Conventional three‐dimensional graphene cellular materials (GCMs) from chemically derived graphene oxide undergo low mechanical strength, severe plastic deformation and poor electrical conductivity. Herein, ultralight, ultraelastic, excellent mechanical and electrically conductive GCMs have been successfully prepared by the self‐assembly of graphene nanosheets by extensive hydrogen bonds generated from a glycolic acid crosslinker. Meanwhile, ethanol‐water solution is used to dramatically restrict the volume expansion of water converting into ice crystal during the freeze process. Eventually, the GCMs exhibit ultralow densities of about 4.3 mg cm−3, and can be fabricated on a large scale (volume of ∼350 cm3). The GCMs have a maximum reversible strain of ca. 90% in the whole density range from 4.3 mg cm−3 to 25.3 mg cm−3. Young's moduli (E) are from 13.7 kPa (ρ=4.3 mg cm−3) to 125.1 kPa (ρ=25.3 mg cm−3), with the scale of E∼ρ2.1, and the exponent n is less than the GCMs previously reported. The GCMs also have high electrical conductivities of about 98.1 S/m (ρ=25.3 mg cm−3). Our work provides a facile method for the fabrication of ultralight, highly compressible and conductive GCMs, paving the way towards future potential applications in energy storage and conversions, adsorbents for the environment, etc.
The microstructure and mechanical properties of Mg–2Zn–0.5Ca–1.0Mn alloy under different treatments were investigated. Nano-TiO2 with biological activity was added to the self-optimized silicate electrolyte in order to enhance the corrosion resistance and
the activity of micro-arc oxidation (MAO) coatings formed in the aged bio-magnesium alloy silicate electrolyte. Results show that the tensile strength and micro-hardness of solution treatment alloy were 194 MPa and 40.55 HV, respectively, which were increased by 11% and 30% comparing with
as-cast alloy. Subsequently, the experimental alloy was aged at 175 °C from 0.5 h to 36 h, the tensile strength of the alloy reached 229 MPa when the alloy was aged to 16 h, which was 55 MPa higher than the as-cast alloy. Besides, the fracture mechanism transformed from the cleavage fracture
to quasi-cleavage fracture after heat treatment. Different content of modified nano-TiO2 (1, 3 and 5 g/L) is added into based silicate electrolyte has been utilized to modify the bio-magnesium coatings for precoated metals. The sealing processes on MAO coatings surface effectively
improve the corrosion resistance property of the bio-magnesium alloy. As the concentration of nano-TiO2 increases from 0 g/L to 5 g/L, the corrosion potential of MAO ceramic film increases gradually. When the concentration of nano-TiO2 is 5 g/L, the corrosion potential
of the formed ceramic film is the highest, reaching – 1.3601 V, this shows that the ceramic membrane has good corrosion resistance.
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