Tribological Properties of the Oxide Coatings Produced onto 6061-T6 Aluminum Alloy in the Hard Anodizing Process

Abstract The subject of the presented work was the analysis of the influence of the distance between the electrodes using in the coating process on the tribological properties of oxide coatings. Oxide coatings were prepared on EN AW-5251 aluminum alloy samples. The samples surfaces were subjected to hard anodizing process in a multicomponent electrolyte based on sulfuric acid with an addition of organic acids. Anodizing was carried out with a constant electric charge density of 180 A·min/dm2. The distances between the electrodes for subsequent samples increased every 0.125 m up to 1 m. The tribological partner in a sliding couple with oxide layers was pin of PEEK/BG. Tribological tests were conducted on a T-17 tester in reciprocating motion, in technically dry friction conditions. Before and after tribological test, examination of the geometrical structure of counter-specimens’ surface was carried out using the Form Talysurf contact profilographometer, via a 3D method. The most satisfactory tribological parameters were obtained for the PEEK/BG association with the coating produced at a distance between the electrodes equal to 0.25 m.

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THE EFFECT OF ELECTROLYTE TEMPERATURE AND SEALING SOLUTION IN ANODIZING OPERATION ON HARDNESS AND WEAR BEHAVIOR OF 7075 -T6 ALUMINUM ALLOY

Surface Review and Letters ◽

10.1142/s0218625x18501433 ◽

2019 ◽

Vol 26 (02) ◽

pp. 1850143

Author(s):

SAEED NIYAZBAKHSH ◽

KAMRAN AMINI ◽

FARHAD GHARAVI

Keyword(s):

Weight Loss ◽

Wear Resistance ◽

Aluminum Alloy ◽

Wear Behavior ◽

Anodic Oxide ◽

Boiling Water ◽

Electrolyte Temperature ◽

Oxide Coatings ◽

Sodium Dichromate ◽

Pin On Disk

Anodic oxide coatings are applied on aluminum alloys in order to improve corrosion resistance and to increase hardness and wear resistance. In the current study, a hard anodic coating was applied on AA7075-T6 aluminum alloy. To survey the anodizing temperature (electrolyte temperature) effect, three temperatures, namely, [Formula: see text]C, 0∘C and 5∘C were chosen and the samples were sealed in boiling water and sodium dichromate to study the role of sealing. For measuring the oxide coatings porosity and hardness and also for comparing the samples’ wear resistance field-emission scanning electron microscopy (FESEM), microhardness test and pin-on-disk method were utilized, respectively. The results showed that by increasing the anodizing temperature, hardness and consequently wear resistance decreased so that hardness and weight loss in the samples with no sealing decreased from 460[Formula: see text]HV and 0.61[Formula: see text]mg at [Formula: see text]C to 405 and 358[Formula: see text]HV and 1.05 and 1.12[Formula: see text]mg at 0∘C and 5∘C, respectively, which is due to the porosity increment by increasing the anodizing temperature. Also, sealing in boiling water and dichromate contributed to soft phases and coating hydration, which resulted in a decrease in hardness and wear resistance. Hardness and weight loss in the coated samples at [Formula: see text]C decreased from 460[Formula: see text]HV and 0.61[Formula: see text]mg in the samples with no sealing to 435 and 417[Formula: see text]HV and 0.72 and 0.83[Formula: see text]mg in the samples sealed in boiling water and dichromate, respectively.

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Dry Sliding Behavior of an Aluminum Alloy after Innovative Hard Anodizing Treatments

Materials ◽

10.3390/ma14123281 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3281

Author(s):

Chiara Soffritti ◽

Annalisa Fortini ◽

Anna Nastruzzi ◽

Ramona Sola ◽

Mattia Merlin ◽

...

Keyword(s):

Aluminum Alloy ◽

Aluminum Substrate ◽

Dry Sliding ◽

Aluminum Oxides ◽

Wear Rates ◽

Anodic Aluminum ◽

Hard Anodizing ◽

Pin On Disc ◽

Diffuse Reflectance Infrared ◽

Wear Tests

This work evaluates the dry sliding behavior of anodic aluminum oxides (AAO) formed during one traditional hard anodizing treatment (HA) and two golden hard anodizing treatments (named G and GP, respectively) on a EN AW-6060 aluminum alloy. Three different thicknesses of AAO layers were selected: 25, 50, and 100 μm. Prior to wear tests, microstructure and mechanical properties were determined by scanning electron microscopy (VPSEM/EDS), X-ray diffractometry, diffuse reflectance infrared Fourier transform (DRIFT-FTIR) spectroscopy, roughness, microhardness, and scratch tests. Wear tests were carried out by a pin-on-disc tribometer using a steel disc as the counterpart material. The friction coefficient was provided by the equipment. Anodized pins were weighed before and after tests to assess the wear rate. Worn surfaces were analyzed by VPSEM/EDS and DRITF-FTIR. Based on the results, the GP-treated surfaces with a thickness of 50 μm exhibit the lowest friction coefficients and wear rates. In any case, a tribofilm is observed on the wear tracks. During sliding, its detachment leads to delamination of the underlying anodic aluminum oxides and to abrasion of the aluminum substrate. Finally, the best tribological performance of G- and GP-treated surfaces may be related to the existence of a thin Ag-rich film at the coating/aluminum substrate interfaces.

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Influence of load and reinforcement content on selected tribological properties of Al/SiC/Gr hybrid composites

Production Engineering Archives ◽

10.30657/pea.2018.18.03 ◽

2018 ◽

Vol 18 (18) ◽

pp. 18-23 ◽

Cited By ~ 3

Author(s):

Sandra Veličković ◽

Slavica Miladinović ◽

Blaža Stojanović ◽

Ružica R. Nikolić ◽

Branislav Hadzima ◽

...

Keyword(s):

Aluminum Alloy ◽

Friction Coefficient ◽

Wear Rate ◽

Tribological Properties ◽

Metal Matrix ◽

Hybrid Composites ◽

Tribological Characteristics ◽

Volume Fractions ◽

Sic Particles ◽

The Matrix

Abstract Hybrid materials with the metal matrix are important engineering materials due to their outstanding mechanical and tribological properties. Here are presented selected tribological properties of the hybrid composites with the matrix made of aluminum alloy and reinforced by the silicon carbide and graphite particles. The tribological characteristics of such materials are superior to characteristics of the matrix – the aluminum alloy, as well as to characteristics of the classical metal-matrix composites with a single reinforcing material. Those characteristics depend on the volume fractions of the reinforcing components, sizes of the reinforcing particles, as well as on the fabrication process of the hybrid composites. The considered tribological characteristics are the friction coefficient and the wear rate as functions of the load levels and the volume fractions of the graphite and the SiC particles. The wear rate increases with increase of the load and the Gr particles content and with reduction of the SiC particles content. The friction coefficient increases with the load, as well as with the SiC particles content increase.

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Effect of ultrasonic melt treatment on the tribological behavior of 7075 aluminum alloy

Materials Testing ◽

10.1515/mt-2020-621214 ◽

2020 ◽

Vol 62 (12) ◽

pp. 1243-1250

Author(s):

Fahri Vatansever ◽

Alpay Tamer Erturk ◽

Erol Feyzullahoglu

Keyword(s):

Surface Roughness ◽

Aluminum Alloy ◽

Tribological Properties ◽

Lower Surface ◽

Test Method ◽

Ring Test ◽

7075 Aluminum Alloy ◽

Melt Treatment ◽

Ultrasonic Melt Treatment ◽

Worn Surfaces

Abstract In this study, the tribological properties of 7075 aluminum alloy produced by ultrasonic melt treatment (UST) are investigated. Tribological properties of untreated and ultrasonically treated samples under dry and lubricated sliding conditions were analyzed experimentally by the block on ring test method. Worn surfaces of untreated and ultrasonically treated samples were scanned by 3D optical profilometer and analyzed to search out wear characteristics in the material. Furthermore, microstructural examinations were conducted to investigate the beneficial effects of UST on the microstructural properties of the alloy using optical and scanning electron microscopy. According to the results obtained, UST refines the α-Al phase of the alloy and disperses precipitates to grain boundaries more uniformly. Also, hardness and density of the alloy increased through the effect of UST. Due to these favorable effects, the wear resistance of the alloy increased and the worn surfaces of the ultrasonically treated samples exhibited lower surface roughness according to 3D surface roughness measurements.

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