Analysis of conductivity in 8YSZ ceramics during AC-flash processes: A two-barrier ionic transport model approach

This work offers a systematic study of the electrical conductivity in dense 8 mol% yttria-stabilized zirconia (8YSZ) during non-isothermal and isothermal AC-flash conditions under a fixed applied voltage. Conductivity data were interpreted using a two-barrier ionic transport model which is able to capture the non-Arrhenius behavior commonly found for 8YSZ. The analysis of the conductivity…

High piezoelectric performance in lead-free BCHT fine-grained ceramics synthesized by mechanochemistry

Lead-free piezoelectric ceramics (Ba1-xCax) (Ti1-yHfy)O-3 with stoichiometries close to the morphotropic phase boundary (MPB) were synthesized by high-energy ball milling. The influence of Hf and Ca contents and the sintering method (conventional and hot-press) on the piezoelectric, dielectric, and ferroelectric response was investigated. It was confirmed that the different phases stabilized at room temperature and…

Flash Joule Heating-Boro/Carbothermal Reduction (FJH-BCTR): An approach for the instantaneous synthesis of transition metal diborides

Transition metal diborides (TMB2), such as ZrB2 and HfB2, are a class of ultra-high-temperature ceramics (UHTCs) that have attracted considerable attention due to their performance in extreme environments. Their implementation is burdened by the high energetic requirement of traditional synthetic procedures. Here, we report a novel methodology, termed as Flash Joule Heating-Boro/Carbothermal Reduction (FJH-BCTR), for the…

Influence of the atmosphere on the formation of high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system via reactive flash sintering

In this study, the feasibility of preparing quinary equimolar high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system was explored using the reactive flash sintering (RFS) technique. Various compositions were tested using this technique under atmosphere pressure, leading to the formation of two primary phases: rock-salt and spinel. Conversely, a new high-entropy oxide was produced as a single-phase…

Influence of graphene-based nanostructures processing routes and aspect ratio in flexural strength and fracture mechanisms of 3Y-TZP-matrix composites

In this work, the influence of the aspect ratio of graphene-based nanostructures (GBNs) and content on the mechanical properties of 3 mol% yttria tetragonal zirconia polycrystalline 3Y-TZP matrix composites was analysed. The influence of the dispersion method and sintering parameters on the flexural strength and elastic modulus of the composites was studied, and the fracture surfaces…

Influence of firing temperature on the ceramic properties of illite-chlorite-calcitic clays

The influence of firing temperature on the ceramic properties of illite-chlorite-calcitic clays has been investigated. Three samples of the same clay deposit have been selected. Weight loss, dimensional changes, water absorption, bulk density, open porosity, flexural and compressive strengths, initial capillary water absorption rate and thermal conductivity have been determined as a function of firing…