Evaluation of Mechanical and Electrical Performance of Aging Resistance ZTA Composites Reinforced with Graphene Oxide Consolidated by SPS

Abstract

This paper presents a study of Al2O3–ZrO2 (ZTA) nanocomposites with different contents of reduced graphene oxide (rGO). The influence of the rGO content on the physico-mechanical properties of the oxide composite was revealed. Graphene oxide was obtained using a modified Hummers method. Well-dispersed ZTA-GO nanopowders were produced using the colloidal processing method. Using spark plasma sintering technology (SPS), theoretically dense composites were obtained, which also reduced GO during SPS. The microstructure, phase composition, and physico-mechanical properties of the sintered composites were studied. The sintered ZTA composite with an in situ reduced graphene content of 0.28 wt.% after the characterization showed improved mechanical properties: bending strength was 876 ± 43 MPa, fracture toughness—6.8 ± 0.3 MPa·m1/2 and hardness—17.6 ± 0.3 GPa. Microstructure studies showed a uniform zirconia distribution in the ZTA ceramics. The study of the electrical conductivity of reduced graphene oxide-containing composites showed electrical conductivity above the percolation threshold with a small content of graphene oxide (0.28 wt.%). This electrical conductivity makes it possible to produce sintered ceramics by electrical discharge machining (EDM), which significantly reduces the cost of manufacturing complex-shaped products. Besides improved mechanical properties and EDM machinability, 0.28 wt.% rGO composites demonstrated high resistance to hydrothermal degradation.

Removal of 2,4-Dichlorophenoxyacetic Acid from Aqueous Solutions Using Al2O3/Graphene Oxide Granules Prepared by Spray-Drying Method

“…The G band is attributed to a perfect graphite structure while the D band shows defects in the microstructure. Therefore, after the spray drying, the sorbent retained the GO structure, which is consistent with the literature [22][23][24].…”

“…The G band is attributed to a perfect graphite structure while the D band shows defects in the microstructure. Therefore, after the spray drying, the sorbent retained the GO structure, which is consistent with the literature [22][23][24]. Since the low content of GO in granules makes it hard to detect using SEM, it was identified using Raman spectroscopy.…”

Direct Ink Writing 3D Printing of Graphene/Al2O3 Composite Ceramics with Gradient Mechanics

“…The result confirmed that the size of Al 2 O 3 phases in G/Al 2 O 3 composite ceramics decreased with increasing in content of G. The result was attributed to good pinning effect of G nanosheets. [ 25 ] When G/Al 2 O 3 composite ceramic was high‐temperature sintering, the Al 2 O 3 phase was general mobility, forming larger Al 2 O 3 phase. [ 27 ] Here, mobility of the Al 2 O 3 phase was pinned by G nanosheets, reducing size of Al 2 O 3 phase.…”

“…For 3D‐printing Al 2 O 3 ceramic, there was no absorption in the range of 1000.0–2500.0 cm −1 (Figure 4B‐a). In contrast, it clearly showed two absorption peaks at 1355.0 and 1587.0 cm −1 (Figure 4B‐b), which were assigned to D and G bands of G. [ 25 ] In addition, the G peak of G in present composite ceramic was redshifted from 1576.0 to 1587.0 cm −1 comparing to traditional reduced oxide G. It indicated more sp 2 orbitals and higher reducing degree for present G, resulting from the high sintering temperature. [ 15 ] These results indicated the formation of G/Al 2 O 3 composite ceramic by DIW 3D‐printing technology.…”

Granulation of Silicon Nitride Powders by Spray Drying: A Review

“…At present, Si 3 N 4 -based parts can be obtained by various methods, such as direct coagulation casting [21,22], reaction sintering [22], spark plasma sintering [23][24][25], tape casting [26], hot-press sintering [27], gel casting [28,29], and others.…”