Measurement of coherency states of metal—ceramic interfaces by HREM image processing

Internal interfaces between metals and ceramics, recorded by high-resolution electron microscopy (HREM), are examined with respect to their coherency relationship between the two sublattices. Four different image processing techniques with complementary properties are introduced and compared, such as spatially resolved space frequency analysis, a moiré technique, and two variations of cross correlation in one and two dimensions. Two experimental images of interfaces are examined, including a semi-coherent interface with large misfit between Al-rich Ni and γ-Al2O3, and secondly an incoherent interface between Cu and α-Al2O3.