Aging Effects on PTCR Ceramics: SEM and C‐AFM Analysis of Electrical Conductivity and Domain Structures

ABSTRACT

This study examines the impact of aging on the electrical and structural properties of positive temperature coefficient of resistance (PTCR) ceramics. The presented study introduces a correlative scanning electron microscopy (SEM)/conductive atomic force microscopy (C‐AFM) approach enabling repeated, site‐specific characterization of electrical conductivity and domain structures within the same microstructural regions during aging.  Specifically, we investigate changes in electrical conductivity and ferroelectric domain structures using a combined SEM/C‐AFM (AFM‐in‐SEM) correlative approach, enabling repeated, site‐specific characterization of electrical conductivity and domain structures within the same microstructural regions. After 1 week of aging, significant alterations were observed, including the emergence of low‐conductivity regions and measurable changes in the electrical behavior of a secondary Ba–Ti–Si–O inclusion within the ceramic matrix. Line‐scan analyses revealed a reduction in domain contrast and the disappearance of less prominent domains, accompanied by a decrease in local current peaks across grain interiors and boundaries. These findings provide new insights into the degradation mechanisms of PTCR ceramics and suggest strategies to improve their long‐term stability and performance in practical applications.