Search results

The purpose of this paper is to study the effect of vapor assembly sequence and assembly temperature on the corrosion protection of the complex silane films Al alloy. The performance and application range of silane films are enhanced.

The complex silane films were successfully prepared on the surface of aluminum alloy using via vapor phase assembly of 1,2,3-benzotriazole (BTA) and dodecyltrimethoxysilanes (DTMS). The protection of the assembly films against corrosion of Al alloy is investigated by the electrochemical measurements and the alkaline solution accelerated corrosion test. Thickness and hydrophobicity of the complex films are studied using ellipsometric spectroscopy and contact angle tests.

It shows that the anti-corrosion ability of the complex films is overall superior to that of the single-component assembled films. DTMS-BTA films have larger thickness and best anti-corrosion ability. The alkyl chains in DTMS have better compatibility with BTA molecules. The rigid BTA molecule can permeate into the long alkyl chain of DTMS as fillers and improve the barrier properties of the complex films.

In this paper, a green and efficient method of vapor phase assembly is proposed to rust prevention during manufacture of Al alloy workpiece.

The purpose of this study is to investigate the application of non-destructive testing methods in measuring bearing oil film thickness to ensure that bearings are in a normal lubrication state. The oil film thickness is a crucial parameter reflecting the lubrication status of bearings, directly influencing the operational state of bearing transmission systems. However, it is challenging to accurately measure the oil film thickness under traditional disassembly conditions due to factors such as bearing structure and working conditions. Therefore, there is an urgent need for a nondestructive testing method to measure the oil film thickness and its status.

This paper introduces methods for optically, electrically and acoustically measuring the oil film thickness and status of bearings. It discusses the adaptability and measurement accuracy of different bearing oil film measurement methods and the impact of varying measurement conditions on accuracy. In addition, it compares the application scenarios of other techniques and the influence of the environment on detection results.

Ultrasonic measurement stands out due to its widespread adaptability, making it suitable for oil film thickness detection in various states and monitoring continuous changes in oil film thickness. Different methods can be selected depending on the measurement environment to compensate for measurement accuracy and enhance detection effectiveness.

This paper reviews the basic principles and latest applications of optical, electrical and acoustic measurement of oil film thickness and status. It analyzes applicable measurement methods for oil film under different conditions. It discusses the future trends of detection methods, providing possible solutions for bearing oil film thickness detection in complex engineering environments.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

The squeeze‐film characteristics between two parallel rectangular plates with an electrically conducting fluid in the presence of a transverse magnetic field are analyzed. The squeeze‐film Reynolds equation applicable to the curved surfaces is derived using the continuity equation and the magneto‐hydrodynamic (MHD) motion equations. A closed‐form solution is obtained for the squeeze‐film pressure of parallel rectangular plates, and applied to predict the squeeze‐film behavior. According to the results, the presence of magnetic fields signifies an enhancement in the squeeze‐film pressure. On the whole, the magnetic‐field effect characterized by the Hartmann number provides an increase in value of the load‐carrying capacity and the response time as compared to the classical non‐conducting lubricant case, especially for larger values of the aspect ratio or smaller values of film height.

This paper aims to study tuning effects on thick film microstripline due to ferrite thick film overlay.

The possibility of obtaining tuning characteristics in the Ku band microwave region in the absence of external magnetic field by a simple process of using Ni_xZn_1−xFe₂O₄ thick film and bulk as in‐touch overlay over Ag thick film microstripline was investigated. The microstripline is basically a non‐resonant component with high‐transmission at a large microwave frequency band. The ferrite was synthesized by precursor method and the thick films were deposited by screen printing.

It was found that tuning characteristics were observed and composition, thickness and precursor dependent changes occurred. The changes with composition are more prominent in the 14.5‐16.5 GHz range. Also, the ferrite thick film overlay produces a deep notch at 15.7 GHz. It is observed that the pellet overlay also makes the microstripline very dispersive with a high‐insertion loss in the 16‐17 GHz range. The presence of permeability‐related effects interfering with the normal propagation of the microstrip circuits might be causing the changes in the circuits.

Owing to the Ni_xZn_1−xFe₂O₄ overlay the simple microstripline can be tuned to have narrow band filter type of characteristics. Thick film Ni_xZn_1−xFe₂O₄ overlay gives the added advantage of planer configuration along with cost‐effectiveness in the absence of magnetic field.

The purpose of this paper was to examine the film-forming behaviour of simple compositions of polyalphaolefin (PAO) containing an oil-soluble polyalkylene glycol (OSP) alone, a zinc dialkyl dithiophosphate (ZDDP) alone and then combinations of an OSP and ZDDP.

A Mini-Traction Machine with Spacer Layer Imaging technology was used to evaluate friction and film formation under a specific contact pressure, temperature and slide-to-roll ratio. Electrical contact resistance measurements were used to follow surface film formation.

The inclusion of an OSP to a PAO showed evidence of friction-reducing behaviour with low friction values over the rubbing cycle but no significant tribo-film build up. When a ZDDP (1 per cent) is added to the PAO, a thick tribo-film forms of about 100 nm. Addition of an OSP (10 per cent) shows this film still forms despite the OSP being a polar and surface-active additive.

The study was conducted under a narrow range of test conditions (e.g. temperature and contact pressure), and future work will focus on friction and film formation across a broader set of conditions.

Despite OSPs being polar and surface-active, they do not interfere with the ZDDP in forming an anti-wear film in a PAO and, therefore, their inherent properties of good deposit control could enhance the performance of modern lubricants.

OSPs offer promising benefits as friction reducers in PAOs. The research also suggests that OSPs do not negate the formation of ZDDP anti-wear tribo-films when in combination in a PAO.

The purpose of this paper was to demonstrate the influence of a 3-aminopropyl-triethoxysilane–polyacrylic acid (amino propyl silane (APS)-PAA) buffer layer on the tribological performance of copper sulfide (CuS) thin film on silicon (Si) substrate.

The APS-PAA buffer layer was first deposited on Si substrate by a self-assembling method. Then, the deposited film was coated by a CuS film by a successive ionic layer absorption and reaction (SILAR) method. The structures and morphologies of the prepared films were characterized by X-ray diffraction and atomic force microscopy. The results showed that the prepared CuS film with a PAA-APS double layer had a good crystallinity and surface morphology. The tribological performance of the prepared film was analyzed on UMT-2 tribometer and scanning electric microscope.

With use of an APS-PAA buffer layer, the CuS thin films became compact, smooth and uniform. The tribological performance of the CuS film was greatly enhanced by using an APS-PAA buffer layer.

The paper is the first to demonstrate that the CuS film exhibited enhanced structure, morphology and tribological characteristics by using an APS-PAA buffer layer.