Pt Wire Weld

Heat the gold plates.

I haven't welded wires quite that fine, but an appropriately sized and adjusted capacitive-discharge spot welder with appropriate electrodes should do it no problem

Thank you for your reply.

Do you have any ideas for the welder tips/electrodes? What the material I can use for that? How to prevent the electrode be welded?

This type of work is done in hybrid circuits and microchips all the time. Look up some semiconductor hardware equipment suppliers.

As wire is thin, you can use 100ns laser pulse in IR or micro-spot welder. Chip assembly uses micro-spot welder.

Thank you for your reply. Do you know any manufacturer of the laser pulse device?

I have had luck with small detailed welds like the one you are attempting using my bench top power supply as a miniature welder. I clamp my mig gun about 1/2" above the work (no wire) and use a foot pedel to activate the shield gas. Argon or CO2 25% Argon 75%. Now, hook 12 gauge test leads with aligator claps into the power supply use the negative as the ground cable and the positive as the electrode holder. My power supply has voltage & current control. I suggest 24 volt with low amperage. Practice with different current to find what you need. If you don't have easy access to shielding gas, paste flux will suffice. Just switch you positve & negative leads.

Hope the info. is helpful. let us know how it turns out.

Sorry, wasn't logged in. Above guest.

Neither Pt nor Au oxidize rapidly , so inert gas should not be necessary. For such fine wire, the problems will be the electrodes (holding the parts in position) and energy control (voltage, current, and time). If this is a do it yourself at home project for only a few connections, ordinary copper wire (shaped to a cone with a small flat on the end) should work for the Pt side, with a copper sheet or block (all VERY clean) for the Gold side. There needs to be some spring in the arrangement so contact is not lost when the heat smashes the wire. Since you probably don't have a way to control the time to a few milliseconds at home, try charging a capacitor, then connecting the capacitor to the weld leads. The 24 volts suggested is a good starting point. If that blows a hole, get a smaller capacitor; if it does not weld, either get a larger capacitor or increase the voltage. The current will be pretty much determined by the size of wire used for the leads, together with the switching arrangement used to make contact. Bigger wire of course will carry more current

You should use the bonding technology which is over 30 years old, that was how they connect the IC on your digital watch.

Danny

On interesting idea is at

http://www.platinummetalsreview.com/dynamic/question/view/10394

do you have to weld? What about conductive bonding agents?

No, epoxy is not good for fixing wires. These people are expert in thin wire welding. Try them

http://www.twi.co.uk/

thank you for the email that you send to me, what do you by help.

I want to make a hot-wire sensor to measure mass air flow.

Don't hijack the thread with a new topic, that is very discourteous.

Just start a new thread on the topic you want to discuss.