Flash sintering of 3Y-TZP/Al2O3 composites

Reference	Presenter	Authors (Institution)	Abstract
12-016	Raphael Euclides Prestes Salem	Salem, R.E.(Universidade Tecnológica Federal do Paraná); Monteiro, F.R.(Universidade Estadual de Ponta Grossa); Ojaimi, C.L.(Universidade de São Paulo - FZEA); Campos, J.V.(Faculdade de Zootecnia e Engenharia de Alimentos-FZEA); Chinelatto, A.L.(Universidade Estadual de Ponta Grossa); Chinelatto, A.S.(Universidade Estadual de Ponta Grossa); Pallone, E.M.(Faculdade de Zootecnia e Engenharia de Alimentos - FZEA);	The flash sintering technique was first reported in 2010. It consists in the conventional sintering combined with application of an electrical field, promoting the consolidation of ceramics in very short time and allowing obtention of fine microstructures in temperatures relatively lower than conventional sintering. This work aimed to study the flash sintering of 3Y-TZP/Al2O3 composites, with 5 and 15 vol% of Al2O3. The powder mixtures were obtained by ball milling. 8 mm-diameter cylindrical shape specimens were pressed uniaxially and isostatically at 200 MPa. Sintering was performed in a tubular vertical furnace, adapted with an AC/DC power supply. The specimens were sintered at a heating rate of 20°C/min and electrical fields were initially set at 150 V/cm and 200 V/cm, using AC (1000 Hz) and DC, applied during the heating cycle. Sintered samples were characterized by apparent density measurements and scanning electronic microscopy (SEM). Results showed start of densification at temperatures as low as 785°C, attaining shrinkage over 20% in 15 s, for the composite with 5 vol% Al2O3 sintered with 200 V/cm DC. Relative densities varied between 79.4 and 94.6%TD. SEM results showed that refined microstructures of submicrometric grains were obtained, with some level of microstructural heterogeneity. Generally, AC electrical fields allowed higher linear shrinkage than DC fields. It can be concluded that the flash sintering technique is an interesting option for rapid consolidation of 3Y-TZP/Al2O3 composites.
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