Relationship between pore coarsening and mass loss during supersolidus liquid phase sintering of alpha brass

The effect of sintering variables on the zinc loss during sintering of brass was investigated. Zinc loss, evident through mass change, starts during heating of the powder at approximately 700 degrees C. By supersolidus liquid phase sintering of the cold-pressed brass powder, the maximum amount of zinc loss occurred at lower temperatures and prolonged sintering times. At higher temperatures, especially near the zinc boiling point, the rate of zinc loss from the surface is surprisingly moderate since closing of the pores causes zinc to be trapped in the samples. At lower temperatures, in contrast, when the pores in the surface are open and there is also a lower volume fraction of liquid phase, zinc can easily escape from the samples. Generally, it was thus concluded that during sintering, zinc loss depends more strongly on the pore connectivity and the specific surface than just on the nominal vapour pressure.