Indium Corporation Blogs

Being the Indium Corporation, we know what indium is, where it comes from, and how to use it.  But sometimes we forget that not everyone is as immersed in indium as we are.

So what is indium?  Of course it is an element with an atomic number of 49, an atomic weight of 114.818amu, a relative density of 7.31g/cm³, and a melting point of 157°C.  I have known that for most of the 27 years I have worked at Indium Corporation, but what exactly does that mean?

Well, the atomic number is important because it is the number of protons in the nucleus - and this is what gives each element its physical characteristics.  It also places it in the periodic table (directly to the left of indium on the chart is cadmium which has an atomic number of 48 and to the right is tin, which has an atomic number of 50).  This puts indium in the group of metals known as "Other Metals", along with bismuth, tin, zinc, antimony, gallium, and germanium.  The atomic weight is a measurement of the total number of particles in the nucleus of the atom.  If you want to know more about protons, electrons, and neutrons, go to the Jefferson Lab site.

The specific gravity or relative density of an element, which, in the case of indium, is 7.31g/cm³, depicts its relative density compared to water.  If the relative density of an element is less than one, then it will float in water.  If it is greater than 1 then it will sink.  If you compare indium's relative density to that of lead, which is 11.35, you will see that, if you had a piece of each material cut to the exact same dimensions, the lead would be heavier than the indium.

Between the atomic number and the specific gravity, I use the specific gravity more often.  It is used in a formula to find the weight of a solder part, or of a length of wire or ribbon.

So where does indium come from?  Since indium is an element, it comes from the earth's crust.  It is generally refined as a by-product of zinc ore mining.  There is an ongoing debate about the availability of indium.  But a lot of work is being done to create more efficient extraction methods and reclaim, particularly of ITO targets, to assure an adequate indium supply for existing and emerging technologies for decades to come.

Okay, now for the fun part. Where is indium used?  It would probably be shorter to say where it ISN'T used!  If you are involved in any of the following areas, you have a need for indium:

• Cryogenic sealing
• Hermetic sealing
• Low temperature soldering for temperature sensitive devices
• Step soldering
• Solar panels (CIS & CIGS)
• Coatings for displays and glass (ITO & IGZO)
• Pb-free soldering
• Fuses
• CTE mismatch when bonding dissimilar materials
• Thermal management

 

Indium is certainly one of the more versatile metals because it works and plays well with others.  Read more about indium:

Indium Solder and Sealing

Thermal Management

Heat Spring

Low Temperature Solder

We like new challenges and applications, so if we can help you (or you think you can stump us), email me at cgowans@indium.com.

 

 

 

The 2013 IPC APEX Expo , the premiere electronics assembly event, is right around the corner - and our technology experts are ready to share their experience and knowledge on a variety of topics.

Ning-Cheng Lee, PhD, VP of Technology will present a paper on voiding control in mixed solder alloy systems. He will also present on the hot topic of QFN voiding.     Dr. Lee is a world-renown soldering expert (EVERYBODY knows Dr. Lee!).  In addition to his work at Indium with solders (for 27 years), he is also an expert on polymers, underfills, and adhesives.

Ronald Lasky, PhD, PE, Senior Technologist will be presenting a paper on Material and Process Optimization for Head-In-Pillow Minimization.  Dr. Lasky is one of our most popular bloggers, check out his blog!  He approaches the world of electronics assembly from some interesting directions, including the exploits of Patty and the Professor.  Dr. Lasky will also talk about Applications of Solder Preforms to Improve Reliability, and A Focus on Productivity: Several Case Studies.  He has also found some time to teach two professional development courses: An Introduction of DOE, SPC and Weibull Analysis; and Manufacturing for High Yields in Assembly. Another busy man!

Senior Technical Support Engineer, Eric Bastow will be presenting on The Effects of Human Induced Contamination on PCB Assembly Electrical Reliability.  Eric has looked at the impact of oil, grease, and hand creams and how they can create reliability issues in small components.  Eric provides technical support to our customers by phone and in person. 

The APEX Expo will feature over 400 exhibitors and lots of technical sessions. It provides you the opportunity to have face-to-face discussions with many of our materials experts, so bring your soldering challenges and visit us at Booth 1127.

Can't make it to San Diego?  Call or email us and we can help you anytime!

 

Carol Gowans

February 2013

There have been a variety of people who were key to the development of indium metal in general, and Indium Corporation in particular, over the years.

People such as:

• Hieronymus Theodor Richter and Ferdinand Reich who discovered indium metal in 1863
• Daniel Gray, William S. Murray and J. Robert Dyer who formed the original Indium Corporation back in March of 1934 and who hold patents on processes and applications involving indium
• Frieda Nojeim who joined the company in 1966 and was elected vice president in 1971

 

And, in 1972, Charles E.T. White joined the Indium Corporation as a vice president (he was elected executive vice president in 1981).  I had the pleasure of knowing Mr. White before he retired.  He was indeed a character, but he also knew a LOT about indium.

In 1986 (a lifetime ago in the electronics industry) Mr. White published an article called: Indium: High Technology Metal in Advanced Materials and Processes magazine.  I ran across a copy of it the other day and, after reading it, was interested in how relevant it still is today, even though technology has marched forward.

Of course the physical characteristics of indium are still as valid today as they were then. 

• Resistance to thermal fatigue
• High thermal conductivity
• Wetting of non-metals (glass, quartz, ceramics)
• Malleability and ductility, even at cryogenic temperatures
• Electrical conductivity for a variety of screens
• Indium does not work harden

 

But one might expect the technology described in an article from nearly 30 years ago to have evolved or gone entirely away, resulting in the elimination of the need for the indium.  The truth is, many of applications that Mr. White mentioned still exist today:

• "Conforming gasket material for cryogenic vessels."
• "Indium is present in every wristwatch and computer screen that uses a liquid-crystal display."  Okay, so no one wears wristwatches anymore, but the screens on our phones (the new time-telling devices) have indium tin oxide coatings.
• "...used in lens blocking and in temperature-overload devices such as safety links, fuses and sprinkler plugs."
• "Many solder alloys containing indium have been developed to take advantage of indium's enhancement of thermal-fatigue resistance, reduced gold scavenging, and resistance to alkaline corrosion."
• "Glass sealing alloys containing indium ...have been developed for electronic device packaging where high temperatures cannot be used."
• "Indium's use in solder alloys is likely to increase as specialty solders become more important in electronic assembly techniques."
• "The whole area of conductive films of indium oxide and indium-tin oxide has good potential for growth.  This includes solar cells: silicon-cell efficiency can be improved with an indium or indium-tin oxide coating."
• "New applications such as solar cells made of indium-copper-diselenide/cadmium-sulphide are under active development."

 

And while these indium applications still exist today, R&D continues to find new opportunities for this very unique metal.  We have several Research Solder Kits that you can use to evaluate the value of indium in your process.  Just go to our e-commerce page or contact our engineers to see how indium can work for you.

Carol Gowans

There are a lot of parameters to consider when choosing the right solder for your application:

1) The operational temperature of the final device

2) The metallizations that you are soldering to

3) Temperature sensitivity of any components that you are soldering

4) Need for Pb-free

5) Drop test requirements

6) Reliability requirements

Each individual application will, no doubt, have additional requirements.  But, generally, one of the first considerations will be the melting temperature of the solder.

Many applications need a low-temperature solder that will reflow below 180C.  For example, LED attach, optics assembly, and MEMS mounting all have low temperature solder requirements.  There are two metals, in particular, that help fulfill this need.  One is indium and the other is bismuth.

There are five common solder alloys that are well suited for your low-temperature, Pb-free requirements.  As a matter of fact, they are so popular we have packaged them together in a kit (in the solder paste version) for you to evaluate.

Our Low Temperature Pb-Free Solder Paste Research Kit allows you to evaluate any two alloys in a side-by-side comparison to determine the optimum paste for your application. The five alloys that you can choose from in our Low Temperature Pb-Free Solder Paste Kit are:

• Indalloy 1E (52In 48Sn) Eutectic at 118C
• Indalloy 281 (58Bi 42Sn) Eutectic at 138C
• Indalloy 282 (57Bi 42Sn 1Ag)  140C/139C
• Indalloy 290 (97In 3Ag) Eutectic at 143C
• Indalloy 4 (99.99In) Melting Point of 157C

In this kit, each alloy is matched with the proper flux vehicle so you can comparatively test multiple alloys to see which is the best option for your application. 

The kit is available on line and our Application Engineers are available to help steer you in the right direction as to which two alloys to choose.

Over the years, solder alloy choices have been pretty stable.  In the last century, SN63 and SN62 could be found at any company making any kind of electronic device, and both alloys were the backbone of every company making solders.

But, when lead was identified as causing health issues, it was legislated out of everything from paint to gasoline to electronics, including solders.  In 2003, RoHS (Restriction of Hazardous Substances) was passed in Europe to restrict the use of lead (as well as mercury, cadmium, hexavalent chromium, and polybrominated diphenyl ethers: PBDE) in electronics and electronic equipment.

The electronics industry is now focused on SAC alloys (so named because they contain Sn, Ag, and Cu).  But, there is also SnAg, which was used in the lead era when a higher melting point was required.  The addition of the copper (in SAC) offers the benefit of improving wetting and potentially reducing the silver content from a non-copper alloy like 96.5Sn 3.5Ag. 

But, there are many applications where SnAg works well. Changing from it would require customer and/or government approval, and that involves a lot of extra money and time. This lead-free alloy works well in the assembly of a variety of medical devices that use non-traditional metallizations and fluxes.  The Cu addition (in a SAC alloy) probably would not improve the results enough to warrant the cost of requalifying an existing medical device through government agencies, so they stay with what works. 

So, if you are using 96.5Sn 3.5Ag (or 96Sn 4Ag), don't be afraid to stick with it.  Indium Corporation offers both of these solder alloys (and over 250 other alloys) in a variety of forms: preforms, wire, paste, and ribbon.   And, if you want to look at the SAC alloy family to see if it works better in your application, we will help you with that, too.  Just contact our Application Engineering Staff for help.

Carol

It is hard to believe, but 50 years ago, on October 9th, the first visible light LED was demonstrated by Nick Holonyak, Jr. of GE Advanced Semiconductor Laboratory in Syracuse, NY (just down the road from Indium Corporation's global headquarters).  Fortunately, he did not listen to his critics who said mixing gallium arsenide and gallium phosphide would not work to make a visible light LED, because they were wrong!

According to Roberto Baldwin at www.wired.com, Holonyak predicted that LEDs would one day replace the incandescent light.  Today there are many efforts underway to make that happen.

Today, Indium Corporation is involved in several LED applications:

1) NanoFoil®:   High brightness LEDs use NanoFoil® to bond thermal pads to heat-sinking substrates.  By using the NanoFoil®, the standard reflow process (that can negatively impact brightness, color, and life time) is avoided.

2) Gallium Trichloride: This is used as the starting material for making gallium-based metal organic precursors, such as tri-methyl gallium, which are used in the LED industry.

3) Indium Trichloride Also used as a starting material, but for indium-based metal organic precursors such as tri-methyl indium.  These compounds are also used in the manufacture of LED lighting as well as batteries and other applications.

4) Engineered Solder Materials: Attaching an LED to a substrate can also be done by using a variety of specialty solders, including bismuth-based (low temperature) solder preforms or solder pastes.  We also have a variety of thermal solutions that can help dissipate the heat generated by the LED.  Flux-coated solder preforms provide solder and flux in a consistent volume, for use under larger LEDs to reduce or eliminate voiding. 

It may have taken 50 years to see the widespread adoption of this technology, but there is no doubt that it is here to stay!

Contact us for more information or visit www.indium.com and see our new web site.

cgowans@indium .com

Carol Gowans

The Indium Corporation has developed a new solder research kit designed specifically to meet the needs of medical manufacturers who are soldering to Nitinol®.

The kit contains the two best fluxes for soldering to Nitinol:

• Indalloy Flux #2
• Indalloy Flux #3

It also contains Indalloy #121 (96.5Sn 3.5Ag) in a 0.030" diameter wire and some Nitinol wire from Fort Wayne Metals.  This kit gives you the tools you need to decide which flux works best for your application by allowing you to try them out with the supplied Nitinol.

You can buy the kit directly from our e-commerce site or contact me at cgowans@indium.com if you have more questions.

Carol Gowans

About a month ago I posted about the various 3D technologies (chip creation, packaging and printed circuit boards) that are being used to optimize the various electronics upon which we all rely.  Molded Interconnect Device (MID) technology has been around for more than 20 years and is being used extensively in cell phone antennae. 

Recently I discussed the state of the art of 3D-MID technology with the Director of 3D MID Technology at Cicor in Switzerland, Nouhad Bachnak.  Cicor is one of the key players in the development of molded interconnect devices.

Carol: MID technology has been around for more than 20 years but, so far, it is only widely adopted in cell phone antennae.  What is sparking the renewed interest for other electronic applications?

Nouhad: The idea to use 3D-MID for electronic applications is much older than the idea to use this technology for antenna applications.  When this technology started in the 1980's there was a high euphoria that it would replace the printed circuit board (PCB).  But there was a lack of qualified materials and a lack of specific know-how for the manufacturing process.

Over the last few years a tremendous amount of development work has been done and considerable progress was made.

New MID-specific design, chemical and 3D assembly machines were developed and successfully implemented in serial production.  Millions of antennae have been produced, but also several other products like sensors, switches and LED carriers for automotive, medical and industrial applications show the benefits of 3D-MID and this encouraged customers to use them.

Carol: What processes do you offer for making these devices and what are the benefits of each?

Nouhad: We use the LPKF Laser Direct Structuring (LDS) and the 2S (two shot molding) processes.  These two processes have to be seen as complementary to each other, rather than competing with each other.

Major advantages of the LDS process are:

• Simple injection molding tool
• Easy layout changes (just by changing the CAD layout)
• Thin structures are possible 150 µm or even smaller

Major advantages of the 2S process are:

• Only two process steps for the substrate manufacturing (molding and plating)
• High reproducibility of the layouts
• Very economical for big plating surfaces and complex layouts

Carol: What are the biggest challenges facing component attachment to 3D-MID?

Nouhad: The first one is the 3D attachment of the components on the MID substrate.  Precise 3D electronic assembly systems with several axes and sophisticated optical systems are required to master this task accordingly.  In this area we are working with Haecker Automation, who develops such high-standing quality systems.  The other aspect is the capabilities of the substrates to withstand high temperature solder profiles.  There are of course several materials which can withstand up to 260C.  But these materials usually have some other weaknesses (fragile, too expensive).

Carol: What markets are showing the most interest in using this technology to replace traditional printed circuit boards?

Nouhad: Using the benefits of 3D-MID is not limited to certain markets.  3D-MID can be used everywhere, where plastics meets electronics and it is not just about replacing PCB.  3D-MID opens a tremendous amount of possibilities by using MID as an interconnectivity module combining electrical and mechanical functions in one part.

Carol: What do you see as the key drivers in moving MID forward in the electronics industry?

Nouhad: The key drivers in moving 3D-MID forward are:

• Miniaturization: due to space problems (automotive, medical, telecommunication, etc.)
• Rationalization and system simplification: reduction of process steps, number of parts and mounting time
• Functionality: new functions which are made possible only because of the high functional integration possibilities, design flexibility and the precision given by 3D-MID

The 3D-MID technology advantages in these areas are:

• Optimal three dimensional space utilization
• High function integration density of mechanical and electronic functions
• Saving of parts and process steps

Carol: Where do you see the industry in another ten years?

Nouhad: This is the most difficult question!  In this context I would like to quote the famous physicist Nils Bohr: "Forecasts are always difficult-especially if they concern the future".

Nevertheless one thing seems to be evident: the 3D-MID technology has already gained a footing in the market and is growing very fast.  For our part, for the next three years, Cicor is planning its manufacturing capacities according to growth rate expectation of more than 50% per year.

 

 

Thanks Nouhad for your time and expertise. 

Like we have often said about indium metal, the possibilities are endless®!

Carol Gowans

 

 

 

 

 

It won't be long until we in the northern hemisphere are complaining about the snow and the cold, but right now, it is all about the heat! 

In particular about the heat that is needed to reflow high melting point (HMP) alloys.  These are generally high-Pb alloys that see very high operational temperatures. They are used for applications such as automotive under-hood or down-hole drilling equipment .

If you try and use a flux that is not formulated to withstand higher (greater than 220C) temperatures, your flux will burn off and char and never get a chance to really do its job.

So, the key is to use a flux that is specially formulated to activate at higher temperatures, like our 807HMP used in our flux cored wire.  It is ROL1 but has only 650 PPM of halogens.

You may also want to consider an alloy with a small amount of indium in it (such as Indalloy #164 which is 92.5Pb 5.0In 2.5Ag) since indium is well known for its thermal fatigue resistance.  This alloy works very well with the 807HMP.

Choosing the right alloy and the right flux are key to keeping your cool!

Carol

Individually, indium and gallium each have some pretty interesting characteristics.

Gallium is liquid at 30°C (86°F) and, because it is less toxic than mercury and has a lower vapor pressure at higher temperatures, it is used as a mercury replacement in thermometers and other applications. 

Indium, as I have discussed in previous blogs, has many unique characteristics including high thermal and electrical conductivity, resistance to thermal fatigue and reduced scavenging of gold in soldering.

But, combine the two, add a little tin, and the resulting alloys are liquid at, and below, room temperature (8°C to 25°C) and are very effective in conducting or dissipating heat away from temperature sensitive components. They can also conduct heat and/or electricity between metallic and non-metallic surfaces.

A recent study published by researchers at the McCormick School of Engineering, working with scientists around the world, discusses the use of an indium-gallium based alloy (EGaIn) to make stretchable electronics.  The indium-gallium content overcomes the loss of conductivity that occurs when the material is stretched.  The liquid alloy allows the "electricity to flow consistently even when the material is excessively stretched".

In 2009, researchers at the North Carolina State University used InGa to form antennae that would not break.  Again it is the flexibility and the electrical conductivity of the liquid alloy that make this work.  Michael Dickey and Gianluca Lazzi who headed the research, indicated they "were surprised" that the alloy operated at about 90% efficiency, similar to the efficiency of copper.

So whether on their own or combined, indium and gallium can be the solution to a variety of electronic challenges faced today.  The Possibilities Are Endless!

Carol

Browse the coming attractions at your local movie theater.  How many 3D movies are being advertised?  3D is a very exciting technology for movie and TV watchers, and the future of it may be based in three other 3D technologies.

Let's start with the initial building block of any electronic device, the chip.  Wikipedia describes the 3D Chip as: "a chip in which two or more layers of active electronic components are integrated both vertically and horizontally into a single circuit."   The result is a chip that is faster, smaller, and consumes less power than a single layer chip.  This is a fairly new technology that has been developed in the last five years and is still gaining popularity.

The next phase of manufacturing, and the area where we focus, is 3D Packaging.  When you stack several chips (regular or 3D) together, you are performing 3D Packaging or Package on Package (PoP) or System in Package (SiP).  This is also a fairly new technology but it is widely used.  As with the 3D chip, the goal of this technology is to provide a faster, smaller device that consumes less power.  Dr. Andy Mackie, Semiconductor Assembly Materials Product Manager here at Indium Corporation, recently blogged about his graphic representation of the complex 3D Packaging processes.  He has included the 3D and the 2.5D packaging into his chart which will be on display at Semicon West 2012.

Once you have the chips, you need a substrate to attach them to -  that is the final 3D technology.  3D MID (molded interconnect device) is a technology that has been around for about 20 years. Typical rigid substrates constrain design and are generally less adaptable to the tiny devices being designed today.  Flexible substrates open up the design possibilities with the ability to twist and turn as needed.  3D MID are made out of lighter materials (like thermoplastics) than rigid substrates and can be molded into a variety of 3D shapes.  This allows for greater design possibilities while producing a substrate that is lighter and more compact.  In automotive applications this can translate to lighter vehicles that need less fuel to operate.  Of course there are the challenges of incorporating the circuitry into the thermoplastic and then soldering to the non-flat (sometimes vertical) surfaces.  This technology will be discussed at the 10th International Congress on 3D MID Technology in Germany in September.

Like most new technologies, the many facets of 3D start off expensive and are not widely adopted.  But as new manufacturing techniques are developed to reduce cost, 3D TVs and all the 3D electronic assembly technology that may support them will become increasingly common place.

Photo from Cicor.

Carol

"I'd put my money on the sun and solar energy.  What a source of power!  I hope we don't have to wait until oil and coal run out before we tackle that."

Whether you agree or not, it certainly isn't a surprising statement in this day and age.  Until you know it was said in 1931 by Thomas Edison to Harvey Firestone and Henry Ford.

Edison was quite a visionary.  The 1,093 patents issued to Edison is a record for one person, and, at the height of his work with electricity, he had 106 successful patents.

I saw this quote in the museum on the grounds of Edison's and Ford's winter homes in Fort Meyers, Florida.  Can you imagine that these two guys spent a couple of weeks a year living next door to each other?

While it took nearly 80 years for Edison's vision to build up some steam, today there are numerous companies trying to harness the sun's energy.  And Indium Corporation is working with many of them.

Our line of solar products includes SunTab(TM) PV Tabbing Ribbon, Liquid Tabbing Fluxes, Copper/Indium/Gallium targets and Evaporation Materials for depositing active layers on CIGS cells and Low Temperature Metallization Paste for thin film cells.

When I shared this quote with my solar colleague, Jim Hisert (read his blog) he said, "Imagine Thomas Edison in 2012: charging his Smartphone with a portable thin-film solar panel, lying on the beach thinking of ways to increase conversion efficiency.  I'm sure he would need some custom materials for prototyping - I hope he would call me."

Read Jim Hisert's blog or visit our solar web page for more information on these products.  Or contact Jim Hisert directly at jhisert@indium.com and see if you think he is more like the guy who created this picture or the one pictured on his blog!

Carol

Indalloy Flux #2 is not the only option for soldering to Nitinol.  There is also Indalloy Flux #3.

Both fluxes are strong enough to clean the tenacious oxides off Nitinol, as well as aluminum and stainless steel.

So what are the differences?  To start with, it is the consistency of the material.  Flux #2 is a liquid flux; Flux #3 is much more viscous and is usually applied by brushing it onto the surface.  Flux #2 can also be brushed on, but it can also be sprayed or dispensed.

If you are using a higher temperature solder or have particularly tough oxides, Flux #3 is the right choice.

If your solder contains indium, you will want to choose the Flux #2 because the indium is sensitive to chloride-induced corrosion.  However, if you are using a tin-based solder, Flux #3 is an excellent alternative.

Where these two fluxes are the same is that they both require good cleaning and should not be used in electronics applications.  Both fluxes MUST be cleaned as soon as possible after reflow.  This can be done with warm (not greater than 50°C) water and mechanical scrubbing.  If the water is greater than 50°C, you risk additional reactions and possible pitting of the material.

Both of these fluxes are available online at http://buy.solder.com/Medical-Assembly-Materials/C1036_1/ .  If you have more questions, check out our medical products page or contact me and I will be glad to help!

Carol Gowans

Do you ever have a need for a "low temperature" solder (meaning an alloy that melts at less than 175C)?

You may have delicate components that cannot withstand standard reflow temperatures, or maybe you are looking to reduce costs by lowering the reflow temperature, or you may be step soldering.  Whatever your reason, there are two unique metals that are used extensively in low temperature solder alloys.

The first one I am sure you can guess: Indium.  The other one is Bismuth. While these two elements are used extensively in the over 100 alloys available in the 50C to 175C range, they couldn't be more different from each other.

Indium is a very soft, malleable metal and remains so even at cryogenic temperatures. It melts at 156C.  Bismuth, on the other hand, is very brittle, even at room temperature, and melts at 271C.  But both lend themselves very nicely to solder alloys that melt below 175C.

Let's look at the two most common alloys in these families.

The two alloys:

• 52In 48Sn (Indalloy #1E) Melts at 118C
• 58Bi 42Sn (Indalloy #281) Melts at 138C

What they have in common are:

• Both are lead-free
• Both are tin-based
• Both are eutectic (liquidus and solidus temperatures are the same, with no plastic range)
• Both can be made into a wide variety of solder forms and can be used in low temperature applications

But the indium-based alloy will give you better compensation of coefficient of thermal expansion (CTE) mismatch than the bismuth alloy.  The bismuth alloy has greater tensile strength but has a lower shear strength than the indium alloy and is generally not recommended in applications where the product has potential to be dropped (like cell phones).  The indium alloy will give you greater thermal conductivity than the bismuth, as well.  The bismuth will give you a cost advantage.

So, which alloy do you use?  Well, that depends on the metallizations you are working with and the environment in which your final product will be operating. For example, if you are soldering to two different surfaces that expand at different rates, then you will want to go with the indium alloy - to keep your solder joints from cracking.  But, there are a lot more considerations when choosing a low temperature solder, and we can help you sort through them.  Check out our Low Temperature Solder page on the web or contact us at AskUs@indium.com or contact me directly at cgowans@indium.com and we can answer your questions or put you in touch with one of our local experts to review your entire process for the best solution.

Let us help!

Carol Gowans

March 13th is the 78th anniversary of the founding of Indium Corporation.  Dr. William S. Murray, J. Robert Dyer JR, and Daniel Gray combined to create a company that was, in 1934, on the cutting edge of technology at the time - and that still is today.

Although some of the initial attempts to utilize indium were decidedly low-tech (plating of silverware and use in gold dental alloys), the first real breakthrough came when Mr. Dyer developed the process to indium-plate aircraft engine bearings to make them last longer.  Today our indium metal is in thermal interface materials, batteries, medical devices, aerospace devices, solar panels, flat panel displays. Of course, the full range of Indium Corporation products (including materials that contain no indium at all) can be found in a myriad of electronic devices.  We hold a wide variety of patents and have conducted endless tests and experiments including some aboard the space shuttle.

In between we have been featured in the Wall Street Journal, Business Week and many other technology journals and received awards for our technical expertise and our customer service.

Our original founders were very "hands on" in their approach to developing their company and we still follow that approach today.  Our sales and technical staff, locally located around the world, are as comfortable in a lab or on a production floor as they are presenting a technical paper.

Contact us at AskUs@indium.com to utilize our expertise and let us help you with your challenge.

Shown here is an original bottle of indium solder preforms with a hand written label.  Today we have a variety of packaging options with printed labels and bar codes to fit your product and application.

Carol Gowans cgowans@indium.com

 

Reducing the surface oxides of Nitinol is just the first step in getting a good solder joint with this versatile medical assembly material.

Next you have to choose the right solder alloy.  You will probably want to stay away from anything containing lead, cadmium, or antimony, particularly in medical applications.  And you will want something with a high tensile strength.

The best choice is Indalloy #121 (96.5Sn 3.5Ag).  It has a tensile strength of 5,620 PSI and a melting temperature of 221C and is obviously lead-free.  It wets well to the cleaned Nitinol.

If you need a higher melting temperature solder (one that can withstand autoclave temperatures for example) you should consider Indalloy #182 (80Au 20Sn) which melts at 280C, has a tensile strength of 40,000 PSI, and has long been considered a highly reliable solder.  Additionally, this alloy is available in very fine diameter solder wires to minimize waste.

Soldering temperatures should be 25C to 50C above the liquidus temperature of whichever solder you use and proper cleaning should be always be performed afterwards.

Contact us at medical@indium.com for more information about soldering for medical devices or visit our web site at www.indium.com/medical

Carol

 

As reported in Metals Bulletin, Malcolm Harrower of Indium Corporation recently addressed the topic of indium availability and supply as he told the delegates at the Minor Metals 2012 conference in Brussels that:

• there is no shortage in the supply of indium metal
• nearly 1,500 tonnes of indium was produced in 2010
• there are 50,000 tonnes of proven indium reserves in existing mines, a volume that will be sufficient to satisfy demand for the next 75 years,

Just 80 years ago, the potential for indium was just being discovered.  An article that I found in the archives of Science News from 1932 indicated that 10 lbs. of indium was due to be produced that year and it would give scientists a chance to do some great research on the possible uses of indium.  Twelve years later in 1944 another article was written on one of those uses which was to lubricate ball bearings to make them last longer (an application still in use today).  That article stated that the output had reached 500,000 troy ounces (34,250 lbs). 

Now 80 years after indium was first commercially produced, the yearly output has reached nearly 1,500 tonnes (3,300,000 lbs) per year, with about two-thirds of that being reclaimed and recycled material.  The versatility of indium has certainly driven that growth into all kinds of applications including:

1) Touch screens

2) Battery chemistry

3) Electronic thermal interface materials

4) Solders

5) Cryogenic and hermetic sealing

6) Solar panels

And as technology evolves, we expect to see more uses as time goes on.  Learn more by visiting our web site at www.indium.com. Or email/call me to discuss your needs.

Carol

cgowans@indium.com

+1-315-853-4900

Eric Bastow recently wrote about using our Indalloy Flux #2 for soldering to Nitinol.  He did many tests and wrote an Application Note called Soldering to Nitinol.

Fort Wayne Metals, a leading supplier of medical wire (including Nitinol) also did a test on various fluxes as they relate to break load (maximum load before the joint breaks.

The fluxes tested included:

• Indalloy Flux #2 and Flux #3
• Indalloy Flux #5RMA; #5R; #5RA
• Indalloy Flux #4R
• Flux #400 (no longer commercially available)

The #5 series and the #4R were found to not be strong enough to clean off the tenacious oxides formed on Nitinol. Therefore, they didn't enable the solder to wet the surface properly.

Flux #2 and Flux#3 gave the best results (of the fluxes tested for break load) since they removed more of the oxides and allowed for a stronger solder bond.

Want to know more about soldering to this important medical material?  You can contact Eric Bastow directly at ebastow@indium.com or email us at medical@indium.com. 

Carol Gowans

cgowans@indium.com

 

Looking for tech papers that answer the most basic soldering questions? These rank among our most frequently downloaded:

• Five Solder Families and How They Work (Eric Bastow)
• Solder Preform Basics (Paul Socha)
• A Quick Guide to Solder Preforms (Jim Slattery and Paul Socha)
• The Basics of Soldering (Chris Nash)

If you are new to soldering, or need a refresher, check them out in the Indium Corporation Tech Library. Information is available in multiple languages.

If you don't see exactly what you are looking for, search the Indium Corporation blogs, or contact an expert directly. You can even send your request directly to me and I will put you in touch with the right person.

Carol
cgowans@indium.com
+1-315-853-4900

Solder wire is generally used for manual soldering operations, including rework.  But, it can also be used in automated applications such as die-attach soldering.  Solder wire can be flux-cored, or solid with a separate flux used.

Each application can have different requirements for the wire.  For example, wire used in die-attach applications needs tight dimensional tolerances to insure an exact, repeatable amount of solder is deposited each time.  Reduced oxides are also critical to eliminate any "splattering" of the molten solder during the deposition process.

Wire can also be used for non-soldering applications. For example, indium (and indium alloys) wire are often used as a sealing material (particularly in cryogenic sealing applications) - more here) and as a thermal interface / management material.

Decades ago, 0.030" (0.76mm) diameter was the standard size, but today we are able to produce diameters as small as 0.001" (0.025mm) in tin silver (Sn Ag), tin silver copper (SAC) and gold tin (Au Sn) alloys.  Considering that a human hair is about 4X that size, that is a very small diameter!  Pure indium wire is limited to 0.010" (0.254mm), but alloys containing indium can be produced smaller than that.

The wide variety of diameters available in Au Sn make this alloy ideal for the complex applications in medical, aerospace, and other high reliability applications.  However, the Sn Ag and the Sn Ag Cu are used across a variety of standard applications that require lead-free materials.  Sn Ag is particularly good in soldering to Nitinol.

At first look, wire seems like a pretty simple product.  But specifying the right alloy, diameter, tolerances, and packaging can make all the difference.  It can help you achieve a repeatable process that gives you high yields, strong solder joints, and enhanced profitability.  For further information - contact me.

Carol Gowans