PVZ Metal Coated Boron Elemental Amorphous Boron Powder Coated with Magnesium / Aluminum up to 20 w.t. % Typical Chemical Analysis Content Chemical Analysis Boron 95 – 75 % Magnesium / Aluminum 0-20 %. Moisture 0.50 % max. Water Soluble Boron 0.50 % max.