required for thicker coatings formed in sulfuric and organic acid. The anodizing current varies with the area of aluminium being anodized and typically ranges from 30 to 300 A/m2. Aluminium anodizing (eloxal or Electrolytic Oxidation of Aluminium) is usually performed in an acidic solution, typically sulphuric acid or chromic acid, which slowly dissolves the aluminium oxide. The acid action is balanced with the oxidation rate to form a coating with nanopores, 10–150 nm in diameter. These pores are what allow the electrolyte solution and current to reach the aluminium substrate and continue growing the coating to greater thickness beyond what is produced by auto-passivation. These pores allow for the dye to be absorbed, however, this must be followed by sealing or the dye will not stay. Dye is typically followed up by a clean nickel acetate seal. Because the dye is only superficial, the underlying oxide may continue to provide corrosion protection even if minor wear and scratches break through the dyed layer. Conditions such as electrolyte concentration, acidity, solution temperature, and current must be controlled to allow the formation of a consistent oxide layer. Harder, thicker films tend to be produced by more concentrated solutions at lower temperatures with higher voltages and currents. The film thickness can range from under 0.5 micrometres for bright decorative work up to 150 micrometres for architectural applications. Dual-finishing Anodizing can be performed in combination with chromate conversion coating. Each process provides corrosion resistance, with anodizing offering a significant advantage when it comes to ruggedness or physical wear resistance. The reason for combining the processes can vary, however, the significant difference between anodizing and chromate conversion coating is the electrical conductivity of the films produced. Although both stable compounds, chromate conversion coating has a greatly increased electrical conductivity. Applications where this may be useful are varied, however the issue of grounding components as part of a larger system is an obvious one. The dual finishing process uses the best each process has to offer, anodizing with its hard wear resistance and chromate conversion coating with its electrical conductivity. The process steps can typically involve chromate conversion coating the entire component, followed by a masking of the surface in areas where the chromate coating must remain intact. Beyond that, the chromate coating is then dissolved in unmasked areas. The component can then be anodized, with anodizing taking to the unmasked areas. The exact process will