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The presence of nickel at grain boundaries greatly increases the grain boundary lattice-diffusion of tungsten.

The presence of nickel at grain boundaries greatly increases the grain boundary lattice-diffusion of tungsten. Correct Answer False

Nickel, which is added as a solution of its salts, gets reduced during sintering and forms a coating of a few monolayer on the surface of the W particles. By diffusing over the W particles, Ni accumulates at the necks of the particles from where the nickel penetrates the grain boundaries. This presence of nickel at the grain boundaries greatly increases the grain boundaryself-diffusion of tungsten. Thus, the segregation of the additive at the interparticle boundary creates a short circuit diffusion path for the rapid diffusion of the base metal resulting in enhanced densification.

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