Effect of Sintering Temperature on the Properties of Highly Electrical Resistive SiC Ceramics as a Function of Y2O3-Er2O3 Additions

Abstract

Silicon carbide (SiC) ceramics with Y2O3-Er2O3 as sintering additives were prepared by spark plasma sintering (SPS). The effects of sintering temperatures and Y2O3-Er2O3 contents on the microstructure, thermal conductivity, electrical, and mechanical properties were investigated. The increasing of sintering temperatures promoted the densification of SiC ceramics, thus increasing the thermal conductivity and electrical resistivity. With the increase of the sintering additive contents, the electrical resistivity increased due to the formation of the electrical insulating network; and the thermal conductivity first increased and then decreased, which was related to the content and distribution of the secondary phase among the SiC grains. The SiC ceramics sintered at 2000 °C with 9 wt.% Y2O3-Er2O3 exhibited higher electrical resistivity and thermal conductivity, which were 4.28 × 109 Ω·cm and 96.68 W/m·K, respectively.

Low‐temperature Pr3Si2C2‐assisted liquid‐phase sintering of SiC with improved thermal conductivity

“…The thermal conductivity of the SiC samples measured in the present work is higher than that reported in the literature for SiC ceramics sintered at similar temperatures, 20,24,42–48 as shown in Figure 6. This is mainly caused by the fact that SiC ceramics usually cannot be well sintered at such low temperatures as 1400–1600°C using traditional liquid‐phase sintering additives, such as Al 2 O 3 and/or RE 2 O 3 .…”

“…39,40 In addition, liquid-phase sintering additives, such as Al 2 O 3 and RE 2 O 3 (RE = Y, Er, Sr, Sc, etc. ), [42][43][44][45][46][47] usually possess a lower thermal conductivity when compared to SiC. Thus, a larger amount of sintering additives at the grain boundaries and/or grain junctions of SiC results in a greater phonon scattering, which leads to a decreased thermal conductivity.…”

Controlling the electrical resistivity of porous silicon carbide ceramics and their applications: A review

“…found that the electrical resistivity of a SiC ceramic with 7wt.% Y 2 O 3 –La 2 O 3 increased from 3.4 × 10 0 to 53 × 10 0 Ω·cm with an increase in the porosity from 3.3 to 9.9%. This correlation between the porosity and electrical resistivity is widely observed if the chemical composition and processing conditions are not altered 28,57,82 . It has also been reported that the open porosity affects the electrical properties of SiC ceramics more than the close porosity and increases the electrical resistivity 81 .…”

“…This correlation between the porosity and electrical resistivity is widely observed if the chemical composition and processing conditions are not altered. 28,57,82 It has also been reported that the open porosity affects the electrical prop-erties of SiC ceramics more than the close porosity and increases the electrical resistivity. 81 Porosity decreases the cross-sectional area for conduction and results in complex alterations in the conduction mechanism, 80,83,84 as schematically shown in Figure 1A.…”

Joining of SiC Ceramic by Si–C Reaction Bonding Using Organic Resin as Carbon Precursor

“…Because of their outstanding mechanical properties and high temperature stability, silicon carbide (SiC) ceramics are potentially suitable materials for many different areas, such as aerospace, electronics, nuclear energy, and transportation [1][2][3][4]. The rapid development of aerospace, national defense, and nuclear energy has put forward urgent requirements for complex-shaped or large SiC ceramic components.…”