Optimization of the Sintering Densification, Microstructure, Mechanical Properties, and Oxidation Resistance of Tib2–Tic–Sic Composite Ceramics via a Two-Step Method

TL;DR

This study optimizes the sintering process of TiB2–TiC–SiC composite ceramics to improve their density, microstructure, mechanical strength, and oxidation resistance.

Contribution

A two-step method is introduced to enhance the properties of TiB2–TiC–SiC ceramics through controlled sintering and SiC addition.

Findings

The optimal sintering temperature of 1900 °C maximizes the relative density and mechanical properties of the ceramics.

SiC addition suppresses grain growth and enhances oxidation resistance compared to TiB2–TiC ceramics.

Rod-like TiB2 microstructures formed with SiC improve the mechanical attributes of the composite.

Abstract

In this investigation, TiB2–TiC composite powders, synthesized via the boron/carbon thermal reduction process, were employed as precursor materials. SiC, serving as the tertiary constituent, was incorporated to fabricate TiB2–TiC–SiC composite ceramics utilizing spark plasma sintering technology. The present study initially elucidates the densification mechanisms and investigates the influence of sintering temperature on the densification behavior, microstructural evolution, and mechanical properties of the resultant ceramics. The experimental findings reveal that the sintering process of TiB2–TiC–SiC ceramics exhibits characteristics consistent with solid-phase sintering. As the sintering temperature escalates, both the relative density and mechanical properties of the ceramics initially improve, reaching a maximum at an optimal sintering temperature of 1900 °C, before subsequently declining. Microstructural examinations conducted at this optimal temperature indicate a homogeneous distribution of the two primary phases, with no evidence of excessive grain growth. Furthermore, this research explores the effects of SiC addition on the mechanical performance and oxidation resistance of TiB2–TiC–SiC composite ceramics. The results demonstrate that the incorporation of SiC effectively suppresses grain growth and promotes the formation of rod-like TiB2 microstructures, thereby enhancing the mechanical attributes of the ceramics. Additionally, the addition of SiC significantly improves the oxidation resistance of the composite ceramics compared to their TiB2–TiC binary counterparts

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