aerospace, sold by Wall Colmonoy.
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Reply to
stagesmith

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