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Article
Publication date: 10 August 2020

Wen Zhan, Shengpeng Zhan, HaiTao Duan, Xinxiang Li, Jian Li, Bingxue Cheng and Chengqing Yuan

This paper aims to study the thermal oxidation performance of antioxidant additives in ester base oils deeply.

Abstract

Purpose

This paper aims to study the thermal oxidation performance of antioxidant additives in ester base oils deeply.

Design/methodology/approach

ReaxFF molecular dynamics was used to simulate the thermal oxidation process of butyl octyl diphenylamine and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate as two antioxidant additives act on the Trimethylolpropane trioleate (TMPTO) base oil. Meanwhile, combining with the infrared spectroscopy characterization results of the thermal oxidation test, this paper provides theoretical support for the development of high-performance synthetic lubricants and their antioxidant additives.

Findings

The results show that butyl octyldiphenylamine easily removes the hydrogen atom on the secondary amine, which promotes the formation of more long carbon chain diene radicals or polyene hydroperoxides from TMPTO. Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate could easily decompose into octadecyl hydroperoxide and 2,6-di-tert-butyl 4-propionylphenol, which could convert into 2-tert-butyl-4-peroxyethyl-6-hydroperoxy-tert-butylphenol in the middle of the thermal oxidation reaction, prompting TMPTO to form more short-chain alkenyl and olefin hydroperoxide or other oxide.

Originality/value

The main change characteristics of base oil molecules are the first thermal decomposition to form oleic acid groups and ethane cyclopropane methyl oleate. Under the action of butyl octyldiphenylamine and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate, the deep oxidation and decomposition reaction are slowed down.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0037/

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Article
Publication date: 9 August 2019

Jinsong Luo, Ligong Zhang, Haigui Yang, Nan Zhang, Yongfu Zhu, Xingyuan Liu and Qing Jiang

This paper aims to study the oxidation kinetics of the nanocrystalline Al ultrathin films. The influence of structure and composition evolution during thermal oxidation

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Abstract

Purpose

This paper aims to study the oxidation kinetics of the nanocrystalline Al ultrathin films. The influence of structure and composition evolution during thermal oxidation will be observed. The reason for the change in the oxidation activation energy on increasing the oxidation temperature will be discussed.

Design/methodology/approach

Al thin films are deposited on the silicon wafers as substrates by vacuumed thermal evaporation under the base pressure of 2 × 10−4 Pa, where the substrates are not heated. A crystalline quartz sensor is used to monitor the film thickness. The film thickness varies in the range from 30 to 100 nm. To keep the silicon substrate from oxidation during thermal oxidation of the Al film, a 50-nm gold film was deposited on the back side of silicon substrate. Isothermal oxidation studies of the Al film were carried out in air to assess the oxidation kinetics at 400-600°C.

Findings

The activation energy is positive and low for the low temperature oxidation, but it becomes apparently negative at higher temperatures. The oxide grains are nano-sized, and γ-Al2O3 crystals are formed at above 500°C. In light of the model by Davies, the grain boundary diffusion is believed to be the reason for the logarithmic oxidation rate rule. The negative activation energy at higher temperatures is apparent, which comes from the decline of diffusion paths due to the formation of the γ-Al2O3 crystals.

Originality/value

It is found that the oxidation kinetics of nanocrystalline Al thin films in air at 400-600°C follows the logarithmic law, and this logarithmic oxidation rate law is related to the grain boundary diffusion. The negative activation energies in the higher temperature range can be attributed to the formation of γ-Al2O3 crystal.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 1 April 1991

J.P. Peng, D. Chidambarrao and G.R. Srinivasan

We have developed a computer oxidation modeling program, named NOVEL, which has been integrated into our process simulator FINDPRO. It combines the modified Deal‐Grove…

Abstract

We have developed a computer oxidation modeling program, named NOVEL, which has been integrated into our process simulator FINDPRO. It combines the modified Deal‐Grove growth rate model with a nonlinear viscoclastic deformation model to predict both the oxide shape and stress. Modeling the thermal oxidation of silicon presents several numerical challenges. First, the oxide region expands and deforms extensively during the process which has to be modeled as a moving boundary, large deformation problem. Second, the SiO2 mechanical property changes from clastic to viscoclastic to viscous as the processing temperature is changed from a value below the the glass transition temperature (960°C) to one above it. The viscoclastic deformation model which is adequate over the entire temperature range of interest has an intrinsic numerical singularity when the oxide viscosity (divided by time) becomes relatively lower than the elastic modulus at high temperatures. These must be handled appropriately to ensure that the modeled results are correct. In this paper, we present details of how NOVEL solves the above mentioned problems. We show examples of low temperature/high pressure oxidation of a LOCOS structure, trench isolation structure, and the technique by which the finite element program NOVEL interfaces with the finite difference process simulator FINDPRO.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 10 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 February 1993

I. Artaki, U. Ray, H.M. Gordon and R.L. Opila

The emergence of new interconnection technologies involving double‐sided surface mounted components has put stronger restrictions on the method of preserving the…

Abstract

The emergence of new interconnection technologies involving double‐sided surface mounted components has put stronger restrictions on the method of preserving the solderable finish on printed circuit (PC) boards. The popular Sn/Pb coatings have come under strong scrutiny due to environmental hazards of lead and also because they do not provide flat, planar surfaces for SM assembly. Organic solderability preservative coatings (OSP) are emerging as strong contenders for replacing Sn/Pb surface finishes. Benzotriazole based organic coatings have been successfully used in the past by several electronics manufacturers. However, assembly technologies involving multiple thermal operations have necessitated a fundamental understanding of the thermal stabilities and the mechanism of corrosion protection provided by the OSPs. This paper reports the results of an investigation of the thermal stabilities of two organic corrosion protection coatings. Although both are organic azole based, they operate in two distinct regimes: one forming thin films (∼100 Å) and the other forming thick films (∼5000 Å). The mechanism of surface protection has been studied using direct surface analytical techniques such as X‐ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), scanning transmission electron microscopy (SEM/TEM) and Fourier transform infrared spectroscopy (FT‐IR). The solderability of the copper was measured by wetting balance techniques and correlated to the amount of copper oxidation. The results indicate that, although the thin films provide excellent protection for storage and handling operations, they decompose under heat, thereby causing oxidation of the copper. The thick films appear to withstand multiple thermal cycling. However, the underlying copper substrate can still be oxidised by oxygen diffusion through pores or cracks, or the film may undergo chemical changes that render the copper unsolderable.

Details

Circuit World, vol. 19 no. 3
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 1 April 1992

G.V. Gadiyak, J.L. Korobitsina and V.I. Kranarenko

Computer code complex for the thermal oxidation of silicon is presented. There are one‐dimensional model and two‐ dimensional models:the model of viscoelastic oxide and…

Abstract

Computer code complex for the thermal oxidation of silicon is presented. There are one‐dimensional model and two‐ dimensional models:the model of viscoelastic oxide and the hydrodynamical models — an ideal fluid and a viscous fluid models. If nitride mask is absent, a one‐dimensional model is used.The influence of an induced stress on the diffusion and reaction is taken into account.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 11 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 December 1998

Hanshan Dong and Tom Bell

Despite their outstanding combination of properties, titanium and its alloys are very susceptible to severe adhesive wear in rubbing with almost all the engineering…

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Abstract

Despite their outstanding combination of properties, titanium and its alloys are very susceptible to severe adhesive wear in rubbing with almost all the engineering surfaces and can exhibit poor corrosion resistance in some aggressive environments. Surface engineering research centred at the University of Birmingham has been focused on creating designed surfaces for titanium components. Great progress has been made recently through the development of such novel surface engineering techniques as thermal oxidation, palladium‐treated thermal oxidation, oxygen diffusion and duplex systems. Such advances thus provide scope for designing titanium components for a diversified range of engineering applications, usually as direct replacements for steel components. By way of example, some of our successful steps towards titanium designed surfaces are demonstrated. To date, the potential of these novel techniques has been realised first in auto‐sport and off‐shore industries.

Details

Industrial Lubrication and Tribology, vol. 50 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 1 December 1980

R.H. WEDGE and A.V. EAVES

One of a series of papers presented at a Symposium on the Cost Effectiveness of Sprayed Metal Coatings, organised by the Association of Metal Sprayers.

Abstract

One of a series of papers presented at a Symposium on the Cost Effectiveness of Sprayed Metal Coatings, organised by the Association of Metal Sprayers.

Details

Aircraft Engineering and Aerospace Technology, vol. 52 no. 12
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 January 1977

Andrew G. Papay

GEAR oil testing is an enterprise involving large numbers of people and equipment and costing millions of dollars per year. It is used as a guide in the development of new…

Abstract

GEAR oil testing is an enterprise involving large numbers of people and equipment and costing millions of dollars per year. It is used as a guide in the development of new gear lubricants (or even new machines) and also serves broad quality control purposes. Since the gear oil business is a multimillion dollar area and since it is serving a multibillion dollar automotive and industrial investment around the world, spending for gear oil testing can be well worth the costs. However, as in every other aspect of business, cost reduction in gear oil testing is becoming more and more a demand of the times. It is therefore important to take a critical look at the expenses incurred in this area, and decide if some of the tests can be eliminated without detrimental effects.

Details

Industrial Lubrication and Tribology, vol. 29 no. 1
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 17 June 2021

Fikrat Yusubov

The purpose of this paper is to investigate the influence of binder effect on tribological behavior of brake friction composite materials: a case study of phenolic resin…

Abstract

Purpose

The purpose of this paper is to investigate the influence of binder effect on tribological behavior of brake friction composite materials: a case study of phenolic resin modified by N-Methylaniline.

Design/methodology/approach

Four different friction materials have been fabricated by varying modified phenolic resin content. The samples were prepared by the conventional powder metallurgy methods following ball milling, mixing, pre-forming, hot pressing and post-curing processes. Thermogravimetric analysis was used to determination of the degradation mechanism of organic components and study of thermal stability of the samples. A friction test was carried out in dry conditions using a vertical tribometer. Analysis of worn surfaces was performed using a scanning electron microscope.

Findings

The experimental results revealed that the sample containing 25 Wt.% phenolic resin has good mechanical and thermal properties with stable friction characteristics.

Originality/value

This paper presents the effect of N-methylaniline modified phenolic resin on friction composites to improve tribological performance by its thermal properties.

Details

Industrial Lubrication and Tribology, vol. 73 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 1 March 1963

P.H. MOLYNEUX

THE BENEFIT of lubricants and of additives an “lubricant modifiers” has been known for centuries. For example, animal fat was used to reduce friction and thus squeaking…

Abstract

THE BENEFIT of lubricants and of additives an “lubricant modifiers” has been known for centuries. For example, animal fat was used to reduce friction and thus squeaking, of Roman chariot wheels sulphur was employed to aid the machining of iron during the Industrial Revolution, The type of additives which will be discussed in this paper are, however, of more recent origin and are complex chemical compounds which are added in controlled quantities to lubricating fluids to enhance or modify their specific natural properties.

Details

Industrial Lubrication and Tribology, vol. 15 no. 3
Type: Research Article
ISSN: 0036-8792

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