Metal (Production and Processing)

Powder-based manufacturing – laser powder bed fusion (L-PBF), directed energy deposition, binder jetting, metal injection moulding, press-and-sinter, thermal spray – as well as catalysis, energy storage and technical ceramics are today limited by the feedstock rather than by the machines. Powders are frequently unavailable in the required chemistry, crack-prone or non-weldable, irregular in shape, poorly flowing, or expensive because they rely on critical or precious raw materials. Recycled, off-spec and mechanically produced powders are downgraded for the same reasons. The belgian research and technology centre has built a powder engineering platform that acts directly on the two properties that govern powder behaviour: the chemistry of the particle surface and the morphology of the particle. Technology 1 – Plasma PVD / PECVD coating of powders (core-shell architectures) Powders, fibres and small parts are treated in a low-pressure plasma reactor equipped with magnetron cathodes and a rotating barrel that continuously renews the particle surface exposed to the plasma, ensuring homogeneous, conformal shells on every particle. Metals, alloys, oxides, nitrides and carbides can be sputtered; reactive PVD and PECVD modes give ceramic, carbon-based and organosilicon shells as well as grafted surface chemical functions (-NH, -OH, -COOH). Shell thicknesses range from a few nanometres to sub-micrometre, i.e. additions typically below 2-3 wt%. Results already demonstrated on the platform: -Core-shell structures: copper shell on 60 μm zinc powder. -Powder decoration: gold on 100 μm glass beads. -Ti-coated copper powder for L-PBF: 1.1 wt% Ti reduced as-built porosity from 23.4 % (pure Cu) to 3.5 %. -PVD alloying of Al 7075 with a crack-inhibiting element: hot cracking suppressed in L-PBF, fine microstructure, no change to the printing parameters, no scandium and no silver – a sustainable alternative to existing high-strength AM aluminium grades. -Compensation of the loss of volatile elements (Zn, Mg) during laser melting, by adding them as a deposited shell rather than by mechanical blending. -Carbon coating of ceramic powders to improve flowability and to introduce carbon into the matrix during sintering. Technology 2 – Inductive plasma spheroidisation An RF inductively coupled plasma system melts irregular particles in flight; surface tension spheroidises the droplets, which are then quenched and collected. Irregular feedstock produced by milling, water or gas atomisation, chemical reduction (sponge route) or spray drying – metals, alloys and ceramics – is converted into dense, satellite-free spherical powder with improved flowability, higher packing and tap density, and better reusability in AM and thermal spray. Because the particles are molten in a controlled plasma atmosphere, the chemistry of the powder can also be modified in the same step – oxidation, reduction, nitriding or carburisation – so that shape correction and chemical conditioning are obtained in a single pass. The route also densifies porous particles and can be used to reintegrate recycled material into a qualified powder stream. Titanium is used as the internal reference material. The two processes are complementary and can be chained: spheroidisation first restores the morphology of an irregular or recycled powder, then plasma PVD/PECVD adds the functional shell (alloying element, crack inhibitor, diffusion barrier, catalytic phase, carbon or organic functionality). This gives access to powder grades that are not available commercially, from raw materials that would otherwise be discarded. Advantages and innovations: Two complementary levers on one platform: particle surface chemistry (PVD/PECVD) and particle morphology (spheroidisation), instead of a single fix. Core-shell alloying rather than powder blending: the alloying element is deposited on every particle as a nanometric shell, giving a homogeneous distribution with no segregation and no risk of demixing during handling or recoating. Very small additions with a large effect: crack inhibition and porosity control demonstrated with additions in the 0.18-1.8 wt% range. Reduced dependence on critical and precious raw materials: high-strength AM aluminium without scandium and without silver. Existing alloy grades can be upgraded instead of being replaced – in the Al 7075 case without modifying the L-PBF process parameters, which avoids re-qualification. Circular economy: non-weldable, off-spec, recycled or mechanically produced powders can be made printable again, reducing reliance on imported gas-atomised powder. Spheroidisation is not only a shape correction: in the same pass the plasma atmosphere can oxidise, reduce, nitride or carburise the powder, combining morphology and chemistry conditioning in one operation. Dry, solvent-free vacuum processes: no wet chemistry, no liquid effluent, no surfactant residue on the particle surface. Very broad material scope: metals, alloys, oxides, nitrides, carbides, glass and ceramic particles, and also fibres and small bulk parts in the same coating reactor. Backed by in-house surface analysis and materials characterisation, so the effect of the treatment is measured, not assumed. Independent, confidential and objective RTO position, with a clear lab-to-pilot scale-up path and eligibility for public co-funding. Technical Specification or Expertise Sought Development approach: Neither route is a catalogue service: each powder requires its own parameter set (plasma chemistry, power, pressure, residence time, barrel kinematics, carrier gas, feed rate, thermal budget). The centre works with the partner from a feasibility trial on a few hundred grams, through parameter optimisation and full physico-chemical characterisation, up to representative pilot batches and definition of the industrial scale-up route. Work is carried out under confidentiality; as an approved research centre, the organisation allows its industrial clients to access regional and European funding schemes. Both technologies are at TRL 5-6: validated and demonstrated in a relevant environment on real feedstock and real end applications, ready for demonstration on a partner's powder. Plasma PVD / PECVD powder coating unit : Low-pressure vacuum reactor, base pressure below 1.3 × 10⁻⁶ mbar, water-cooled, fully automated control. Two magnetron sputtering cathodes; rotating barrel for continuous renewal of the treated surface. Batch volume up to 5 litres of powder per run. Particle / object size from a few micrometres to a few centimetres; also fibres and small loose parts. Process gases and precursors: Ar, He, N₂, O₂, hydrocarbons, silicon precursors and mixtures – enabling metallic, oxide, nitride, carbide, carbon-based and organosilicon shells, and grafted -NH, -OH, -COOH functions. Typical shell: a few nm to sub-μm, i.e. below ~2-3 wt% added mass. Complementary access to laboratory- and semi-industrial-scale PVD/PECVD equipment for flat and 3D substrates. Inductive plasma spheroidisation unit : RF inductively coupled plasma spheroidisation system, R&D / small-batch pilot scale. Throughput of the order of 0.5 kg/h; rapid changeover between materials. Typical particle size range 5-300 μm; metals, pure metals, alloys and ceramics. Accepts feedstock from milling, water and gas atomisation, chemical reduction (sponge) and spray drying. In-flight modification of the powder chemistry in the same step: oxidation, reduction, nitriding and carburisation. Output: near-spherical, satellite-free, densified particles with high spheroidisation yield. Characterisation and validation : Morphology and shell quality: SEM/EDX, cross-sections, image analysis. Surface chemistry: XPS and complementary surface analysis techniques. Structure and phases: XRD; particle size distribution; apparent, tap and true density; flowability. Application-level validation: L-PBF printing trials, sintering, porosity and defect quantification, mechanical testing and tailored heat treatment. Life cycle assessment and eco-design support available in-house. What is expected from the partner's side : A representative sample of the powder to be treated, with its specification sheet and safety data sheet. The target application and the acceptance criteria (chemistry, PSD, flowability, printability, mechanical or functional performance). Constraints on cost, batch size and industrial volumes, so that the scale-up route can be assessed realistically. Expected role of a partner: Profiles targeted: Powder producers and atomisers wishing to widen their grade portfolio or upgrade existing grades. Powder recyclers and metal-scrap valorisation companies wanting to bring off-spec, milled or recycled material back to AM quality. AM service bureaus and OEMs in aerospace, space, automotive, energy, tooling and medical devices facing cracking, porosity or flowability issues with a given alloy. Producers and users of technical ceramics, hardmetals, catalysts, battery and energy-storage materials needing functionalised or free-flowing particles. Equipment manufacturers interested in industrialising the process route. Universities and research organisations building consortia for European or national collaborative projects. Role and tasks, depending on the type of agreement: Research and development cooperation agreement: co-define and co-execute a development programme, or join / co-build a consortium for a collaborative project (Horizon Europe, EUREKA / Eurostars, national and regional schemes), with the partner contributing feedstock, the industrial use case and application-level validation. Technical cooperation agreement: provide the powder and the target specification, and work with the centre through feasibility, parameter optimisation and pilot batches until the treated powder meets the acceptance criteria in the partner's own process. Commercial agreement with technical assistance: order treated pilot quantities of powder together with the technical support needed to qualify them and to prepare industrial transfer.