Field emission performance of graphene-incorporated aluminum-based metal matrix composite†

The ‘close proximity’ configuration was used for field emission analysis of graphene-incorporated aluminum (Al) composites. The turn-on field was found to be 2 V μm⁻¹ for the AlGr1 (1% graphene (by weight) inside the Al matrix) composite compared to 4.75 V μm⁻¹ for the pristine aluminum sample. As the potential was increased, the current due to emission expeditiously increased in an electric field of 4 V μm⁻¹, with 1 mA cm⁻² current density due to emission for the AlGr1 composite, compared to that of 1.08 μA cm⁻² for Al. The turn-on value was visually perceived to be superior for the AlGr1 composite as compared to the value for Al. Also, a quite stable emission current was recorded for the AlGr1 composite as compared to Al. Furthermore, the composites maintained approximately 98.7% of the density of pure aluminum following the sintering process. The structural wholeness and the nonexistent porous quality of the sintered specimens was confirmed via X-ray micro-computed tomography (micro-CT). The thermal amalgamation of the AlGr composite materials at 640 °C was found to be adequate, and produced composites with the desired strength. These evaluations indicate that AlGr composites can be excellently applied as cathodes and for the prevention of crumpling of electrical line cables.