Surface modification of nickel-aluminum bronze alloy with gradient Ni-Cu solid solution coating via thermal diffusion

The surface modification of NAB alloys was developed by thermal diffusion with the gradient outer layer of the Ni-Cu solid solution and the inner layer of the Ni-Al-Cu intermetallic layer. The evolution of the surface coating was a diffusion controlled model. The Cu atoms diffused faster than Al atoms within Ni matrix, which resulted in the continuous accumulation of Al atoms in the inner layer to generate the Ni-Al-Cu intermetallic layer.336