HfB₂-doped ZrB2-30 vol.% SiC composites: oxidation resistance behavior

Abstract

To investigate the HfB2 on microstructure and oxidation resistance of ZrB2-30 vol% SiC, ZrB2-30 vol% SiC composites with different amounts of HfB2 (4, 8, and 12 vol%) were consolidated by Spark Plasma Sintering method (SPS). Microstructural evaluations were done by scanning electron microscopic (SEM). To investigate the oxidation resistance, the samples were placed in a box furnace at the temperature of 1400 C for different times. The samples were weighed before and after the oxidation and the Δw was applied as a criterion of oxidation. The thickness of SiO2 layer and Si depleted layer were also used as oxidation criterion. The results showed that HfB2 addition caused to decrease Δw and better oxidation resistance.

Influence of TiN addition on densification behavior and mechanical properties of ZrB2 ceramics

“…To overcome such problems, several research works have suggested the selection of suitable consolidation techniques and/or activating the toughening and sintering mechanisms utilizing the addition of additives [6][7][8]. Among spark plasma sintering (SPS), pressureless sintering (PS), reactive hot pressing (RHP), and hot pressing (HP) [9,10], as the sintering techniques for the fabrication of UHTCs, the first one is a newly developed route that utilizes direct current pulsing and external mechanical pressure to densify the materials synchronously [11][12][13]. According to the role of additives/ reinforcements, both metals and non-metals can be utilized as the sintering aid to prevail over mentioned shortcomings of ZrB2 and improve its properties.…”