Characterization of Sintered Bronze–MoS2 Composite With Solid Lubrication Effect

2020 ◽  
Vol 143 (7) ◽  
Author(s):  
L. E. Vieira ◽  
A. L. Gonçalves ◽  
N. I. R. Arraya ◽  
J. B. Rodrigues Neto ◽  
A. Dias ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Metallic Matrix ◽  
Solid Lubricants ◽  
Solid Lubrication ◽  
Material Loss ◽  
Wear Rates ◽  
Sintered Bronze ◽  
Material Wear ◽  
Self Lubricating Composites

Abstract The most efficient method to reduce material loss and frictional energy losses is by using lubrication. An alternative is the use of solid lubrication, specifically by using solid lubricants evenly distributed in a metallic matrix, thus forming self-lubricating composites, which are capable to induce low coefficients of friction in mechanical systems. Molybdenum disulfide (MoS2) is a very versatile solid lubricant, suitable for lubrication in critical circumstances such as vacuum, high temperatures, and pressures. Therefore, the aim of this study is to produce samples of sintered composites consisting of homogeneously distributed MoS2 in a bronze matrix obtained by cold uniaxial pressing and to compare the wear-rates and friction coefficient between the MoS2-free bronze and the self-lubricating composites. Different MoS2 percentages were used to characterize the tribological properties of the composites as a function of the MoS2 content. At the end of the experiments, it was found that samples with 20% MoS2 did not sinter properly due to the large amount of lubricant between the bronze particles. It was also found that the mixture with 5.0 vol% MoS2 had proper sintering, satisfactory hardness, achieved lower friction coefficient, and better material wear performance due to the optimal amount and good distribution of MoS2 when compared with the rest of conditions studied.

Effect of Sintering Temperature on the Tribological Behavior of Plasma Assisted Debinded and Sintered MIM Self Lubricating Steels

2010 ◽  
Author(s):  
Jose´ Daniel B. de Mello ◽  
Cristiano Binder ◽  
Aloisio Nelmo Klein ◽  
Roberto Binder
Keyword(s):  
Friction Coefficient ◽  
Sintering Temperature ◽  
Metallic Matrix ◽  
Solid Lubricants ◽  
Solid Lubrication ◽  
Metal Injection Molding ◽  
Processing Route ◽  
Second Phase ◽  
New Processing ◽  
Feedstock Preparation

Solid lubrication and solid lubricants are one of the most promising choices for controlling friction and wear in energy efficient modern systems. The production of self lubrication composites containing second phase particles incorporated into the volume of the material appears to be a promising solution. A new processing route to obtaining a homogeneous dispersion of discrete solid lubricant particles in the volume of sintered steels produced by metal injection molding (MIM) was recently presented. This new route was achieved by in situ formation of graphite nodules due to the dissociation of precursor (SiC particles) mixed with the metallic matrix powders during the feedstock preparation. Nodules of graphite (size ≤ 20μm) presenting a nanostructured stacking of graphite foils a few nanometers thick were obtained. The thermal debinding, as well as the sintering, was performed in a single thermal cycle using a Plasma Assisted Debinding and Sintering (PADS) process. In this work, we present and discuss the effect of sintering temperature on the tribolayer durability and average friction coefficient in the lubricious regime (μ<0.2) of plasma assisted debinded and sintered self lubricating steel produced by metal injection mould technique. Three different temperatures (1100, 1150 and 1200 °C) and six different SiC contents (0–5%) were analyzed. Friction coefficient was little affected by the sintering temperature. However, the durability of the tribo layer formed on the sliding interface was greatly increased (5X) for the lower sintering temperature (1100°C).

High Temperature Tribology and Solid Lubrication of Advanced Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1088-1091 ◽  
Author(s):  
Jia Hu Ouyang ◽  
Takashi Murakami ◽  
Shinya Sasaki ◽  
Yu Feng Li ◽  
Ya Ming Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Friction And Wear ◽  
Hexagonal Boron Nitride ◽  
Precious Metals ◽  
Ceramic Matrix Composites ◽  
Solid Lubricants ◽  
Extreme Environment ◽  
Solid Lubrication ◽  
Matrix Composites ◽  
Wear Rates

The high-temperature friction and wear characteristics of different ceramics and ceramic matrix composites (CMCs) incorporated with various solid lubricants have been investigated from room temper- ature to 1000oC. The solid lubricants considered in this paper include representative precious metals, hexagonal boron nitride, graphite, fluorides, soft oxides, chromates, sulfates, and combinations of various solid lubricants. General design considerations relevant to solid lubrication were proposed on the basis of friction and wear data of self-lubricating CMCs. The self-lubricating composites incorporated with SrSO4 or/and CaSiO3 exhibits low and stable friction coefficients of 0.2 to 0.3 and small wear rates in the order of 10-6 mm3/Nm from room temperature to 800oC. The optimized composites appear to be promising can- didates for long-duration, extreme environment applications with low friction and small wear rate.

Effect of Liquid Phase during Sintering on Mechanical and Tribological Properties of Self-Lubricating Composites

2017 ◽  
Vol 899 ◽  
pp. 523-527 ◽  
Author(s):  
Renata Steinbach ◽  
Tatiana Bendo ◽  
G. Hammes ◽  
C. Binder ◽  
J.D.B. de Mello ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Liquid Phase ◽  
Friction Coefficient ◽  
High Performance ◽  
Hexagonal Boron Nitride ◽  
Solid Lubricants ◽  
Liquid Phase Sintering ◽  
Mechanical And Tribological Properties ◽  
The Matrix ◽  
Self Lubricating Composites

The present work aimed to contribute to the development of high performance self-lubricating sintered composites, with low friction coefficient and high mechanical strength. Self-lubricating composites presenting embedded solid lubricants in a ferrous matrix were produced. Hexagonal boron nitride (hBN) and graphite were the solid lubricants powders added during the mixing step. The composites were processed by conventional powder metallurgy. The liquid phase sintering, by adding copper, improved the degree of continuity of the matrix by rearranging the solid lubricant particles. With this, besides the hardening effect on the matrix, the mechanical properties of the composites were improved, with tensile strength increasing when compared to the same composite without copper. By using the proposed methodologies, optimized composites presenting friction coefficient of 0.12, tensile strength of 500 MPa and scuffing resistance of 29300 N.m were obtained.

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.

Friction and Wear Behavior of Textured Al2O3/TiC Ceramic Surface Filled with MoS2 Solid Lubricants

2012 ◽  
Vol 229-231 ◽  
pp. 35-39 ◽  
Author(s):  
You Qiang Xing ◽  
Jian Xin Deng ◽  
Ze Wu ◽  
Yun Song Lian
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Solid Lubricants ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Ceramic Surface ◽  
Textured Surfaces ◽  
Wear Properties ◽  
Wear Rates

Three different textures were produced by Laser Surface Texturing (LST) on Al2O3/TiC ceramic surfaces. MoS2 solid lubricants were filled into the textures. The friction and wear properties of textured and untextured surfaces were investigated by carrying out sliding tests against AISI440C stainless steel balls. Results showed that the textured surfaces filled with MoS2 solid lubricants exhibited lower friction coefficient and excellent anti-wear properties compared with untextured surfaces. At the texture spacing of 100μm, 150μm and 200μm, wavy textured surface had the lowest friction coefficient, while it was the dimpled surface at the texture spacing of 250μm. MoS2 film in the spaces between the textures was formed by mechanical engagement of particles in the rough surfaces and solid lubricants in textures. The friction coefficient and wear rates were reduced by supply of solid lubricants from the textures to the surfaces, bulges around the textures and TiO2 formed after laser texturing.

scholarly journals Microstructure and High-Temperature Wear Performance of FeCr Matrix Self-Lubricating Composites from Room Temperature to 800 °C

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 51 ◽  
Author(s):  
Gongjun Cui ◽  
Yanping Liu ◽  
Guijun Gao ◽  
Huiqiang Liu ◽  
Ziming Kou
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Synergistic Effects ◽  
Solid Lubricants ◽  
Oxide System ◽  
Critical Threshold ◽  
Wear Rates ◽  
Tribological Behaviors ◽  
Self Lubricating Composites

FeCr matrix high-temperature self-lubricating composites reinforced by Mo, Ag, and CuO were fabricated by the powder metallurgy technique. The tribological behaviors of composites were studied at temperatures up to 800 °C. The CuO content was optimized according to the tribological results. Mo showed an obvious lubricating effect when it converted into MoO3. The bimetallic oxide system formed high-temperature solid lubricants with low shear strength. CuO reacted with MoO3 and formed CuMoO4 and Cu3Mo2O9. The composites showed an increase in the friction coefficient with the increase of CuO. However, the wear rates decreased with the increase of CuO. The critical threshold at which there was a transition of friction coefficients and wear rates from room temperature (RT) to 800 °C was 10 wt.% CuO. The Fe(Cr)-14% Mo-10.5% Ag-10% CuO composite showed the most reasonable high-temperature tribological behaviors. This was ascribed to the synergistic effects of silver, Mo, in situ formed solid lubricants (metal oxides and salt compounds), and the stable oxide film on the worn surfaces. At elevated temperatures, the dominant wear mechanism was oxidation wear.

Friction and Wear Behaviors of Solid Lubricants/Polyimide Composites in Liquid Mediums

2010 ◽  
Vol 654-656 ◽  
pp. 2763-2766 ◽  
Author(s):  
Li Wen Mu ◽  
Xin Feng ◽  
Yi Jun Shi ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Alkaline Solution ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricants ◽  
Polyimide Composites ◽  
Inorganic Fillers ◽  
Ptfe Composites

The tribological properties of polyimide (PI) composites reinforced with graphite or MoS2 sliding in liquid alkali and water as well as dry friction were investigated using a ring-on-ring tester. The results show that the friction coefficient (μ) and wear rate (W) for both graphite/PI and MoS2/PI composites in different liquid mediums are μdry>μwater >μalkali and Wwater>Wdry >Walkali. Results also indicate that the friction coefficient and wear rate of the PI composites filled with different solid lubricants are μMoS2 >μgraphite and W MoS2 >Wgraphite in different liquid mediums. In addition, the hydrophobic inorganic fillers are fit for the reinforcement of polymer-based composites sliding in liquid mediums. It is also concluded from the authors’ work that the wear rate and friction coefficient of polymer-based (such as PI, PTFE) composites in the alkali lubricated conditions is lowest among all the friction conditions. This may be attributed to the ionic hydration in the alkaline solution.

Comparison in Tribological Properties of YBa2Cu3OX/Ag and Bi2Sr2CaCu2OX/Ag Self-Lubricating Composites

2011 ◽  
Vol 291-294 ◽  
pp. 34-40
Author(s):  
Hua Tang ◽  
Wen Jing Li ◽  
Chang Sheng Li
Keyword(s):  
Friction Coefficient ◽  
Tribological Properties ◽  
Room Temperature ◽  
Superconducting Transition ◽  
Friction Test ◽  
Average Value ◽  
Structure And Morphology ◽  
Disk Friction ◽  
Pin On Disk ◽  
Self Lubricating Composites

The YBa2Cu3Ox/Ag and Bi2Sr2CaCu2Ox/Ag self-lubricating composites were prepared using powder metallurgic method. The crystal structure and morphology of the as-synthesized samples were characterized by XRD and SEM. The YBa2Cu3Ox/Ag and Bi2Sr2CaCu2Ox/Ag self-lubricating composites were found to compose of superconductor phase and Ag phase. The tribological properties from ultra-low temperature to room temperature of the composites were studied by pin-on-disk friction test. It was found that the friction coefficients of pure YBa2Cu3Ox(YBCO) and Bi2Sr2CaCu2Ox(BSCCO) were both dropped abruptly when the temperature cooled below the superconducting transition temperature. At room temperature, the friction coefficient of pure YBa2Cu3Oxis 0.68~0.95, when mixing 15wt% Ag, the friction coefficient of the sample decreased to the lowest value 0.11. The friction coefficient of pure Bi2Sr2CaCu2Ox is 0.15~0.17, When Ag content reach 10wt%, the coefficient was lowest (average value is 0.13). The addition of appropriate amount of Ag obviously improve the tribological property of YBCO, while only slightly meliorate that of BSCO. On the other hand, the YBCO/Ag composites exhibit better tribological properties than BSCCO/Ag composites at higher load under the same experimental condition.

Tribological performance of self-lubricated polyamide6/boric oxide composites after water conditioning

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kawaljit Singh Randhawa ◽  
Ashwin Patel
Keyword(s):  
Friction Coefficient ◽  
Abrasion Resistance ◽  
Tribological Performance ◽  
Boric Oxide ◽  
Resistance Testing ◽  
Tribological Behaviour ◽  
Content Type ◽  
Wear Rates ◽  
Water Conditioning ◽  
Oxide Composites

Purpose This paper aims to investigate the tribological performance, i.e. abrasion resistance, friction coefficient and wear rates, of self-lubricated water conditioned polyamide6/boric oxide composites. Design/methodology/approach Polyamide6 and polyamide6/boric oxide self-lubricated composites were immersed in water for 15 days to analyze the effect of water conditioning on friction, wear and abrasion resistance. Tribological testing on pin-on-disc tribometer and abrasion resistance testing on TABER abrader were performed to see the friction coefficient and wear rates of materials. The scanning electron microscopy (SEM) characterizations were performed to analyze the wear tracks. Findings Tribological testing results revealed the loss in abrasive resistance, but there was an improvement in frictional coefficient and wear rates with steel after water absorption. The SEM images clearly show less depth of wear tracks in water-conditioned materials than dry ones. Water conditioning was found supportive in the formation of smooth lubricating transfer film on steel disc during the tribological testing. Originality/value The tribological behaviour of polymer composites is different in dry and in high humidity or water conditions. Experiments were performed to investigate B2O3 solid lubricant filler effectiveness on tribological behaviour of water-conditioned polyamide composites. Bonding between polyamide6 and water molecules plus the formation of orthoboric acid was found advantageous in decreasing the friction coefficient and wear rates of composites.

Design and Characterization of an Ultra Low Loss, Dispersion-Flattened Slotted Photonic Crystal Fiber for Terahertz Application

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohammad Rakibul Islam ◽  
Md. Arif Hossain ◽  
Syed Iftekhar Ali ◽  
Jakeya Sultana ◽  
Md. Saiful Islam
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Single Mode ◽  
Confinement Loss ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Low Loss ◽  
Material Loss ◽  
Crystal Fiber

AbstractA novel photonic crystal fiber (PCF) based on TOPAS, consisting only rectangular slots is presented and analyzed in this paper. The PCF promises not only an extremely low effective material loss (EML) but also a flattened dispersion over a broad frequency range. The modal characteristics of the proposed fiber have been thoroughly investigated using finite element method. The fiber confirms a low EML of 0.009 to 0.01 cm−1 in the frequency range of 0.77–1.05 THz and a flattened dispersion of 0.22±0.01 ps/THz/cm. Besides, some other significant characteristics like birefringence, single mode operation and confinement loss have also been inspected. The simplicity of the fiber makes it easily realizable using the existing fabrication technologies. Thus it is anticipated that the new fiber has the potential to ensure polarization preserving transmission of terahertz signals and to serve as an efficient medium in the terahertz frequency range.

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