Even in a crystaline structure? Forgive me, IANAMS.
Yes, even in a crystalline structure. Diffusion in solids at the macroscopic scale seems slow compared to say, cream in your coffee, but at the atomic scale... They did this at the surface, which makes it even worse. I can't imagine this lasting any useful amount of time without some SEVERE cooling measures. I'm not sure if even liquid nitrogen could save it. IAAMS.