Aluminum slurry coatings to replace cadmium for aeronautic applications

Abstract

ARTICLE INFO ABSTRACT Keywords:Cadmium coating replacement Aluminum slurry Steel Atmospheric corrosión Aeronautical applicationsCadmium has been widely used as a coating to provide protection against galvanic corrosión for steels and for its natural lubricity on threaded applications. However, it is a toxic metal and a known carcinogenic agent, which is plated from an aqueous bath containing cyanide salts. For these reasons, the use of cadmium has been banned in Europe for most industrial applications. However, the aerospace industry is still exempt due to the stringent technical and safety requirements associated with aeronautical applications, as an acceptable replacement is yet to be found. Al slurry coatings have been developed as an alternative to replace cadmium coatings. The coatings were deposited on AISI 4340 steel and have been characterized by optical and electrón microscopy. Testing included salt fog corrosión exposure, fluid corrosión exposure (immersion), humidity resistance, coating-substrate and paint-coating adhesión, electric conductivity, galvanic corrosión, embrittlement and fatigue. The results indicated that Al slurry coatings are an excellent alternative for Cd replacement.

Slippery Liquid-infused Porous Surface Fabricated on Aluminum Maintains Stable Corrosion Resistance at Elevated Temperatures

“…The resistance value of lubricant (Rc) significantly decreases from 1.94 × 10 8 Ω cm 2 to 1.89 × 10 7 Ω cm 2 with an increase in temperature. These phenomenon can be attributed to two factors: 1 The relationship between surface tension and water droplet temperature and the relationship between surface tension and contact angle are as follow: [32][33][34]       75 714 0 1414 0 25399 10 3 2 .…”

The replacement of cadmium coating on parts of the weapon with tungsten-disulphide coating

“…Galvanic cadmium based coatings are widely used in the air and military industries [1]. Cadmium provides a good combination of protective properties in terms of a low coefficient of friction, high plasticity, lubrication and corrosion resistance [2]. However, cadmium based coatings are very harmful to the environment and ask for finding the alternative, environmentally friendly coatings that will meet the requirements of their exploitation.…”

“…However, cadmium based coatings are very harmful to the environment and ask for finding the alternative, environmentally friendly coatings that will meet the requirements of their exploitation. According to European regulations, it is foreseen that by 2020 cadmium will be completely removed from the production [1,2].…”

Corrosion of cadmium plating by runway de-icing chemicals: Study of surface phenomena and comparison of corrosion tests

“…However, cadmium and its vapors are toxic [7]. Therefore, more health-and eco-friendly alternatives to cadmium plating are currently sought [9][10][11][12][13][14][15][16][17]. Although the replacement of cadmium plating is a timely topic, it has to be recognized that such process is slow, particularly in aviation sector, with relatively long lifetime of the aircraft and prolonged standardization procedures for new coating processes.…”