The electrodeposition of chromium in programmed direct current (DC) was
investigated in the regime of high current density (77Adm -2 ). Chromium was
deposited in a system of plane-parallel electrodes in chromic-sulphuric acid
solution, on specimens of steell, during one hour. The basic properties of
deposits, the appearance, thickness, morphology, microhardness and
brightness were investigated. Thicknesses of the coatings (between 28 and 82
mm) were measured at 36 points on the surface of the specimens by the
non-destructive ferromagnetic method. Based on these results, graphic models
of the surface distribution of the deposits were made. Three ranges of
thickness could be seen on the model (range 1 - average thickness 29.87 mm,
range 2 - average thickness 42.0 mm and range 3 - thickness 67.87 mm). For
the whole speciments, the average thickness was 50.8 mm with a coefficient
of variation of 0.3281. The basic properties of the coating, morphology and
brightness changed depending on the deposit thickness being very different
at different points of one and the same specimen. For this reason these
chromium deposits should not be considered reliable protection against
aggressive gases at high pressures and temperature of systems from corrosion,
wear and erosion.
Optical properties of direct current glow discharge plasmas at high pressures
