By Vladimir Paserin, Consultant to the Nickel Institute, and Gary Coates, Nickel Institute.
While we are still in the midst of Industry 4.0 (smart manufacturing via integration of artificial intelligence, cloud computing, just-in-time manufacturing and the Internet of Things), the term Industry 5.0 or its Japanese variant Society 5.0, is gradually gaining in popularity.
The basic principle behind the fourth industrial revolution recognises that by linking production equipment, intelligent monitoring and control devices, as well as real-time, internet-based connection to customers, manufacturers are creating smart networks throughout the supply and value chains.
In the upcoming stage of this development, the return of direct human involvement is envisioned to provide the next level of sophistication, responsiveness and relevance to meet the evolving human needs – hence the term Society 5.0.
Closer integration of the production systems and participation of humans in their operation and guidance merges the high-speed accuracy of industrial automation with the cognitive, critical and intuitive creative skills of humans.
The concept of Society 5.0 has been promoted by the Japanese Government since about 2015 – an idea which places the society as a whole at the centre of technology development, rather than the industry.
Giving technology the role of a catalyst and a driver, Society 5.0 aims at the general welfare of the members of the society and strives towards building a super-intelligent society-technology ecosystem. Society 5.0 takes Industry 4.0 and places the human being at its centre.
How do these developments impact the production and use of metals, and nickel in particular?
Let’s look at this topic with a brief overview of the latest trends in manufacturing technology, with particular emphasis on additive manufacturing (AM, or 3D printing) with metals (Metal AM).
Metal AM is a rapidly growing field catalysing a revolution in modern manufacturing. The most common approach involves the use of metal powders as feedstock material and laser sintering to assemble, layer-by-layer, 3D objects.
The laser process involves heating particles to the melting point of the given metal (~1,500 °C for nickel-containing steels) to fuse or ‘weld’ the particles, and careful selection of the laser beam control parameters (power, laser beam spot size, beam scanning pattern among many others) to produce a fully dense object, such as in Figure 1.
Various other approaches involve different energy delivery methods, including electron beam, ultrasound, kinetic energy (cold spray), electric/plasma arc, and extrusion or material jetting of metal-polymer composites (such as metal powder-containing filaments), followed by conventional debinding and sintering processes.
Figure 2 is a high-level, stage-of-development map (industrialisation vs. technology maturity index), showing that the most advanced deposition processes on both scales are the laser beam powder-bed fusion (LB-PBF), powder laser deposition (also known as powder-fed, or Directed Energy Deposition process), electron beam, electric/plasma arc and wire-based electron beam deposition processes.
Filament FDM (fused deposition modelling with metal powder-containing filaments) and binder jetting are rapidly approaching the same mature territory.
Figure 3 shows a more detailed list of the various Metal AM techniques. Judging by the number of players, laser beam powder bed fusion is clearly the dominant approach in Metal AM today.
Forming 3D objects layer-by-layer is not a foreign concept in the nickel industry. This is exactly how carbonyl nickel and ferronickel pellets are made, utilising chemical vapor deposition from iron pentacarbonyl, Fe(CO)5 and nickel tetracarbonyl, Ni(CO)4, discovered by Ludwig Mond in late 1800s.
Figure 4 shows a cross- section image of a ferronickel pellet, revealing alternating layered structure of Ni- and Fe-rich layers. The individual layers form a regular pattern.
The pellets are at a uniform temperature and the deposition of each layer takes place on all pellet surfaces simultaneously within the reactor.
Owing to the differences in nickel and iron carbonyl properties, the decomposition of each takes place preferentially within certain reactor space, resulting in the segregation of Ni and Fe-rich layers.
One can easily envision selected area deposition if the energy is supplied by a precise laser beam, writing a 3D nickel object (Figure 5).
The development of such vapor-phase Metal AM techniques is still in a laboratory stage. As of 2020, the dominant metals used in Metal AM are titanium, stainless steel, tool steels, aluminium, and nickel-based superalloys.
In addition to the nickel content in stainless steels, the nickel alloys play an important role in aerospace, tools production and other demanding applications, positioning nickel as an important component of high-value, additively printed metal parts.
While the total volume of metal powders used as feed materials in Metal AM printers is very small compared to the conventional metal forming techniques (~3000 tonnes of all combined metal powders in 2020), the rapid growth of Metal AM is expected to persist and nickel will continue to play a key role in many applications.
3D printing of nickel superalloys is a particularly active area of research, owing to the high potential in application areas such as aerospace and tooling.
The rapid growth of Metal AM continues to evolve and has the potential to become one of the most revolutionary technologies in metalworking.
Aerospace, usually one of the earliest adopters of novel technologies, has been leading the applications development along with tooling and the medical market segment.
Significant challenges that remain include safety (working with metal particulates) and regulations, limited production volumes due to process inefficiencies, equipment size constraints and long build-times, limited availability of economical metal powders, the need to develop best practices, specifications, and standards for acceptance by various industry segments.
Nickel is bound to be one of the dominant participants among this new category of metallic feed materials, driving the development of high-performance parts in the next generation products in a variety of industries.