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Local porous aluminum anodizing with a photolithography mask has been carried
out at anodic voltages varying from 15 to 200 V in sulfuric acid electrolytes. Record anodic
voltages at room temperature have been achieved leading to new parameters of porous
alumina such as interpore distance up to 320 nm, forming cell factor up to 1.2 nm/V,
thickness expansion factor up to 3.5, porosity up to 1%, sulfur concentration up to 7.7 at.%. A
central angle of porous alumina cells has been measured in concave points as well as in peak
points of porous alumina cells at the border with aluminum. The measurements have shown
that central angles can reach 90œ at anodic voltages larger than 100 V. The electric field
distribution in porous alumina cells has been simulated for different central angles. It is found
that the electric field reaches 2.7 × 1010 V/m in the layers with a porosity of 1% in growing
alumina.
Keywords: : combustion, explosion, mechanical pulse, microthruster, multichip structure, nanoporous silicon |
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