Surface modification of plasma sprayed Al2O3–40wt% TiO2 coatings by pulsed Nd:YAG laser melting

Sure, Jagadeesh; Shankar, A. Ravi; Mudali, U. Kamachi

doi:10.1016/j.optlastec.2012.09.025

Cited by 21 publications

(12 citation statements)

References 46 publications

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“…A particularly great potential lies in the technologies that use concentrated heat sources, e.g. laser beam, plasma jet, electron beam or electric arc [7][8][9][10][11][12][13]. The efforts to use concentrated heat sources in practice in surface engineering taken at the end of the 20 th century determined new directions and trends in the process of forming the surface layers of metals and metal alloys.…”

Section: Introductionmentioning

confidence: 99%

Surface modification of AZ91 magnesium alloy using GTAW technology

Iwaszko

Strzelecka

Kudła

2017

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. In this study, surface remelting treatment of the AZ91 magnesium alloy by means of welding using a non-consumable electrode in an inert gas shield was carried out. Three variants of surface treatment were used, i.e. the single torch variant with a single heat source without cooling down the samples, the single torch variant with a single heat source and a cooling system with liquid nitrogen, and the double welding torch variant with a double heat source in the torches operating in a tandem configuration. Experimental verification of the applied apparatus solutions was based on both macro-and microstructural assessment of the obtained effects. Comparative analysis of the variants used and the obtained microstructural results allowed the authors to indicate the deficiencies and limitations of particular solutions and to single out the best solution that would be useful for modifying the surface layers of magnesium alloys, as well as other materials having a strong oxygen affinity.Key words: remelting treatment, GTAW technology, AZ91 magnesium alloy.Surface modification of AZ91 magnesium alloy using GTAW technology [14][15][16][17][18][19]. To this end, both lasers with continuous operation characteristics and pulse lasers are used. Among the advantages of using the laser beam one can mention is the short time of process execution, the possibility of precise concentration of the beam on a particular surface, as well as obtaining high temperature gradients in the material. The use of methods that are alternative to laser technologies, e.g. conventional welding arc heat sources, is sporadic. Difficulties may occur during the remelting treatment carried out by means of welding methods. Those difficulties are often the effect of the physical and chemical properties of magnesium and magnesium alloys, and particularly their strong oxygen affinity, whose consequence is the presence of a compacted, non-conductive MgO oxide layer on the material surface. Until recently, welding heat sources were used almost only for joining materials and their regeneration. This situation has been systematically changing in recent years. The GTAW method has been used, among others, by the authors of study [20], who subjected the AK7 aluminium alloy to surface treatment. The favourable microstructural changes triggered by remelting of the alloy resulted in an increase in hardness and resistance to abrasion. In turn, in study [21] iron castings were subjected to GTAW method treatment, and equally satisfactory treatment results were obtained. The GTAW method was used also by D. Wenbin et al. in study [22] to form a composite structure in the surface layer of the AZ31 magnesium alloy. Within this study assessment of the GTAW method effectiveness in the remelting treatment of the AZ91 magnesium alloy surface layer was conducted, as well as the comparative analysis of various apparatus and parameter variants.

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Section: Introductionmentioning

confidence: 99%

Surface modification of AZ91 magnesium alloy using GTAW technology

Iwaszko

Strzelecka

Kudła

2017

Bulletin of the Polish Academy of Sciences Technical Sciences

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“…The conclusion of the paper says that input parameters potentially affect the microhardness and surface roughness, which is well proven by the current work. Sure et al [25] used Al 2 O 3 -40% TiO 2 for coating of high density graphite substrate. In the current experiment also, Al 2 O 3 -40% TiO 2 is used for coating.…”

Section: Introductionmentioning

confidence: 99%

Parameter Optimization of Amalgamated Al2O3-40% TiO2 Atmospheric Plasma Spray Coating on SS304 Substrate Using TLBO Algorithm

Rajesh¹,

Rao²

2016

JSEMAT

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SS304 is a commercial grade stainless steel which is used for various engineering applications like shafts, guides, jigs, fixtures, etc. Ceramic coating of the wear areas of such parts is a regular practice which significantly enhances the Mean Time Between Failure (MTBF). The final coating quality depends mainly on the coating thickness, surface roughness and hardness which ultimately decides the life. This paper presents an experimental study to effectively optimize the Atmospheric Plasma Spray (APS) process input parameters of Al2O3-40% TiO2 ceramic coatings to get the best quality of coating on commercial SS304 substrate. The experiments are conducted with a threelevel L18 Orthogonal Array (OA) Design of Experiments (DoE). Critical input parameters considered are: spray nozzle distance, substrate rotating speed, current of the arc, carrier gas flow and coating powder flow rate. The surface roughness, coating thickness and hardness are considered as the output parameters. Mathematical models are generated using regression analysis for individual output parameters. The Analytic Hierarchy Process (AHP) method is applied to generate weights for the individual objective functions and a combined objective function is generated. An advanced optimization method, Teaching-Learning-Based Optimization algorithm (TLBO), is applied to the combined objective function to optimize the values of input parameters to get the best output parameters and confirmation tests are conducted based on that. The significant effects of spray parameters on surface roughness, coating thickness and coating hardness are studied in detail.

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“…⎯surface melting (laser treatment) [14]; ⎯application of solid lubricants (MoS 2 , MoSe 2 , etc.) [4].…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the speed-dependence tribotechnical characteristics of some plasma-sprayed oxide coatings at elevated temperatures

2014

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The effect of the sliding speed on friction and wear characteristics of plasma sprayed ceramic coatings (Al 2 O 3 -13% TiO 2 , ZrO 2 -8% Y 2 O 3 , Al 2 O 3 modified) was studied. Plasma sprayed coatings are not hard and have high layered structure. Abrasion of coatings in the friction pair with steel and bronze counter bodies occurs through brittle detachment conglomerated regions with low cohesive resistance. The modified coating (Al 2 O 3 ) has the highest wear resistance and the lower coefficient of friction compared to the coatings (Al 2 O 3 -13% TiO 2 , ZrO 2 -8% Y 2 O 3 ) in the studied velocity range (0.1-10 mm/s). Laser melting can be used as an efficient way of increasing the tribotechnical properties of plasma sprayed oxide coatings.

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Surface modification of plasma sprayed Al2O3–40wt% TiO2 coatings by pulsed Nd:YAG laser melting

Cited by 21 publications

References 46 publications

Surface modification of AZ91 magnesium alloy using GTAW technology

Surface modification of AZ91 magnesium alloy using GTAW technology

Parameter Optimization of Amalgamated Al<sub>2</sub>O<sub>3</sub>-40% TiO<sub>2</sub> Atmospheric Plasma Spray Coating on SS304 Substrate Using TLBO Algorithm

Experimental study of the speed-dependence tribotechnical characteristics of some plasma-sprayed oxide coatings at elevated temperatures

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Surface modification of plasma sprayed Al2O3–40wt% TiO2 coatings by pulsed Nd:YAG laser melting

Cited by 21 publications

References 46 publications

Surface modification of AZ91 magnesium alloy using GTAW technology

Surface modification of AZ91 magnesium alloy using GTAW technology

Parameter Optimization of Amalgamated Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-40% TiO&lt;sub&gt;2&lt;/sub&gt; Atmospheric Plasma Spray Coating on SS304 Substrate Using TLBO Algorithm

Experimental study of the speed-dependence tribotechnical characteristics of some plasma-sprayed oxide coatings at elevated temperatures

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Parameter Optimization of Amalgamated Al<sub>2</sub>O<sub>3</sub>-40% TiO<sub>2</sub> Atmospheric Plasma Spray Coating on SS304 Substrate Using TLBO Algorithm