Environmental friendly and safer chromium-free process for hard coatings

PROJECT DESCRIPTION

BACKGROUND

Hexavalent Chromium (Cr(VI)) is crucial in metal plating, manufacture of pigments and dyes and corrosion inhibitors, chemical synthesis, refractory production, leather tanning, and wood preservation. The total EU Cr(VI) production is around 250 000 tons per year and about 900 000 workers in the EU are estimated to be exposed to the substance. In the specific case of Beretta, Cr(VI) is deposited in the internal part of the rifle barrel, providing hardness, heat resistance and thermal barrier properties, as well as corrosion resistance, adhesion and low friction properties, resistance to corrosive combustion gases and no detrimental interactions associated with the firing of ammunition. The level of performance provided by the use of hard chromium represents a key factor in the decision of Beretta to keep the manufacturing activities in Italy. At the same time, Cr(VI) is highly toxic and carcinogenic and poses severe health risks, including higher risk of lung cancer among workers in certain industries and cancer of the nose and nasal sinuses. Industrial Cr(VI) emissions also result in critical air, soil and water contamination. It has therefore been formally banned in the EU as of September 2017, eliciting the need for a replacement. However, in 2017 the EC granted a temporary authorisation to continue the production and sale of Cr(VI) until September 2024 for certain functions: formulation, hard chrome and surface treatment.

OBJECTIVES

The LIFE CROMOZERO project will develop and validate an alternative, chromium-free process for hard chromium plating to be used by Beretta as wear and corrosion protection layer for the internal part of rifle barrels. More specifically, the project aims to substitute the traditional galvanic chromate process with a Plasma Enhanced Chemical Vapor Deposition (PECVD) technology, based on the results from a single barrel prototype machine already developed by associated beneficiary DURALAR.

The final industrial pilot plant (TRL = 8) will be reached in two main phases:

• Phase 1. Design and construction of an engineered prototype equipment, allowing the coating of up to 5 barrels at the same time. This first phase is necessary for the validation of the technology before the design and building of the industrial-scale plant.
• Phase 2. Design and construction of a large-scale industrial pilot equipment to coat up to 30-50 barrels in one single step, meeting industrial requirements of performance, increased environmental and health protection, operating with reduced time and costs.

Through this, the project will contribute to the EU REACH Regulation and Industrial Emissions Directive (IED) 2010/75/EU. Cr(VI) is included in the revised Annex XIV to the REACH Regulation, and hard chrome coatings must be progressively phased-out and will not be allowed after September 2024. It also contributes to the Industrial Strategy for Europe (COM(2020) 102), in particular, the revision process of the BAT document “Surface Treatment of Metals and Plastics” (European Commission 2006) on industrial emissions started in 2020 and it is expected that further developments regarding the substitution of Cr(VI) will be positively evaluated.

RESULTS

Expected results:

The substitution of the hard chrome plating by PECVD will lead to the elimination of:

• 115 tons/year of irritant, corrosive, toxic substances such as chromic acid, sodium bisulfide, sulfuric acid and hydrated lime;
• 46 tons/year of mutagenic and carcinogenic chemicals (chromic and sulfuric acids);
• 137.5 tons/year of hazardous waste contaminated by very high Cr(VI)  concentrations;
• 115 000 m³/year of wastewater contaminated by 0.023 g/m³ of Cr(VI); and
  
• Air pollutants in the exhaust fumes of the plating bath with a concentration of 0.064 ppm of Cr(VI).

Reduction of:

• 22 000 m³/year of water consumption used in the galvanic bath (equal to 100% of water savings);
• 60 000 kWh/year of energy consumption with respect to chrome plating (equal to 50% of energy savings); and
  
• 13 tons/year of eq. CO₂ emissions.