... become Nickel Oxide when 600. Density 6.67,melting point 1990°C,absorb oxygen to become Nickel Sesquioxide when 400°C ,Nickel ... Sesquioxide to become Nickel Oxide when 600°C .Indissoluble in ... glass's colorant. magnetic material ferrite,catalyst, raw material of nickel salt,storage battery,electronics industry and so on.