Effects of theTiB2-SiC Volume Ratio and Spark Plasma Sintering Temperature on the Properties and Microstructure of TiB2-BN-SiC Composite Ceramics

Abstract

TiB2-BN composite ceramics combine excellent electrical conductivity, thermal shock resistance, high-temperature resistance, corrosion resistance, and easy processing of TiB2 and BN. However, in practical applications, their high-temperature oxidation resistance is poor and the resistivity distribution is uneven and changes substantially with temperature. A TiB2-BN-SiC composite ceramic with stable and controllable resistivity was prepared by introducing SiC into the TiB2-BN composite ceramics. In this work, spark plasma sintering (SPS) technology was used to prepare TiB2-BN-SiC composite ceramics with various TiB2-SiC ratios and sintering temperatures. The samples were tested by XRD, SEM, and thermal and mechanical analysis. The results show that as the volume ratio of TiB2-SiC was increased from 3:1 to 12:1, the resistivity of the sample decreased from 8053.3 to 4923.3 μΩ·cm, the thermal conductivity increased from 24.89 to 34.15 W/(m k), and the thermal expansion rate increased from 7.49 (10−6/K) to 10.81 (10−6/K). As the sintering temperature was increased from 1650 to 1950 °C, the density of the sample increased, the mechanical properties were slightly improved, and the resistivity, thermal expansion rate, and thermal conductivity changed substantially. The volume ratio and sintering temperature are the key factors that control the resistivity and thermal characteristics of TiB2-SiC-BN composite ceramics, and the in situ from liquid phases of FeB and FeO also promotes the sintering of the TiB2-BN-SiC ceramics.

The Influence of Molasses Concentration on the Physical and Mechanical Properties of Evaporation Boat Waste-Based Crucibles

“…It illustrates that as the temperature increases, the crystallization capability of the BN phase improves, resulting in a purer BN matrix. The investigation has revealed several impurity peaks, such as FeO, Fe3Si, as well as FeB [10].…”

“…Boron nitride (BN) and titanium diboride (TiB2) have remarkable properties such as outstanding resistance to wear, great hardness, stability at high temperatures, and a high melting point. This makes it easier to use BN and TiB2 in many industrial processes, such as metallic evaporation plating, wear-resistant coatings, and aerospace applications [9][10][11]. Composite ceramics made of TiB2 and BN are good at conducting electricity, resist wear well, and are easy to machine [10,12].…”

“…This makes it easier to use BN and TiB2 in many industrial processes, such as metallic evaporation plating, wear-resistant coatings, and aerospace applications [9][10][11]. Composite ceramics made of TiB2 and BN are good at conducting electricity, resist wear well, and are easy to machine [10,12]. Moreover, the combination of TiB2 with BN provides enhanced electrical conductivity and lubricating properties for molten metals [10].…”

“…Composite ceramics made of TiB2 and BN are good at conducting electricity, resist wear well, and are easy to machine [10,12]. Moreover, the combination of TiB2 with BN provides enhanced electrical conductivity and lubricating properties for molten metals [10]. Based on the previous description, TiB2−BN is a suitable material for the manufacture of crucibles due to its superior properties, including chemical stability, corrosion resistance, thermal shock resistance, high-temperature resistance, thermal and electrical conductivity [8], [10].…”