Anodic Aluminum Oxide Surface Research Articles

The State of Tin in Tin‐Anodized Aluminum

We have used Mössbauer spectroscopy of Sn119 to determine the state of the tin in anodized aluminum surfaces which are colored brown by anodization in acidic stannous sulfate solutions. We conclude that the tin is present predominantly in the form of tin metal.

Oxide thickness measurements by infrared ellipsometry

Current interest' in anodized aluminum surfaces as substrates for adhesive bonding has created a need to measure the properties of the oxide layer in a non-contacting manner. Visible light ellipsometry is a very sensitive non-contacting technique for measuring the thickness of very thin films on smooth surfaces whose optical constants are known. However, the method is limited to film thicknesses which are generally less than 2000 Å and validity is lost when there is appreciable scattering caused by the roughness of the substrate and the structure of the oxide itself. These objections become much less severe if the operating wavelength is in the infrared region. Such an infrared ellipsometer has been developed to measure the thickness of oxides produced by anodization of aluminum with production-finished surfaces. The instrument operates with a 10.6 μm beam from a low power CO 2 laser and uses a 6328 Å beam from a He-Ne laser for alignment and location of the measurement region. The oxides were formed on unclad 7075 aluminum by anodization in an ammonium pentaborate solution at constant current to termination voltages of from 25 to 275 V in 25 V increments. The measured ellipsometric quantities Δ and ψ were used to compute the corresponding metal oxide film thicknesses using a complex refractive index N = 2.39− i41.36 for the substrate. The results for a film refractive index of 1.50 were in close agreement with those measured with a scanning electron microscope. Elemental concentration profiles for each surface were made by Auger electron spectroscopy.

Measurement of Shock and Free Surface Velocities with Anodized Aluminum Switches

The utilization of an anodized aluminum surface as a shorting switch for shock time of arrival measurements was found to have several advantages over methods previously used. These pressure sensitive switches are stable up to 450°C, have breakdown times less than 10 nsec, and can be made insensitive to elastic shocks of about 4 kilobar amplitude. They can also be adapted to many experimental configurations.

Special Silicone Treatments of Anodized Aluminium Surfaces

SummaryIn a new process for reducing adhesion of ice to aluminium alloy used in refrigerators, an application of a special organosiloxane to the anodized surface is followed by heat treatment. Three organohydrosiloxanes and three variations of heat treatment were examined in respect of their effect on resistance to abrasion and corrosion. The treatments were more effective with 2S grade aluminium than with 3S. The abrasion resistance was increased about tenfold and it is considered that this improvement results from chemical bonding between the organohydrosiloxanes and anodized layers.

Appearance Criteria for Uncolored Anodized Aluminum Surfaces

Appearance Criteria for Uncolored Anodized Aluminum Surfaces

Special Silicone Treatments of Anodized Aluminium Surfaces

SummaryIn a new process for reducing adhesion of ice to aluminium alloy used in refrigerators, an application of a special organosiloxane to the anodized surface is followed by heat treatment. Three organohydrosiloxanes and three variations of heat treatment were examined in respect of their effect on resistance to abrasion and corrosion. The treatments were more effective with 2S grade aluminium than with 3S. The abrasion resistance was increased about tenfold and it is considered that this improvement results from chemical bonding between the organohydrosiloxanes and anodized layers.