International Journal of Microstructure and Materials Properties (4 papers in press)

Regular Issues

• Effect of sealed sintering on properties of Al doped ZnO varistor ceramics with high voltage gradient and low residual voltage  
  by Xiao Lei, Xin Ning, Peng Liu, Jingke Guo, Yin Yue, Pengfei Meng 
  Abstract: Zinc oxide varistor have excellent nonlinear voltmeter characteristics and are the core components of key equipment for overvoltage protection in power systems. This study delves into how sealed sintering affects the electrical properties of Al-doped ZnO varistor ceramics. By comparing two formulas (a traditional one and an optimised low-residual-voltage one with higher Al and BiO content) across different sintering environments (open vs. sealed) and temperatures, significant findings were obtained. Under sealed sintering, the optimised formula achieved a 15% lower residual voltage ratio than the traditional formula. Notably, samples sintered at 1,150 C showed optimal performance: a residual voltage ratio(K) of 1.39, leakage current of 1.38 A, and voltage gradient of 285.5 V/mm. Mechanistically, Al doping reduced grain resistivity and residual voltage, while added Bi, Ni, and Co elements increased the grain-boundary surface state density, suppressing leakage current. These outcomes are highly significant for enhancing the overvoltage protection capabilities of power systems.
  Keywords: sealed sintering; ZnO varistor; microstructure; electrical performance.
  DOI: 10.1504/IJMMP.2026.10075608
   
  
• Condensation reaction pathway of free formaldehyde and surface hydroxyl groups of nano-TiO2  
  by Li Lyu, Binxu Xie, Shuangshuang Wang 
  Abstract: This study aims to investigate the specific pathways and mechanisms of the condensation reaction between free formaldehyde and hydroxyl groups on the surface of nano TiO2. Firstly, free formaldehyde and nano TiO2 are applied to the urea formaldehyde resin system and subjected to condensation reaction at a constant temperature. Secondly, Fourier transform infrared spectroscopy (FTIR) is used to track the evolution of characteristic hydroxyl peaks during the reaction process. In addition, solid-state nuclear magnetic resonance (NMR) is used to detect newly formed methylene bridge structures in condensation systems. Finally, the thermal decomposition of the resin after the reaction is simultaneously monitored using thermogravimetric differential scanning calorimetry (TG-DSC). The results showed that DFT simulation successfully identified the key transition state TS1, with a maximum reaction potential barrier of 0.87 eV and a methylene bridge content of up to 45.3%.
  Keywords: free formaldehyde condensation reaction; nano-TiO2 surface hydroxyl groups; UF resin structure; thermal stability analysis; density functional theory simulation.
  DOI: 10.1504/IJMMP.2025.10079707
   
  
• Phase dependent mechanoluminescence in ZnS:Mn: from zinc blende to wurtzite  
  by Usha Shukla 
  Abstract: Mechanoluminescence (ML), the phenomenon of light emission under mechanical stress, has emerged as a promising pathway for developing stress sensors, structural health monitors, and self-powered devices. Among ML materials, manganese-doped zinc sulphide (ZnS:Mn) has gained particular attention due to its bright and reproducible luminescence. A critical factor governing its ML performance is the crystal phase transition between zinc blende (ZB) and wurtzite (WZ). The centrosymmetric ZB phase exhibits weaker piezoelectric effects, with luminescence largely driven by defect-mediated mechanisms, whereas the non-centrosymmetric WZ phase generates strong piezoelectric fields that facilitate efficient charge detrapping and recombination at Mn2+ centres. This review highlights how phase transformation, defect distributions, and dopant interactions collectively modulate the luminescence efficiency of ZnS:Mn. We discuss experimental evidence of ZB-WZ transition at bulk and nanoscale, its correlation with defect chemistry, and its impact on luminescence reproducibility. Recent advances in controlled synthesis, co-doping strategies, and pressure/temperature-induced phase modulation are also reviewed. By establishing a clear structure phase luminescence relationship, this work underscores the importance of phase engineering in designing ZnS:Mn-based materials for next-generation mechano optical applications.
  Keywords: mechanoluminescence; ML; ZnS:Mn; phase transition; piezoelectric effect; defect engineering.
  DOI: 10.1504/IJMMP.2025.10079708
   
  
• AES analysis of difference of SS304 and SS 316 utilised to fabricates metallic structures to bridges of Tijuana, Baja California, Mexico  
  by Israel Sauceda Meza, Arilí Cardenas Robles, Eddna Teresa Valenzuela Martínez, Jesús Márquez González, Daniel Barrera Román, Cicerón González Toxqui, Yidanes Alejandra Ibáñez Acevedo, Verónica Arredondo Robledo, Luis Mario Rodríguez Valenzuela, Gustavo López Badilla 
  Abstract: In the metallic industry of the Tijuana city are utilised two types of the stainless steel, being the SS 304 and SS 316, which are used to manufactures metallic structures to build bridges in modernised cities, such as this important city of the northwest of Mexico. In this investigation was made a comparative analysis of the utilise the SS 304 and SS316 about the corrosion resistance and the protection of both types of stainless steel using the Auger Electron Spectroscopy (AES) technique and the Scanning Electron Microscopy (SEM), considering the chemical compounds, crystalline structure and the physicochemical properties of each stainless steel evaluated. This scientific study was made in 2023.
  Keywords: industry; SS 304; SS 316; Auger Electron Spectroscopy; AES; environmental agents; Mexico.
  DOI: 10.1504/IJMMP.2025.10079779