# Palladium sponge to button



## Marcel (Apr 8, 2013)

I tried to melt some buttons from MLCCs to a larger one using a oxy torch and heat from below.
All of a sudden the molten metal "jumped" right up as if a bubble was inside (maybe some borax?). In the end I got the ugly sponge type Pd and it would not melt back to liquid metal.
What is there a way to get this sponge into a button shape?
Is there any literature that describes the melting of Pd, which flux to use etc..?
Pd melting is really tricky...


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## etack (Apr 8, 2013)

Marcel are you using a melting dish or a crucible? If you are using a graphite crucible it might be possible to make a lid for it and to put charcoal into you Pd powder in order to melt it in an O free atmosphere. The charcoal will use up any free O and take it from the PdO too to make CO2

Something like this might work too. http://fusedquartz.qsiquartz.com/viewitems/quartz-crucibles/low-form-quartz-crucibles-with-lid?

Eric


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## lazersteve (Apr 8, 2013)

I once melted Pd sponge with MAPP directly on the sponge in a white silica dish with no flux. The BB ended up with a porous surface from the oxides on it. I soaked the BB in HCl for about an hour and all of the oxides where gone (dissolved by the HCl which turned orange). The resulting BB was shiny and silver-gray in color.

I prefer melting Pd with Oxy/Hydrogen to avoid the surface oxide. I never use flux with Pt or Pd. The dish is always unglazed. I prefer high refractory (not silica or fireclay) dishes and surfaces for melting/polishing my PGMs.

Depending on how you produced your Pd sponge, the pop could have been from water trapped in the dish, water trapped in the sponge, or residual base metals in the Pd sponge (zinc or magnesium). The pop may have been trapped hydrogen in the Pd sponge as well.

Steve


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## Dan Dement (Apr 8, 2013)

Marcel,

In my business of Manufacturing Palladium Jewelry, melting powder in an Induction Melter can be a challenge. Several methods that I know of as melting Pd in Oxygen atmosphere is a very quick way to make it unusable for jewelry. The easiest method is to melt the powder along with a button. The IM usually will not melt loose powder so with a button and the melted button absorbs the powder. A second method is to compress the powder into pill. Our friend Lou sends me compressed Palladium which melts very easily in an IM. Of course, all of this is done in a Induction/Vacuum/Argon/ Centrigual casting machine. If you are going to sell it, no problem but if you are going to try to make jewelry out of it usually you are going to have lots of cracking in the metal. I know this really does not address your torch melting question but understand it can cause problems.

Dan


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## Lino1406 (Apr 11, 2013)

Supposedly 5% ruthenium help minimize Pd cracking


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## lazersteve (Apr 11, 2013)

I keep all of my Pd in sponge form unless someone request a metal button.

Steve


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## Dan Dement (Apr 11, 2013)

Lino,

Ruthenium is very gray and Iridium makes for a whiter metal. If you need to harden it, a Small of amount of Gallium (under 1% ) hardens it up but still stays fairly white. The trick to keeping it from cracking is Never heat or melt in O2. Also, keeping it away from silica is very important. Our buddy Lou has REALLY helped me. Lou is the PGM expert not me. I just parrot what he has teached me.  

Dan


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## Jasoncroxen (Nov 23, 2019)

I'm dealing with a new material and palladium has all the perimeters fit and was wonder if the bubbles remain on the bottom threw the hardening process? It the only precious metal I've seen fo this so is it a characteristic of palladium? Thanks Jason


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## Lino1406 (Nov 23, 2019)

Please give the parameters


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## snoman701 (Nov 24, 2019)

Pd absorbs all of the gasses from the flame. That's why it's used as catalyst. Any Pd melted in atmosphere is going to be a refining lot.

In order to get dense, workable Pd, it must be melted under vacuum or cover gas...preferably vacuum. So you are looking at arc melt, induction or electron beam.


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## Jasoncroxen (Dec 13, 2019)

I have been wondering what I had since it would bubble and jump? If poured into a spoon to make a small jewelry piece it has cool pits on the bottom part when hard. I'm sending in 11 ounces to the refinery on Monday. Keeping my fingers crossed. It's to hard and bright to be silver and the boiling point is around 3000°! I don't have a thermometer but my torch is 3700° and it takes 30 seconds to start melting. Plus the puck is smaller than 11 silver dollars. ✌


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