Fusible alloy
A fusible alloy is a
eutectic
alloys.
Sometimes the term "fusible alloy" is used to describe alloys with a melting point below 183 °C (361 °F; 456 K). Fusible alloys in this sense are used for solder.
Introduction
From a practical view, low-melting alloys can be divided into the following categories:
- Mercury-containing alloys
- Only alkali metal-containing alloys
- Gallium-containing alloys (but neither alkali metal nor mercury)
- Only bismuth, lead, tin, cadmium, zinc, indium, and sometimes thallium-containing alloys
- Other alloys (rarely used)
Some reasonably well-known fusible alloys are
NaK
.
Applications
Melted fusible alloys can be used as
neutron cross-section are used for cooling nuclear reactors
.
Such alloys are used for making the fusible plugs inserted in the furnace crowns of
steam boilers, as a safeguard in the event of the water level being allowed to fall too low. When this happens the plug, being no longer covered with water, is heated to such a temperature that it melts and allows the contents of the boiler to escape into the furnace. In automatic fire sprinklers the orifices of each sprinkler is closed with a plug that is held in place by fusible metal, which melts and liberates the water when, owing to an outbreak of fire in the room, the temperature rises above a predetermined limit.[1]
Bismuth on solidification expands by about 3.3% by volume. Alloys with at least half of bismuth display this property too.[2] This can be used for mounting of small parts, e.g. for machining, as they will be tightly held.[citation needed]
Low-melting alloys and metallic elements
Well-known alloys
| Alloy | Melting point | Eutectic ? |
Bismuth % |
Lead % |
Tin % |
Indium % |
Cadmium % |
Thallium % |
Gallium % |
Antimony % |
|---|---|---|---|---|---|---|---|---|---|---|
| Rose's metal | 98 °C (208 °F) | no | 50 | 25 | 25 | – | – | – | – | – |
| Cerrosafe | 74 °C (165 °F) | no | 42.5 | 37.7 | 11.3 | – | 8.5 | – | – | – |
| Wood's metal | 70 °C (158 °F) | yes | 50 | 26.7 | 13.3 | – | 10 | – | – | – |
| Field's metal | 62 °C (144 °F) | yes | 32.5 | – | 16.5 | 51 | – | – | – | – |
Cerrolow 136 |
58 °C (136 °F) | yes | 49 | 18 | 12 | 21 | – | – | – | – |
| Cerrolow 117 | 47.2 °C (117 °F) | yes | 44.7 | 22.6 | 8.3 | 19.1 | 5.3 | – | – | – |
| Bi-Pb-Sn-Cd-In-Tl | 41.5 °C (107 °F) | yes | 40.3 | 22.2 | 10.7 | 17.7 | 8.1 | 1.1 | – | – |
| Gallium | 30.0 °C (86 °F) | Pure metal | - | - | - | - | - | - | 100 | – |
| Galinstan | −19 °C (−2 °F) | no | <1.5 | – | 9.5–10.5 | 21–22 | – | – | 68–69 | <1.5 |
Other alloys
| Composition in weight-percent | Melting point | Eutectic? | Name or remark |
|---|---|---|---|
| Cs 73.71, K 22.14, Na 4.14 [3] | −78.2 °C (−108.8 °F) |
yes | "CsNaK", reactive with water and air |
| Hg 91.5, Tl 8.5 | −58 °C (−72 °F) |
yes | used in low-reading thermometers |
| Hg 100 | −38.8 °C (−37.8 °F) |
(yes) | |
| Cs 77.0, K 23.0 | −37.5 °C (−35.5 °F) |
||
| K 76.7, Na 23.3 | −12.7 °C (9.1 °F) |
yes | |
| K 78.0, Na 22.0 | −11 °C (12 °F) |
no | NaK
|
| Ga 61, In 25, Sn 13, Zn 1 | 8.5 °C (47.3 °F) |
yes | |
| Ga 62.5, In 21.5, Sn 16.0 | 10.7 °C (51.3 °F) |
yes | Galinstan alloy |
| Ga 69.8, In 17.6, Sn 12.5 | 10.8 °C (51.4 °F) |
no | Galinstan alloy |
| Ga 68.5, In 21.5, Sn 10 | 11 °C (52 °F) |
no | Galinstan alloy |
| Ga 75.5, In 24.5 | 15.7 °C (60.3 °F) |
yes | |
| Cs 100 | 28.6 °C (83.5 °F) |
(yes) | |
| Ga 100 | 29.8 °C (85.6 °F) |
(yes) | |
| Rb 100 | 39.30 °C (102.74 °F) |
(yes) | |
| Bi 40.3, Pb 22.2, In 17.2, Sn 10.7, Cd 8.1, Tl 1.1 | 41.5 °C (106.7 °F) |
yes | |
| Bi 40.63, Pb 22.1, In 18.1, Sn 10.65, Cd 8.2 | 46.5 °C (115.7 °F) |
||
| Bi 44.7, Pb 22.6, In 19.1, Cd 5.3, Sn 8.3 | 47 °C (117 °F) |
yes | Cerrolow 117. Used as a solder in low-temperature physics.[4] |
| Bi 49, Pb 18, In 21, Sn 12 | 58 °C (136 °F) |
ChipQuik Used for mounting small delicate oddly-shaped components for machining. | |
| Bi 32.5, In 51.0, Sn 16.5 | 60.5 °C (140.9 °F) |
yes | Field's metal |
| K 100 | 63.5 °C (146.3 °F) |
(yes) | |
| Bi 50, Pb 26.7, Sn 13.3, Cd 10 | 70 °C (158 °F) |
yes | Cerrobend. Used in low-temperature physics as a solder.[4] |
| Bi 49.5, Pb 27.3, Sn 13.1, Cd 10.1 | 70.9 °C (159.6 °F) |
yes | Lipowitz's alloy
|
| Bi 50.0, Pb 25.0, Sn 12.5, Cd 12.5 | 71 °C (160 °F) |
yes | Wood's metal |
| In 66.3, Bi 33.7 | 72 °C (162 °F) |
yes | [7] |
| Bi 42.5, Pb 37.7, Sn 11.3, Cd 8.5 | 74 °C (165 °F) |
no | Cerrosafe |
| Bi 57, In 26, Sn 17 | 79 °C (174 °F) |
yes | [7] |
| Bi 54, In 29.7, Sn 16.3 | 81 °C (178 °F) |
yes | [7] |
| Bi 56, Sn 30, In 14 | 79–91 °C (174–196 °F) |
no | ChipQuik desoldering alloy, lead-free |
| Bi 50, Pb 30, Sn 20, Impurities | 92 °C (198 °F) |
no | Lichtenberg's alloy,[8] also called Onions' Fusible Alloy[9] |
| Bi 52.5, Pb 32.0, Sn 15.5 | 95 °C (203 °F) |
yes | |
| Bi 52, Pb 32.0, Sn 16 | 96 °C (205 °F) |
yes | Bi52. Good fatigue resistance combined with low melting point. Reasonable shear strength and fatigue properties. Combination with lead-tin solder may dramatically lower melting point and lead to joint failure.[10] |
| Bi 50.0, Pb 31.2, Sn 18.8 | 97 °C (207 °F) |
no | Newton's metal |
| Na 100 | 97.8 °C (208.0 °F) |
(yes) | |
| Bi 50.0, Pb 28.0, Sn 22.0 | 94–98 °C (201–208 °F) |
no | Rose's metal |
| Bi 55.5, Pb 44.5 | 125 °C (257 °F) |
yes | |
| Bi 58, Sn 42 | 138 °C (280 °F) |
yes | Bi58. Reasonable shear strength and fatigue properties. Combination with lead-tin solder may dramatically lower melting point and lead to joint failure.[10] Low-temperature eutectic solder with high strength.[11] Particularly strong, very brittle.[12] Used extensively in through-hole technology assemblies in IBM mainframe computers where low soldering temperature was required. Can be used as a coating of copper particles to facilitate their bonding under pressure/heat and creating a conductive metallurgical joint.[13] Sensitive to shear rate. Good for electronics. Used in thermoelectric applications. Good thermal fatigue performance. Yield strength 7,119 psi (49.08 MPa), tensile strength 5,400 psi (37 MPa).[14] |
| Bi 57, Sn 43[15] | 139 °C (282 °F) |
yes | |
| In 100 | 157 °C (315 °F) |
(yes) | In99. Used for die attachment of some chips. More suitable for soldering cryogenic temperatures.[16] Wets many surfaces incl. quartz, glass, and many ceramics. Deforms indefinitely under load. Does not become brittle even at low temperatures. Used as a solder in low-temperature physics, will bond to aluminium. Can be used for soldering to thin metal films or glass with an ultrasonic soldering iron.[4]
|
| Li 100 | 180.5 °C (356.9 °F) |
(yes) | |
| Sn 62.3, Pb 37.7 | 183 °C (361 °F) |
yes | |
| Sn 63.0, Pb 37.0 | 183 °C (361 °F) |
no | Eutectic solder. Sn63, ASTM63A, ASTM63B. Common in electronics; exceptional tinning and wetting properties, also good for stainless steel. One of the most common solders. Low cost and good bonding properties. Used in both SMT and through-hole electronics. Rapidly dissolves gold and silver, not recommended for those.[11] Sn60Pb40 is slightly cheaper and is often used instead for cost reasons, as the melting point difference is insignificant in practice. On slow cooling gives slightly brighter joints than Sn60Pb40.[17]
Yield strength 3,950 psi (27.2 MPa), tensile strength 4,442 psi (30.63 MPa).[18] |
| Sn 91.0, Zn 9.0 | 198 °C (388 °F) |
yes | KappAloy9 Designed specifically for Aluminum-to-Aluminum and Aluminum-to-Copper soldering. It has good corrosion resistance and tensile strength. Lies between soft solder and silver brazing alloys, thereby avoiding damage to critical electronics and substrate deformation and segregation. Best solder for Aluminum wire to Copper busses or Copper wire to Aluminum busses or contacts.[19] UNS#: L91090
|
| Sn 92.0, Zn 8.0 | 199 °C (390 °F) |
no | Tin foil |
| Sn 100 | 231.9 °C (449.4 °F) |
(yes) | Sn99. Good strength, non-dulling. Use in food processing equipment, wire tinning, and alloying.[20] Susceptible to tin pest. |
| Bi 100 | 271.5 °C (520.7 °F) |
(yes) | Used as a non- superconducting solder in low-temperature physics. Does not wet metals well, forms a mechanically weak joint.[4]
|
| Tl 100 | 304 °C (579 °F) |
(yes) | |
| Cd 100 | 321.1 °C (610.0 °F) |
(yes) | |
| Pb 100 | 327.5 °C (621.5 °F) |
(yes) | |
| Zn 100 | 419.5 °C (787.1 °F) |
(yes) | For soldering aluminium. Good wettability of aluminium, relatively good corrosion resistance.[21] |
See also
- Liquid metal
- List of elements by melting point
References
- ^ One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Fusible Metal". Encyclopædia Britannica. Vol. 11 (11th ed.). Cambridge University Press. p. 369.
- ^ "F.A.Q." Archived from the original on 2004-08-07.
- ^ Oshe, R.W. (ed.), "Handbook of Thermodynamic and Transport Properties of Alkali Metals", Oxford. UK, Blackwell Scientific Publications Ltd, 1985, p. 987
- ^ ISBN 978-0-19-851428-2.
- ^ Johnson Manufacturing Co, MSDS for Chip Quik Alloy w/Lead. Retrieved on February 6, 2015.
- ^ "Lens Blocking alloy 136 58oC". Archived from the original on 2016-10-17.
- ^ a b c "A Guide to Low Temperature Solder Alloys | Indium Corporation® | Indium Corporation Blogs | Indium | Solder Alloys". indium.com. Retrieved 2022-10-08.
- ISBN 978-1-84628-669-8.
- ISSN 0021-9584.
- ^ ISBN 0-442-00260-2.
- ^ ISBN 0-412-12921-3.
- ISBN 0-07-140214-4.
- ISBN 0-8247-4870-0.
- ^ Qualitek. Technical Data Sheet Sn42/Bi58 Solid Wire Rev.A 03/14 (PDF). Retrieved 3 May 2018.
- ^ "Oregon State University". Oregon State University. Retrieved 2022-04-06.
- ISSN 1065-0555.
- ^ msl747.PDF. (PDF). Retrieved 2010-07-06.
- ^ Qualitek. Technical Data Sheet Sn42/Bi58 Solid Wire Rev.A 03/14 (PDF). Retrieved 3 May 2018.
- ^ "Tin-Zinc Solders for Aluminium to Aluminium and Copper". Kapp Alloy & Wire, Inc. Archived from the original on 16 July 2013. Retrieved 23 October 2012.
- ISBN 1-4120-3850-2.
- ISBN 978-0-07-134417-3. Retrieved 17 April 2011.
Further reading
- ASTM B774—Standard Specification for Low Melting Point Alloys. doi:10.1520/B0774.
- Weast, R.C., "CRC Handbook of Chemistry and Physics", 55th ed, CRC Press, Cleveland, 1974, p. F-22
External links
- Fusible (Low Temp) Alloys
- Fusible Alloys. Archived from the original on 2012-10-12.
- Jenson, W.B. "Ask the Historian - Onion's fusible alloy" Archived 2016-03-04 at the Wayback Machine