Effect of Plasma Electrolytic Surface Treatment on the Corrosion Characteristics of the Ti-6Al-4V in Acidic, Industrial and Marine Environments

2012 ◽  
Vol 710 ◽  
pp. 677-682 ◽  
Author(s):  
S. Suresh ◽  
K. Pavankumar ◽  
N. Rameshbabu ◽  
K. Venkateswarlu
Keyword(s):  
Corrosion Resistance ◽  
Surface Treatment ◽  
Coating Thickness ◽  
Potentiodynamic Polarization ◽  
Ceramic Coatings ◽  
Test Results ◽  
Wide Range ◽  
Structural Parts ◽  
Plasma Electrolytic ◽  
Corrosive Environments

Titanium and its alloys find wide range of applications in aerospace, marine and automobile industries due to their excellent properties like high strength to weight ratio and good mechanical behaviour. Accordingly, the structural parts made of these alloys are being exposed to different corrosive environments. Therefore, the electrochemical stability of these structural parts needs to be significantly improved for their extended life time and effective functioning. The objective of the present work is to examine the effect of plasma electrolytic surface treatment in improving the corrosion resistance of Ti-6Al-4V in simulated acidic (0.5M H2SO4), marine (3.5% NaCl) and sulphur containing industrial (0.5M Na2SO4) environments. PEO is a relatively new technique for producing ceramic coatings on light metal alloys by employing higher voltage and current than anodizing. The Ti-6Al-4V was surface treated by plasma electrolytic oxidation (PEO) technique for 12 min under optimized conditions of electrical processing parameters and electrolyte chemistry. The logically selected electrolyte system consisting of 10 g of tri-sodium ortho phosphate (Na3PO4.12H2O), 2 g of sodium meta silicate (Na2SiO3.9H2O) and 2 g of potassium hydroxide (KOH) in 1 L of double distilled water was employed. The decisively optimized electrical parameters were fixed as 75% for the duty cycle, 1500 Hz for the pulse frequency and 0.1 A/cm2 for the current density. The phase composition of the resulted coating was analyzed by the X-ray diffraction (XRD) technique. The coating thickness and the elemental composition of the coating were assessed using a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The corrosion characteristics were determined by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) measurements. The XRD results demonstrated that the resulted coatings consisted of both anatase and rutile phases. The SEM results showed a coating thickness of about 15 µm and a canal like surface morphology with inter-connected open pores over the coating surface. The potentiodynamic polarization test results, in general, showed a minimum of about two orders of magnitude improvement in the corrosion resistance of the treated Ti-6Al-4V compared to that of the untreated in all the three corrosive environments. The EIS test results exhibit comparatively higher AC impedance and higher bode angle over the entire frequency range indicating an improved corrosion resistance of the surface treated Ti-6Al-4V. Thus the plasma electrolytic surface treatment with optimized process parameters, made the Ti-6Al-4V electrochemically stable by significantly improving its corrosion resistance in all the three environmental conditions.

ALCOA 7075

Alloy Digest ◽  
1998 ◽  
Vol 47 (7) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Stress Corrosion ◽  
Tensile Properties ◽  
Stress Corrosion Cracking ◽  
High Strength ◽  
Structural Parts ◽  
7075 Alloy ◽  
Very High

Abstract Alcoa 7075 alloy has very high strength and is used for highly stressed structural parts. The T7351 temper offers improved stress-corrosion cracking resistance. The alloy’s strength level equals or exceeds mild steels. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion resistance as well as machining and surface treatment. Filing Code: AL-350. Producer or source: ALCOA Wire, Rod & Bar Division.

SAE 1345

Alloy Digest ◽  
1987 ◽  
Vol 36 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Alloy Steel ◽  
Heat Treating ◽  
Hand Tools ◽  
Manganese Alloy ◽  
Steel Mills ◽  
Wide Range

Abstract SAE 1345 is a through-hardening, manganese alloy steel with intermediate hardenability. It is most commonly used where good strength is needed but low-to-medium toughness is sufficient. Its wide range of uses in tools and machinery includes hand tools, gears, shafts, bolts and housings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-425. Producer or source: Alloy steel mills and foundries.

SAE 8642

Alloy Digest ◽  
1981 ◽  
Vol 30 (7) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Alloy Steel ◽  
High Strength ◽  
Heat Treating ◽  
Steel Mills ◽  
Wide Range ◽  
Strength And Toughness

Abstract SAE 8642 is a triple-alloy steel that can be hardened by austenitizing and quenching in oil. This steel has moderate hardenability with relative high strength and toughness, especially in the quenched-and-tempered condition. It is used in a wide range of components, parts and tools; examples are bolts, shafts, gears, wrenches, axles and housings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-382. Producer or source: Alloy steel mills and foundries.

UNS G50461

Alloy Digest ◽  
1985 ◽  
Vol 34 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Alloy Steel ◽  
Heat Treating ◽  
Chromium Alloy ◽  
Good Ductility ◽  
Steel Mills ◽  
Wide Range

Abstract UNS NO. G50461 is a low-chromium alloy steel with boron added to increase its hardenability. This steel has medium hardenability and strength with good ductility. It is used in a wide range of machinery and tool applications where its properties meet the requirements. Another grade (UNS No. H50461) has similar properties but slightly wider ranges in percentages of carbon, manganese and chromium; this is known as the H-grade (Hardenability grade). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-408. Producer or source: Alloy steel mills and foundries.

Protective and Thermophysical Characteristics of Plasma-Electrolytic Coatings on the Ultra-Light Magnesium Alloy

2021 ◽  
pp. 1-15
Author(s):  
Sergey Grigoriev ◽  
Igor Kondratsky ◽  
Boris Krit ◽  
Valery Ludin ◽  
Varvara Medvetskova ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Thermal Diffusivity ◽  
Magnesium Alloys ◽  
Ceramic Coatings ◽  
Specific Electrical Conductivity ◽  
Technological Parameters ◽  
Thermophysical Characteristics ◽  
Light Alloy ◽  
Plasma Electrolytic ◽  
Integral Assessment

Abstract Magnesium alloys are now widely used for various purposes due to their unique properties despite the significant disadvantage associated with low corrosion resistance. The plasma-electrolytic oxidation (PEO), which allows the formation of ceramic coatings on the surface of magnesium alloys, is the most advanced and effective method for their protection. But firstly, PEO process of magnesium alloys has some difficulties, and secondly, PEO coatings affect the thermophysical characteristics of the modified materials, in particular they reduce thermal diffusivity. The presented work is devoted to the development of the technological parameters for formation of protective coating on the ultra-light alloy Mg-8Li-1Al-0.6Ce-0.3Y by the PEO method. The results analyses of electrolytes acidity and specific electrical conductivity before and after PEO process and also investigation data of the coatings structure and surface morphology are presented. An integral assessment of the ability of thermal diffusivity and corrosion resistance of the modified alloy was made. Studying of protective and thermophysical characteristics of the obtained coating showed that it provides a sufficiently high corrosion protection, despite the relatively small thickness, and the presence of pores and slightly (not more than 5%) reduces the thermal diffusivity of the magnesium ultra-light alloy.

The Growth Process of the PEO Films under Escalating Voltage Waveform

2011 ◽  
Vol 239-242 ◽  
pp. 720-723
Author(s):  
Li Wang ◽  
Wen Fu ◽  
Li Chen
Keyword(s):  
Corrosion Resistance ◽  
Growth Process ◽  
Ceramic Coatings ◽  
Voltage Waveform ◽  
Potentiodynamic Polarization Curves ◽  
Initial Stage ◽  
Electrolytic Oxidation ◽  
Superior Corrosion Resistance ◽  
Plasma Electrolytic ◽  
Peo Coatings

In order to get a clear picture for describing the growth process of plasma electrolytic oxidation coatings under escalating voltage waveform, the characteristics of PEO coatings formed at different reaction stages were systemically investigated. The morphology and corrosion resistance of the films were studied by scanning electron microscope and potentiodynamic polarization curves. The uniform, semi-transparent and better corrosion resistance of the oxide films on the magnesium electrode surface were formed owe to the extended anodizing time at the initial stage under escalating voltage mode. After sparking occurred, generated ceramic coatings were brokedown, melted, cooled and solidified continuously, so the ceramic coatings were uniform and dense. It also exhibited superior corrosion resistance.

Increase in Corrosion Resistance of Commercial Pure Titanium by Anode Plasma Electrolytic Nitriding

2016 ◽  
Vol 844 ◽  
pp. 125-132 ◽  
Author(s):  
Pavel N. Belkin ◽  
Sergei A. Kusmanov ◽  
V.S. Belkin ◽  
V.I. Parfenyuk
Keyword(s):  
Corrosion Resistance ◽  
Ammonium Chloride ◽  
Pure Titanium ◽  
Oxide Coating ◽  
Strength Properties ◽  
Additional Advantage ◽  
Commercial Pure Titanium ◽  
Plasma Electrolytic Treatment ◽  
Plasma Electrolytic ◽  
Corrosive Environments

Features of the anode electrolytic plasma processing of commercial pure titanium and its alloys in aqueous solutions of ammonium chloride and ammonia additives are studied. It is identified that structure of modified layer contains an external TiO2 or TiO layer with micropores of up to 100 nm and a diffusion sub-layer after nitriding in the solution with the ammonia addition. Some increase in the surface microhardness is found. The plasma electrolytic treatment of titanium makes it possible to enhance its corrosion resistance by short-term (5 min) saturation with nitrogen at 750 °C in an electrolyte containing 5% ammonia and 10% ammonium chloride. The oxide coating formed during the anodic treatment has a positive effect on the corrosion resistance of titanium and results in reduce of the corrosion rate by two orders under continuous tests. Saturation of titanium samples with nitrogen leads to an increase in their strength properties after corrosion tests with a slight decrease in ductility. An additional advantage of this coating is to reduce of leaching of alloying elements from samples in corrosive environments.

Simultaneous Reduction of Wear and Corrosion of Titanium, Magnesium and Zirconium Alloys by Surface Plasma Electrolytic Oxidation Treatment

2008 ◽  
Vol 38 ◽  
pp. 27-35 ◽  
Author(s):  
H.M. Nykyforchyn ◽  
V.S. Agarwala ◽  
M.D. Klapkiv ◽  
V.M. Posuvailo
Keyword(s):  
Corrosion Resistance ◽  
Plasma Electrolytic Oxidation ◽  
Synthesis Method ◽  
Zirconium Alloys ◽  
Ceramic Coatings ◽  
Oxide Ceramic ◽  
Wear And Corrosion ◽  
Electrolytic Oxidation ◽  
Wear And Corrosion Resistance ◽  
Plasma Electrolytic

Titanium, magnesium and zirconium alloys are widely used in industrial applications, which require high wear and corrosion resistance. However current methods of improving these properties often do not satisfy the requirements of service and functional properties. An alternative approach is the application of oxide-ceramic coatings using high temperature process. The coatings are applied by spark discharge plasma in the metal-electrolyte system at high voltages - PEO (plasma electrolytic oxidation) as an oxide synthesis method. This method has shown good results for aluminium alloys and with good prospects to be used for titanium, magnesium and zirconium alloys. Development of PEO technology to improve the wear and corrosion resistance of titanium, magnesium and zirconium alloys is discussed in this paper. It describes the methods for obtaining the required layer-thickness for a specified hardness, porosity, wear and corrosion resistance, sets up the optimal process parameters (voltage/current) by taking the relation of anodic to cathodic currents into account, and establishing the electrolyte content of different dopants.

NICKEL 233

Alloy Digest ◽  
1970 ◽  
Vol 19 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Heat Treating ◽  
Bearing Strength ◽  
Temperature Performance ◽  
Vacuum Tubes ◽  
Structural Parts

Abstract NICKEL 233 is used primarily for plates (anodes) in vacuum tubes. It is also suitable for structural parts of tubes other than cathodes and it exhibits good magnetostriction properties. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive, shear, and and bearing strength It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-154. Producer or source: Huntington Alloy Products Division.

Sign in / Sign up

Export Citation Format

Share Document