The Steel Industry Meets Nanotechnology

How a new Nano-Manufacturing process is making steel 10x stronger

By Frank Rovella

Seattle-based Modumetal is in the early phases of testing a new type of nanolamination coating process that has the potential to reshape the metal manufacturing industry. By creating multiple discrete layers only nanometers thick they are able to impart characteristics such as high strength and corrosion resistance and do it very economically. Until now, the only way to get these qualities was through the use of high-strength alloys or with methods such as heat treating, ion implantation, or a number of plating and coating processes. All of these can be very cost-effective in limited quantities but, for industries that consume large amounts of steel such as petro-chem, oil & gas, and construction there is no low-cost solution.

The concept of creating laminations using nanolayers is not new; however, Modumetal’s application method is. Previously, nanolaminates could only be created via a vapor deposition process the problem is that it’s expensive and not easily scalable. Modumetal’s process takes a markedly different approach; though simple in nature, its success hinges on precise chemistry and process parameters.  It’s based on hydrolysis, similar to the electroplating process, and utilizes a submersion bath. But, unlike electroplating, it relies on hyper exact amounts of electrical current applied at specific intervals. The bath contains predetermined types of metal ions that allow for the creation of distinct alloys; this means that each layer can be composed of a different material.  Multiple layers may be applied to total up to one centimeter thick. This flexibility in layer composition allows for the engineering of custom nanolaminations that can provide whatever characteristics the application requires.

To understand how high strength and corrosion resistance can be applied to a metal with what is essentially a coating, we need to consider scale. For example, electroplated layer thicknesses typically run between 5 to 100 microns, 1 micron (µ) = 0.00003937 inches, while 1 nanometer (nm) = 0.000000039 inches. This is on the atomic scale; to put that into perspective, 0.1 nm is the diameter of a helium atom.  As the image below highlights, at the nanoscale, our understanding of surface profile changes. There is far more surface area to work with, which means greater adhesion can be achieved. At this scale, the metal ions become a physical part of the substrate. The ability to dial in an alloy combination to address a specific corrosion requirement outside of a steel mill is unprecedented, but the main component that makes this technology so attractive is strength.



Carbon steel surface taken through an electron microscope, the actual
size is 10 micrometers (µm) across that is equal to 10,000 nanometers.

Tensile strength is a material’s ability to withstand pressure before failing, and failing begins with cracking. To demonstrate how nanolaminations can make steel 10 times stronger, think about a sheet of plywood; this is the most common example of a lamination.  Plywood contains multiple layers of materials with different strength characteristics and varying grain structures—the more layers added the greater the strength. The strength is further enhanced when the lamination is nailed or glued into place. Now imagine a cross-section of structural steel with all of its surfaces encapsulated in layers of nanometer-thick superalloys of varying compositions, bonded to the substrate at the atomic level. The advantages are obvious. 

Stress cracking in a cross-section of stainless steel pipe.

The potential this has for large-scale applications such as those found in oil & gas and the construction industries could be a game-changer. But to gain a foothold in manufacturing, a lot more data will be needed, and many questions will need to be answered. Beginning with the application process, will it be better suited for pre or post-treatment? Will ductility be affected, how will it react to rolling or stamping, and what about welding?  The ability to weld treated metals could be one of the key questions; this is essentially a coating—when it’s welded what happens at the joints? Even coatings a centimeter thick will be burned through, leaving a seam of bare substrate. However, these issues may already be moot points, as Modumetal is currently ramping up its production facility in Washington State. Of course, before this resembles anything close to wide-scale adoption, all of the standard bodies including ASTM, API, ASTM, and CEN will have to give it their blessing, and that certainly won’t happen overnight.   

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A New Class of Polymer that Defies the Laws of Physics

By Frank Rovella

If you find yourself going straight for the technology section every time you get online or open a paper, then you’re not alone. There are a lot of us just waiting for the next big thing, seeking to be awed by some new technological development. The Industrial Space is fertile ground for this enterprise; just take a look at emerging materials technology.  

Unlike automation that has a level of predictability akin to a train that always runs on time; we can see it downrange, hear the tracks rumble, and watch it flash by.  However, materials technology is more like a seismic event, we know it’s coming but no one is sure when or how big it’s going to be.

An example is a recent discovery by the French physicist Ludwik Leibler, who is this year’s winner of the European Inventor Award in the category research.  Leibler along with his team at the Laboratoire Matière Molle et Chimie at ESPCI ParisTech, have developed a whole new class of plastics called Vitrimers. 

"Classified as supramolecular substances, Vitrimers are a derivative of thermoset plastics and exhibit self-repairing characteristics."

What’s really intriguing about Vitrimers is how they do what they do. To understand this, we’ll have to look at the mechanics of their most basic elements.  At the molecular level, the atoms that comprise standard thermosets maintain their crystalline structure through permanent or rigid chemical bonds, the strength of these bonds ultimately determines the characteristics of the material. Flex, friction, and thermal cycles break down these bonds resulting in weakening that leads to cracks and fractures. Once these bonds are broken, they cannot be repaired  However, the molecular bonds that makeup Vitrimers are neither permanent nor rigid; their state is more akin to a dynamic equilibrium. This means that molecular bonds are forming and breaking simultaneously. Regardless of the molecular structure, the number of bonds remains the same. This reaction is thermally activated allowing VItrimers to go from solid to liquid and back with no change in crystalline structure; this is known as a glass transition. These characteristics, in essence, are what make Vitrimers a self-repairing plastic. Testing conducted at the University of Minnesota concluded that fractured samples that were healed recovered 102% of tensile strength, 133% of the original tensile modulus value, and 67% of ultimate elongation. Vitrimers glass-like qualities, allow it to be welded like glass, meaning that if two surfaces are brought to a molten state and welded, when they solidify the molecules are aligned like a solid section, with no seam. This is similar to friction stir welding, but far more complete.

The self-repairing qualities of Vitrimers are paving the way for a number of impressive innovations, and will surely lead to many more.  One of these is in the medical industry, where Vitrimers are being used in what is being called “Organ Glue.” This is a self-healing polymer hydrogel that acts as an anti-hemorrhaging, wound-healing aqueous solution. Vitrimers have the ability to form “nanobridging”, that is a molecular bridging of tissue; it can be used in situations where stitches are impractical.

For the more mundane, however, these same self-healing properties can make a significant impact on manufactured goods. Self-repairing plastics means that products made from it will have a far longer service life. Simply put less material is required because fewer parts are needed to accommodate for wear.

Then there are the effects on recycling, Vitrimers by nature are ideal for recycling because they can be liquefied and solidified over and over. Think about all the plastic that can’t be recycled, they end up in landfills, and some of these plastics can take hundreds of years to decompose fully. Vitrimers could make plastics as recyclable as aluminum.

The concept of materials that self-repair, or do things that seem physically impossible certainly has an awe factor, but Vitrimers are just one example. NASA is currently developing materials that can self-heal after a meteor strike and even self-repairing alloys. As we move forward keep your eyes open, because there is a lot more from this came from.

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A 3D Printing Industry Game Changer… This Time for Sure

By Frank Rovella

If you’ve been holding your breath waiting for 3D printing to change manufacturing as we know it then your face is probably blue, or you’ve already passed out.  For years a succession of technological breakthroughs has emerged but, each time falling short of the ultimate goal. I’ve even heard proponents say that someday we’ll all have 3D printers in the home so we can manufacture our own products on demand. Manufacture what, plastic

silverware, Legos?

The plain truth is that for 3D printing to make any kind of an impact, it will have to displace existing technology and do it economically.

For the most part, 3D printing has been relegated to the world of prototypes, short runs, and hobbyists. These days when I hear about the latest in 3D printing technology I get a little skeptical. However, this time around it includes some big names such as HP and Voxeljet, using phrases like “high-speed, low-cost manufacturing” and the Holy Grail “cheaper than injection molding”.

Today the new savior of manufacturing futurists is called “High-Speed Sintering” which has been in development for over a decade. One of the people behind high-speed sintering technology is mechanical engineering professor Neil Hopkinson, of the University of Sheffield in England. He believes that this really is the way forward for 3D printing. Hopkinson’s entry is based on the layering principals of laser sintering. As its name implies in laser sintering, a laser is used to melt material in thin layers. Though the results can be very precise, the technology is expensive and slow. In Hopkinson’s high-speed sintering approach, the laser is replaced by an infrared lamp and what is basically an ink-jet print head. In this process, the print head moves at high speed layering a polymer powder that is blended with light/radiation absorbing material. As each layer is laid down on the print bed, an infrared light fuses the powder. Hopkinson claims that given a large enough build area high-speed sintering can be 100 times faster than laser sintering, and deliver the same level of dimensional precision. This seems to be where injection molding may finally be impacted. High-speed sintering has no expensive tooling, design changes can be made on the fly, and there is little or no setup, essentially providing manufacturing on demand.

At this point, the technology has proven viable but there are still some hurdles to overcome. The biggest is that because the polymer must be mixed with a radiation absorbing material, it will only work with a limited number of polymers. Although this may be in the early stages, there is a lot of R&D money backing up this technology.

Hewlett-Packard has been working on a similar technology called “Multi Jet Fusion.” In HP’s product, the radiation absorbing powder is called a detailing agent. HP’s Multi Jet Fusion system is already available but is still being advertised for short-run and prototype work. Hopkinson’s high-speed sintering technology is now owned by the German 3D printer manufacturer Voxeljet. Voxeljet certainly has the know-how and resources to make this work, and German engineering can’t hurt either.

So to put it all into perspective, we have an obvious market need and two competing manufactures developing very similar technology. Both have a lot of capital, in HP’s case revenues of over $112 billion a year. Voxeljet, on the other hand, is quite modest in size, but totally focused on the industrialization of 3D printing and proving it with a pretty impressive product line. They are heavy into innovation and manufacture one of the largest commercially available 3D printers. Their VX4000 has a workpiece envelope of 157” x 79” x 40”. HP is certainly the 800-ton gorilla, but I’d put my money on Voxeljet to get this to market first. Their concentration on developing large scale volume manufacturing based 3D print systems is right in line with what this technology is meant for.

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