Porosity of sintered tin bronzes


Mihai Ovidiu COJOCARU, Leontin Nicolae DRUGA, Daniela DRAGOMIR, Florică TUDOSE, U.P.B. Sci. Bull., Series B, Vol. 79, Iss. 1, 2017 ISSN 1454-2331

The paper aimed at quantifying effects of change of raw materials used for tin bronzes (Cu-Sn mechanically pre-alloyed powders compared to Cu-Sn pure components mixture), and of thermal and temporal sintering parameters on sintered products porosity; the relation between these parameters has been defined mathematically. Compacted specimens made of mentioned raw materials-mechanically alloyed powders and mixture of pure components- have been sintered in several stages; the initiation of the process occurs by pre-sintering in the stability range of α solid solution (360oC/30’-Transient Liquid Phase Sintering); further thermal processing has been performed in the range of high temperatures, below (SSS) and above the starting temperature of solid solution melting (SLPS), depending on conditions required by experiment programming method chosen. To explicit the relation between sintered products porosity and raw materials as well as sintering parameters has been applied the 2nd order non- linear compositional – orthogonal programming method of experiment. The metallographic evaluation of porosity has been realized with image analysis software. The obtained results under the form of regression relations outline with high probability (95%) the correlations taken into analysis and thus allow the porosity control and evaluation in real processing conditions.