Tribological and Wetting Properties of TiO2 Based Hydrophobic Coatings for Ceramics

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Sridhar Lanka ◽  
Evgeniya Alexandrova ◽  
Marina Kozhukhova ◽  
Md Syam Hasan ◽  
Michael Nosonovsky ◽  
...  
Keyword(s):  
Coefficient Of Friction ◽  
Dry Friction ◽  
Civil Engineering ◽  
Future Research ◽  
Ceramic Tiles ◽  
Engineering Applications ◽  
Hydrophobic Coatings ◽  
Wetting Properties ◽  
The Coefficient Of Friction ◽  
Self Cleaning

Hydrophobic and self-cleaning photocatalytic ceramics and concrete with potential for the superhydrophobicity are promising novel materials for civil engineering applications including buildings, bridges, road pavements, and airport runways. Due to embedded liquid-repellent properties, such materials have low water and salt absorption and, therefore, enhanced durability. However, in applications requiring high traction (e.g., tire and pavement), there is a concern that reduced adhesion may compromise the friction. This paper reports on wetting, dry friction, and roughness properties of TiO2 coated (hydrophilic) and polymethyl hydrogen siloxane (PMHS) coated (hydrophobic) self-cleaning ceramic tiles. The coefficient of friction values of the tile–rubber interface do not change significantly with the applications of the coatings up to 0.67 for hydrophilic TiO2 based and up to 0.46 for hydrophobic TiO2 + PMHS coatings versus 0.45 for uncoated reference. Friction has adhesion and roughness-related components and this response can be attributed to the roughness component of friction due to TiO2 coating. The challenges related to hydrophobic coatings, including the durability and future research, are also discussed.

Tribometer for Dry Friction Measurement

1999 ◽  
Author(s):  
Marc Brandl ◽  
Friedrich Pfeiffer
Keyword(s):  
Coefficient Of Friction ◽  
Dry Friction ◽  
Stribeck Curve ◽  
Body System ◽  
Friction Measurement ◽  
Detailed Model ◽  
The Coefficient Of Friction ◽  
Simulation Results ◽  
Multi Body

Abstract This paper deals with the measurement of dry friction. A tribometer was developed in order to identify both the sticking and the sliding coefficient of friction. The aim was to determine the so called Stribeck-curve of any material in contact. The design of the plant is presented. Avoiding errors in recalculating the coefficient of friction, a detailed model of the plant as a multi body system with motor feedback was generated. Advantages of the tribometer are shown in simulations. Some results of measurements in comparison with simulation results are presented.

The Influence of Surface Roughness on the Mechanism of Friction

1970 ◽  
Vol 92 (2) ◽  
pp. 264-272 ◽  
Author(s):  
T. Tsukizoe ◽  
T. Hisakado
Keyword(s):  
Surface Roughness ◽  
Metal Surface ◽  
Coefficient Of Friction ◽  
Dry Friction ◽  
Metal Surfaces ◽  
Roughness Effects ◽  
Real Area Of Contact ◽  
The Coefficient Of Friction ◽  
Tangential Forces ◽  
Soft Metal

A study was made of surface roughness effects on dry friction between two metals, assuming that the asperities are cones of the slopes which depend on the surface roughness. The theoretical explanations were offered for coefficients of friction of the hard cones and spheres ploughing along the soft metal surface. A comparison of calculated values based on these with experimental data shows good agreement. Moreover, theoretical discussion was carried out of surface roughness effects on dry friction between two metal surfaces on the basis of the analyses of the frictional mechanism for a hard slider on the metal surface. The theoretical estimation of the coefficient of friction between two metal surfaces can be carried out by using the relations between the surface roughness and the slopes of the asperities, and the coefficient of friction due to the adhesion at the interface. The experiments also showed that when two metal surfaces are first loaded normally and then subjected to gradually increasing tangential forces, real area of contact between them increases and the maximum tangential microslip of them increases with the increase of the surface roughness.

An Empirical Approach to Modeling the Friction Coefficient for Wheel-Rail Contact

2009 ◽  
Author(s):  
HyunWook Lee ◽  
Corina Sandu ◽  
Carvel Holton ◽  
Mehdi Ahmadian
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Dry Friction ◽  
Damping Ratio ◽  
Contact Dynamics ◽  
Nonlinear Dependence ◽  
Accurate Estimation ◽  
Highly Nonlinear ◽  
The Coefficient Of Friction ◽  
Wheel Vibration

The coefficient of friction (CoF) is one of the most important parameters for the contact between the wheel and the rail. Accurate estimation or measurement of the CoF has a very important role, both in terms of modeling the train dynamics and in terms of reducing operational costs in the long-term. For ease of implementation, since the nature of the wheel-rail contact dynamics is very complex, the assumption of a constant CoF is still used in most theoretical studies. Nevertheless, experimental work indicates that the CoF depends on dynamic changes in various wheel-rail conditions, like sliding velocity, contact patch shape and size for stick and sliding region, wheel and rail geometry, wheel vibration, rail surface roughness and/or lubrication, etc. In this paper we present the proposed equation to model the nonlinear dry friction coefficient at the wheel-rail contact. The friction coefficient is calculated at the three different values for change in the damping ratio while maintaining all the other conditions the same. As expected, the analysis performed to estimate the dry friction coefficient based on the proposed equation and using NUCARS® simulation results shows that the coefficient of friction has a highly nonlinear dependence on its parameters.

scholarly journals Effect of Bulk Current Density on Tribological Properties of Fe-W, Co-W and Ni-W Coatings

2015 ◽  
Author(s):  
S.A. Silkin ◽  
A.V. Gotelyak ◽  
N. Tsyntsaru ◽  
A.I. Dikusar ◽  
R. Kreivaitis ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Coefficient Of Friction ◽  
Current Density ◽  
Dry Friction ◽  
Scratch Test ◽  
Tribological Behaviour ◽  
The Coefficient Of Friction ◽  
Current Densities ◽  
Scratch Tests ◽  
The Given

Evaluation of tribological behaviour of Fe-W, Ni-W and Co-W coatings produced by electrodeposition at various bulk current densities (BCD) was under investigation in the given study. BCD does not have essential effect on the microhardness and wear characteristics of Fe-W and Co-W coatings. But the scratch tests reveal the presence of such influence. These tests showed superior wear resistance for the coatings obtained at low BCD. It was found that BCD has influence on wear resistance of Ni-W coatings under dry friction conditions. The BCD also has an influence on the coefficient of friction of Fe-W and Ni-W coatings at dry friction conditions. However, such an effect is opposite to that, observed at the scratch test.

scholarly journals Study of tribological properties of epoxy and resins composites under technically dry friction conditions

2018 ◽  
Vol 19 (12) ◽  
pp. 658-661
Author(s):  
Sylwester Stawarz ◽  
Magdalena Stawarz ◽  
Robert Gumiński ◽  
Wojciech Kucharczyk
Keyword(s):  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Dry Friction ◽  
Friction And Wear ◽  
Surface Condition ◽  
Selective Transfer ◽  
X Ray ◽  
Tribological Tests ◽  
Transfer Phenomenon ◽  
The Coefficient Of Friction

The article discusses the results of tribological tests of epoxy and resol composites. There was examined the surface condition of samples of composites operating in sliding nodes. It has been found that it is possible to use cheaper resole resins for sliding composites (instead of Epidian 5). Tests that have been carried out showed that increasing the PTFE content in the composite resulted in lowering both the coefficient of friction and wear. X-ray analysis results con-firmed the occurrence of the selective transfer phenomenon

Effect of artificial aging on the tribological properties of an Al-25Zn-1Mg alloy

2021 ◽  
Vol 63 (9) ◽  
pp. 836-841
Author(s):  
Recai Fatih Tunay ◽  
Hayder Isam Abdulzahra Al Saadi
Keyword(s):  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Dry Friction ◽  
Aging Process ◽  
Artificial Aging ◽  
Solution Treatment ◽  
Process Solution ◽  
Test Speed ◽  
The Coefficient Of Friction ◽  
Increasing Load

Abstract The tribological properties of aluminum based Al-25Zn-1Mg alloy was experimentally investigated in an MSc thesis, and the results are presented in this study. To this purpose, Al-25Zn-1Mg was commercially produced by casting. The prepared samples were divided into seven groups: no-process, solution treatment, and artificial aging for 1, 3, 6, 12 and 24 hours. Aged and untreated samples were subjected to tribological experiments under conditions of dry friction under 5 N and 10 N loads at speed of 200 rpm, 400 rpm and 800 rpm for a distance of 500 m. As a result of the tests, it was found that hardness increases in all samples depending on the aging process. It was also found that when the test speed was kept constant, the coefficient of friction increased with increasing load.

A PIEZOELECTRIC CONTACT PROBLEM WITH SLIP DEPENDENT COEFFICIENT OF FRICTION

2004 ◽  
Vol 9 (3) ◽  
pp. 229-242 ◽  
Author(s):  
M. Sofonea
Keyword(s):  
Mathematical Model ◽  
Weak Solution ◽  
Contact Problem ◽  
Coefficient Of Friction ◽  
Dry Friction ◽  
Variational Formulation ◽  
Frictional Contact ◽  
Coupled System ◽  
Piezoelectric Body ◽  
The Coefficient Of Friction

We consider a mathematical model which describes the static frictional contact between a piezoelectric body and an obstacle. The constitutive relation of the material is assumed to be electroelastic and involves a nonlinear elasticity operator. The contact is modelled with a version of Coulomb's law of dry friction in which the coefficient of friction depends on the slip. We derive a variational formulation for the model which is in form of a coupled system involving as unknowns the displacement field and the electric potential. Then we provide the existence of a weak solution to the model and, under a smallness assumption, we provide its uniqueness. The proof is based on a result obtained in [14] in the study of elliptic quasi‐variational inequalities.

The Nature of Static Friction in Elastomers

1961 ◽  
Vol 34 (2) ◽  
pp. 461-465 ◽  
Author(s):  
G. M. Bartenev ◽  
V. V. Lavrent'ev
Keyword(s):  
Coefficient Of Friction ◽  
Dry Friction ◽  
Tangential Force ◽  
Static Friction ◽  
Initial Moment ◽  
Elastomeric Materials ◽  
The Coefficient Of Friction ◽  
Accuracy Of Measurement

Abstract 1. A method free from the shortcomings of earlier work is proposed for the measurement of the friction of elastomeric materials in the initial moment of shear. 2. From results of measurement of friction of rubber on steel it follows that static friction, determined as the coefficient of friction in the initial moment of slip, is a conventional parameter, since it depends upon the accuracy of measurement of the movement and upon the rate of application of the tangential force. 3. The conventional coefficient of static friction of elastomeric materials is particularly evident at low rates of application of the tangential force, which fact is connected with the nature of dry friction of rubberlike polymers.

MECHANICAL AND TRIBOLOGICAL PROPERTIES OF PROTECTIVE AND RECOVERING COATINGS OF THE WORKING CHAMFER OF INTERNAL COMBUSTION ENGINE VALVES

2021 ◽  
Vol 2 (143) ◽  
pp. 135-143
Author(s):  
Aleksey G. Ipatov ◽  
◽  
Kirill G. Volkov ◽  
Evgeniy V. Kharanzhevskiy ◽  
Keyword(s):  
Coefficient Of Friction ◽  
Dry Friction ◽  
Combustion Engine ◽  
Economic Effect ◽  
Combustion Products ◽  
Operating Conditions ◽  
Research Purpose ◽  
Steady Increase ◽  
Valve Seat ◽  
The Coefficient Of Friction

Over the past 7-10 years, there has been a steady increase in the cost of gasoline and gas fuel. This circumstance forces the enterprises operating automotive equipment to switch to the use of gas-powered fuel. (Research purpose) The research purpose is in creating a protective and recovering coating that can withstand the wear of the working chamfer of the valve caused by high operating temperatures, dry friction in the valve–seat interface, as well as high flow rates of exhaust gas. (Materials and methods) The article presents an analysis of a priori information, which resulted in the following powder compositions: Ni- ZrO2-SiC; Ni–B4C–BN–ZrO2; Ni–B4C–ZrO2–MgO; Ni-B4C. The samples were subjected to tests on the SMT 2070 friction machine under boundary friction conditions to determine the tribological parameters of coatings made of these materials. The parameters of the friction moment and the coefficient of friction were taken during the tests, depending on the applied load on the tribo-coupling. (Results and discussion) At the first stage of the research, the microhardness of the coatings was analyzed. Tribological studies were performed depending on the microhardness of the coatings. Along with the economic effect, there are negative factors that affect the performance of the valve-seat coupling: increased temperatures up to 750-800 degrees Celsius, the transition to dry friction, high exhaust rates of combustion products (over 1000 meters per second). The best value of the coefficient of friction obtained during the tests belongs to the composition Ni–ZrO2–SiC, which takes values below 0.1. (Conclusions) The use of standard and well-known methods of protecting the working chamfer of the valve in this case is ineffective, since it does not provide the required operating conditions. The article recommens the use of Ni-ZrO2-SiC as the material of the protective and restorative coating of the working chamfer of the valve.

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