Innovation in corrosion protection and improvement of mechanical and tribological properties

The POLVERI & ECOCOATING 2019 Conference and Exhibition is a specialised meeting point for technological and commercial exchange aimed at companies that supply machinery, equipment, consumables and services in the powder paint and surface coating application sector.

The highly technological conferences provide an opportunity to analyse the technologies related to innovations in powder coatings and application and curing systems, as well as technological breakthroughs in industrial paint products, systems and processes.

Thermochemical treatments

At this prestigious meeting, Iñigo Braceras presented new thermochemical treatments to improve the mechanical, tribological and corrosion properties of stainless steel valves and pumps. The surface characteristics of the stainless steels are significantly improved by suitably designing the treatment processes (including surface cleaning) and using active screen plasma nitriding (ASPN). This prevents some of the problems posed by conventional plasma nitriding (inadequate microstructures, discontinuous nitrated layers and/or variable thickness, etc.) without compromising the behaviour of the steel against corrosion.

Hybrid coating

Specifically within the corrosion framework, Usoa Izaguirre presented a thin layer (3-5 µm thick) hybrid coating system (organic-inorganic) with a formulation that does not use toxic elements (chromium-free). This system is capable of providing a high level of protection against corrosion for metal substrates such as aluminium alloys, galvanised steel and carbon steel for structural use in extremely corrosive settings such as marine environments.

This hybrid coating can be used as a top coat or as an intermediate coat before applying paint. The assessment of the coating system has included accelerated laboratory tests (testing in a salt spray chamber and cyclic ageing tests), as well as exposure tests in real marine environments. The real offshore exposure tests were carried out on the Harshlab 1.0 floating laboratory located in the BiMEP open sea space.

Characterisation based on electrochemical methods

In the field of assessment systems, Jean-Baptiste Jorcin displayed a new, more objective, characterisation technique based on electrochemical methods. By using electrochemical impedance spectroscopy (EIS) and integrating it into complex ageing cycles, degradation mechanisms can be generated that are closer to those observed when the coating systems are exposed to actual operating conditions. This allows the efficiency of protective paints to be assessed more accurately compared to traditional methods which use visual observations of test specimens/components that are aged in a salt spray chamber.

Contact: Marta Brizuela Parra Surface Engineering Manager at TECNALIA