A method of coating magnetic particles with pseudo-boehmite (AlOOH) by forming an aqueous suspension of magnetic particles, adding aluminium nitride powder to the suspension in an amount of 0.1-10 % by weight of the suspension with a mass ratio of AlN : magnetic particles in the range 1:1 to 99:1 and heated to a temperature in the range 50-200 0C for 5-600 minutes. Refluxing can also be performed. The magnetic particles can be an oxide (e.g. iron oxide), a carbide or a metal (e.g. iron, nickel or cobalt alloys) with a size in the range 3 nm to 10 mum and can be coated with a stabiliser such as citric acid, acetic acid, malic acid, formic acid or tartaric acid. The coated magnetic particles can then be removed, dried and calcined to form magnetic particles coated with gamma-alumina which can be used as adsorbents, catalyst carriers or drug carriers.
