Abstract:In this work, plasma electrolytic oxidation coating was formed on aluminium alloy in a cheap and inexpensive electrolyte to improve its wear resistance. It was found the micro-hardness of coatings increased first and then decreased with increasing the oxidised time. It was showed that the specimen treated under the time of 35 minutes exhibited the highest micro-hardness and lowest wear loss. The surface and cross-sectional morphology indicated that the coatings have a dense structure with low porosity. The pre… Show more
“…The areas removed were of 23,300, 30,200, 32,900 and 41,600 mm 2 , respectively, for the angles of 20, 40, 60 and 90°. The images at high magnification show that the deformation caused on the substrate change from that of shear to compression once the coating is removed, as it would be expected on ductile materials [16][17][18].…”
Section: Resultsmentioning
confidence: 99%
“…The areas removed were of 23,300, 30,200, 32,900 and 41,600 mm 2 , respectively, for the angles of 20, 40, 60 and 90°. The images at high magnification show that the deformation caused on the substrate change from that of shear to compression once the coating is removed, as it would be expected on ductile materials [16-18]. Figure 7 Damage made on the surface of coatings of 80 (a), 110 (b), 120 (c) and 150 (d) µm in thickness after testing the samples following the modified test ASTM G76-04 [12].…”
Aluminium alloys lack resistance to wear when subjected to erosive conditions. A solution has been the development of ceramic coatings on the surface of the alloy to sustain wear. This work reports the study conducted to evaluate the resistance to abrasion by sand of plates of an aluminium alloy processed to develop ceramic coatings of different thicknesses used in the manufacture of silica sand cores. The samples were subjected to erosion by either silica sand or with the mixture of sand and binder that were blown on the surface of the coated plates to reproduce the conditions to which core moulds are subjected to during sand-core manufacturing. The experimental design contemplated changing the angle of impingement of the plate as well as the pressure and velocity of the sand stream. The results of the tests show the feasibility of replacing traditional tool steel moulds by aluminium coated ones.
“…The areas removed were of 23,300, 30,200, 32,900 and 41,600 mm 2 , respectively, for the angles of 20, 40, 60 and 90°. The images at high magnification show that the deformation caused on the substrate change from that of shear to compression once the coating is removed, as it would be expected on ductile materials [16][17][18].…”
Section: Resultsmentioning
confidence: 99%
“…The areas removed were of 23,300, 30,200, 32,900 and 41,600 mm 2 , respectively, for the angles of 20, 40, 60 and 90°. The images at high magnification show that the deformation caused on the substrate change from that of shear to compression once the coating is removed, as it would be expected on ductile materials [16-18]. Figure 7 Damage made on the surface of coatings of 80 (a), 110 (b), 120 (c) and 150 (d) µm in thickness after testing the samples following the modified test ASTM G76-04 [12].…”
Aluminium alloys lack resistance to wear when subjected to erosive conditions. A solution has been the development of ceramic coatings on the surface of the alloy to sustain wear. This work reports the study conducted to evaluate the resistance to abrasion by sand of plates of an aluminium alloy processed to develop ceramic coatings of different thicknesses used in the manufacture of silica sand cores. The samples were subjected to erosion by either silica sand or with the mixture of sand and binder that were blown on the surface of the coated plates to reproduce the conditions to which core moulds are subjected to during sand-core manufacturing. The experimental design contemplated changing the angle of impingement of the plate as well as the pressure and velocity of the sand stream. The results of the tests show the feasibility of replacing traditional tool steel moulds by aluminium coated ones.
“…In particular, low abrasive wear resistance during friction was reported by Udoye et al [ 1 ]. These properties of aluminum alloys can be enhanced by surface hardening performed by micro-arc oxidation (MAO), plasma electrolytic oxidation (PEO) and deposition of hard materials by electroplating [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ], or by thermal spraying of hard coatings based on tungsten, titanium, and tantalum carbides with metal bond. The most common method for the thermal spraying of WC-based coatings applied in industry is the High Velocity Oxygen Fuel (HVOF) process [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”
One of the methods of local improvement of the wear resistance of aluminum alloy parts is the deposition of hard tungsten carbide-based coatings on the surfaces subjected to intense external influence. This paper is devoted to the characterization of the WC–10Co–4Cr (wt.%) coating deposited on an Al–4Cu–1Mg (wt.%) alloy by the detonation spray method. In comparison with the common thermal spray techniques like High Velocity Oxygen Fuel (HVOF) or Atmospheric Plasma Spraying (APS), the heat input delivered to the substrate during detonation spray is significantly lower, that is especially important in case of coating deposition on aluminum alloys. The paper presents the results of morphology investigation, microstructure, phase composition, microhardness, and cohesive strength of deposited carbide-based detonation spray coating. Results showed that the coating has a porosity less than 0.5% and the carbide grain refinement down to the submicron size during coating deposition was detected. According to the investigation, the variation of spraying distance from 270 to 230 mm does not influence on the coating microstructure and composition.
“…Other ways of modifying the surface are ion implantation [26][27][28][29][30][31], electrophoretic deposition [32], and laser surface treatment [33][34][35][36]. Development of materials engineering and technology in the following years has allowed new challenges to be posed regarding surface engineering, including, but not limited to, fabrication of porous coatings by the Plasma Electrolytic Oxidation (PEO) or Micro Arc Oxidation (MAO) [37] on light metals and alloys, such as aluminum [38][39][40][41][42][43][44] and its alloys [45][46][47][48][49][50][51][52][53][54], magnesium [38,39,[55][56][57] and its alloys [58][59][60][61][62][63][64], titanium and its alloys [57,[65][66][67][68][6...…”
This paper shows that the subject of porous coatings fabrication by Plasma Electrolytic Oxidation (PEO), known also as Micro Arc Oxidation (MAO), is still current, inter alia because metals and alloys, which can be treated by the PEO method, for example, titanium, niobium, tantalum and their alloys, are increasingly available for sale. On the international market, apart from scientific works/activity developed at universities, scientific research on the PEO coatings is also underway in companies such as Keronite (Great Britain), Magoxid-Coat (Germany), Mofratech (France), Machaon (Russia), as well as CeraFuse, Tagnite, Microplasmic (USA). In addition, it should be noted that the development of the space industry and implantology will force the production of trouble-free micro- and macro-machines with very high durability. Another aspect in favor of this technique is the rate of part treatment, which does not exceed several dozen minutes, and usually only lasts a few minutes. Another advantage is functionalization of fabricated surface through thermal or hydrothermal modification of fabricated coatings, or other methods (Physical vapor deposition (PVD), chemical vapor deposition (CVD), sol-gel), including also reoxidation by PEO treatment in another electrolyte. In the following chapters, coatings obtained both in aqueous solutions and electrolytes based on orthophosphoric acid will be presented; therein, dependent on the PEO treatment and the electrolyte used, they are characterized by different properties associated with their subsequent use. The possibilities for using coatings produced by means of plasma electrolytic oxidation are very wide, beginning from various types of catalysts, gas sensors, to biocompatible and antibacterial coatings, as well as hard wear coatings used in machine parts, among others, used in the aviation and aerospace industries.
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