INVESTIGATION OF THE EFFECTS OF DIFFERENT RETROGRESSION AND RE-AGING PARAMETERS APPLIED TO THE 7075 ALLOY ON THE MICRO-ARC OXIDATION PROCESS

2021 ◽  
Vol 28 (09) ◽  
pp. 2150078
Author(s):  
MUSTAFA SAFA YILMAZ ◽  
GÖKHAN ÖZER ◽  
ORHAN ŞAHIN ◽  
AHMET KARAASLAN
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Surface Properties ◽  
Anode Voltage ◽  
Coating Layer ◽  
Surface Hardness ◽  
Process Time ◽  
Cathode Voltage ◽  
Open Time ◽  
Micro Arc Oxidation

In this paper, retrogression and re-aging (RRA) heat treatment was applied to 7075 aluminum alloy in T6 condition at different times (30 and 90[Formula: see text]min) and temperatures (180∘C and 240∘C). While RRA heat treatments increase the corrosion resistance of the material, it does not harm its mechanical properties. On the other hand, the surface resistance of aluminum is low. Surface modifications are applied to overcome this deficiency. Among these, the micro-arc oxidation (MAO) method increases the corrosion resistance and attains excellent values in surface hardness. To better understand the RRA/MAO relationship, heat-treated (RRA) samples with four different parameters were coated with the MAO method. In this way, a ceramic oxide coating layer was created on the material surfaces. In order to determine the RRA parameter effect, the MAO process parameters are kept constant (anode voltage ([Formula: see text]): 500[Formula: see text]V, cathode voltage ([Formula: see text]): 300[Formula: see text]V, anode voltage open time ([Formula: see text]: 300[Formula: see text][Formula: see text]s, cathode voltage open time ([Formula: see text]): 200[Formula: see text][Formula: see text]s, frequency: 160 coating with Hz, and process time: 20[Formula: see text]min). Surface properties (coating thickness, surface roughness, surface arc duct’s structure, etc.), phase analysis (X-ray diffraction (XRD)) and microstructures (coating cross-section studies: distance-dependent hardness, coating/backing material interface character, coating porosity ratio) were examined. XRD analysis showed that the main phase of the coatings is [Formula: see text]-Al2O3. A coating layer of around 125[Formula: see text][Formula: see text]m was achieved with the growth rate of 6[Formula: see text][Formula: see text]m/min. Surface roughness was between 5.5[Formula: see text][Formula: see text]m and 8[Formula: see text][Formula: see text]m for different RRA parameters. RRA/MAO relation with the characterization made was detailed, and predictions were made for the surface properties of the material (hardness, corrosion resistance, wear, etc.).

Effect of Ultrasonic Surface Rolling Process Parameters on Surface Properties of S30408 Austenitic Stainless Steel

2020 ◽  
Vol 305 ◽  
pp. 111-116
Author(s):  
Rong Juan Sui ◽  
Zhen Hua Qin ◽  
Lei Yu Sun ◽  
Cheng Bin Fang ◽  
Xiao Mei Chen
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Corrosion Rate ◽  
Surface Properties ◽  
Process Parameters ◽  
Surface Hardness ◽  
Rolling Process ◽  
Step Size

S30408 austenitic stainless steel was treated by using hawking processing which is a type of ultrasonic surface rolling process (USRP). The effects of USRP parameters on surface roughness, surface hardness and corrosion resistance were investigated. Compared with the untreated specimen, the surface roughness and surface hardness is decreased by 87%, the surface hardness is increased by 51% and the corrosion rate reduces after USRP. The surface roughness decreases obviously as the step-size decreases, while the step-size has little effect on the surface hardness and corrosion resistance.

Corrosion and Wear Protection through Micro Arc Oxidation Coatings in Aluminum and Its Alloys

2019 ◽  
Author(s):  
L. Rama Krishna ◽  
G. Sundararajan
Keyword(s):  
Corrosion Resistance ◽  
Surface Properties ◽  
High Hardness ◽  
Basic Mechanism ◽  
Industrial Applications ◽  
Corrosion Properties ◽  
Micro Arc Oxidation ◽  
Coating Formation ◽  
Wear And Corrosion Resistance ◽  
Technological Limitations

This article presents the brief overview of fairly recent and eco-friendly micro arc oxidation (MAO) coating technology. The weight-cost-performance benefits in general raised the interest to utilize lightweight materials, especially the aluminum and its alloys. Despite numerous engineering advantages, the aluminum alloys themselves do not possess suitable tribology and corrosion resistance. Therefore, improvements in surface properties are essential to enable developing potential industrial applications. For improving wear and corrosion resistance of Al alloys, the most demanding surface properties are high hardness and chemical inertness. The technical and technological limitations associated with traditional anodizing and hard anodizing processes have been the strongest driving force behind the development of new MAO technology. While presenting the key technological elements associated with the MAO process, the basic mechanism of coating formation and its phase gradient nature is presented. Influence of various process parameters including the electrolyte composition has been discussed. The typical microstructural features and distribution of α- and γ-Al2O3 phases across the coating thickness as a key strategy to form dense coatings with required mechanical, tribological, and corrosion properties which are vital to meet potential application demands are briefly illustrated.

scholarly journals PENGARUH SPUTTERING TiN TERHADAP KEKASARAN, KEKERASAN PERMUKAAN MATERIAL AISI316L

2019 ◽  
Vol 18 (3) ◽  
pp. 331-338
Author(s):  
Jemssy Ronald Rohi ◽  
Priyo Tri Iswanto ◽  
Tjipto Sujitno ◽  
Erich Umbu Kondi
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Corrosion Resistance ◽  
Deposition Time ◽  
Low Cost ◽  
Surface Hardness ◽  
The Body ◽  
Aisi 316L ◽  
Good Corrosion Resistance ◽  
Long Time

AISI 316L is widely used for implantation in orthopedic surgery due to its good corrosion resistance, mechanical properties and low cost. However, AISI 316L is not well suited for biocompatibility with the body, so implant material with AISI 316L can’t be used for a long time. One way to improve the corrosion resistance and mechanical properties of AISI 316L is to perform a surface treatment such as sputtering. This study discusses the effect of deposition sputtering TiN of 60, 90, 120 and 150 minutes on roughness and surface hardness at a ratio of argon gas and nitrogen to 80% Ar:20% N2. The results of the surface roughness value of the TiN sputtering layer deposited to AISI 316L for 60, 90, 120, and 150 minutes were 0.02 μm, 0.04 μm, 0.06 μm, and 0.04 μm respectively. This shows that the coating time of TiN in AISI 316L has no significant influence on value of surface roughness. Surface hardness results at 60, 90, 120, and 150 minutes were obtained with 268 HVN, 275 HVN, 278 HVN and 282 HVN. Increased hardness value, as the TiN thin layer has a higher hardness value compared to AISI 316L. The longer the deposition time, the more layers are formed and the layer becomes thicker. With the thickness of the layer, the density at the grain boundary increases. Because the higher density leads to grain growth, in which form micropores.

A Study of Micro-Arc Oxidation Coatings on Aluminum Alloy Drill Pipe for Offshore Platform

2017 ◽  
Vol 51 (3) ◽  
pp. 16-22 ◽  
Author(s):  
Yan Shen ◽  
Prasanta K. Sahoo ◽  
Yipeng Pan
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Experimental Work ◽  
Structural Characteristics ◽  
Drill Pipe ◽  
Offshore Platform ◽  
Cathode Voltage ◽  
Micro Arc Oxidation ◽  
Anticorrosion Performance

AbstractIn order to enhance the corrosion resistance of a drill pipe for an offshore platform, micro-arc oxidation (MAO) coatings were deposited on the surface of an aluminum alloy drill pipe by MAO technology. The microstructure and anticorrosion performance of the MAO coatings were investigated experimentally. This paper mainly focuses on the experimental work to determine the influence of cathode voltage on the structural characteristics and corrosion resistance of MAO coatings. The results show that the cathode voltage has a significant effect on the preparation of MAO coating during the process. The surface of the coating becomes more compact and smooth with the increase of the cathode voltage. Furthermore, the anticorrosion performance of MAO coatings can effectively be improved with the increase of cathode voltage.

Analysis of corrosion behaviour and surface properties of plasma-sprayed composite coating of hydroxyapatite–tantalum on biodegradable Mg alloy ZK60

2019 ◽  
Vol 53 (19) ◽  
pp. 2661-2673 ◽  
Author(s):  
Balraj Singh ◽  
Gurpreet Singh ◽  
Buta Singh Sidhu
Keyword(s):  
Corrosion Resistance ◽  
Surface Properties ◽  
Corrosion Behaviour ◽  
Surface Hardness ◽  
Mg Alloy ◽  
Hydroxyapatite Coating ◽  
Hydroxyapatite Coatings ◽  
Plasma Sprayed ◽  
Incremental Increase

Magnesium (Mg) and its alloys are promising candidates for biodegradable bio-implants. However, the excessive corrosion in the physiological environment and subsequent decline in the mechanical integrity of Mg and its alloys have limited their utility as biomaterials. In the present study, an attempt has been made to improve the corrosion resistance of Mg alloy ZK60 plasma sprayed with tantalum (Ta)-reinforced hydroxyapatite coating. The experiment was conducted with three varied levels, i.e. 10, 20 and 30 weight percent (wt%) of Ta-content in hydroxyapatite coating. The coatings were characterized and in vitro corrosion behaviour was investigated by electrochemical measurements in Ringer's solution along with the analysis of surface properties. The corrosion resistance of the Mg alloy increased with the incremental increase in Ta reinforcement in hydroxyapatite coating. An increase in the protection efficiency was analysed for the Ta-reinforced hydroxyapatite coatings (∼10%, 18% and 23% for hydroxyapatite-10Ta, hydroxyapatite-20Ta and hydroxyapatite-30Ta, respectively) as compared to the pure hydroxyapatite coating. The hydroxyapatite coating effectively increased the surface hardness of the Mg alloy and Ta reinforcement further enhanced it. Surface roughness decreased with the incremental increase in Ta-content in hydroxyapatite coating. Wettability analysis revealed the hydrophilic nature of pure hydroxyapatite and Ta-reinforced hydroxyapatite coatings. The results of the study suggest that the proposed Ta reinforcement in hydroxyapatite is potentially important for biodegradable Mg bio-implants.

Influence of Processing Factors on the Surface Properties of Zirconia Coatings Fabricated by Room Temperature Spray Process

2020 ◽  
Vol 20 (7) ◽  
pp. 4152-4157
Author(s):  
Jeong Jun Kim ◽  
Jong Kook Lee
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Surface Properties ◽  
Room Temperature ◽  
Coating Layer ◽  
High Surface ◽  
Phase Changes ◽  
Deposition Cycle ◽  
Implant Surface ◽  
Processing Factors

Highly roughened surfaces on dental implants enhance the bone-bonding ability and in vivo cell adhesion on the implant surface. In this study, zirconia substrates were coated by powder coating using room temperature spray processing to improve their surface properties. Processing factors (particle size of the starting powder, number of repetitions of the deposition cycle, and spraying distance) were controlled to form a dense coating layer with high surface roughness on the zirconia substrate. Starting zirconia powders for coating were heat-treated at high temperature to control the particle size and kinetic energy. The coating layer fabricated from starting powder with a particle size of about 1.52 μm shows a homogeneous and dense microstructure, and it has a maximum surface roughness about 0.37 μm. The surface roughness of the film coatings increased with the number of times that the deposition cycle was repeated. No phase changes between the starting powder and the coating layer were observed, and all of the materials show identical tetragonal phases.

Properties and Corrosion Resistance of Borided AISI H11 Tool Steel

2019 ◽  
pp. 1-19
Author(s):  
Ali Günen
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Corrosion Resistance ◽  
Treatment Condition ◽  
Single Phase ◽  
Surface Hardness ◽  
Dual Phase ◽  
Barrier Effect ◽  
Mechanical Properties And Corrosion ◽  
Boriding Process

Abstract In this study, the effect of different boriding parameters on the some mechanical properties and corrosion resistance of AISI H11 steel, which is extensively used in hot and cold processing applications, was investigated. The grown boride layers were compact and crack-free for all boriding conditions and they were detected as single phase (Fe2B) at 800°C and dual phase (FeB+Fe2B) at 900 and 1000°C. Depending on the treatment condition, the thickness, surface hardness and Ra values of the coatings were ranged between 10.25-94.5 µm, 1704-2015 HV, and 0.285-0.650 µm, respectively. The corrosion resistance was observed to be related to the phase structure, coating thickness, surface roughness and the density of the boride layers. There found to be an increase in the corrosion resistance up to almost 65 times after the boriding process, due to the barrier effect of the grown boride layers (such as B2O3).

A study on the Surface Properties of Nitrogen Implanted H13 Steel by Plasma Immersion Ion Implantation

2006 ◽  
Vol 118 ◽  
pp. 275-280
Author(s):  
Y.Z. You ◽  
D.I. Kim ◽  
H.G. Chun
Keyword(s):  
Surface Roughness ◽  
Ion Implantation ◽  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Surface Hardness ◽  
Wear Loss ◽  
Wear Property ◽  
H13 Steel ◽  
Near Surface ◽  
Plasma Immersion Ion Implantation

The near surface of the H13 steel was implanted by using Plasma immersion ion implantation (PIII) system at constant bias voltage of −20 kV with varying nitrogen (N+ ) ion dose (3, 6, 9, 12, 15×1017 ions/cm2 ). The surface properties of the N+ ion implanted steel were investigated by measuring the microhardness, wear loss and friction coefficient. As increasing N+ ion dose (12×1017 ions/cm2), both wear property and surface hardness were increased. However, these properties were decreased as the incident ion dose increased over 12×1017 ions/cm2. The elemental depth profile and surface roughness were obtained with X-ray photoelectron spectroscopy (XPS) and surface roughness tester, respectively.

Correlation between Applied Voltage and Electrochemical Properties of Micro Arc Oxidation Coatings Formed on AZ31B Magnesium Alloy

2013 ◽  
Vol 849 ◽  
pp. 32-37
Author(s):  
Xiang Hua Song ◽  
Jian Hong Lu ◽  
Xi Jiang Yin ◽  
Jian Ping Jiang ◽  
Annie Tanlai Kuan ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Properties ◽  
Applied Voltage ◽  
Coating Layer ◽  
Electrical Parameter ◽  
Corrosion Current ◽  
Coating Properties ◽  
Voltage Range ◽  
Atomic Force ◽  
Micro Arc Oxidation

The correlation between the electrical parameter of applied voltage and the coating properties, especially the electrochemical properties of micro arc oxidation coating layer was studied in environmental friendly electrolyte under single-polar pulse power supply. The coating surface morphology and corrosion resistance was characterized by atomic force microscope (AFM) and electrochemical method. The coating thickness and the pores in the coating layer grow with increasing the applied voltage; also the surface becomes rougher at higher voltages. In the voltage range of 240 V to 320 V, the relative optimal voltage parameter is 260 V, which presents the smallest corrosion current density, three orders of magnitude lower than that of bare Mg substrate and the highest coating impedance value among all coatings. With increasing applied voltage from 240 V to 260 V, the corrosion resistance was improved significantly; then decreased slightly at higher voltages of 280 V to 320 V. The impedance spectroscopy fitting results show that the voltage parameter has more effect on the inner layer than on the outer layer of micro arc oxidation coatings and the coating property is more dependent on the compact inner layer.

Effect of Current Density on the Microstructure and Corrosion Properties of MAO Coatings on Aluminum Alloy Shock Absorber

2018 ◽  
Vol 764 ◽  
pp. 28-38 ◽  
Author(s):  
Yan Shen ◽  
Hong Xiang Wang ◽  
Yi Peng Pan
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Current Density ◽  
Shock Absorber ◽  
Structural Characteristics ◽  
Ceramic Coatings ◽  
Corrosion Performance ◽  
Cathode Voltage ◽  
Corrosion Properties ◽  
Micro Arc Oxidation

In order to improve the corrosion resistance of shock absorber for ships, the alumina ceramic coatings are carried out on the surface of aluminum alloy shock absorber by micro arc oxidation (MAO) technology. The microstructure and anti-corrosion performance of the MAO coatings were investigated experimentally. This paper mainly focuses on the experimental work to determine the effect of current density on the structural characteristics and corrosion resistance of MAO coatings. The results show that the current density has a significant influence on the preparation of MAO coating during the process. The surface of the coating becomes more compact and smooth with the cathode voltage of 7 A.dm-2. Furthermore, the anti-corrosion performance of the MAO coatings can effectively be improved at the current density of 7 A.dm-2.

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