Call: Aeronautical Technological Program (PTA), subsidized by the CDTI within the framework of the Recovery, Transformation and Resilience Plan of the Ministry of Science and Innovation.

  • Starting date: 1st September 2022
  • Finishing date: 31st December 2024

  • Participants: Elhco (SPA, Project leader company), Chemplate Materials (SPA), Surtech Engineering (SPA), Egile Mechanics (SPA) and with the collaboration of CIDETEC (SPA).

SUMMARY

For determined aeronautical systems that are subjected to stress, the use of Ultra High Strength Steels (UHSS) is required. When these steels they have additional friction associated, the plating of these zones with hard chrome is crucial. Currently, hard chrome is electrolytically produced with a solution that contains hexavalent chrome, which has high toxicity and is included in annex XIV of the REACH regulation. To date, there is no alternative that can directly replace the current applications of hard chrome. The situation becomes even more complex in the case of the aeronautical sector, where the approval of new treatments needs 3-4 years starting from the development finish of the new treatment.

Following the trail of the project TRUE-REPLACE, the main objective of the SUSCROM project is based on the need to find an alternative that allows the replacement of hard chrome for other more sustainable solutions. The strategy of the SUSCROM project has been conceived from the results obtained in the project TRUE-REPLACE and combines known electroless nickel-phosphorous processes and the development of chromium plating that contains trivalent chrome. The project proposes a holistic approach that considers the chemistry of the formulations and its monitoring, process conditions, the necessary auxiliary equipment for electrolyte regeneration and the validation of the alternatives in test bench, alongside the connectivity of the equipment in a virtual environment.

The consortium that will carry out this project is made by 4 national SMEs which have complementary skills: CHEMPLATE, SURTECH, EGILE and ELHCO, where each one of them provides their specific knowledge to the rest to get the best results.

For determined aeronautical systems that are subjected to stress, the use of Ultra High Strength Steels (UHSS) is required. When these steels they have additional friction associated, the plating of these zones with hard chrome is crucial. Currently, hard chrome is electrolytically produced with a solution that contains hexavalent chrome, which has high toxicity and is included in annex XIV of the REACH regulation. To date, there is no alternative that can directly replace the current applications of hard chrome. The situation becomes even more complex in the case of the aeronautical sector, where the approval of new treatments needs 3-4 years starting from the development finish of the new treatment.

Following the trail of the project TRUE-REPLACE, the main objective of the SUSCROM project is based on the need to find an alternative that allows the replacement of hard chrome for other more sustainable solutions. The strategy of the SUSCROM project has been conceived from the results obtained in the project TRUE-REPLACE and combines known electroless nickel-phosphorous processes and the development of chromium plating that contains trivalent chrome. The project proposes a holistic approach that considers the chemistry of the formulations and its monitoring, process conditions, the necessary auxiliary equipment for electrolyte regeneration and the validation of the alternatives in test bench, alongside the connectivity of the equipment in a virtual environment.

The consortium that will carry out this project is made by 4 national SMEs which have complementary skills: CHEMPLATE, SURTECH, EGILE and ELHCO, where each one of them provides their specific knowledge to the rest to get the best results.

OBJECTIVES OF THE PROJECT

The specific objectives of the SUSCROM project are the following:

  • To obtain coatings with tribological and mechanical properties comparable to those of hard chrome or even with superior corrosion resistance as well as superior specifications than those required by EGILE and by costumers of the aeronautics industry from ELHCO, CHEMPLATE and SURTECH. To this purpose, three partial goals were proposed:

    • 1.1. To develop chrome coatings from Cr(III) electrolytes: i) without complexing agents (validated at lab scale by INEOSURF) and ii) with complexing agents (commercial, ATOTECH), defining the optimal experimental conditions to achieve coatings with the defined requirements.
    • 1.2. To study the effect of the application of different thermal treatments on mono- and multi-layer Ni-P plating (with different %P), obtained from an electrolyte that was validated in the recently finished TRUE-REPLACE project, in a way that the corrosion resistance of these layers is improved, while keeping their mechanical and tribological properties within the required standards for an aeronautical application.
    • 1.3. To investigate the combination of Cr and Ni-P coatings, studying different architectures (number of layers and thickness in multi-layer plating, P content, thermal treatment, etc), looking for an increase of corrosion resistance of the coatings and reach the defined mechanical, tribological and protecting requirements.
  • To achieve a new, more ecological and efficient industrial process, able to provide excellent functional qualities to pieces and metal components with applications in strategic industrial sectors such as aeronautics. Also, we intend to get ahead of the REACH regulations (annex XIV) that defines Cr(VI) as a highly contaminant substance with a use deadline by September 2024, as well as to get ahead of other European rules that control its use. Finally, we intend to eliminate the toxic emanations generated by handling chromic acid (Cr(VI)) during all phases of the manufacturing process, removing the risk for the workers’ health in their workplace.
  • To know the features and limitations of Cr (III) and Ni-P electrolytes, defining the work window and the concentration limits of the most suitable components that lead to coatings with an adequate quality, without causing problems neither in the stability nor in the yield of the electrolytes. Besides, we seek to define electrolyte analysis methods and to establish both control and maintenance protocols, so that the electrolyte evolution could be studied over time and applied charge. Likewise, it is projected the possibility of analyzing the regeneration of the Cr(III) electrolytes as undesired substances are generated in the bath during use.

  • To develop monitoring, control and regeneration systems for Cr(III) and Ni-P electrolytes, so they could be controlled and kept in optimal conditions for long process times, increasing their useful life, while keeping their performance and decreasing the percentage of coating rejections.
  • To escalate both chrome and nickel plating to pilot plant scale over prototypes of different materials, sizes and geometries, with continuous and remote monitoring and controlling of the electrolytes. Validation of the coatings under standards and through a test bench, which will be designed and fabricated for the evaluation of the prototypes in a relevant environment (TRL 6).
  • To divulge in journals the results of the project that would be of scientific interest

OTROS PROYECTOS

  • Development of new masks based on thermo-strippable resins for selective surface treatments.
    Actual state: In progress

  • Investigation and modelling of Hydrogen effusion in electrochemically plated ultra-high-strength-steels used for landing gear structures
    Actual state: In progress

  • Development of a viable and sustainable alternative to hexavalent hard chrome for functional applications in aeronautical and automotive industries.
    Actual state: Finalized