Researches on macroscopic fouling behavior and micromorphology are usually conducted separately. In this paper

the relationship between the macroscopic fouling behavior and micromorphology on different materials is established. A direct fractal-characterization approach based on the micrographs of calcium carbonate fouling crystals is presented. The box-counting method is used to characterize the fouling crystals. For fractal measurements

t

-distribution tests of linear regression hypothesis are performed at the significance level of 0.01. If all listed absolute

t

-statistics with the minimum of 164 are higher than the corresponding

t

value

the fouling crystals are determined as fractal

with a confidence level of 99%. The fractal dimensions obtained from the micrographs of different visual fields of a specimen are demonstrated to be almost identical

with maximum and minimum relative values of 4.42% and 0.75%

respectively

and standard deviations ranging from 0.0062 to 0.0266. The irregularity of the crystal morphology indicates larger fractal dimensions. Comparison and analysis of the relationship between macroscopic fouling behavior and mi

cromorphology show that the larger fractal dimension of crystal morphology suggests a small amount of surface fouling. Thus

the reasons for the differences in the macroscopic fouling behaviors of different materials are revealed geometrically.