Structural materials tempered martensitic steels

As with chemical etches, developing optimum conversion coatings requires assessment of the microstructure of the steel. Correlations have been found between the microstructure of the substrate material and the nature of the phosphate films formed. Aloru et al. demonstrated that the type of phosphate crystal formed varies with the orientation of the underlying steel crystal lattice [154]. Fig. 32 illustrates the different phosphate crystal morphologies that formed on two heat-treated surfaces. The fine flake structure formed on the tempered martensite surface promotes adhesion more effectively than the knobby protrusions formed on the cold-rolled steel. 

Another important two-phase structure in steel is observed in tempered martensite. The parent material, martensite, is a supersaturated single-phase... 

A. Abdollah-Zadeh, A. Salemi, and H. Assadi, "Mechanical behavior of CrMo steel with tempered martensite and ferrite-bainite-martensite microstructure". Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 483-84, 2008 pp. 325-328. 

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