**Author details**


Figure 11. Intensity‐angle, intensity‐sin2(Psi) fit curves residual stress values calculated from

(Psi) fit curves residual stress values calculated from

The coatings are compared with respect to the conventional hard chromium coatings. In regard to the electrochemical behavior, the chromium‐carbon black composite coatings heat‐ treated under nitrogen atmosphere showing a rehabilitated crack‐free microstructure, exhibited better corrosion resistance than the conventional hard chromium structures. Therefore, the increase in corrosion potential suggests improvement of corrosion resistance due to the formation of carbide/nitride. Characteristic properties such as hardness and

The coatings are compared with respect to the conventional hard chromium coatings. In regard to the electrochemical behavior, the chromium-carbon black composite coatings heat-treated under nitrogen atmosphere showing a rehabilitated crack-free microstructure, exhibited better corrosion resistance than the conventional hard chromium structures. Therefore, the increase in corrosion potential suggests improvement of corrosion resistance due to the formation of carbide/nitride. Characteristic properties, such as hardness, and modulus of elasticity are determined for carbide and nitride formed composite coatings. It is observed that the following phase transformations support the recovery of friction-wear characteristics and accordance of substrate-coating interface belonging to the material. According to the detailed inspections, it is assigned that the definite results directly correlate with both the magnitude and the direction of the residual stresses. As a result, the corrosion behaviour and the mechanical properties of the in-situ electro codeposited coatings are believed to be controlled by microstructure and surface properties of the metallic chromium layer, which is modified by the formation of carbide and/or nitride phase, and can be used for many engineering applications instead of

Finally, as another mechanical result, residual stress values of the coatings were measured for these electro codeposited composites in this research. It is stated that the reference sample, which has only the pure metallic chromium phase, showing tensile stress in a high level as it was expected. Against, residual stresses are compressive and found to be about ‐ 380MPa and ‐664MPa for the Sample‐A and ‐N, respectively, while it is about +225MPa for Sample‐R (reference coating). The reason for the decrease of residual stress is given as the increase in the volume of the in‐situ transformed ceramic phase structures (see Figure 11 for

Only a little amount of cohesive damage occurred. In contrast, for the nitride formed samples this effect was seen much less. The coherence between the coating and the substrate is explained and supported by the diffusion of C atoms from the substrate to the coating and

the formation of carbide interface for the samples.

details) [12].

78 Electrodeposition of Composite Materials

**Figure 11.** Intensity-angle, intensity-sin2

traditional metallic coatings.

Orkut Sancakoğlu\*

Address all correspondence to: orkut.sancakoglu@deu.edu.tr

Orkut Sancakoğlu, Dokuz Eylül University, Metallurgical and Materials Engineering Department, Izmir, Turkey
