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Article
Publication date: 21 October 2022

Longxiao Zhang and Ting Xie

The purpose of this paper is to explore the geometric parameter difference of the terrace-like structural transfer film under different working parameters [pressure and…

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Abstract

Purpose

The purpose of this paper is to explore the geometric parameter difference of the terrace-like structural transfer film under different working parameters [pressure and velocity (PV) values] and filled particle types (three fillers: SiO2, TiO2 and ZnO), and find the geometric parameter related to the wear of polytetrafluoroethylene (PTFE)-based composites.

Design/methodology/approach

PTFE composites were filled with SiO2, TiO2 and ZnO particles, and the morphology parameter of the PTFE composite transfer film under different PV values obtained from the rotary reciprocating pin-on-disk frictional tester was quantified by using a three-dimensional laser scanning microscope.

Findings

The results showed that the effective layer coverage rate and effective thickness of the transfer film had a good relationship with the wear of the three PTFE composites. On the whole, increasing the speed or load was helpful to increase the effective thickness of the three PTFE composite transfer films, but reduced the effective layer coverage rate. The greater the effective layer coverage rate and effective thickness of the transfer film, the better the wear resistance of the PTFE composites in the entire speed and load range.

Originality/value

This work will promote further understanding of the transfer film and lay a foundation for realizing its morphology regulation and improving the wear of the PTFE composites.

Details

Industrial Lubrication and Tribology, vol. 75 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 12 July 2022

Yue Dai, Qing Wang, Yongbin Zhang, Guangmin Liu, Lin Zhang and Feng Wang

The purpose of this paper is to explore the optimum average current density and pulse width for electrodeposition of gold in citrate electrolyte, and it is verified that…

Abstract

Purpose

The purpose of this paper is to explore the optimum average current density and pulse width for electrodeposition of gold in citrate electrolyte, and it is verified that the uniformity of film thickness can be effectively improved by periodic pulse reverse electroplating.

Design/methodology/approach

Apply forward pulse current, forward group pulse current and periodic pulse reverse current to the electrolyte and compare the film quality. High-frequency group pulses are used in both forward and reverse directions of the periodic pulse reverse current.

Findings

It is verified by experiments that periodic pulse reverse plating is superior to forward pulse plating and forward group pulse plating in terms of particle size, compactness, impurity content and thickness uniformity of the film. Add low-frequency vibration to the cathode under the same pulse electrical parameters as a comparative experiment to prove the beneficial effect of vibration on the allowable limiting current density and plating rate.

Originality/value

Gold film is often used as the sealing layer of precision parts. Increasing the thickness uniformity and improving the compactness of gold film will help to reduce the size error, improve the subsequent assembly accuracy and increase the service life of wear-resistant layer. Citrate gold plating electrolyte combines the advantages of cyanide electrolyte and cyanide-free electrolyte. Hence, this research focuses on the characteristics of periodic pulse reverse plating in terms of particle size, compactness, impurity content and thickness uniformity of the film and compare it with forward pulse plating and forward group pulse plating.

Details

Anti-Corrosion Methods and Materials, vol. 69 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 8 August 2022

Rongrong Li, Yanguo Yin, Kaiyuan Zhang, Ruhong Song and Qi Chen

This paper aims to investigate how ball milling (BM) and load influence transfer film on counterbody and the correlation between transfer film and tribological properties…

Abstract

Purpose

This paper aims to investigate how ball milling (BM) and load influence transfer film on counterbody and the correlation between transfer film and tribological properties of copper-based composites.

Design/methodology/approach

The copper-based mixed powders preprocessed by BM for different times were used to manufacture sintered materials. Specimens were tested by a custom pin-on-flat linear reciprocating tribometer and characterized prior and after tests by optical microscope, scanning electron microscope and energy-dispersive spectroscopy. Image J® and Taylor-hobson-6 surface roughness meter were used to quantify the coverage and thickness of the transfer film.

Findings

Main results show that an appropriate amount of BM time and applied load can contribute to the formation of the transfer film on counterbody and effectively improve the tribological properties of the copper-based material. The transfer film coverage is linearly related to the friction coefficient, thickness of transfer film and wear volume. As the transfer film coverage increases, the coefficient of friction decreases. As the thickness of the transfer film increases, the amount of wear increases.

Originality/value

This work intends to control and optimize the formation of transfer film, thereby helping improve the tribological properties of materials and providing a reference to guide the preparation of Cu-based composites with excellent tribological properties.

Details

Industrial Lubrication and Tribology, vol. 74 no. 9
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 3 June 2022

Chengchang Niu, Shiqing Deng, Yu Yan, Leigang Wu, Ran Tao and Jun Chen

The purpose of this paper is to fill the knowledge gap in the microscopic origin of high corrosion resistance in the passivated 316 L stainless steel.

Abstract

Purpose

The purpose of this paper is to fill the knowledge gap in the microscopic origin of high corrosion resistance in the passivated 316 L stainless steel.

Design/methodology/approach

Here, the pitting corrosion potential of the passivated 316 L stainless steel is measured, as well as the non-passivated one. Using the aberration-corrected scanning transmission electron microscopy, the microstructure of the passive film is unambiguously revealed. Combining the electron energy loss spectroscopy with the X-ray photoelectron spectroscopy, the depth profiling analysis is conducted and the variations in composition from the very surface of the passive film to the internal steel are clarified.

Findings

By optimizing the passivation treatment process, the authors significantly increase the pitting corrosion potential of the passivated 316 L stainless steel by 300 mV, compared with the non-passivated one. The passive film features a unique amorphous multilayer structure. On the basis of the depth profiling analysis, the origin of the high corrosion resistance achieved is unraveled, in which the redistribution of elements in the multilayer passive film, especially the enrichment of Cr in the topmost layer and Ni at the film-metal interface, prevent the oxidization of the inner iron of the steel.

Originality/value

This study advances understanding of the nature of the passive film from a microscopic view, which can be helpful for the further improvement of the corrosion resistance performance.

Graphical Abstract

This study introduces a model for the multilayer structure of passive films that reveals the reconstitution of the passive films after the opportune passivation treatments. Due to the redistribution of elements caused by passivation, the enrichment of Cr in the outer layer and Ni near the film-metal interface leads to enhance corrosion resistance performance.

Details

Anti-Corrosion Methods and Materials, vol. 69 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 12 May 2022

Cheng Zhang, Jianfeng Zhou and Xiannian Meng

In the magnetorheological fluid (MRF) sealing, a large amount of friction heat is generated in the fluid film with micron thickness due to the viscosity dissipation, which…

Abstract

Purpose

In the magnetorheological fluid (MRF) sealing, a large amount of friction heat is generated in the fluid film with micron thickness due to the viscosity dissipation, which leads to seal failure and MRF deterioration. The purpose of this study is to investigate the mechanism of temperature rise of MRF film under the action of the three-field coupling of the flow field, temperature field and magnetic field.

Design/methodology/approach

The fluid film was simplified as a Couette flow in this work to simulate the temperature change in the sealing fluid film under different working conditions. The corresponding experiment for test the temperature rise was also carried out, and the temperature of the characteristic point of the stationary ring was measured to validate the model.

Findings

The results show that the temperature rise is mainly affected by the rotational speed, magnetic field strength and fluid film thickness. The magnetic field enhances the convective heat transfer in the MRF film. The thinner the fluid film, the more frictional heat generated. The MRF film reaches its maximum temperature at the contact with the end face of rotating ring due to frictional heat.

Originality/value

A method for temperature rise analysis of MRF fluid sealing films based on Couette flow is established. It is helpful for the study of liquid film frictional heat in MRF seals.

Details

Industrial Lubrication and Tribology, vol. 74 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 25 February 2022

Jiabao Pan, Huaibiao Wu, Ao Wang, Qingwen Dai and Xiaolei Wang

This paper aims to investigate the influence of high-temperature thermal action on grease performance from the angle of film-forming performance.

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Abstract

Purpose

This paper aims to investigate the influence of high-temperature thermal action on grease performance from the angle of film-forming performance.

Design/methodology/approach

A static thermal aging method was used to prepare high-temperature thermal grease samples after high-temperature thermal action. On the basis of optical interference technology, the film-forming characteristics of fresh grease samples and the grease samples after high-temperature thermal action under variable speed and fixed speed conditions were explored.

Findings

The decrease in the structural entanglement performance of the grease after short-term high-temperature thermal action makes its film-forming performance better. The mechanism is that the lubricating grease soap fiber entanglement is reduced. Although the continuous high-temperature thermal action can make the grease film-forming performance better, its mechanism is that the soap fiber structure caused by high-temperature thermal action is damaged and is easy to be cut off under the action of shear.

Originality/value

The effect of structural system change on its film formation performance was discussed in combination with the change in grease structure characteristics, and the mechanism of action was revealed.

Details

Industrial Lubrication and Tribology, vol. 74 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 2 February 2023

Shanmugan Subramani and Mutharasu Devarajan

Polymer-based thermal interface materials (TIMs) are having pump out problem and could be resolved for reliable application. Solid-based interface materials have been…

Abstract

Purpose

Polymer-based thermal interface materials (TIMs) are having pump out problem and could be resolved for reliable application. Solid-based interface materials have been suggested and reported. The purpose of this paper is suggesting thin film-based TIM to sustain the light-emiting diode (LED) performance and electronic device miniaturization.

Design/methodology/approach

Consequently, ZnO thin film at various thicknesses was prepared by chemical vapour deposition (CVD) method and tested their thermal behaviour using thermal transient analysis as solid TIM for high-power LED.

Findings

Low value in total thermal resistance (Rth-tot) was observed for ZnO thin film boundary condition than bare Al boundary condition. The measured interface (ZnO thin film) resistance {(Rth-bhs) thermal resistance of the interface layer (thin film) placed between metal core printed circuit board (MCPCB) board and Al substrates} was nearly equal to Ag paste boundary condition and showed low values for ZnO film prepared at 30 min process time measured at 700 mA. The TJ value of LED mounted on ZnO thin film (prepared at 30 min.) coated Al substrates was measured to be 74.8°C. High value in junction temperature difference (ΔTJ) of about 4.7°C was noticed with 30 min processed ZnO thin film when compared with Al boundary condition. Low correlated colour temperature and high luminous flux values of tested LED were also observed with ZnO thin film boundary condition (processed at 30 min) compared with both Al substrate and Ag paste boundary condition.

Originality/value

Overall, 30 min CVD processed ZnO thin film would be an alternative for commercial TIM to achieve efficient thermal management. This will increase the life span of the LED as the proposed material decreases the TJ values.

Details

Microelectronics International, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 19 May 2021

Yanqiu Xia, Yanan Cao, Xin Feng and Haris M_ P_

The purpose of this paper is to compare the electrical conductivity and tribological properties of magnetron sputtered silver (Ag), copper (Cu) and aluminum (Al) thin films

Abstract

Purpose

The purpose of this paper is to compare the electrical conductivity and tribological properties of magnetron sputtered silver (Ag), copper (Cu) and aluminum (Al) thin films under conductive grease lubrication.

Design/methodology/approach

Three types of silver (Ag), copper (Cu) and aluminum (Al) thin films were prepared by magnetron sputtering. Current-carrying friction tests were carried out by a ball-on-plate reciprocating friction and wear tester. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) were used to observe and analyze the worn surface and cross-section morphology of the films.

Findings

Silver and Cu films exhibited good conductivity and tribological properties, which were mainly attributed to the synergy of the protective tribofilm generated by conductive grease, current-induced thermal effect and magnetron sputtered films effect. Al film was worn through. Large pitting storing lubricate were only found in Ag film. Cu film showed a similar surface uniformity with Ag film.

Originality/value

This study provides a reference for the design and application of conductive grease and investigates the current-carrying friction behaviors of magnetron sputtered films as electrical contact materials. The comparison of current-carrying friction behaviors of the three films was rarely covered in previous studies.

Details

Industrial Lubrication and Tribology, vol. 73 no. 10
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 14 September 2010

Qi Zheng Li, Yu Zuo, Jing Mao Zhao, Yu Ming Tang, Xu Hui Zhao and Jin Ping Xiong

By adding a Ce salt and an Nd salt to an anodizing electrolyte, modified anodic films are obtained on aluminum surfaces. This paper aims to study the effects of rare‐earth…

Abstract

Purpose

By adding a Ce salt and an Nd salt to an anodizing electrolyte, modified anodic films are obtained on aluminum surfaces. This paper aims to study the effects of rare‐earth elements on the corrosion resistance of the anode film.

Design/methodology/approach

The crystalline film was studied by X‐ray diffraction. The methods of scanning electron microscope, energy dispersive X‐ray analysis, electrochemical polarization, and electrochemical impedance spectroscopy (EIS) were used to characterize the properties of the films.

Findings

After rare‐earth element modification, the pores of the porous layer were very evidently smaller, the anodic film was more compact, and the thickness and hardness of the films had increased. The corrosion resistance of the anodic films modified with rare‐earth elements clearly was improved in neutral, acidic, and basic NaCl solutions. Ce showed a better effect than Nd in increasing the corrosion resistance of the films, and the film modified with Ce+Nd showed the highest corrosion resistance. EIS analysis showed that the impedances of both the barrier layer and porous layer of the anodic films increased after modification with the rare‐earth elements, indicating that the anodizing process was affected by the presence of the rare‐earth elements.

Originality/value

The results presented in this paper offer a foundation for further research and application of rare‐earth elements in aluminum anodic oxide films.

Details

Anti-Corrosion Methods and Materials, vol. 57 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 1 February 1955

BERNARD CHIBNALL

The National Film Library was established in 1935. Since that time, under the guidance of Ernest Lindgren, the Curator, it has grown into a collection of 6,000 films

Abstract

The National Film Library was established in 1935. Since that time, under the guidance of Ernest Lindgren, the Curator, it has grown into a collection of 6,000 films dating from 1895.

Details

Journal of Documentation, vol. 11 no. 2
Type: Research Article
ISSN: 0022-0418

1 – 10 of over 34000