Enhancing thermal conductivity of 6061 Al plate via graphene dip coating

The development of thermally conductive lightweight materials holds paramount importance for optimizing heat dissipation in automobile components. This study investigated three distinct techniques for coating graphene onto 6061 Al plates: direct, aluminum nitride (AlN)-aided, and poly-vinyl-alcohol (PVA)-aided coatings. The direct coating approach, via dipping into a graphene suspension, resulted in nonuniform graphene distribution due to the poor wettability of Al with graphene. AlN formation on the surface of a 6061 Al plate before graphene dip coating (AlN-aided coating) considerably improved the wettability of the surface with graphene. When using the PVA-aided coating method, 6061 Al plate was treated with PVA, followed by immersion in a graphene oxide (GO) suspension, achieving uniform GO coverage. This was facilitated by strong bonding between functional groups formed on the plate through treatment with PVA and those present on the GO surface. Directly coated samples exhibited a bonding strength of ∼1 MPa, whereas the samples coated using AlN- and PVA-aided methods showed bonding strengths of ∼3 and ∼10 MPa, respectively. Furthermore, AlN- and PVA-aided coatings improved thermal conductivity by ∼5.6% and ∼8.5%. This study proposes a facile and effective graphene-derivative coating process to improve the heat dissipation of Al-based materials.