Investigation of the electrolyte volume effect in the anodizing process on optical-thermal, wear and corrosion properties of the black anodic coating

Document Type : Original Article

Authors
mojtaba forghani 1
Maedeh sadat Zoei 2
Mohammad Reza Pakmanesh 3
mohammad chiani 4
Saeed Asghari 5
1 Iran Space Research Center-Researcher expert
2 Faculty Member/Institute of Materials and Energy/ Iranian Space Research Center/ Isfahan/ Iran
3 Institute of Materials and Energy, Iranian Space Research Center, Isfahan, Iran
4 Institute of Materials and Energy, Iranian Space Research Center
5 Iranian Space Research Center
10.22034/jssta.2023.392334.1119
Abstract
The sandwich panel is an important element of the satellite structure which various metal and composite materials are used to make its faces. Anodizing is used as a conversion coating in order to achieve the final properties of the panel surface and stability in the space environment. Anodizing is an electrochemical process in which an oxide layer is formed using electricity. During the anodizing process, concentration polarization is created and the process is stopped when the limiting current resulting from the movement of electrical charges between the surface of the anodic layer and the electrolyte is increased. By stopping the process without spending enough time to obtain a sufficient thickness for the colorability, a black anodic layer for use in space coatings is not achieved. In this research, by performing the anodizing process in four container of 250, 500, 2000 and 40000 cm3, the effect of the volume of the electrolyte on the wear and corrosion and optical-thermal properties of the layer obtained in each of the processes were investigated. Optical- thermal properties were investigated by infrared emission coefficient and solar absorption tests, wear resistance by pin on disk test and corrosion resistance by salt spray test. The results showed that with the increase in the volume of the electrolyte caused by the increase in the volume of the container, the stopping time of the process increases. The results of measuring optical-thermal and wear and corrosion properties for three container with volumes of 500, 2000 and 40000 cm3 showed that with the increase in the volume of electrolyte and the process completion time of the process, the thickness of the anodic layer increased, which improved the optical-thermal properties, corrosion and wear resistance.
Keywords
Conversion coating# Anodizing# Concentration polarization# Optical
thermal properties# corrosion resistance# wear resistance
Subjects
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  • Receive Date 08 April 2023
  • Revise Date 17 May 2023
  • Accept Date 17 June 2023