Leadfree soldering and surface finishing

[joniengr]

I am wondering which solder can be used for leadfree soldering. Does it need higher temperature ? Normally soldering with Sn63 is done between 320 C and 350 C. Can we solder at the same temperature with leadfree solder ?

The most commonly used surface finish is Lead-free HASL how much it differ from ENIG Gold (Ni/Au) in terms of characteristic and price. How to de-gold the ENIG Gold (Ni/Au) to prepare for soldering ? Which solder can be used on ENIG Gold (Ni/Au) surface finish.

 

[FvM]

Lead-free solder has about 30 K higher melting point than Sn/Pb alloy. Solar temperatures are typically higher by this amount, 350 °C should work in most cases.

Surface finish has no big effect on soldering.

 

[joniengr]

Can you give some example of leadfree solder. Which solder are commonly used in leadfree soldering ? 30 K higher melting point also means 30 C higher, right ? Sn63Pb37 has melting point 183, so does it means that the melting point for leadfree solder is around 213 C ?

 

[joniengr]

I am still looking for some example of lead-free solders. Do they still have lead in it or they are completely lead-free ?

 

[G4BCH]

Do they still have lead in it or they are completely lead-free ?

Lead free means lead free, or at least virtually no lead. IIRC the ROHS limit for products is 0.1% Pb.
For some examples search for 'lead free surface mount solder alloy'. They are mainly tin-silver-copper alloys.
Some results that may help are:

Choosing Solder - Navigate the Different Alloys, Types of Flux, etc.

Learn how to select the right solder for use in electronics projects. Explore the different solder alloys and types of flux. Learn how to properly clean your circuit boards of flux after soldering.

neurochrome.com

https://www.mbouk.co.uk/pdf/leadfreepaper.pdf

Lead Free Solder Alloys: Part One :: Total Materia Article

www.totalmateria.com