NEI Corporation has announced that it has completed initial development of a chromate‐free, self‐healing conversion coating that significantly improves the corrosion resistance of magnesium alloys. A conversion coating, only a few micrometers thick, forms on the surface of a magnesium part when immersed in Nanomyte PT‐60, which is a waterborne solution. The coating has the ability to ‘self‐heal,’ ie repair itself if scratched or damaged, thereby providing active corrosion protection.
In salt-fog exposure experiments (ASTM B117), magnesium AZ91D panels coated only with Nanomyte PT‐60 show minimal corrosion pitting after 10 days (240hrs). In contrast, AZ91D panels with conventional pretreatments begin to pit after only 24hrs. Magnesium alloys are of increasing interest to several industries, such as automotive, construction, medical, computers, communication and consumer electronics, as well as the military. The light weight of magnesium allows increased fuel efficiency and energy savings. However, magnesium alloys have a high tendency to corrode.