TiN coatings modified by an interlayer of electroplated chromium on mild steel

TiN films on mild steel were deposited by reactive d.c. magnetron sputtering; electroplated chromium was incorporated as an interlayer. Surface hardness, measured by the Knoop indentation method under a load of 25 gf. phase analysis by the X-ray diffraction method and corrosion behaviour by the potentiodynamic measurement technique of these coatings have been evaluated. Surface hardness values were found to increase from about 1000-1100 for TiN coatings on mild steel to about 1800-1900 (HK25) for TiN coatings with chromium as interlayer. Potentiodynamic corrosion tests, performed in 1N H2SO4 solutions, have shown that with chromium interlayer the corrosion resistance increases significantly as compared to TiN only sputtered coatings on mild steel samples. No spalling of TiN coatings was observed during full sweep voltage of -1000 mV to +1000 mV when they were tested with a chromium interlayer

Electrochemical Deposition and Dissolution of Alloys and Metal Composites—Fundamental Aspects

It is general experience in materials science that alloys can exhibit qualities that are unobtainable with the parent metals. This is true of electroplated deposits as well. Thus, such properties as hardness, tensile strength, ductility, Young’s modulus, density, corrosion resistance, solderability, wear resistance, and antifriction service may be enhanced. Also, special properties not exhibited by the parent metals can be obtained, such as high magnetic permeability or other desired magnetic and electrical properties, amorphous structure, etc. Alloy plates may be more suitable than the parent metals for subsequent electroplate overlays and conversion chemical treatments