Low Temperature Applications
Indium Corporation makes a wide range of alloys that melt or reflow below 180°C and can be used to solve a great many assembly and other challenges. Most of these alloy options contain indium and/or bismuth and are also RoHS-compliant.
Low-temperature solder is often used in electronics assembly including for these applications:
- Attachment of temperature sensitive components to printed circuit boards
- Step soldering, when a secondary, lower temperature reflow process is required after a standard SAC soldering process is completed
- Eliminating warpage of thinner chips due to high temperature reflow
- Low melting or low-Tg flex circuitry which are used in cellphones, smartwatches, and many internet-of-things (IoT) devices
- Large area array devices, such as BGAs, to avoid head-in-pillow (HIP) and non-wet-open (NWO) failures
Some popular solder alloys:
Alloy systems that are liquid at room temperature have a high degree of thermal conductivity, far superior than ordinary non-metallic liquids. This allows for the use of these materials in specific heat-conducting applications, such as heat dissipation in sensitive components during operation, machining, and/or manufacturing.
Other advantages of these liquid alloy systems are their inherent electrical conductivity. Typical applications for these materials include thermostats, switches, barometers, heat transfer systems, and thermal cooling and heating designs.
Some popular thermally conductive liquid alloys include:
|Liquidus C||Solidus C||Composition||Specific
|Thermal Conductivity(W/mK)||Electrical Resistivity(10-8 Ω-m)|
|46L||7.6||6.5||61.0Ga / 25.0In / 13.0Sn / 1.0Zn||6.37||15*||33*|
|51E||11||11||66.5Ga / 20.5In / 13.0Sn||6.32||16.51||28.91|
|51||17||11||62.5Ga / 21.5In / 16.0Sn||6.50||16.51||28.91|
|60||15.7||15.7||75.5Ga / 24.5In||6.35||20*||29.42|
- Geratherm Medical AG, Safety Data Sheet, 93/112/EC, 2004
- Michael D. Dickey, et al., Eutectic Gallium-Indium (EGaIn): A Liquid Metal Alloy for the Formation of Stable Structures in Microchannels at Room Temperature, Advanced Functional Materials, 2008, 18, 1097–1104
- C.Y.Ho, et al., Thermal Conductivity of the Elements, Journal of Physical Chemical Reference Data, Vol. 1. No 2, 1972.
- Charles Kittle, Introduction to Solid State Physics, 7th Ed., Wiley and Sons, 1996.
Some sealing operations use pure indium and require no heat at all. The sealing process uses mechanical pressure to create the bond. The softness and malleability of indium, not to mention its ability to retain these characteristics at cryogenic temperatures, allows it to fill in imperfections in mating surfaces to create a hermetic seal.
Other Low Temperature Applications
Low-temperature alloys or fusible alloys are commonly used in a variety of safety devices where they are designed to melt at a peak temperature to initiate a process.
Eye glass lens blocking is another application where low-temperature alloys or fusible alloys work very well. The lens is held in place using a block of the alloy which is then easily removed with hot water.
Some of the more common Fusible Alloys used in safety and other applications:
|Melting Point or Range Deg/F||117||158||160-190||217-440||255||281|
|Tensile Strength lbs/in2||5,400||5,990||5,400||13,000||6,400||8,000|
|Brinell Hardness No.||12||9.2||9||.19||10.2||22|
30 sec lbs/in2
|Safe Load Sustained||---||300||300||300||300||500|
Compared with Pure Copper
With the exception of the alloys that are liquid at room temperature, these low-temperature alloys are available in most of the forms that we produce.
Low Temperature Products
Low Temperature Videos
Chris Bastecki of Indium Corporation at SMTAi 2019
Low Temperature Alloys Technical Documents
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Safety Data Sheets
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Low Temperature Alloy Blog Posts
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