As an oxide ceramic of the substrate alloy, Keronite is inert to most chemicals and therefore performs extremely well in most corrosive environments in protecting the surface of magnesium and aluminium alloys.
One of the key factors limiting the wider use of magnesium alloys is their poor resistance to corrosion. However, a Keronite layer on magnesium provides protection far superior to that of chemical conversion or anodised coatings.
Independent tests have demonstrated that magnesium alloy AZ91D, coated with 25-35 µm of Keronite only, will survive one month of immersion in a saline solution, or 1000 hours in a salt spray environment with very little evidence of corrosion attack.
Further tests whereby samples were rated in accordance with ASTM D1654 demonstrated that 5-7 µm of Keronite on AZ91D magnesium alloys such as AZ91D and AM60B, together with 40-50 µm of e-coat or powdercoat, consistently achieved a top rating of 9 or above after 2000 hours of exposure to salt spray (ASTM B117), even on scribed samples.
On aluminium alloys, even those such as AA7075 and AA2219 which contain copper and have very poor corrosion resistance, an unsealed layer of Keronite will provide a minimum of 360 hours of corrosion resistance to a rating of 9 or higher under the conditions outlined in ASTM B117. |
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