REACH regulation challenge: Development of alternative coatings to hexavalent chromium for minting applications

Carneiro, Edgar; Castro, José D.; Marques, S. M.; Cavaleiro, A.; Carvalho, S.

doi:10.1016/j.surfcoat.2021.127271

Cited by 21 publications

(14 citation statements)

References 65 publications

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“…In this way, it was possible to combine the beneficial characteristics of plastics with those of the metals that coat them, i.e., maintaining a shiny metallic finish and a high reflectivity and conductivity [ 3 ]. The chrome plating process, in particular, can provide greater protection against wear and corrosion while giving the parts a metallic decorative appearance [ 5 ]. In this process, however, coatings have been mostly produced from a chemical bath containing hexavalent chromium ions.…”

Section: Introductionmentioning

confidence: 99%

“…In this process, however, coatings have been mostly produced from a chemical bath containing hexavalent chromium ions. Contact with this ion has proven to be dangerous for the environment and human health [ 5 ]. Over the years, it has been found that there are several health problems associated with exposure to hexavalent chromium [ 6 ], among which are eye irritation, respiratory problems (asthma), lung cancer, nasal irritation, and other nasal damage, as well as skin irritation, ulcers, or allergy [ 7 , 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

“…On June 2007, the European Union’s REACH regulation (Registration, Evaluation, Authorization, and Restriction of Chemicals) came into force. This regulation has the power to restrict or ban the use of certain substances (depending on their risks) and to replace fuel chemicals with less dangerous ones, promoting a constant sustainable development of the industry [ 5 , 10 , 11 , 12 , 13 ]. That said, on 21 September 2017, the use of chromium VI in coatings was banned in the European Union, forcing companies to find feasible alternatives to the chrome plating process, which are at the same time more environmentally friendly [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

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Decorative Chromium Coatings on Polycarbonate Substrate for the Automotive Industry

et al. 2023

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Metal-coated plastic parts are replacing traditional metallic materials in the automotive industry. Sputtering is an alternative technology that is more environmentally friendly than electrolytic coatings. Most metalized plastic parts are coated with a thin metal layer (~100–200 nm). In this work, the challenge is to achieve thicker films without cracking or without other defects, such as pinholes or pores. Chromium coatings with different thicknesses were deposited onto two different substrates, polycarbonate with and without a base coat, using dc magnetron sputtering in an atmosphere of Ar. Firstly, in order to improve the coating adhesion on the polymer surface, a plasma etching treatment was applied. The coatings were characterized for a wide thickness range from 800 nm to 1600 nm. As the thickness of the coatings increased, there was an increase in the specular reflectivity and roughness of the coatings and changes in morphology due to the columnar growth of the film and a progressive increase in thermal stresses. Furthermore, a decrease in the hardness and the number of pinholes was noticed. The maximum thickness achieved without forming buckling defects was 1400 nm. The tape tests confirmed that every deposited coating showed a good interface adhesion to both polymers.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Decorative Chromium Coatings on Polycarbonate Substrate for the Automotive Industry

et al. 2023

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“…The coatings are deposited by reactive magnetron sputtering from a chromium target using N 2 and O 2 as reactive gases onto polycarbonate (PC) substrates. In addition to depositing a pure Cr layer, CrN and chromium oxynitrides were produced to improve the hardness and allow a variation of the decorative appearance [17]. Adding oxygen to CrN coatings provides a wide range of shades of grey without scarifying wear and corrosion resistance [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Cr-Based Sputtered Decorative Coatings for Automotive Industry

et al. 2021

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The present work aims to study the impact of O and N addition on Cr-sputtered coatings on plastic (polycarbonate, PC) used in automobile parts, as a promisor alternative for auto part metallization, while eliminating the usage of toxic hexavalent chromium. The coatings were deposited using DC magnetron sputtering from a single pure Cr target in a reactive atmosphere (N2 and/or O2). The deposition of the coatings was performed maintaining the total pressure constant and close to 1 Pa by tuning Ar pressure while reactive gases were added. The target current density was kept at JW = 20 mA·cm−2. Structural characterization revealed a mixture of α-Cr, δ-Cr, β-Cr2N, and CrN crystalline structures as well as amorphous oxides. The coating hardness ranged from 9 GPa for the CrON coating to 15 GPa for the CrN coating. All deposited coatings showed a particularly good interface adhesion; adjusting the amount of O and N made it possible to tune the optical properties of the Cr-based coatings as desired. The promising results open future industrialization of sputtered Cr-based coatings for automotive industries.

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“…However, it should be noted that the FeinAl coating was applied to the original hard chrome coating. Another possible substitute for hard chrome plating is the use of thermal spraying, e.g., HVOF (High Velocity Oxygen Fuel) technology [11][12][13][14]. However, HVOF technology is not suitable for all applications, as the coatings created by this technology must in many cases be further processed, e.g., by grinding or polishing [15,16].…”

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confidence: 99%

Possibilities of Using the Duplex System Plasma Nitriding + CrN Coating for Special Components

et al. 2022

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The article deals with the replacement of hard chrome plating by applying the duplex system plasma nitriding + CrN coating (hereinafter referred to as PN + CrN). The goal of the research was to find a suitable alternative for steel surface treatment that would replace hard chrome plating and ensure similar mechanical and tribological properties. An exposed part of a small-bore weapon was selected for evaluation, namely the gas piston of the 42CrMo4 steel breech mechanism drive. The PN + CrN duplex system was compared with a hard chrome coating as well as a self-deposited CrN coating. The mentioned surface treatments were evaluated in terms of metallography, mechanical and tribological properties and surface texture. From the mechanical properties, the hardness of the surface was analyzed, an indentation test was performed (Mercedes test) and adhesive-cohesive behavior was evaluated (Scratch test). Furthermore, an instrumented penetration test was performed (an evaluation of plastic and elastic deformation work and indentation hardness). As part of the assessment of tribological properties, the Ball-on-Flat test, the measurement of the coefficient of friction and the measurement of traces of wear were performed. The surface texture was evaluated in terms of morphology and surface roughness measurement by selected 2D and 3D parameters. The PN + CrN duplex system showed higher hardness than hard chrome, better tribological properties (lower friction coefficient), but worse surface texture. The PN + CrN duplex system has proven to be a suitable alternative to the hard chrome coating for exposed parts of small-caliber weapons, which can be applied in arms production.

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REACH regulation challenge: Development of alternative coatings to hexavalent chromium for minting applications

Cited by 21 publications

References 65 publications

Decorative Chromium Coatings on Polycarbonate Substrate for the Automotive Industry

Decorative Chromium Coatings on Polycarbonate Substrate for the Automotive Industry

Cr-Based Sputtered Decorative Coatings for Automotive Industry

Possibilities of Using the Duplex System Plasma Nitriding + CrN Coating for Special Components

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