Electrochemical depositing rGO-Ti-rGO heterogeneous substrates with higher thermal conductivity and heat transfer performance compared to pure Ti

Abstract

Titanium (Ti) and its alloys are widely applied in many high strength, light weight applications, but their thermal conductivity is lower compared to that of other metals, which limits their further applications. In this paper, we demonstrated experimentally that rGO-Ti-rGO heterogeneous substrates with higher thermal conductivity, up to ∼38.8% higher than Ti, could be fabricated by electrochemical depositing rGO on their surface. The rGO layers are grown on the surface of Ti substrates, with appearance of bedclothes on the beds. The thickness of rGO layers is around 300-500 nm and around 600-1000 nm when deposited for 5 cycles and 10 cycles, respectively. According to the cooling experiment results, as-prepared Ti + rGO substrates can present excellent thermal conduction performance, and reduce the chip temperature close to 3.2 °C-13.1 °C lower than Ti alloy substrates with the heat flow density of 0.4-3.6 W cm. Finally, the approach to electro-chemically deposit hundreds of nanometer rGO layers on the surface of Ti substrates can improve their thermal conductivity and heat transfer performance, which may have further application in the increasing thermal conduction of other metal-alloys, ceramics and polymers.

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“…Then, the RGO/Ti−Fe−O NTs are prepared by potentiostatic deposition in GO dispersion solution. Under an efficient negative potential of −1.0 V (determined by the peak potential of the large cathode current when GO is reduced by CV electrodeposition, 30 GO is electrochemically reduced to RGO and deposited on the electrode. Compared with the CV electrodeposition reported previously, 17 the continuous negative potential bias helps to efficiently and stably reduce the surface functional groups of GO, 31 so that a fairly uniform thin layer of RGO can be obtained on the Ti−Fe−O NT array in a shorter time (100 s), which can be seen from the SEM image (Figure 1b).…”

“…Graphene oxide (GO) prepared by the improved Hummers method 29 was ultrasonically dispersed in phosphate-buffered solution (PBS, 0.1 M, pH = 9.18) to obtain a homogenous solution of 0.5 mg mL −1 . A conventional three-electrode system with Ti−Fe−O NTs as a working electrode, a Pt wire as a counter electrode, and a saturated calomel electrode (SCE) as a reference electrode was utilized for electrochemical reduction of GO at a bias of −1.0 V for 100 s. 30,31 After immersing in distilled water to remove the undeposited GO, the RGO/Ti−Fe−O NT electrode was obtained. The as-prepared RGO/Ti−Fe−O NT electrode was immersed in 10 mL of NaAc-HAc buffer solution (0.2 M, pH = 5.2) containing 10 μM o-PD and 1 μM MC-LR.…”