Synthesis of uniform BN-coated aluminum borate nanowhiskers and their applications in reinforced magnesium matrix composites

► BN tubular layers-coated Al18B4O33 nanowhiskers were synthesized using a new boron source as reactant. ► Al18B4O33 nanowhiskers are homogeneously sheathed over their entire lengths with thin BN tubular layers. ► BN coatings can effectively prevent the interfacial reaction between Al18B4O33 nanowhiskers and Mg alloys. ► A remarkable increase in composite hardness has been obtained by the addition of coated nanowhiskers into Mg alloys.