Cyclic Oxidation of Titanium Grade 2

This paper presents the results of research into the cyclic oxidation of titanium Grade 2. The value of titanium Grade 2 oxidation activation energy was determined based on an analysis of the Arrhenius diagram. The result was 205.3 kJ/mol. After cyclic oxidation at a temperature of 600 °C, the presence of oxides in an acicular system was observed on the surface. The specimen surface after oxidation at 650 °C was characterised by the presence of fine oxide particles, while after oxidation at 700 °C, the obtained oxide layer was composed of large oxide particles. The layers obtained after oxidation at 600 °C had the lowest thickness (1.26 and 2.12 µm), while those obtained at 700 °C had the highest thickness (5.17 and 9.45 µm). Examination of the phase composition after cyclic oxidation showed that the oxide layers obtained at temperatures of 600, 650 and 700 °C were composed of TiO2 (rutile) only. No presence of other phases was found. The oxide layers formed in the cyclic oxidation process were characterised by different thicknesses, depending on the oxidation parameters. It was found that cyclic oxidation contributed to a considerable increase in the surface hardness of titanium Grade 2.

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THE INFLUENCE OF ISOTHERMAL OXIDATION PARAMETERS ON THE TRIBOLOGICAL PROPERTIES OF TITANIUM

Tribologia ◽

10.5604/01.3001.0010.5973 ◽

2017 ◽

pp. 5-9 ◽

Cited By ~ 1

Author(s):

Krzysztof ANIOŁEK ◽

Adrian BARYLSKI ◽

Marian KUPKA ◽

Michał DWORAK

Keyword(s):

Thermal Oxidation ◽

Tribological Properties ◽

Sliding Wear ◽

Isothermal Oxidation ◽

Oxide Layers ◽

Wear Analysis ◽

Resistance To Sliding ◽

Oxide Particles ◽

Titanium Grade ◽

Oxidation Parameters

The paper presents the results of tests concerning the tribological properties of titanium Grade 2 subjected to thermal oxidation at a temperature of 600°C and 700°C for 72 hours. Morphology of the obtained oxide scale was determined using a scanning electron microscope. After oxidation at 600°C, the resultant oxides concentrated mostly on the roughness elevations formed during the grinding of samples. On raising temperature to 700°C, finer and more agglomerated oxide particles were formed. Tribological tests have shown that titanium Grade 2 in a non-oxidised condition is characterised by very poor resistance to sliding wear. It has been found that the presence of an oxide layer on the surface of titanium significantly improves its poor tribological properties. Oxide layers obtained at temperatures of 600°C and 700°C allowed obtaining as much as a triple reduction of volumetric wear. Analysis of the morphology of the wear trace surface has shown the presence of corrugation wear on a non-oxidised specimen in the form of two alternate regions with different morphologies. It has been demonstrated that oxide layers obtained during thermal oxidation eliminate the phenomenon of corrugation wear.

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Oxidation of 1,2-Propanediol to Lactic Acid under Novel Supported Au Catalysts and Reaction Kinetics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.850.41 ◽

2020 ◽

Vol 850 ◽

pp. 41-47

Author(s):

Svetlana Zhizhkuna ◽

Svetlana Chornaja ◽

Jevgenija Vladiko ◽

Reinis Drunka ◽

Dzidra Jankoviča ◽

...

Keyword(s):

Lactic Acid ◽

Reaction Kinetics ◽

Oxidation Process ◽

Gold Catalysts ◽

Reaction Conditions ◽

Oxidation Parameters

This work demonstrates that 5wt% gold catalysts supported on Al2O3 and TiO2 nanopowders as well as on TiO2 nanofibers are active in the 1,2-propanediol (1,2-PDO) oxidation to lactic acid. The influence of catalysts different parameters and reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. The best result was achieved using 5wt%Au/TiO2 catalyst over the following oxidation parameters: c0(1,2-PDO) = 0.3 mol/L, n (1,2-PDO)/n (Au) = 4000 mol/mol, p (O2) = 6 bar, c0(NaOH) = 2 mol/L, t = 60 °C: 1,2-propanediol conversion was 98 % and lactic acid selectivity 89 %.

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Cyclic Oxidation Resistance of Co-10Cr-5Al-0.3Y Alloy at 800 oc

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1015.505 ◽

2014 ◽

Vol 1015 ◽

pp. 505-508

Author(s):

Ling Yun Bai ◽

Hong Hua Zhang ◽

Huai Shu Zhang ◽

Yun Xiang Zheng ◽

Jun Huai Xiang

Keyword(s):

Oxidation Resistance ◽

Oxidation Rate ◽

Cyclic Oxidation ◽

Oxidation Behavior ◽

Oxidation Process ◽

Oxidation Mechanism ◽

Local Zone

The cyclic oxidation behavior of Co-10Cr-5Al alloys with and without 0.3 at% Y doped in atmosphere at 800oC was investigated. The addition of 0.3 at.% Y increased the oxidation rate of the alloy and changed the oxidation mechanism. The scales grown the alloys with and without Y were both composed of an outer Co2O3layer and an inner complex layer of Al2O3, Co2O3and Cr2O3, except that the addition of 0.3 at% Y enhanced the adhesion of the scale. 0.3 at% Y agglomerated in local zone which accelerated the oxidation rate and was not conductive to the oxidation process of the Co-10Cr-5Al alloy.

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Surface Friction-Electric Treatment of Aluminum Alloys

Proceedings of Higher Educational Institutions Маchine Building ◽

10.18698/0536-1044-2020-10-47-53 ◽

2020 ◽

pp. 47-53

Author(s):

V.R. Edigarov

Keyword(s):

Surface Layer ◽

Aluminum Oxide ◽

Electric Current ◽

Technological Factor ◽

Surface Hardness ◽

Local Deformation ◽

Working Zone ◽

Treatment Zone ◽

Electric Treatment ◽

Oxide Particles

This paper examines a combined friction-electric treatment of surface layers of machine parts made of aluminums alloys. The temperature released during the friction process is the main technological factor of the treatment, and the heat released during the passage of electric current through the local volume of friction-thermal action is an additional heat source. The paper presents the results of studying a surface modification method involving friction-electric treatment of aluminium alloys with reinforcement by aluminium oxide particles under varied technological conditions: density of electric current, pressing force of the tool, shape of the tool working zone and speed of treatment. A hard alloy tool with high temperature resistance was used as a tool for friction-electric treatment. The tool was installed in a mandrel of a special design allowing supply of a modifier representing a mixture of aluminum oxide particles with a surfactant to the treatment zone. Using the friction-electric treatment of the surface layer of samples with reinforcement by aluminum oxide particles it was possible to increase the surface hardness by about 30–40 % and thickness of the hardened layer by 3–5 times due to the local deformation and passage of electric current through the treatment zone, and to improve wear resistance of the surface layer.

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Effects of Yttrium on Cyclic Oxidation Resistance of Co-10Cr-5Al Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.785-786.844 ◽

2013 ◽

Vol 785-786 ◽

pp. 844-847

Author(s):

Jun Huai Xiang ◽

Xian Chao Xu ◽

Ling Yun Bai ◽

Yun Xiang Zheng ◽

Huai Shu Zhang

Keyword(s):

Oxidation Resistance ◽

Oxidation Kinetics ◽

Oxidation Rate ◽

Cyclic Oxidation ◽

Oxidation Behavior ◽

Oxidation Process ◽

Local Zone ◽

Rate Law ◽

Parabolic Rate

The cyclic oxidation behavior of Co-10Cr-5Al alloys with and without Y in atmosphere at 800 °C was investigated. The addition of 0.3 at.% Y increased the oxidation rate of the alloy and changed the behavior from irregular oxidation kinetics to approximate parabolic rate law. The scales grown the alloys with and without Y were both composed of an outer Co2O3layer and an inner complex layer of Al2O3, Co2O3and Cr2O3, except that the addition of Y impaired the adhesion of the scale. Over-doped Y agglomerated in local zone plays an adverse role in the oxidation process by accelerating the oxidation rate.

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Densification and microstructure development during the sintering of submicrometre magnesium oxide particles prepared by a vapour-phase oxidation process

Journal of Materials Science ◽

10.1007/bf01151248 ◽

1993 ◽

Vol 28 (3) ◽

pp. 719-728 ◽

Cited By ~ 11

Author(s):

K. Itatani ◽

A. Itoh ◽

F. S. Howell ◽

A. Kishioka ◽

M. Kinoshita

Keyword(s):

Magnesium Oxide ◽

Oxidation Process ◽

Vapour Phase ◽

Microstructure Development ◽

Phase Oxidation ◽

Oxide Particles ◽

Vapour Phase Oxidation

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The Influence of Thermal Oxidation Parameters on Structural, Friction, and Wear Characteristics of Oxide Layers Produced on the Surface of Ti–6Al–7Nb Alloy

Journal of Tribology ◽

10.1115/1.4042001 ◽

2018 ◽

Vol 141 (3) ◽

Author(s):

Krzysztof Aniołek ◽

Adrian Barylski ◽

Marian Kupka ◽

Joanna Tylka

Keyword(s):

Oxide Scale ◽

Thermal Oxidation ◽

Friction And Wear ◽

Sliding Friction ◽

Fourfold Increase ◽

Resistance To Sliding ◽

Developed Surface ◽

Biomedical Titanium Alloy ◽

Oxide Particles ◽

Oxidation Parameters

The effects of thermal oxidation of a biomedical titanium alloy (Ti–6Al–7Nb) on its morphology, structure, mechanical properties, and sliding friction and wear against alumina were investigated. It was found that at 600 °C, the surface of the alloy was characterized with a thin inhomogeneous oxide scale. Increasing the temperature of oxidation to 700 °C and 800 °C allowed obtaining homogeneous layers, which fully covered the examined surfaces. By contrast, the oxide scale obtained at 800 °C was composed of big oxide particles with a developed surface. Thermal oxidation process allows a fourfold increase in the hardness of Ti–6Al–7Nb alloy. It was shown that the oxide scale on the examined alloy efficiently enhances its resistance to sliding wear against alumina.

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Effect of RE on Cyclic Oxidation Behavior of Ferrite Stainless Steel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.4063 ◽

2012 ◽

Vol 204-208 ◽

pp. 4063-4066

Author(s):

Xiao Liu ◽

Long Mei Wang

Keyword(s):

Stainless Steel ◽

High Temperature Oxidation ◽

Cyclic Oxidation ◽

Oxidation Process ◽

Primary Study ◽

Temperature Oxidation ◽

Cr2o3 Scale ◽

Pinning Effect ◽

Before And After ◽

Re Elements

A primary study on the resistance to high-temperature-oxidation of 430 ferrite stainless steel and its oxidation process before and after the addition of RE elements was reported. Results show that the oxidation resistance of 430 ferrite stainless steel after adding RE is indeed great. The value of oxidation rate of Sample 1 (without adding RE) is 2.87 times higher than Sample 2, respectively at 1423K after oxidizeing for totally 144h. And the dense and adherent Cr2O3 scale and FeCr2O4 scale are formed and played the protection role to the 430 ferrite stainless steel. In the internal oxidation layer, the pinning effect of silicon dioxide is strengthened by RE.

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