TY - JOUR
T1 - Ablation threshold and temperature dependent thermal conductivity of high entropy carbide thin films
AU - Milich, Milena
AU - Quiambao-Tomko, Kathleen
AU - Hossain, Mohammad Delower
AU - Tomko, John
AU - Maria, Jon Paul
AU - Hopkins, Patrick E.
N1 - Publisher Copyright:
© 2023 Old City Publishing, Inc.
PY - 2023
Y1 - 2023
N2 - High entropy carbides (HECs) are a promising new class of ultra-high temperature ceramics that could provide novel material solutions for leading edges of hypersonic vehicles, which experience extreme temperatures and thermal gradients. Although the mechanical and thermal properties of HECs have been studied extensively at room temperature, few works have examined HEC properties at high temperatures or considered these materials' responses to thermal shock. In this work, we measure the thermal conductivity of a five-cation HEC up to 1200°C. We find that thermal conductivity increases with temperature, consistent with trends demonstrated in single-metal carbides. We also measure thermal conductivity of a HEC deposited with varying CH4 flow rate, and find that although thermal conductivity is reduced when carbon content surpasses stoichiometric concentrations, the films all exhibited the same temperature dependent trends regardless of carbon content. To compare the thermal shock resistance of HECs with a refractory carbide, we conduct pulsed laser ablation measurements to determine the fluence threshold the HECs can withstand before damaging. The fluence threshold of the HEC thin films trends with the theoretical hardness of the HECs as expected.
AB - High entropy carbides (HECs) are a promising new class of ultra-high temperature ceramics that could provide novel material solutions for leading edges of hypersonic vehicles, which experience extreme temperatures and thermal gradients. Although the mechanical and thermal properties of HECs have been studied extensively at room temperature, few works have examined HEC properties at high temperatures or considered these materials' responses to thermal shock. In this work, we measure the thermal conductivity of a five-cation HEC up to 1200°C. We find that thermal conductivity increases with temperature, consistent with trends demonstrated in single-metal carbides. We also measure thermal conductivity of a HEC deposited with varying CH4 flow rate, and find that although thermal conductivity is reduced when carbon content surpasses stoichiometric concentrations, the films all exhibited the same temperature dependent trends regardless of carbon content. To compare the thermal shock resistance of HECs with a refractory carbide, we conduct pulsed laser ablation measurements to determine the fluence threshold the HECs can withstand before damaging. The fluence threshold of the HEC thin films trends with the theoretical hardness of the HECs as expected.
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U2 - 10.32908/hthp.v52.1343
DO - 10.32908/hthp.v52.1343
M3 - Article
AN - SCOPUS:85151910596
SN - 0018-1544
VL - 52
SP - 151
EP - 164
JO - High Temperatures - High Pressures
JF - High Temperatures - High Pressures
IS - 2
ER -