Simultaneously improved surface hardness and thermal diffusivity of carbon nanotube/zinc silicate composites via colloidal processing

Abstract

Materials with ideal thermal dissipation can prevent electronic devices from overheating and sustaining internal damage. However, obtaining passive heat sink materials with a well-distributed thermal transport network remained challenging. In this study, carbon nanotubes (CNTs) reinforced zinc silicate (Zn2SiO4) composites (CNTs/ZS) were fabricated via colloidal processing and pressureless sintering. The CNTs was first dispersed in 1,2,3,4-tetrahydronapathalene (C10H12) through sonication, before composite-mixing and densification with zinc silicate ceramic. It revealed that the dispersed CNTs simultaneously improved the mechanical and thermal properties of the composites, along with reducing relative density. The Vickers hardness, thermal diffusivity, and thermal conductivity of the optimized composite containing 1.0 wt% CNTs increased by 42%, 179%, and 537%, respectively, compared to the pristine ZS. The SEM observation on the 1.0 wt% CNTs/ZS composite surface determined that the area fraction of the CNTs inclusions was approximately 60%, which was advantageous for phonon propagation and electron transmission path. The combined effect of the phonon and electron transmission path outperformed the polycrystalline-induced Umklapp scattering and porosity-induced phonon-pore scattering, which were identified as obstacles to the heat-transfer process. Thus, this CNTs reinforcement through colloidal processing can be a strategy for designing of efficient silicate-based heatsink candidates in optoelectronic applications.