Poly(butylene succinate) (PBS) is a biobased and biodegradable polyester with strong potential as a sustainable coating binder. However, its application in coatings requires prcise control over molecular weight, crystallinity, thermal transitions, mechanical integrity, and biodegradoin behavior. These properties are directly governed by polycondensation kinetics, which are highly sensitive to catalyst selection and reaction conditions. This study investigates the catalytic synthesis and optimization of PBS from biobased succinic acid and 1,4-butanediol, focusing on catalyst-driven structure-property relationships relevant to coating performance. Specifically, titanium butoxide, titanium isopropoxide, and antimony trioxide were utilized as polycondensation catalysts and systematically compared. The effect of catalyst type on chain growth, crystallization behavior, and degradation phenomena were examined. PBS samples were collected at defined intervals during the polycondensation step to monitor polymer evolution. Fourier transform infrared spectroscopy (FTIR) was used to track ester bond formation, X-ray diffraction (XRD) to assess crystalline structure, and differential scanning calorimetry (DSC) to evaluate melting and crystallization behavior. Enzymatic hydrolysis provided insight into structure-biodegradability relationships, while tensile testing correlated molecular architecture with mechanical performance. Distinct catalytic behaviors were observed, with titanium-based catalysts promoting faster polycondensation and antimony trioxide offering improved control over molecular weight development. Optimized PBS materials demonstrated a favorable combination of thermal stability, mechanical performance, and controlled biodegradation, supporting their applicability in sustainable coating systems.

Per- and polyfluoroalkyl substances (PFAs) have traditionally been used in automotive surface finishing applications due to their exceptional functional performance, particularly in the corrosion protection of metallic surfaces and in imparting easy-to-clean properties to plastics and glass. Increasing evidence of their environmental persistence, long-range transport potential and potential human and occupational health effects has intensified regulatory action and driven the search for safer alternatives. This ranges from existing REACH restrictions on specific PFAs, including PFOs, PFOA and long‑chain PFCAs, all of which belong to the PFAs class, to the ongoing broad PFAs restriction proposal.

Although OECD assessments indicate that PFAs-free coatings are commercially available, substantial gaps remain in understanding their hazard profiles, long-term stability, processability, and sustainability within automotive manufacturing. These information gaps hinder informed substitution and increase the risk of regrettable substitution.

The revised Safe and Sustainable by Design (SSbD) framework developed by the European Commission’s Joint Research Centre (JRC) provides a structured approach to integrating design and re-design, safety, sustainability, and functional performance in material and process development. However, explicit application of SSbD framework to PFAs-free coatings, particularly within the automotive coatings processes, remains limited in the literature.

This work provides a comprehensive overview of the current state of the art in PFAs-free alternatives for automotive surface finishing, with particular emphasis on methodologies (e.g., formulation strategies, application methods, and curing processes) that impact safety, sustainability, and technical performance, thereby influencing the feasibility of substitution. Existing literature and European initiatives were analysed to identify methodologies and strategies for the development and characterisation of PFAs-free alternatives, highlighting how these dimensions are addressed individually or in combination. Special attention is given to anti-corrosion coatings for metal substrates and easy-to-clean finishes for plastic and glass components, which represent high-impact applications where performance, safety, and sustainability intersect.

By mapping existing approaches and identifying knowledge gaps, this review aims to support future research and industrial development towards the design of safe, sustainable, and technically effective PFAs-free coatings. The findings underscore the need for holistic SSbD approaches that explicitly incorporate process-level considerations into the design and evaluation of next-generation automotive coatings.

The availability of nanoparticles in a form suitable for industrial processes remains a key limitation for the deployment of nanocomposite coatings. This work presents the scaling of high-energy ball milling (HEBM) as a combined route for nanoparticle synthesis, size refinement, and direct predispersion in liquid media, enabling the production of concentrated, ready-to-use nanoparticle masterbatches.

High-energy ball milling was adapted from laboratory to pilot scale to process ceramic nanoparticle systems, with a primary focus on SiC and Al₂O₃. The approach allows simultaneous particle size reduction and deagglomeration while promoting effective wetting and stabilisation in liquid carriers. The resulting masterbatches exhibit narrow particle size distributions, reduced agglomeration tendency, and long-term colloidal stability, enabling straightforward dosing into downstream processes without additional dispersion steps or handling of dry powders.

In addition to the demonstrated systems, other carbide-based nanoparticles, including TiC and B₄C, showed strong potential when processed via the same methodology. Their intrinsic mechanical properties indicate suitability for advanced nanocomposite applications.

The scaling of HEBM for liquid predispersion provides a robust and versatile pathway for supplying industrially relevant nanoparticle masterbatches. This contribution highlights how process engineering of nanoparticle production and formulation can bridge the gap between nanomaterial development and practical industrial use.

The transition toward advanced and sustainable materials is increasingly challenged by the volatility of raw material supply chains, particularly in the European context, where a strong dependence on critical raw materials requires rapid adaptation in material design and selection. In this scenario, decision-making tools play a crucial role in enabling timely responses to changes in availability, cost, and environmental impact, while maintaining required performance levels.

This contribution presents an integrated Life Cycle Performance Analysis (LCPA) approach embedded within a Sustainable Decision Support System to support material selection and, where relevant, process optimisation. The methodology goes beyond conventional life cycle assessment by coupling environmental indicators with performance-related metrics, enabling a balanced evaluation of functional efficiency, durability, and sustainability across the entire life cycle of a material solution. The approach facilitates systematic comparison of alternative material compositions and processing routes, while explicitly addressing trade-offs between technical performance, resource efficiency, and environmental footprint.

The resulting decision support system enables multi-criteria analysis that jointly considers performance targets, sustainability objectives, and supply-chain constraints. By organising information in a flexible and modular structure, the system supports rapid re-evaluation of material solutions when boundary conditions evolve, such as reduced availability of specific alloying elements or the need to prioritise lower-impact or locally sourced raw materials.

High-Entropy Alloys and compositionally complex CerMet systems are opening access to an unprecedented materials design space, offering significant potential for tailoring mechanical, functional, and environmental performance. This expansion has been strongly enabled by advances in computational power, which now allow extensive modelling and simulation campaigns to explore large compositional domains. However, translating these virtual material concepts into reliable, experimentally validated solutions remains a major challenge, particularly when data at an industrially relevant scale are required.

A critical bottleneck lies in the availability of suitable feedstock for thermal spray processes, where compositional complexity, phase stability, and powder quality must be controlled simultaneously. Many synthesis routes struggle to deliver powders beyond laboratory scale or to achieve sufficiently low variability at pilot or industrial scale, thereby limiting the validation of modelling predictions under realistic processing conditions.

This contribution presents the solid-state mechanical alloying approach developed by MBN to address this challenge. The flexibility of mechanical alloying enables the synthesis of complex alloy systems without melting, allowing the combination of elements with widely different thermophysical properties while maintaining compositional homogeneity. The intrinsic scalability of the process supports the transition from laboratory batches to pilot-scale production, providing feedstock quantities compatible with industrial thermal spray trials.

For CerMet systems, the ceramic reinforcement phase is formed directly within the metallic matrix through a carbothermic reaction activated during mechanical alloying, resulting in a fine and well-dispersed microstructure suitable for coating deposition. The resulting powders can be tailored in terms of particle size distribution and morphology to meet the requirements of different thermal spray technologies.

The presented approach demonstrates how solid-state feedstock manufacturing acts as a key enabler for bridging computational materials design and experimental validation, supporting the exploration of complex material systems under realistic industrial conditions.

Developing next‑generation high‑performance coatings requires quantitative tools capable of resolving how local heterogeneities and microstructural gradients influence mechanical behaviour. In this work, we present an advanced nanoindentation‑mapping methodology for producing high‑resolution 3D mechanical property maps, enabling spatially resolved assessment of hardness and modulus across highly heterogeneous thermally sprayed surfaces. This approach reconstructs continuous mesoscale mechanical landscapes that capture the effects of splat boundaries, porosity, amorphous regions, and interfacial transitions, features that conventional indentation grids cannot resolve.

As a representative case study, we apply this methodology to High Entropy Alloy (HEA) and cermet coatings developed within the EU project CoBRAIN[1], which aims to create sustainable and high‑performance alternatives to cobalt‑containing materials for advanced manufacturing. The coatings, produced using thermal spraying techniques, exhibit pronounced microstructural and mechanical heterogeneity due to rapid solidification and the intrinsic complexity of multi‑principal element systems. The resulting 3D mechanical maps reveal distinct mechanical phases, including FCC, BCC, oxides and TiC‑rich regions, with hardness values and spatial distributions consistent with phase‑specific statistical clustering obtained through GMM deconvolution.

Overall, the use of high-resolution nanomechanical 3D mapping provides a powerful framework for correlating microstructure and performance in thermally sprayed HEA and cermet coatings, supporting the design and optimization of next‑generation CoBRAIN materials.

https://www.cobrain-project.eu/

The goal of the “CoBRAIN” project is to design novel coating formulations for protection against wear and corrosion using an integrated materials development workflow. We aim to replace existing coatings which employ toxic, carcinogenic substances either as raw materials (e.g. chromium electroplating from CrO₃ solutions in water) and/or as constituents of the final product (e.g. cobalt in Stellite alloys and WC-Co hardmetals) and/or employ critical raw materials, such cobalt itself or tungsten. We specifically focus on the novel class of High-Entropy Alloys (HEAs), i.e. nearly equiatomic alloys made of four, five or six elements, employing these alloys either for purely metallic coatings or as matrices for hardmetal coatings, combined with TiC as hard phase.

To explore a vast range of possible compositions, we combined various high-throughput physical modelling techniques to simulate properties such as the equilibrium crystalline phase(s), the stacking-fault energy, the microstructural evolution, and the micromechanical properties of HEAs, and then we trained neural network-based AI models on this extensive dataset. We also developed high-throughput laboratory methods to provide as much input and validation data as possible for these models. An overarching ontology allowed semantic mapping of the dataset into a cloud-based knowledge base to ensure interoperability.

The main results obtained by the CoBRAIN project so far have been:

• Contributing, to the creation of an improved version of the EMMO ontology for the mapping and storage of data and metadata.
• Creating an AI-based API to predict the properties of a given HEA composition, or identify candidate HEA compositions based on predefined targets.
• Setting up an LCPA tool to estimate the costs, environmental impact and health hazards of each novel formulation in comparison to benchmark materials.
• Developing a sustainable decision support system based on the integration of the AI and LCPA tools, which is now available for demonstration and trial by the project partners and interested stakeholders.
• Gaining experience on the actual production of HEA-based feedstock powders and of coatings by thermal spraying processes. This is now being scaled-up to industrial case-studies.

Hardmetal coatings for high-temperature applications are usually based on Cr₃C₂-NiCr; however, the limited hardness and wear resistance of these systems are a drawback which is sometimes overcome through the addition of controlled amount of WC. However, W is a critical raw material subjected to significant supply insecurity and price volatility. Hence, in order to find potential alternatives, we aim to investigate TiC-based hardmetals with High-Entropy Alloy (HEA) matrices, since HEAs can maintain good mechanical strength and oxidation resistance up to elevated temperatures, and can be formulated without critical elements like W and/or Co.

In this work, we therefore studied the ball-on-disc sliding wear resistance of HVOF-sprayed coatings with 60 vol.% TiC and four different HEA coatings based on the AlCrFeNi alloys added with Cu and/or Mo, since these elements can specifically provide favorable tribo-oxidation behavior. The compositions were chosen to have a mainly FCC matrix, since HEAs with FCC lattices are typically tougher than those with BCC or hexagonal structure, which is desirable in the matrix of a hardmetal.

Especially the formulations containing simultaneously Mo and Cu exhibit stably low specific wear rates of 10^-6 mm³/(N·m) from room temperature to 800 °C under high contact pressure conditions, one order of magnitude lower than for a Cr₃C₂–25 wt%NiCr benchmark. SEM, XRD and micro-Raman analyses of the worn samples indicated that this performance was related to a tribo-oxidation mechanism based on the formation of a uniform film of molybdates. Accordingly, increasingly more continuous coverage by the oxide tribofilm resulted in a drop of the friction coefficient from 0.8 at room temperature to 0.3 at 800 °C. The results demonstrate that TiC-AlCrCuFeMoNi coatings are promising candidates for industrial applications requiring stable wear performance over a wide temperature range.

The adoption of additive manufacturing, particularly resin-based 3D printing, has enabled rapid production of complex geometries for industries such as automotive, aerospace, electronics, biomedical devices, and increasingly in jewelry applications. Metal plating of 3D printed resin components is increasingly used to enhance mechanical, thermal, and electrical properties, extending their applicability in demanding industrial environments. However, the environmental and economic impacts associated with these processes remain largely unexplored. This study presents a comparative Life Cycle Assessment (LCA) and preliminary Life Cycle Costing (LCC) of electroless metal plating on resin-based 3D printed articles. Two 3D printing methods were considered, followed by post-printing treatment (curing and cleaning), pre-treatment, and a multi-step etching and activation process before electroless deposition of metals including Cu, Au, Ag, and Ni-P. The etching process, particularly sensitive to metal type and resin formulation, was analyzed as a critical contributor to both environmental impact and production cost.

The LCA framework (following ISO 14040/44 guidelines, implementing the Environmental Footprint (EF) 3.1 (2022) methodology) is applied and compares scenarios involving different printing technologies, metal types, and etching conditions, identifying environmental “hot spots”. The LCC analysis complements the LCA by evaluating material consumption, processing steps, energy use, and waste management for each scenario, aiming to identify trade-offs between environmental performance and economic feasibility and highlighting key cost drivers. Life Cycle inventory (LCI), apart from available secondary data, is also supported by primary ones (real pilot-scale data) provided by CREATIVE NANO, ensuring practical relevance and validation of the results.

By integrating LCA and LCC, this study provides a holistic understanding of the sustainability and cost drivers of metal plating on 3D printed resin substrates. The results are expected to support industrial process optimization, sustainable material selection, and economically responsible adoption of advanced manufacturing technologies.