This paper presents the result of the brazed Iron-chromium-aluminum alloy (Fecralloy) with nickel filler metal (MBF20). The heat plates with the machined 2 mm diameter channels were brazed using 60 µm thick MBF20. In the experiment, the brazing bonding was performed at three different temperatures, and the SEM-EDS images of the cross sections were acquired to analyze. By performing image processing, the change of the filler metal thickness was estimated, and the thickness increased from 53.8 µm, 64.1 µm, and 115.8 µm at 900 • C, 950 • C and 1000 • C, respectively. In addition, the image-processed distributions of Cr x B y and Ni x Al y phases with the change of bonding temperatures were quantified. The image processing methods in this work are proposed to be used for quantitative analysis.