Fretting Corrosion of Mild Steel in Air and in Nitrogen

1954 ◽  
Vol 21 (4) ◽  
pp. 395-400
Author(s):  
I-Ming Feng ◽  
Herbert H. Uhlig
Keyword(s):  
Weight Loss ◽  
Mild Steel ◽  
Room Temperature ◽  
Ambient Air ◽  
Frequency Effect ◽  
Fretting Corrosion ◽  
Relative Slip ◽  
Dry Air ◽  
Weight Losses ◽  
Fretting Damage

Abstract Data are presented on fretting corrosion of mild steel using weight loss as a measure of damage. Relative slip was measured both by use of stroboscopic light and strain gages. Load was applied pneumatically. Humidity of ambient air was found to be a sensitive variable requiring control, a fact first discovered through discrepancies of weight-loss data obtained in winter compared with those obtained in summer. Fretting corrosion of mild steel in moist air is only 55 to 65 per cent of the weight loss in dry air, depending on duration of test. Because of this large difference, all tests were carried out in dry air. At the same time, it was observed that fretting corrosion is appreciably greater below room temperature than above room temperature (up to 150 C). Weight losses of specimens fretted at 50 C are approximately 50 per cent losses at 0 C. Rate of fretting corrosion in air is found to be constant with time after an initial run-in period during which the rate is temporarily higher. In moist or dry nitrogen, weight losses are much less, although not zero. The greater the relative slip, the greater is fretting damage, and in complete absence of slip the data indicate that no weight loss occurs. Increased pressure or load is found to increase fretting damage. Weight loss is greater the lower the frequency for the same number of test cycles. The frequency effect increases with relative slip, and in nitrogen the frequency effect disappears.

A new method for evaluating decay: the effect of oxygen on Polyporuscompactus in red oak

1985 ◽  
Vol 15 (6) ◽  
pp. 1021-1024 ◽  
Author(s):  
T. J. Hall ◽  
Curt Leben
Keyword(s):  
Weight Loss ◽  
Continuous Flow ◽  
Constant Pressure ◽  
White Rot Fungi ◽  
Dry Weight ◽  
Ambient Air ◽  
White Rot ◽  
Weight Losses ◽  
Soil Block ◽  
Effect Of Oxygen

The effects of oxygen decay (weight loss) incited by Polyporuscompactus Overh. was studied using small fresh and dried wood blocks containing both sapwood and heartwood of similar radial position and age. A manifold was used to deliver hydrated gas mixtures of 1.0, 4.2, or 21% (ambient air) oxygen at constant pressure and continuous flow to jars containing inoculated or noninoculated blocks. Means (P = 0.05) for dry weight losses in inoculated blocks at 1.0, 4.2, and 21% oxygen were 3.3, 8.9, and 21.4%, respectively; losses may be comparable to decay by other white rot fungi using the soil-block procedure. Losses in noninoculated blocks at the above oxygen levels were 2.0, 4.6, and 7.0%, respectively. Differences in dry weight losses between fresh and dry blocks were found. In particular, losses in inoculated fresh blocks were significantly less than losses in inoculated dry blocks in ambient air. Native inhabitants occurring in fresh wood appear to interfere with the decay processes of P. compactus. Losses in noninoculated fresh blocks were significantly greater than in noninoculated dry blocks at 21% oxygen but not at 1.0 or 4.2% oxygen; losses were attributed to natural inhabitants in fresh wood.

scholarly journals Corrosive Effect of Tomato, Pepper and Onion Pulps on Selected Grinding Machine Components

2021 ◽  
pp. 20-28
Author(s):  
J. O. Babalola ◽  
B. F. Olanipekun ◽  
V. E. Onyiaoha ◽  
O. C. Adejumobi ◽  
N. O. Oladipo ◽  
...  
Keyword(s):  
Weight Loss ◽  
Stainless Steel ◽  
Mild Steel ◽  
Food Industry ◽  
Room Temperature ◽  
Galvanized Steel ◽  
Electrochemical Characteristics ◽  
Corrosive Effect ◽  
Grinding Machine ◽  
Microbiologically Induced Corrosion

As a result of cost considerations, local grinding machine manufacturing outfits are employing non-stainless-steel components for equipment fabrication. Despite the fact that the components are known to corrode, the number of the manufacturing outfits has increased over the years. Corrosion is a major concern to the food industry because the ingestion of corroded metals can harm and affect the function of some body organs. Potentiodynamic polarization method and a weight loss approach at room temperature was used to investigate the influence of tomato, pepper, and onion pulps on the electrochemical characteristics and weight loss of mild, galvanized, and stainless steel over a period of 30 days, at 5-day intervals. The results revealed that highest corrosion rate was found in mild steel (2.95x10-8mm/y) but low compared to the corrosion value obtained for galvanized steel (3.4x10-8mm/y) in the hybrid medium. Consequently, the use of mild steel as a substitute for stainless steel is suggested, provided that it is coated, and that the machine is cleaned regularly to remove residues from the metal surface or to inhibit microbiologically induced corrosion.

Mechanism of Fretting Corrosion

1954 ◽  
Vol 21 (4) ◽  
pp. 401-407
Author(s):  
Herbert H. Uhlig
Keyword(s):  
Weight Loss ◽  
Reaction Rate Constant ◽  
Frequency Effect ◽  
Hyperbolic Function ◽  
Fretting Corrosion ◽  
Chemical Factor ◽  
Mechanical Factor ◽  
Quantitative Expression ◽  
Number Of Cycles ◽  
Reported Data

Abstract A review of the facts suggests that the mechanism of fretting corrosion includes a chemical factor and a mechanical factor, with observed damage, in general, resulting from both. An asperity rubbing on a metal surface is considered to produce a track of clean metal which immediately oxidizes, or upon which gas rapidly adsorbs. The next asperity wipes off the oxide or initiates reaction of metal with adsorbed gas to form oxide. This is the so-called chemical factor of fretting. In addition, asperities dig below the surface to cause a certain amount of wear by welding or shearing action in which metal particles are dislodged. This is the mechanical factor of fretting. Metallic debris produced by fretting is thought not to oxidize spontaneously, as proposed by the molecular-attrition theory, but instead converts partially to iron oxide by secondary fretting action of particles rubbing against themselves or adjacent surfaces. This accounts for the fact that Fe2O3 is found by x ray to be the major corrosion product and metallic iron is present, if at all, in only very small amount. The quantitative expression for fretting corrosion derived on the basis of the foregoing model for relatively large values of load, frequency, and slip is W ( total ) = ( k 0 L 1 ⁄ 2 - k 1 L ) C f + k 2 l L C where W is the specimen weight loss, L is the load, C is the number of cycles, f is the frequency, l the slip, and k0, k1, and k2 are constants. The first two terms are the chemical factor of fretting corrosion and the third term is the mechanical factor. Accordingly, the equation predicts that fretting-corrosion weight loss is a hyperbolic function of frequency, is parabolic with load and linear with number of cycles or magnitude of slip. Furthermore, the terms concerned with a frequency effect disappear when the chemical factor is suppressed, as is observed when fretting tests are conducted in nitrogen. These conclusions are confirmed by the reported data. In addition, the calculated reaction-rate constant for oxidation of a freshly formed iron surface obtained from fretting data is reasonable and falls between two independently observed values. In our experiments, the chemical or corrosion factor falls within 6 to 78 per cent of the total observed fretting damage, depending on conditions of test. Remedial measures are outlined in light of the data and the proposed mechanism.

Investigation of Plasma Treatment Conditions for Wafer-Scale Room-Temperature Bonding Using Ultrathin Au Films in Ambient Air

2019 ◽  
Vol 139 (7) ◽  
pp. 217-218
Author(s):  
Michitaka Yamamoto ◽  
Takashi Matsumae ◽  
Yuichi Kurashima ◽  
Hideki Takagi ◽  
Tadatomo Suga ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Room Temperature ◽  
Ambient Air ◽  
Wafer Scale ◽  
Treatment Conditions

Visible-light-initiated Catalyst-free Oxidative Cleavage of Triaryl-Substituted Alkenes C=C Bonds under Ambient Conditions

2021 ◽  
Author(s):  
Wenjing Li ◽  
Shun Li ◽  
Lihua Luo ◽  
Yichen Ge ◽  
Jiaqi Xu ◽  
...  
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Ambient Air ◽  
Oxidative Cleavage ◽  
Ambient Conditions ◽  
Blue Led ◽  
Catalyst Free

The catalyst-free oxidative cleavage of (Z)-triaryl-substituted alkenes bearing pyridyl motif with ambient air under irradiation of blue LED at room temperature has been developed. The reaction was facile and scalable,...

On the use of Ozawa/Flynn/Wall method to determine aging activation energy for elastomers

2021 ◽  
pp. 009524432110203
Author(s):  
Sudhir Bafna
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Weight Loss ◽  
Oxygen Consumption ◽  
Dwell Time ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Degradation Mechanism ◽  
Kinetics Of ◽  
Wall Method

It is often necessary to assess the effect of aging at room temperature over years/decades for hardware containing elastomeric components such as oring seals or shock isolators. In order to determine this effect, accelerated oven aging at elevated temperatures is pursued. When doing so, it is vital that the degradation mechanism still be representative of that prevalent at room temperature. This places an upper limit on the elevated oven temperature, which in turn, increases the dwell time in the oven. As a result, the oven dwell time can run into months, if not years, something that is not realistically feasible due to resource/schedule constraints in industry. Measuring activation energy (Ea) of elastomer aging by test methods such as tensile strength or elongation, compression set, modulus, oxygen consumption, etc. is expensive and time consuming. Use of kinetics of weight loss by ThermoGravimetric Analysis (TGA) using the Ozawa/Flynn/Wall method per ASTM E1641 is an attractive option (especially due to the availability of commercial instrumentation with software to make the required measurements and calculations) and is widely used. There is no fundamental scientific reason why the kinetics of weight loss at elevated temperatures should correlate to the kinetics of loss of mechanical properties over years/decades at room temperature. Ea obtained by high temperature weight loss is almost always significantly higher than that obtained by measurements of mechanical properties or oxygen consumption over extended periods at much lower temperatures. In this paper, data on five different elastomer types (butyl, nitrile, EPDM, polychloroprene and fluorocarbon) are presented to prove that point. Thus, use of Ea determined by weight loss by TGA tends to give unrealistically high values, which in turn, will lead to incorrectly high predictions of storage life at room temperature.

scholarly journals Room-Temperature Solution-Processed 0D/1D Bilayer Electrodes for Translucent CsPbBr3 Perovskite Photovoltaics

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1489
Author(s):  
Bhaskar Parida ◽  
Saemon Yoon ◽  
Dong-Won Kang
Keyword(s):  
Solar Cells ◽  
Indium Tin Oxide ◽  
High Performance ◽  
Room Temperature ◽  
Low Cost ◽  
Perovskite Solar Cells ◽  
Ambient Air ◽  
Plasma Damage ◽  
Temperature Solution ◽  
Ito Nanoparticles

Materials and processing of transparent electrodes (TEs) are key factors to creating high-performance translucent perovskite solar cells. To date, sputtered indium tin oxide (ITO) has been a general option for a rear TE of translucent solar cells. However, it requires a rather high cost due to vacuum process and also typically causes plasma damage to the underlying layer. Therefore, we introduced TE based on ITO nanoparticles (ITO-NPs) by solution processing in ambient air without any heat treatment. As it reveals insufficient conductivity, Ag nanowires (Ag-NWs) are additionally coated. The ITO-NPs/Ag-NW (0D/1D) bilayer TE exhibits a better figure of merit than sputtered ITO. After constructing CsPbBr3 perovskite solar cells, the device with 0D/1D TE offers similar average visible transmission with the cells with sputtered ITO. More interestingly, the power conversion efficiency of 0D/1D TE device was 5.64%, which outperforms the cell (4.14%) made with sputtered-ITO. These impressive findings could open up a new pathway for the development of low-cost, translucent solar cells with quick processing under ambient air at room temperature.

scholarly journals Effect of Temperature on the Corrosion Inhibition of Trans-4-Hydroxy-4′-Stilbazole on Mild Steel in HCl Solution

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Ayssar Nahlé ◽  
Ideisan I. Abu-Abdoun ◽  
Ibrahim Abdel-Rahman
Keyword(s):  
Weight Loss ◽  
Double Bond ◽  
Adsorption Isotherm ◽  
Mild Steel ◽  
Corrosion Inhibitor ◽  
Thermodynamic Parameters ◽  
The Other ◽  
Effect Of Temperature ◽  
Temkin Adsorption Isotherm ◽  
Hcl Solution

The inhibition and the effect of temperature and concentration of trans-4-hydroxy-4′-stilbazole on the corrosion of mild steel in 1 M HCl solution was investigated by weight loss experiments at temperatures ranging from 303 to 343 K. The studied inhibitor concentrations were between  M and  M. The percentage inhibition increased with the increase of the concentration of the inhibitor. The percentage inhibition reached about 94% at the concentration of  M and 303 K. On the other hand, the percentage inhibition decreased with the increase of temperature. Using the Temkin adsorption isotherm, the thermodynamic parameters for the adsorption of this inhibitor on the metal surface were calculated. Trans-4-hydroxy-4′-stilbazole was found to be a potential corrosion inhibitor since it contained not only nitrogen and oxygen, but also phenyl and pyridine rings that are joined together with a double bond (–C=C–) in conjugation with these rings.

scholarly journals Session 3 (Joint with the British Dietetic Association): Management of obesity Weight-loss interventions in the treatment of obesity

2009 ◽  
Vol 69 (1) ◽  
pp. 34-38 ◽  
Author(s):  
C. R. Hankey
Keyword(s):  
Physical Activity ◽  
Weight Loss ◽  
Energy Expenditure ◽  
Energy Intake ◽  
Weight Maintenance ◽  
Dietary Advice ◽  
Excess Body Weight ◽  
Lifestyle Interventions ◽  
Post Intervention ◽  
Weight Losses

Treatments to induce weight loss for the obese patient centre on the achievement of negative energy balance. This objective can theoretically be attained by interventions designed to achieve a reduction in energy intake and/or an increase in energy expenditure. Such ‘lifestyle interventions’ usually comprise one or more of the following strategies: dietary modification; behaviour change; increases in physical activity. These interventions are advocated as first treatment steps in algorithms recommended by current clinical obesity guidelines. Medication and surgical treatments are potentially available to those unable to implement ‘lifestyle interventions’ effectively by achieving losses of between 5 kg and 10 kg. It is accepted that the minimum of 5% weight loss is required to achieve clinically-meaningful benefits. Dietary treatments differ widely. Successful weight loss is most often associated with quantification of energy intake rather than macronutrient composition. Most dietary intervention studies secure a weight loss of between 5 kg and 10 kg after intervention for 6 months, with gradual weight regain at 1 year where weight changes are 3–4 kg below the starting weight. Some dietary interventions when evaluated at 2 and 4 years post intervention report the effects of weight maintenance rather than weight loss. Specific anti-obesity medications are effective adjuncts to weight loss, in most cases doubling the weight loss of those given dietary advice only. Greater physical activity alone increases energy expenditure by insufficient amounts to facilitate clinically-important weight losses, but is useful for weight maintenance. Weight losses of between half and three-quarters of excess body weight are seen at 10 years post intervention with bariatric surgery, making this arguably the most effective weight-loss treatment.

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