Resumo

OLMOS, L. et al. Study of constrained sintering of powers used to cracks reparation. Rev. Mex. Ing. Quím [online]. 2014, vol.13, n.3, pp.887-896. ISSN 1665-2738.

Sintering is a thermal treatment normally used to produce parts from different types of powders, and it is a phenomenon that has been studied since the 1950's. Mechanisms and diffusion paths for several materials have already been established. However, the use of sintering; powders to repair fissures on solid materials has rarely been studied. The aim of this work is to study the solid state sintering of copper powders filling artificial grooves in a bar of solid copper. Sintering was carried out in an electrical furnace under H₂ and Ar (10-90 respectively) atmosphere at two different temperatures, 1000 and 1050°C. The powder used to fill the grooves was a spherical atomized copper powder with a wide particle size distribution, 0-63/μm. Sintering of particles wat evaluated at the edge of the solid bar and at the center of the groove by scanning electron microscopy (SEM). It was observed that particles sintered well on the wall's surface at the site of the artificial groove. Greater densification reached by the smaller particles and higher sintering temperatures creates defects inside the groove. Those defects are the consequence of the constraints of sintering, and the necks developed during the thermal cycle could be broken by the higher stresses generated during densification.

Palavras-chave : constrained sintering; copper; solid state sintering; defects evolution; cracks healing.