Processing and properties of pressable ceramic with non-uniform reinforcement for selective-toughening

Nanoscaled Interface Between Microgold Particles and Biphase Glass‐Ceramic Matrix

“…The average bending strength of 329 ± 28 MPa for the GP/glass‐ceramic composite is surprisingly high as only 5 wt% of GP on average for the overall volume was used. However, the realistic GP percentage, close to the tensile surface, should be around 10 wt% or even higher because of the selective‐toughening design of the composite and the flow of GPs within the molten glass‐ceramic during hot‐pressing, as illustrated in Fig. .…”

“…However, with further heat treatment, amorphous leucite phase regions were transformed into leucite crystals. Gold aluminum compounds were also found in the glass‐ceramic matrix close to GP, as the hot‐press process altered the reaction layer formed at the interface, for example more gold aluminum compounds could exist at the trailing edge of GP. Si and Al also existed on the GP surface after large‐scale plastic deformation and debonding of the interface, indicating strong chemical bond at the interface. The processing temperature of 1000°C, relatively close to the melting temperatures of both GP and glass‐ceramic matrix, is beneficial to surface wetting and formation of the defect‐free interface between GP and glass‐ceramic matrix. Finally, the processing condition, wetting of GP by the amorphous leucite phase within the biphase glass‐ceramic matrix, and more pronounced chemical reactions between GP and the leucite phase made it possible to fabricate a metal‐reinforced ceramic matrix composite with the feature of “selective‐toughening”, or nonuniform composite structures with toughening metal reinforcements positioned only at locations where they are mostly needed.…”

“…Material compositions of the glass‐ceramic and dental gold have been listed in our previous study . Microsized irregular elongated GPs, measured in few hundreds of microns in length, were produced in‐house from a dental gold bar (Type IV; Esteticor, Neuchâtel, Swiss) using a standard dental laboratory hand piece with a tungsten carbide bur at a high speed.…”

“…However, there are only limited reports on the nanostructures of those leucite‐reinforced glass‐ceramics, and virtually no reports on using ductile metal particles to improve the low strength and low toughness of those widely used leucite/feldspar glass‐ceramics. Our recent study shows that a ductile metal phase (dental gold) can be introduced to reinforce those brittle and low strength glass‐ceramics, and as a result, both flexural strength and fracture toughness have been significantly improved. The interface between the elongated microgold particles (GP) and glass‐ceramic matrix plays a significant role in the strength and toughness mechanisms.…”

Research and application of biomimetic modified ceramics and ceramic composites: A review

“…However, ceramic materials are typical brittle materials with low tensile strength, poor plasticity, and toughness 5 . In addition, traditional single structure ceramics have the disadvantages of high density, small specific surface area, and poor functionality, which has affected its reliability in engineering, and has greatly limited its application in engineering 6,7 . Therefore, how to improve the mechanical and functional properties of ceramic materials, improve their comprehensive properties, and expand their application scope has become a long‐term pursuit of material scientists.…”