Variable melting point solders and brazes
US6613123B2 · kind B2 · utility
Inventors
Key dates
| Filing date | May 24, 2001 |
| Grant date | Sep 2, 2003 |
| Priority date | — |
| Expiry date | May 24, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2201/0272
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Variable melting point solders and brazes having compositions comprising a metal or metal alloy powder having a low melting point with a metal powder having a higher melting point. Upon heating, in-situ alloying occurs between the low and high melting point powders such that solidification occurs at the solder or braze temperature thus creating a new, higher solidus (or melting) temperature with little or no intermetallic formation. A solder comprising Sn powder mixed with a Sn—Bi eutectic powder having a composition of 63 wt % Sn:57 wt % Bi such that the bulk composition of the mixture is 3 wt % Bi has an initial melting point of 140° C. and a re-melt temperature of 220° C. after heating due to in-situ alloying. A composition of Pb powder mixed with a Pb—Sn eutectic powder having a composition of 62 wt % Sn:58 wt % Pb such that the bulk composition of the mixture is 15 wt % Sn has an initial melting point of 183° C. and a re-melt temperature of 250° C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.