Corrosiveness of Aluminum Hypophosphite (AHP)

Aluminum hypophosphite (AHP) flame retardant offers advantages such as a high decomposition temperature, good dispersibility, being halogen-free, and environmentally friendly. However, it also has certain disadvantages. The pH of AHP ranges from 3 to 5, with a measured value around 3.5, making it a weakly acidic inorganic flame retardant. Therefore, AHP is somewhat corrosive. To reduce its corrosiveness, it should be dried in a dryer before mixing to reduce the moisture content. This can also reduce the corrosiveness. Furthermore, before twin-screw mixing and pelletizing, it is important to use medium-weak shear to prevent the decomposition of aluminum hypophosphite and the generation of phosphine.

Under varying storage conditions and during processing, aluminum hypophosphite (AHP) can generate trace amounts of phosphine. Phosphine can corrode metals such as gold, silver, copper, and iron. In the presence of high humidity, acids, or other chemicals, phosphine can generate inorganic acids, which can increase corrosion under these operating conditions.

In general, it is important to avoid corrosion from aluminum hypophosphite flame retardants on materials and equipment. Try to use a low processing temperature to avoid moisture generation. Avoid strong acids, strong bases, or other chemicals that react with aluminum hypophosphite, potentially producing phosphine or inorganic acids. We do not recommend mixing it with alkaline materials such as magnesium hydroxide, as this increases the likelihood of acid-base neutralization, negatively impacting flame retardancy and the material.