Calculate the critical radius for a Nickel embryo (nucleus) that is undercooled 150 degrees C. The melting point of Ni is 1453 0C. The surface energy for Ni is 555 e-7 J/cm^2 and the heat of fusion is 2756 J/ cm^3.
How many Ni atoms would have to get together and form an embryo before it would start to grow, at the previous conditions. When Ni solidifies it is FCC. Use a lattice parameter of 0.356 nm.