Formation of Wear- and Corrosion-Resistant Coatings by the Microarc Oxidation of Aluminum

Markov, M. A.; Bykova, A. D.; Красиков, А. В.; Farmakovskii, B. V.; Gerashchenkov, D. A.

doi:10.1007/s11148-018-0207-3

Cited by 22 publications

(6 citation statements)

References 9 publications

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“…The dielectric properties of coatings on AK6 alloy formed with a microarc oxidation method in two electric modes in alkaline-silicate electrolytes are estimated in [8][9]. It is shown that both modes, a galvanostatic mode and an arbitrarily falling power mode in alternating current circuits, make it possible to obtain coatings with a thickness of 30-60 μm, with sufficiently high electrophysical parameters: bulk specific resistance ρv = 3-9 × 10 9 Ω m and dielectric strength E = 9-14 V/μm.…”

Section: Analysis Of Research and Publicationsmentioning

confidence: 99%

Tribological properties of anode-spark coatings on aluminum alloys

Dykha

Babak

Makovkin

et al. 2022

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It is established that at present the technology of anode-spark coatings in general is well studied. However, the lack of recommendations for the choice of modes of technological processes and tribological characteristics in different operating conditions limit the widespread introduction of this technology. The task of this work was to analyze the processes of anode-spark coatings, improve technology and study the wear resistance of samples processed by this and traditional anode technology. The development of technology for the application of protective coatings on valve metals in the conditions of spark discharge included the choice of electrolyte and mode of operation of the bath: voltage, current density, hydrodynamic conditions and other parameters. Wear resistance tests were performed on a special installation. Structurally, the installation is made in two positions, which allows you to test two samples with different load conditions at a constant sliding speed. The design of the installation implements the friction scheme of the liner shaft. The study of anode-spark coatings in the mode of limiting lubrication was studied in the environment of industrial oil. The wear criterion was the weight wear of the samples according to the results of weight measurements before and after wear. It is established that prolonged electrolysis in the conditions of sparking leads to the formation of anode coatings that exceed in their properties the films obtained by non-sparking oxidation. Comparative studies of the wear resistance of anode-spark coatings and galvanic anode coatings under the same test conditions showed that the wear of anode-spark coatings is almost twice lower for the entire load range. The considered technology is recommended for increase of wear resistance of elements of devices from the aluminum alloys working in the conditions of corrosion and mechanical wear

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Section: Analysis Of Research and Publicationsmentioning

confidence: 99%

Tribological properties of anode-spark coatings on aluminum alloys

Dykha

Babak

Makovkin

et al. 2022

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“…For carrying out the comparative tests to estimate energy efficiency and the consumption of tool material when obtaining parts with a given roughness, samples with ceramic coatings were made, with the use of various electrolytes according to the improved and traditional technology (Table 2). The composition of electrolytes and current modes of formation were selected in the widest possible range [10], for an objective estimation of the effectiveness of the proposed technology.…”

Section: Techniques and Equipment Usedmentioning

confidence: 99%

The Peculiar Properties of Economically Effective Technology of Forming of the Ceramic Coating Based on Aluminum Oxide

Болотов

Новиков

Новикова

2022

KEM

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Increasing of the hardness and wear resistance of the working surfaces of parts made of aluminum and its alloys is achieved by modifying them by the method of micro-arc oxidation in alkalescent electrolytes. This technology consists in the formation of a highly hard and wear-resistant ceramic layer by means of the spark discharges and implies an enormous investment of energy and time. The finished product surface roughness in numerous cases fails to meet the requirements, and demands additional machining. High hardness of the hardened layer, at the same time causes an increased wear of the processing tool. A method in which the technological process is carried out in two stages allows improving energy efficiency of this technology. At the beginning, when using an electrolyte with a high content of liquid glass, a primary oxide layer, consisting predominantly of silicon oxide, is formed. At the next stage of micro arc oxidation, the content of the liquid glass in the electrolyte decreases, which allows the formation of predominantly high rigid aluminum oxide in ceramic layer. This technology can significantly reduce the time of formation of a coating and reduces energy consumption. To reduce the processing tool wear it is proposed to keep the surface of the modified by oxidation workpiece in hydrofluoric acid for 5 - 30 minutes. This operation allows to reduce the hardness of the upper layer, consisting mainly of silicates, without affecting the lower layer, formed mainly of aluminum oxide. As a result, it is possible to receive the required surface micro geometry with less tools wear, less time and energy. There was achieved a reduction of time for getting the finished product by 1.6 - 2.3 times, electricity by 2 - 2.7 times, tool wear by 8.7 - 12 times.

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“…Compared with the traditional anodic oxidation layer, [ 23 ] the modified layer of plasma electrolytic oxidation (PEO) has better compactness, a more stable structure, and better hot salt corrosion resistance. [ 24,25 ] At the same time, we found that when the thickness of the PEO film ranged from hundreds of nanometers to several microns, the fatigue strength of the titanium alloy was not significantly affected. [ 26,27 ] However, the fatigue performance of the titanium alloy decreased significantly when the thickness of the film was more than 10 μm.…”

Section: Introductionmentioning

confidence: 96%

Effect of plasma electrolytic oxidation on the hot salt corrosion fatigue behavior of the TC17 titanium alloy

Shi

Liu

Zhang

et al. 2021

Materials & Corrosion

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In this paper, the effect of plasma electrolytic oxidation (PEO) on the hot salt corrosion fatigue (HSCF) behavior of the TC17 titanium alloy at 420°C was investigated. Through microstructure characterization and fatigue fracture analysis, combined with a comparative study of its hot salt corrosion behavior, the mechanism of PEO on HSCF behavior was also investigated. The results showed that the high‐temperature fatigue resistance of the TC17 titanium alloy was significantly reduced by the deposition of 0.4 mg/cm2 of solid NaCl compared with that without a salt coating. This behavior was observed because the corrosion pits caused by hot salt corrosion promoted the initiation of fatigue cracks, and hydrogen penetration promoted the growth of fatigue cracks. However, the HSCF resistance of the TC17 alloy with the PEO ceramic coating could be effectively increased. This was because the PEO ceramic coating with high bonding strength and good compactness effectively inhibited hot salt corrosion damage and delayed the formation of the resident slip zone and hydrogen permeation, thereby inhibiting the initiation and propagation of fatigue cracks.

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Formation of Wear- and Corrosion-Resistant Coatings by the Microarc Oxidation of Aluminum

Cited by 22 publications

References 9 publications

Tribological properties of anode-spark coatings on aluminum alloys

Tribological properties of anode-spark coatings on aluminum alloys

The Peculiar Properties of Economically Effective Technology of Forming of the Ceramic Coating Based on Aluminum Oxide

Effect of plasma electrolytic oxidation on the hot salt corrosion fatigue behavior of the TC17 titanium alloy

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