Fusible alloy

Last updated

A fusible alloy is a metal alloy capable of being easily fused, i.e. easily meltable, at relatively low temperatures. Fusible alloys are commonly, but not necessarily, eutectic alloys.

Contents

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:

Some reasonably well-known fusible alloys are Wood's metal, Field's metal, Rose metal, Galinstan, and NaK.

Applications

Melted fusible alloys can be used as coolants as they are stable under heating and can give much higher thermal conductivity than most other coolants; particularly with alloys made with a high thermal conductivity metal such as indium or sodium. Metals with low 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

AlloyMelting point Eutectic? Bismuth
%
Lead
%
Tin
%
Indium
%
Cadmium
%
Thallium
%
Gallium
%
Antimony
%
Rose's metal 98 °C (208 °F)no502525
Cerrosafe 74 °C (165 °F)no42.537.711.38.5
Wood's metal 70 °C (158 °F)yes5026.713.310
Field's metal 62 °C (144 °F)yes32.516.551
Cerrolow 136 58 °C (136 °F)yes49181221
Cerrolow 117 47.2 °C (117 °F)yes44.722.68.319.15.3
Bi-Pb-Sn-Cd-In-Tl41.5 °C (107 °F)yes40.322.210.717.78.11.1
Gallium 30.0 °C (86 °F)Pure metal------100
Galinstan −19 °C (−2 °F)no<1.59.5–10.521–2268–69<1.5

Other alloys

Low melting alloys and metallic elements
Composition in weight-percentMelting pointEutectic?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)
yesused 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 18.5 °C
(47.3 °F)
yes
Ga 62.5, In 21.5, Sn 16.010.7 °C
(51.3 °F)
yes Galinstan alloy
Ga 69.8, In 17.6, Sn 12.510.8 °C
(51.4 °F)
noGalinstan alloy
Ga 68.5, In 21.5, Sn 1011 °C
(52 °F)
noGalinstan alloy
Ga 75.5, In 24.515.7 °C
(60.3 °F)
yes
Cs 10028.6 °C
(83.5 °F)
(yes)
Ga 10029.8 °C
(85.6 °F)
(yes)
Rb 10039.30 °C
(102.74 °F)
(yes)
Bi 40.3, Pb 22.2, In 17.2, Sn 10.7, Cd 8.1, Tl 1.141.5 °C
(106.7 °F)
yes
Bi 40.63, Pb 22.1, In 18.1, Sn 10.65, Cd 8.246.5 °C
(115.7 °F)
Bi 44.7, Pb 22.6, In 19.1, Cd 5.3, Sn 8.347 °C
(117 °F)
yes Cerrolow 117. Used as a solder in low-temperature physics. [4]
Bi 49, Pb 18, In 21, Sn 1258 °C
(136 °F)
ChipQuik desoldering alloy. [5] Cerrolow 136. Slightly expands on cooling, later shows slight shrinkage in couple hours afterwards. Used as a solder in low-temperature physics. [4] Lens Alloy 136, used for mounting lenses and other optical components for grinding. [6] Used for mounting small delicate oddly-shaped components for machining.
Bi 32.5, In 51.0, Sn 16.560.5 °C
(140.9 °F)
yes Field's metal
K 10063.5 °C
(146.3 °F)
(yes)
Bi 50, Pb 26.7, Sn 13.3, Cd 1070 °C
(158 °F)
yesCerrobend. Used in low-temperature physics as a solder. [4]
Bi 49.5, Pb 27.3, Sn 13.1, Cd 10.170.9 °C
(159.6 °F)
yes Lipowitz's alloy
Bi 50.0, Pb 25.0, Sn 12.5, Cd 12.571 °C
(160 °F)
yes Wood's metal
In 66.3, Bi 33.772 °C
(162 °F)
yes [7]
Bi 42.5, Pb 37.7, Sn 11.3, Cd 8.574 °C
(165 °F)
noCerrosafe
Bi 57, In 26, Sn 1779 °C
(174 °F)
yes [7]
Bi 54, In 29.7, Sn 16.381 °C
(178 °F)
yes [7]
Bi 56, Sn 30, In 1479–91 °C
(174–196 °F)
noChipQuik desoldering alloy, lead-free
Bi 50, Pb 30, Sn 20, Impurities92 °C
(198 °F)
noLichtenberg's alloy, [8] also called Onions' Fusible Alloy [9]
Bi 52.5, Pb 32.0, Sn 15.595 °C
(203 °F)
yes
Bi 52, Pb 32.0, Sn 1696 °C
(205 °F)
yesBi52. 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 18.897 °C
(207 °F)
no Newton's metal
Na 10097.8 °C
(208.0 °F)
(yes)
Bi 50.0, Pb 28.0, Sn 22.094–98 °C
(201–208 °F)
no Rose's metal
Bi 55.5, Pb 44.5125 °C
(257 °F)
yes
Bi 58, Sn 42138 °C
(280 °F)
yesBi58. 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 100157 °C
(315 °F)
(yes)In99. Used for die attachment of some chips. More suitable for soldering gold, dissolution rate of gold is 17 times slower than in tin-based solders and up to 20% of gold can be tolerated without significant embrittlement. Good performance at 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 100180.5 °C
(356.9 °F)
(yes)
Sn 62.3, Pb 37.7183 °C
(361 °F)
yes
Sn 63.0, Pb 37.0183 °C
(361 °F)
noEutectic 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 9.0198 °C
(388 °F)
yesKappAloy9 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 8.0199 °C
(390 °F)
no Tin foil
Sn 100231.9 °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 100271.5 °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 100304 °C
(579 °F)
(yes)
Cd 100321.1 °C
(610.0 °F)
(yes)
Pb 100327.5 °C
(621.5 °F)
(yes)
Zn 100419.5 °C
(787.1 °F)
(yes)For soldering aluminium. Good wettability of aluminium, relatively good corrosion resistance. [21]

See also

Related Research Articles

<span class="mw-page-title-main">Indium</span> Chemical element, symbol In and atomic number 49

Indium is a chemical element; it has symbol In and atomic number 49. It is a silvery-white post-transition metal and one of the softest elements. Chemically, indium is similar to gallium and thallium, and its properties are largely intermediate between the two. It was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods and named for the indigo blue line in its spectrum.

<span class="mw-page-title-main">Solder</span> Alloy used to join metal pieces

Solder is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces after cooling. Metals or alloys suitable for use as solder should have a lower melting point than the pieces to be joined. The solder should also be resistant to oxidative and corrosive effects that would degrade the joint over time. Solder used in making electrical connections also needs to have favorable electrical characteristics.

<span class="mw-page-title-main">Tin</span> Chemical element, symbol Sn and atomic number 50

Tin is a chemical element; it has symbol Sn and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, the so-called "tin cry" can be heard as a result of twinning in tin crystals.

A period 5 element is one of the chemical elements in the fifth row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The fifth period contains 18 elements, beginning with rubidium and ending with xenon. As a rule, period 5 elements fill their 5s shells first, then their 4d, and 5p shells, in that order; however, there are exceptions, such as rhodium.

<span class="mw-page-title-main">Sodium–potassium alloy</span> Chemical compound

Sodium–potassium alloy, colloquially called NaK, is an alloy of the alkali metals sodium and potassium that is normally liquid at room temperature. Various commercial grades are available. NaK is highly reactive with water and may catch fire when exposed to air, so must be handled with special precautions.

<span class="mw-page-title-main">Brazing</span> Metal-joining technique

Brazing is a metal-joining process in which two or more metal items are joined by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal.

<span class="mw-page-title-main">Wood's metal</span> Alloy of bismuth, lead, tin and cadmium

Wood's metal, also known as Lipowitz's alloy or by the commercial names Cerrobend, Bendalloy, Pewtalloy and MCP 158, is a metal alloy that is useful for soldering and making custom metal parts, but its vapor is toxic to touch or breathe. The alloy is named for Barnabas Wood, who invented and patented the alloy in 1860. It is a eutectic, fusible alloy of 50% bismuth, 26.7% lead, 13.3% tin, and 10% cadmium by mass. It has a melting point of approximately 70 °C (158 °F).

<span class="mw-page-title-main">Galinstan</span> Eutectic alloy that is liquid at room temperature

Galinstan is a brand name for an alloy composed of gallium, indium, and tin which melts at −19 °C (−2 °F) and is thus liquid at room temperature. In scientific literature, galinstan is also used to denote the eutectic alloy of gallium, indium, and tin, which melts at around +11 °C (52 °F). The commercial product Galinstan is not a eutectic alloy, but a near eutectic alloy. Additionally, it likely has added flux to improve flowability, to reduce melting temperature, and to reduce surface tension.

The fusibility of a material refers to the ease at which the material can be fused together, or to the temperature or amount of heat required to melt a material. Materials such as solder require a relatively low melting point so that when heat is applied to a joint, the solder will melt before the materials being soldered together melt, i.e. high fusibility. On the other hand, firebricks used for furnace linings only melt at very high temperatures and so have low fusibility. Perhaps refractory materials often have low fusibility.

<span class="mw-page-title-main">Fire sprinkler</span> Component that discharges water to protect buildings

A fire sprinkler or sprinkler head is the component of a fire sprinkler system that discharges water when the effects of a fire have been detected, such as when a predetermined temperature has been exceeded. Fire sprinklers are extensively used worldwide, with over 40 million sprinkler heads fitted each year. In buildings protected by properly designed and maintained fire sprinklers, over 99% of fires were controlled by fire sprinklers alone.

Field's metal, also known as Field's alloy, is a fusible alloy that becomes liquid at approximately 62 °C (144 °F). It is named after its inventor, Simon Quellen Field. It is a eutectic alloy of bismuth, indium, and tin, with the following mass fractions: 32.5% Bi, 51% In, 16.5% Sn.

A liquid metal cooled nuclear reactor, or LMR is a type of nuclear reactor where the primary coolant is a liquid metal. Liquid metal cooled reactors were first adapted for breeder reactor power generation. They have also been used to power nuclear submarines.

<span class="mw-page-title-main">Fusible plug</span> Thermally triggered safety valve

A fusible plug is a threaded cylinder of metal, usually bronze, brass or gunmetal, with a tapered hole drilled completely through its length. This hole is sealed with a metal of low melting point that flows away if a pre-determined high temperature is reached. The initial use of the fusible plug was as a safety precaution against low water levels in steam engine boilers, but later applications extended its use to other closed vessels, such as air conditioning systems and tanks for transporting corrosive or liquefied petroleum gases.

A fusible link is a mechanical or electrical safety device. They are used in fire sprinkler heads to activate the sprinkler in the presence of heat. They are used in automobile electrical systems as a fuse.

Lead-Bismuth Eutectic or LBE is a eutectic alloy of lead and bismuth used as a coolant in some nuclear reactors, and is a proposed coolant for the lead-cooled fast reactor, part of the Generation IV reactor initiative. It has a melting point of 123.5 °C/254.3 °F and a boiling point of 1,670 °C/3,038 °F.

<span class="mw-page-title-main">Bismuth</span> Chemical element, symbol Bi and atomic number 83

Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs naturally, and its sulfide and oxide forms are important commercial ores. The free element is 86% as dense as lead. It is a brittle metal with a silvery-white color when freshly produced. Surface oxidation generally gives samples of the metal a somewhat rosy cast. Further oxidation under heat can give bismuth a vividly iridescent appearance due to thin-film interference. Bismuth is both the most diamagnetic element and one of the least thermally conductive metals known.

<span class="mw-page-title-main">Soldering</span> Process of joining metal pieces with heated filler metal

Soldering is a process of joining two metal surfaces together using a filler metal called solder. The soldering process involves heating the surfaces to be joined and melting the solder, which is then allowed to cool and solidify, creating a strong and durable joint.

<span class="mw-page-title-main">Post-transition metal</span> Category of metallic elements

The metallic elements in the periodic table located between the transition metals to their left and the chemically weak nonmetallic metalloids to their right have received many names in the literature, such as post-transition metals, poor metals, other metals, p-block metals and chemically weak metals. The most common name, post-transition metals, is generally used in this article.

<span class="mw-page-title-main">Bismuth–indium</span>

The elements bismuth and indium have relatively low melting points when compared to other metals, and their alloy bismuth–indium (Bi–In) is classified as a fusible alloy. It has a melting point lower than the eutectic point of the tin–lead alloy. The most common application of the Bi-In alloy is as a low temperature solder, which can also contain, besides bismuth and indium, lead, cadmium, and tin.

<span class="mw-page-title-main">Solder alloys</span>

Solder is a metallic material that is used to connect metal workpieces. The choice of specific solder alloys depends on their melting point, chemical reactivity, mechanical properties, toxicity, and other properties. Hence a wide range of solder alloys exist, and only major ones are listed below. Since early 2000s the use of lead in solder alloys is discouraged by several governmental guidelines in the European Union, Japan and other countries, such as Restriction of Hazardous Substances Directive and Waste Electrical and Electronic Equipment Directive.

References

  1. Wikisource-logo.svg 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.
  2. "F.A.Q." Archived from the original on 2004-08-07.
  3. Oshe, R.W. (ed.), "Handbook of Thermodynamic and Transport Properties of Alkali Metals", Oxford. UK, Blackwell Scientific Publications Ltd, 1985, p. 987
  4. 1 2 3 4 5 White, Guy Kendall; Meeson, Philip J. (2002). Experimental techniques in low-temperature physics. Clarendon. pp. 207–. ISBN   978-0-19-851428-2.
  5. Johnson Manufacturing Co, MSDS for Chip Quik Alloy w/Lead. Retrieved on February 6, 2015.
  6. "Lens Blocking alloy 136 58oC". Archived from the original on 2016-10-17.
  7. 1 2 3 "A Guide to Low Temperature Solder Alloys | Indium Corporation® | Indium Corporation Blogs | Indium | Solder Alloys". indium.com. Retrieved 2022-10-08.
  8. François Cardarelli (2008-03-19). Materials Handbook: A Concise Desktop Reference. Springer Science & Business Media. pp. 210–. ISBN   978-1-84628-669-8.
  9. Jensen, William B. (2010-10-01). "The Origin of the Name "Onion's Fusible Alloy"". Journal of Chemical Education. 87 (10): 1050–1051. Bibcode:2010JChEd..87.1050J. doi:10.1021/ed100764f. ISSN   0021-9584.
  10. 1 2 John H. Lau (1991). Solder joint reliability: theory and applications. Springer. p. 178. ISBN   0-442-00260-2.
  11. 1 2 Ray P. Prasad (1997). Surface mount technology: principles and practice. Springer. p. 385. ISBN   0-412-12921-3.
  12. Charles A. Harper (2003). Electronic materials and processes. McGraw-Hill Professional. pp. 5–8. ISBN   0-07-140214-4.
  13. Karl J. Puttlitz, Kathleen A. Stalter (2004). Handbook of lead-free solder technology for microelectronic assemblies. CRC Press. ISBN   0-8247-4870-0.
  14. Qualitek. Technical Data Sheet Sn42/Bi58 Solid Wire Rev.A 03/14 (PDF). Retrieved 3 May 2018.
  15. "Oregon State University". Oregon State University. Retrieved 2022-04-06.
  16. T.Q. Collier (May–Jun 2008). "Choosing the best bumb for the buck". Advanced Packaging. 17 (4): 24. ISSN   1065-0555.
  17. msl747.PDF. (PDF). Retrieved 2010-07-06.
  18. Qualitek. Technical Data Sheet Sn42/Bi58 Solid Wire Rev.A 03/14 (PDF). Retrieved 3 May 2018.
  19. "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.
  20. Madara Ogot, Gul Okudan-Kremer (2004). Engineering design: a practical guide. Trafford Publishing. p. 445. ISBN   1-4120-3850-2.
  21. Howard H. Manko (8 February 2001). Solders and soldering: materials, design, production, and analysis for reliable bonding. McGraw-Hill Professional. pp. 396–. ISBN   978-0-07-134417-3 . Retrieved 17 April 2011.

Further reading