at 500 rpm control samples which were not mixed with tpp react vigorously upon contact with water and undergo ignition in contrast the tpp containing sample upon exposure to water exhibited surface charring and provided a crust surface to the metal amide it is believed that the curst reduces the contact of the underlying material with water and air and prevents ignition while a 5 mole ratio of tpp to metal amide was evaluated similar effects were observed at lower ratios of approximately 3 mole as best seen in reference to fig1 the modified material as set forth in fig1 b shows significant improvement and cyclic durability during hydrogen sorption experiments in comparison to control samples it is noted that the tpp coating process and resulting coated material has increased hydrogen cycling durability which is believed attributed to the formation of a new stable compound by the reaction of tpp with the metal hydrides during ball milling without being unduly limited by theory it is applicant 39 s belief that the new compound formed is less reactive on exposure to air and water further it is believed that the wax like properties of tpp when ball milled with a metal hydride provides.