Founded in 1911, the Donelli Group has evolved from a family coating business into a specialist in industrial corrosion protection. Its development combines investment in coating facilities, robotic surface preparation and engineered maintenance solutions for energy and infrastructure assets.
The Donelli Group marks its 115th anniversary in 2026, bringing together more than a century of experience in surface treatment and the protection of industrial assets.
Established by Giovanni Donelli in Legnano (Italy), the company initially employed four people and specialised in decorative painting, oil-based enamels for metals and lime paints for masonry.
Its subsequent expansion followed the changing requirements of Italian industry. Activities progressed from painting Milan’s trams to protecting power stations, chemical and petrochemical plants, offshore structures and major civil engineering works. Today, the Group combines on-site contracting with specialised facilities for surface preparation and protective coating application.
The development of its production network began with the opening of the Cuggiono blasting and coating plant in 1982, followed by Ravenna in 1997 and the acquisition of the Voghera facility in 2011. Later investments included Cuggiono CX and the MXP facility at Ferno, opened in 2023.
These sites provide complementary capabilities for components with different dimensions, geometries and service requirements. CX brings together powder coating and liquid painting equipment, dedicated handling systems
and high-temperature ovens, while MXP extends capacity for large valves and industrial equipment. Across the network, protective treatments include fusion-bonded epoxy (FBE) powders, liquid paints, chemical-resistant linings and metallic thermal-spray systems.
Hydroelectric maintenance has become a significant area of technical development. Penstock rehabilitation requires surface preparation and coating operations to be coordinated with restricted access, confined-space working, environmental controls and limited shutdown periods.
To address these conditions, Donelli has developed and deployed robotic ultra-high-pressure waterjetting and surface preparation systems adapted to pipe geometry, diameter changes, and substrate conditions.
Research has also resulted in European patent protection for technology incorporating recovery of water and removed material at source. A separate development with a German technology partner concerns the spraying of coating materials onto internal pipe walls.
At Randens in the French Alps, the Group renewed the internal protection of two penstocks between 2021 and 2022. Each included a vertical section approximately 93 metres high and 3.7 metres in diameter. Before deployment, a full-scale trial installation at Cuggiono was used to test robotic systems, extraction equipment, pumping, and handling arrangements.
Another project involved refurbishing 422 metres of hydroelectric penstock at Bolzano, including an original riveted section dating from 1901. The work combined robotic preparation, targeted manual intervention, inspection, and process-water recovery and treatment.
Alongside infrastructure maintenance, the Group has developed specialised coating processes for heat exchangers. These applications require protection of complex geometries while accommodating chemical exposure, temperature fluctuations and heat-transfer requirements.
Donelli Alexo holds licences to apply Säkaphen systems in Italy and France, as well as a Heresite application licence. Impresa Donelli operates under Blygold and Thermoguard application licences.
This expertise also supports work in waste-to-energy facilities, where protective systems must withstand conditions including hot flue gases, aggressive condensates and thermal cycling. One completed project involved specialist cleaning and renewed protection of six finned-tube air coolers to support equipment durability and operational continuity.
International development includes established activities in France and initiatives in Albania and Mozambique serving energy and infrastructure markets. Investments in production capacity are accompanied by training, inspection capabilities and closer control of application and curing parameters.
Water recovery, capture of removed coatings and energy monitoring are further areas of development. Together with robotic preparation and specialised application processes, these measures reflect the Group’s focus on managing the complete protective treatment process, from initial assessment to inspection, with the aim of extending the service life of industrial assets.