Adaptive Solid Lubricant Transfer Films for Conductivity and Oxidation Control

2012 ◽  
Author(s):  
Patrick S. M. Dougherty ◽  
Cecily M. Sunday ◽  
C. Fred Higgs
Keyword(s):  
Solid Lubricant ◽  
Composite Coatings ◽  
Solid Lubricants ◽  
Operating Conditions ◽  
Low Friction ◽  
Composite Powders ◽  
Electrically Conductive ◽  
Transfer Films ◽  
Oxidation Resistant ◽  
Complex Deposition

The success of solid lubricants to exhibit ultra-low friction and wear behaviors in oil-prohibiting environments, has led to a major effort to optimize their performance and enhance their applicability. Depending on the operating conditions, solid lubricants may take on a plethora of forms including fabricated composite coatings, thick-film powder lubricants, nano-particle additives for hard surfaces or liquid lubricants, and self-replenishing transfer films. One of the benefits of transfer films are their freedom from the complex deposition techniques required for most other solid lubricant systems. In this work, the potential for adaptive self-replenishing transfer films was explored by creating composite powders of well-known powder lubricants and electrically conductive or anti-oxidation materials. MoS2, WS2, and Graphite Powders were mixed in varying composition with Cu, Sb2O3, and BO3 additives and compacted to form “tuned” or adaptive powder pellets. Relationships between friction, wear, electrical resistance, tribo-induced oxidation and powder composition, will be presented in order to investigate the potential of composite property optimization for lubricious, highly conductive, and oxidation resistant transfer films.

Tribological Behavior of Ni-Based Self-Lubricating Composites at Elevated Temperatures

2015 ◽  
pp. 72-106
Author(s):  
Jianliang Li ◽  
Dangsheng Xiong ◽  
Yongkun Qin ◽  
Rajnesh Tyagi
Keyword(s):  
High Temperature ◽  
Friction And Wear ◽  
Solid Lubricant ◽  
Elevated Temperatures ◽  
Wear Behavior ◽  
Composite Coatings ◽  
Solid Lubricants ◽  
Friction And Wear Behavior ◽  
Nickel Base ◽  
Self Lubricating Composites

This chapter illustrates the effect of the addition of solid lubricants on the high temperature friction and wear behavior of Ni-based composites. Ni-based composites containing solid lubricant particles both in nano and micrometer range have been fabricated through powder metallurgy route. In order to explore the possible synergetic action of a combination of low and high temperature solid lubricant, nano or micro powders of two or more solid lubricants were added in the composites. This chapter introduces the fabrication of the Ni-based self-lubricating composites containing graphite and/or MoS2, Ag and/or rare earth, Ag and/or hBN as solid lubricants and their friction and wear behavior at room and elevated temperatures. The chapter also includes information on some lubricating composite coatings such as electro-deposited nickel-base coating containing graphite, MoS2, or BN and graphene and their tribological characteristics.

scholarly journals Understanding the Unique Role of Phospholipids in the Lubrication of Natural Joints: An Interfacial Tension Study

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 264 ◽  
Author(s):  
Aneta D. Petelska ◽  
Katarzyna Kazimierska-Drobny ◽  
Katarzyna Janicka ◽  
Tomasz Majewski ◽  
Wiesław Urbaniak
Keyword(s):  
Interfacial Tension ◽  
Lipid Bilayers ◽  
Solid Lubricant ◽  
Solid Lubricants ◽  
Phospholipid Bilayer ◽  
Low Friction ◽  
Unique Role ◽  
Lamellar Phases ◽  
Chemical Inertness

Some solid lubricants are characterized by a layered structure with weak (van der Waals) inter-interlayer forces which allow for easy, low-strength shearing. Solid lubricants in natural lubrication are characterized by phospholipid bilayers in the articular joints and phospholipid lamellar phases in synovial fluid. The influence of the acid–base properties of the phospholipid bilayer on the wettability and properties of the surface have been explained by studying the interfacial tension of spherical lipid bilayers based on a model membrane. In this paper, we show that the phospholipid multi-bilayer can act as an effective solid lubricant in every aspect, ranging from a ‘corrosion inhibitor’ in the stomach to a load-bearing lubricant in bovine joints. We present evidence of the outstanding performance of phospholipids and argue that this is due to their chemical inertness and hydrophilic–hydrophobic structure, which makes them amphoteric and provides them with the ability to form lamellar structures that can facilitate functional sliding. Moreover, the friction coefficient can significantly change for a given phospholipid bilayer so it leads to a lamellar-repulsive mechanism under highly charged conditions. After this, it is quickly transformed to result in stable low-friction conditions.

scholarly journals Evaluation of environmental friendly Ag-PTFE composite coating for use in threaded compression fittings

2017 ◽  
Vol 232 (5) ◽  
pp. 503-512 ◽  
Author(s):  
Raymond Sieh ◽  
Huirong Le
Keyword(s):  
Stainless Steel ◽  
Solid Lubricant ◽  
Composite Coatings ◽  
Operating Conditions ◽  
Vacuum System ◽  
Environmental Friendly ◽  
Potential Risks ◽  
Fluid Transfer ◽  
Electroplating Process ◽  
Torque Angle

Threaded tubular fittings are used in a wide variety of industries for critical applications involving fluid transfer in a pressurised or vacuum system. These fittings are made of corrosion resistant metals such as stainless steel which are desirable in corrosive operating conditions; however, stainless steel is prone to galling which can cause threads to seize, resulting in loss of productivity. To prevent this, threads are electroplated using silver (Ag) coatings which prevent galling and serve as a solid lubricant during the connection make-up process. The Ag cyanide electroplating process currently used in industry is both hazardous to human health and its wastes are detrimental to the environment. The objective of this work is to evaluate environmental friendly self-lubricating Ag and Ag-polytetrafluoroethylene composite coatings using a non-cyanide electroplating process against the commercially available cyanide Ag coating through the analysis of torque-angle signatures and the torque-angle slope which characterises the make-up process. Results from the experiments suggest that the non-cyanide Ag-polytetrafluoroethylene coating is a potentially viable replacement option. Investigation and analysis of the coating performance have also highlighted potential risks of failure through poor lubrication during the make-up process and suggestions for improving the make-up process.

High temperature friction and wear properties of graphene oxide/polytetrafluoroethylene composite coatings deposited on stainless steel

RSC Advances ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 5977-5987 ◽  
Author(s):  
N. Nemati ◽  
M. Emamy ◽  
S. Yau ◽  
J.-K. Kim ◽  
D.-E. Kim
Keyword(s):  
Stainless Steel ◽  
Graphene Oxide ◽  
Friction And Wear ◽  
Solid Lubricant ◽  
Composite Coatings ◽  
Friction Material ◽  
Wear Properties ◽  
Low Friction ◽  
Solid Lubricant Coating ◽  
Friction And Wear Properties

Polytetrafluoroethylene (PTFE) coating is known as a low friction material that is often used as a solid lubricant coating.

Sliding Friction Behavior of Sintered Ni-Cr Composites with Solid Lubricants

2021 ◽  
Vol 875 ◽  
pp. 272-279
Author(s):  
Wan Farhana Mohamad ◽  
Amir Azam Khan ◽  
Pierre Barroy ◽  
Olivier Durand-Drouhin ◽  
Clement Puille ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Solid Lubricant ◽  
Sliding Friction ◽  
Solid Lubricants ◽  
Sem Analysis ◽  
Low Friction ◽  
Friction Behavior ◽  
Hardness Tester ◽  
Disc Configuration ◽  
Ball On Disc

High temperature applications of self-lubricated sliding surfaces have gained industrial importance during the recent years. One popular system is based on sintered Ni-Cr composites with addition of solid lubricants. In the present work these composites were prepared under controlled sintering conditions with different combinations of solid lubricants (MoS2, Ag and CaF2) at 1200 °C under flowing argon. The physical properties such as sintered density, relative density and porosity were studied. The microstructures and phase studies of the Ni-Cr based composites were conducted using SEM analysis while the hardness of the composites was measured by Vickers Micro Hardness Tester. The friction tests were conducted with ball on disc configuration following ASTM G-99-95a standard. The MoS2 solid lubricant provides best lubrication at room temperature which is demonstrated by a low friction coefficient compared to pure Ni-Cr composites. The SEM pictures of worn out tracks show solid debris distribution, and filling of pores with solid lubricant phases. The time taken for stabilization of friction coefficient also varies with the type of solid lubricant. Dual and multiple additions of solid lubricants are also able to reduce the friction of coefficient compared to pure Ni-Cr composite.

scholarly journals Composite Coatings with Ceramic Matrix Including Nanomaterials as Solid Lubricants for Oil-Less Automotive Applications

2016 ◽  
Vol 61 (2) ◽  
pp. 1039-1043 ◽  
Author(s):  
A. Posmyk ◽  
J. Myalski ◽  
B. Hekner
Keyword(s):  
Carbon Nanotubes ◽  
Shear Strength ◽  
Friction Coefficient ◽  
Solid Lubricant ◽  
Composite Coatings ◽  
Ceramic Matrix ◽  
Solid Lubricants ◽  
Metal Nanowires ◽  
Theoretical Point ◽  
Low Shear

Abstract The paper presents the theoretical basis of manufacturing and chosen applications of composite coatings with ceramic matrix containing nanomaterials as a solid lubricant (AHC+NL). From a theoretical point of view, in order to reduce the friction coefficient of sliding contacts, two materials are required, i.e. one with a high hardness and the other with low shear strength. In case of composite coatings AHC+NL the matrix is a very hard and wear resistant anodic oxide coating (AHC) whereas the solid lubricant used is the nanomaterial (NL) featuring a low shear strength such as glassy carbon nanotubes (GC). Friction coefficient of cast iron GJL-350 sliding against the coating itself is much higher (0.18-0.22) than when it slides against a composite coating (0.08-0.14). It is possible to reduce the friction due to the presence of carbon nanotubes, or metal nanowires.

Formation Mechanisms of Tribo-Coating for Low Friction in UHV

2005 ◽  
Author(s):  
Koshi Adachi ◽  
Hisakazu Sato ◽  
Koji Kato
Keyword(s):  
Friction Coefficient ◽  
Composite Structure ◽  
Solid Lubricant ◽  
Silicon Oxide ◽  
Solid Lubricants ◽  
Solid Lubrication ◽  
Formation Mechanisms ◽  
Coating Film ◽  
Low Friction ◽  
Indium Film

Solid lubrication film formed by tribo-coating, which deposits a solid lubricant by evaporation to the contact interface during friction in vacuum, gives low friction coefficient below 0.03 that can not be observed by any other solid lubricants of soft metals. The tribo-coating film formed on the pin has nano-order composite structure which the crystalline indium of nano size are distributed in an amorphous matrix of silicon oxide and chromium oxide. Because of the nano composite structure, a very thin indium film is formed without break down like conventional pre-coated thin film. The thinner indium film can give smaller value of friction coefficient than that of conventional solid lubricant.

Pulsed Electric Current Sintering of the Al2O3 - 15wt% ZrO2 Nanocomposites with 3wt% of Different Solid Lubricants

2011 ◽  
Vol 695 ◽  
pp. 473-476 ◽  
Author(s):  
M. Erkin Cura ◽  
Seung Ho Kim ◽  
Sung Hun Cho ◽  
Tomi Suhonen ◽  
Tatu Muukkonen ◽  
...  
Keyword(s):  
Electric Current ◽  
Solid Lubricant ◽  
Solid Lubricants ◽  
Instrumented Indentation ◽  
Scratch Testing ◽  
Low Friction ◽  
Laser Method ◽  
Optimal Processing ◽  
Pulsed Electric Current ◽  
Reduce Energy Consumption

High temperature low friction materials are sought for use in engines in order to reduce energy consumption of the machines. Due to the high service temperatures solid lubricating materials are necessary. This study is designed to find the optimal processing conditions for preparing these materials by pulsed electric current sintering. In this study, the Al2O3- 15wt% ZrO2(AZ) nanocomposite was modified with 3 wt% of self-lubricating component (CaF2, BaF2, MoS2, WS2, h-BN, or graphite). After the preparation of the alumina-zirconia powder mixture solid lubricant powder was added. Powders were then mixed in ethanol for 24 h, dried in a rotary evaporator, and in oven at 80°C for 24 h. The particle size distribution of the powders was established with the laser method. Powders were compacted by using pulsed electric current sintering technique at 1300 °C with 50 MPa for 5 min in vacuum. The structure of the materials was studied with XRD and SEM. Density of the compacts was measured with the Archimedes method and their hardness was evaluated by applying HV1 hardness with the instrumented indentation techniques. Their mechanical behavior was further studied with the instrumented scratch testing.

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