Hello Researchers,
I have Nickel, Manganese and Tin powder (particle size is less than 100 micrometer for all). I want to make single phase alloy by arc melting technique. Oxides are not desired. My question is:
1. Can I use them directly in powder form for arc melting?
2. If answer is no, in that case, I am planning to mix all of them by mechanical alloying for 5 hrs. After 5 hours alloying, this alloyed powder can be consolidated into small pellets which can be further used for arc melting. I am planning to take total 60 gm of powder.
Will this idea work?
Kindly give your valuable suggestion.
You can go for arc melting. But, depends on the quantity how much use for melting.
Melting point of nickel should be considered.
Pellet form is better.
You can melt Ni-Mn-Sn alloy by vacuum arc melting.
However, vacuum arc furnafes (VAF) are of two types: consumable electrode and non-consumable electrode type. For example Ti alloys are melted in consumable VAF even in commercial scale where the melt size can go up to several tons. For other alloys, specially for small quantities (laboratory scale) non-consumable VAF with Tungsten electrodes are used where partial pressure of Argon is used and not vaccum. In both type, VAF is a clean melting method and avoids oxidation and other contamination from crucible materials.
In your case you can use pure Ni, Mn and Sn as charge and 100µm size is reasonable. However, Ni and Sn has large difference in melting point and this will lead to loss of Sn by evapouration. We routinely melt Co-Re alloy by VAF and it has the same problem - Co and Re has very different melting temperatures. So there is expected to be loss in alloying additions (in our case Cr, Ta, C etc.). To avoid this we first melt the Co and Re together and then in a second melt we add the other alloying elements.
In VAF because one uses water cooled copper crucible, you cannot control the liquid bath temperature (like in VIM for example) and no supper heating of liquid bath is possible. So for getting homogenous melts one routinely uses 3-4 or more meltings in non-consumable melting.
Dear Dr. Debashis Mukherjee,
Thank you so much for your scientific answer. Kindly explain the proper procedure for my case also. Please suggest me, in which sequence I should melt Ni,Mn and Sn powder to minimize the lose of Sn. Melting point of Nickel= 1455 degree centigrade, Manganese= 1246 degree, Tin = 231 degree.
In the case of powder melting the loss will be high and you will not get proper stochiometry.
To make a pallet is a good idea.
I think you can go for it but to compensate Sn loss some hits and trial are needed.
As Ms Nehla suggested making pellets of suitable size from the powder will help to minimize loss and also you can try mixing the powders before making the pellets. Composition you want to finally have is also important - i.e. does it have high amounts of Tin or only small amounts. The sequence of addition can depend on this and other factors. Trial and error is necessary if you have no prior information. And as suggested you may have to cater for the loss of a particular element.
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