Tracking the formation of double schottky barriers during sintering of ZnO varistor ceramics using in-situ dielectric spectroscopy
Peer-Reviewed Publication
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Understanding the formation and evolution of double Schottky barriers during sintering is essential for controlling the electrical performance of ZnO varistor ceramics. Here, in-situ high-temperature dielectric spectroscopy is used to continuously track this process. Negative permittivity caused by electron plasma oscillations is observed above 700°C. Densification and grain growth occur mainly during heating and soaking, whereas barrier formation is concentrated at 800-650℃ during cooling and is further regulated by Bi-rich phase transitions at 650-500℃. These findings establish a direct link between sintering, microstructural evolution, and electrical functionalization in ZnO varistor ceramics.
High-performance structural ceramics are critical materials for extreme-service applications. Recently, high-entropy carbide ceramics have attracted great attention due to their exceptional hardness, wear resistance, and high-temperature stability, although their intrinsic brittleness still limits further applications. Among the various strategies available, the synergistic regulation of spinodal decomposition and precipitation has emerged as a promising approach to overcoming the hardness-toughness trade-off, enabling (Ti, Zr, V, Nb, Mo)C high-entropy carbide to achieve simultaneous increases of 36% in hardness and 45% in fracture toughness, respectively. This strategy provides a new route toward the design of damage-tolerant advanced ceramics with superior mechanical performance.
High-entropy design is widely used to tailor structural disorder and local polarization in ferroelectric ceramics, but whether it necessarily enhances relaxor characteristics in tetragonal tungsten bronze (TTB) systems remains unclear. Here, entropy-tunable K(NaPr)1-x(SrBa)xNb5O15 ceramics were constructed to decouple the factors governing diffuse phase transition and relaxor-ferroelectric evolution. Contrary to conventional expectations, increasing configurational entropy does not enhance relaxor behavior; instead, the system evolves from an ergodic relaxor state toward a ferroelectric-like state. This evolution is governed by crystal structure, BO6 local environment, and polar nanoregions dynamics, whereas diffuse phase transition is associated with incommensurate modulation.
Engineers at the China Ship Scientific Research Center have developed an autoregressive deep-learning framework (VMD-BiGRU-QRNN) that predicts complex dynamic midship bending moments in severe ocean waves. Tested against physical tow-tank data from a 205,000 DWT bulk carrier, the system reached an average R² of 0.9533 and accurately captured high-frequency whipping peaks, providing crucial risk-assessment data to prevent structural catastrophic failures.
Development of an aqueous zinc-ion battery using precision removal of lithium ions, replaced with zinc ions, to produce a new material called ZLVP (Zn0.62Li1.2V2(PO4)3) shows promise in developing a sustainable and powerful energy storage solution. ZLVP maintains stable performance over 5,000 cycles with an operating voltage of 1.51 V, offering a safer alternative to conventional lithium-ion systems.