Effects of in-situ formed TiB2 Phase on Mechanical Properties of Spark Plasma Sintered Boron Carbide

Abstract

Due to their exceptional properties, B4C ceramics are favored in a wide range of application areas, including defense and ballistic protection, coating, aerospace, and high temperature electronic devices. However, its use will increase if its low fracture toughness and poor sinterability are improved. In this study, the effects of TiO2 as a sintering additive on B4C's density and mechanical properties were examined, along with the identification of the in-situ second phase that is likely to form during sintering with SPS. To achieve this, 5, 10, 15, and 20 wt. % TiO2 were added to B4C. The in-situ TiB2 phase was formed as a result of the reactions between B4C and TiO2 during sintering, according to XRD analyses performed on SPS-sintered samples. The release of CO gases due to reactions between TiO2 and B4C during sintering caused a slight decrease in the relative density of the B4C matrix as the TiO2 content increased. Density measurements and BSE-SEM images supported each other. The fracture toughness of the B₄C matrix improved by approximately 6, 43, 51, and 57 % with the addition of 5, 10, 15, and 20 wt.% TiO2, respectively. This enhancement is attributed to crack deflection, bridging, and blocking toughening mechanisms facilitated by the in-situ formed TiB2 phase.

Keywords

• TiO2
• B4C
• TiB2
• Fracture Toughness
• SPS

In-situ olarak oluşmuş TiB2 Fazının Spark Plazma Sinterleme ile Üretilmiş Bor Karbürün Mekanik Özellikleri Üzerindeki Etkileri

Abstract

Due to their exceptional properties, B4C ceramics are favored in a wide range of application areas, including defense and ballistic protection, coating, aerospace, and high temperature electronic devices. However, its use will increase if its low fracture toughness and poor sinterability are improved. In this study, the effects of TiO2 as a sintering additive on B4C's density and mechanical properties were examined, along with the identification of the in-situ second phase that is likely to form during sintering with SPS. To achieve this, 5, 10, 15, and 20 wt. % TiO2 were added to B4C. The in-situ TiB2 phase was formed as a result of the reactions between B4C and TiO2 during sintering, according to XRD analyses performed on SPS-sintered samples. The release of CO gases due to reactions between TiO2 and B4C during sintering caused a slight decrease in the relative density of the B4C matrix as the TiO2 content increased. Density measurements and BSE-SEM images supported each other. The fracture toughness of the B₄C matrix improved by approximately 6, 43, 51, and 57 % with the addition of 5, 10, 15, and 20 wt.% TiO2, respectively. This enhancement is attributed to crack deflection, bridging, and blocking toughening mechanisms facilitated by the in-situ formed TiB2 phase.

Keywords

• TiO2
• B4C
• TiB2
• Kırılma Tokluğu
• SPS

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