Ni prepared by the reduction of Ni (2) being finely divided is pyrophoric (spontaneously or self flammable).When disrpersed/heated on an alumino silica matrix, it can form 1:1Ni/Si alloy [Raney in 1924] as well as 1:1Ni/Al alloy [Raney in 1926].Each one these alloy is five times better (Raney1926 even more) than the finely divided Ni.These heat-treated samples are no more pyrophoric at room temperature.

Thanks Mr. Sehgal for replying. Do you have information at what temperature such alloy formation takes place? My material was heat treated at 350 oC under hydrogen atmosphere.

[1] Though the original Raney Nickel as prepared by Raney himself in 1926 was by dissolving nickel in molten aluminium (660.3C) followed by cooling (quenching), but now a days its much better forms called W-6 Raney Nickel and W-7 Raney Nickel are prepared even at 55-60 C; of course by different methods which are already reprted in the literatrure.

[2] Again, the Ni-Si (1:1) alloy was prepared at a temperature 400-450C. Now a day a better one Ni-Si (3:1) is also reporetd in the literature but no temperature is reported. Instead, it is reported -----by mixing Si in molten Ni.

[3] My humble suggestion is that depending upon the the ratio of contituents and methods of preparation, the temperatures may differ and so will be their activity.