Agro-waste ash and mineral oxides derived glass-ceramics and their interconnect study with Crofer 22 APU for SOFC application

Abstract

In this study, silicate glass-ceramic is synthesized from wheat straw ash (WSA) using melt-quench technique. X-ray diffraction is done to confirm the nature of the as-quenched samples. Inductive coupled plasma-mass spectroscopy (ICP-MS) and energy dispersive spectroscopy (EDS) are performed to evaluate the exact chemical composition of the as-prepared samples. Similar composition is also melted using conventional mineral oxides for comparison with WSA sample. The WSA sample shows good thermal stability in temperature range of 300–900 °C. The coefficient of thermal expansion (CTE) of WSA sample is more or less in the required range for solid oxide fuel cells (SOFC) application. The powder of WSA derived glass-ceramic is used to form the diffusion couple with the interconnect (Crofer 22 APU) for interfacial study. The excellent adhesion with the smooth and porosity-free interface is formed between glass-ceramic and Crofer 22 APU, when WSA is used as a sealant as compared to the mineral based glass-ceramics. Semi-coherent interface does not show any delimitation or separation even after five thermal cycles. The micro hardness (384 HV) of the interface is indicated good bonding between interconnect and glass-ceramic.