scholarly journals Tribological Characterization of Polyether Ether Ketone (PEEK) Polymers Produced by Additive Manufacturing for Hydrodynamic Bearing Application

Lubricants ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 112
Author(s):  
Davide Massocchi ◽  
Giacomo Riboni ◽  
Nora Lecis ◽  
Steven Chatterton ◽  
Paolo Pennacchi
Keyword(s):  
Additive Manufacturing ◽  
Optical Microscope ◽  
Wear Volume ◽  
Coating Materials ◽  
Hydrodynamic Bearing ◽  
Polyether Ether Ketone ◽  
Strength Tests ◽  
Ether Ketone ◽  
Tribological Characterization

The coating materials commonly used in hydrodynamic bearings are the so-called “Babbitt metals” or “white metals”, as defined by ASTM B23-00. Their low Young’s modulus and yield point have encouraged researchers to find new coatings to overcome these limitations. In this paper, the friction and wear of PEEK are studied in a dry sliding environment (without lubrication) using a ball-on-disk tribometer and compared to those of Babbitt metal. Furthermore, the bond strength tests between PEEK and metals/alloys are evaluated. PEEK polymer samples were obtained from cylindrical rods, manufactured by an innovative process for polymer bonding on bearing surfaces, using additive manufacturing technology. The morphologies of the degraded surfaces were examined using a high-resolution metallurgical optical microscope (OM) and a scanning electron microscope (SEM). The coefficients of friction (CoF) were obtained under the alternating ball-on-disk dry tribometer. The results of the experimental activity show that PEEK polymers have CoFs of about 0.22 and 0.16 under the 1 and 5 N applied load, respectively. The CoF and wear volume loss results are reported and compared to the reference Babbitt coating.

scholarly journals Additive Manufacturing of Polyether Ether Ketone (PEEK) for Space Applications: A Nanosat Polymeric Structure

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 11
Author(s):  
Marianna Rinaldi ◽  
Federico Cecchini ◽  
Lucia Pigliaru ◽  
Tommaso Ghidini ◽  
Francesco Lumaca ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Material Selection ◽  
Raw Material ◽  
Space Applications ◽  
Printing Process ◽  
Polymeric Structure ◽  
Fused Deposition ◽  
Polyether Ether Ketone ◽  
3D Printed ◽  
Ether Ketone

Recent improvements in additive layer manufacturing (ALM) have provided new designs of geometrically complex structures with lighter materials and low processing costs. The use of additive manufacturing in spacecraft production is opening up many new possibilities in both design and fabrication, allowing for the reduction of the weight of the structure subsystems. In this aim, polymeric ALM structures can become a choice, in terms of lightweight and demisability, as far as good thermomechanical properties. Moreover, provided that fused-deposition modeling (FDM) is used, nanosats and other structures could be easily produced in space. However, the choice of the material is a crucial step of the process, as the final performance of the printed parts is strongly dependent on three pillars: design, material, and printing process. As a high-performance technopolymer, polyether ether ketone (PEEK) has been adopted to fabricate parts via ALM; however, the space compatibility of 3D-printed parts remains not demonstrated. This work aimed to realize a nanosat polymeric structure via FDM, including all the phases of the development process: thermomechanical design, raw material selection, printing process tuning, and manufacturing of a proof of concept of a technological model. The design phase includes the application of topology optimization to maximize mass saving and take full advantage of the ALM capability. 3D-printed parts were characterized via thermomechanical tests, outgassing tests of 3D-printed parts are reported confirming the outstanding performance of polyether ether ketone and its potential as a material for structural space application.

Morphology of a Functional POSS/Bismaleimide Nanocomposite and its Monitoring Phase Separation with a Thermoplastic Blend

2011 ◽  
Vol 266 ◽  
pp. 166-170
Author(s):  
Xiao Lan Hu ◽  
Rong Lu Yu ◽  
Gang Liu ◽  
Xiao Su Yi
Keyword(s):  
Phase Separation ◽  
Optical Microscope ◽  
Separation Process ◽  
Polyether Ether Ketone ◽  
Phase Separation Process ◽  
Potential Matrix ◽  
Ether Ketone ◽  
Oligomeric Silsesquioxane ◽  
Similar Phase ◽  
Monitoring Phase

A functional polyhedral oligomeric silsesquioxane (POSS) with eight vinyl groups was used to fabricate a POSS/bismaleimide (BMI) nanocomposite as a potential matrix for RTM processing, and its blend with a thermoplastic polyether-ether ketone (PEK-C) was prepared. A self-designed optical microscope with a hot stage has been performed to monitor phase separation process of the thermoplastic-thermoset blend. The phase separation and final morphology of POSS/PEK-C/BMI system were characterized in the research. SEM pictures of POSS/BMI nanocomposite exhibit that the vinyl POSS has significant improvement in toughness of the materials, and its eight vinyl groups lead to chemical bonding interface with BMI resin in the nanocomposite. Results of optical microscope indicate that the corporation of POSS in PEK-C/BMI blend postponed phase separation process. The morphologies show that POSS/PEK-C/BMI systems have a similar phase separation structure with PEK-C/BMI blend.

Tribological Characterization of AZ91 and AE42 Magnesium Alloys in Fretting Contact

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
D. Khabale ◽  
M. F. Wani
Keyword(s):  
Magnesium Alloys ◽  
Coefficient Of Friction ◽  
Normal Load ◽  
Fretting Wear ◽  
Wear Volume ◽  
Dry Sliding ◽  
Running Time ◽  
Average Coefficient ◽  
Tribological Characterization

Fretting wear studies were conducted on AZ91 and AE42 magnesium alloys against steel ball. Average coefficient of friction (COF) remains steady with the increase in running time. However, average coefficient of friction decreases with the increase in normal load and frequency and marginally increases with the increase in amplitude. A constant average coefficient of friction of 0.06 was observed for both AZ91 and AE42 under dry sliding conditions at normal load of 50 N. Wear volume increases linearly with increasing running time. Wear volume first decreases sharply, attains minima, and then increases marginally with the increase in normal load. However, wear volume increases with increasing amplitude and frequency. Higher specific wear rate of 10.5 × 10−6 mm3 N−1·m−1 was observed for AE42, as compared to 4.5 × 10−6 mm3 N−1·m−1 for AZ91. The wear in magnesium alloy was caused by a combination of adhesion, abrasion, oxidation, delamination, and plastic deformation under different fretting conditions.

Tribological Characterization of Porous TiO2 Coatings Produced by Electrodeposition

2011 ◽  
Vol 493-494 ◽  
pp. 430-435
Author(s):  
E. Santos ◽  
S.S. Camargo ◽  
G.A. Soares ◽  
Neide K. Kuromoto
Keyword(s):  
Electrolyte Solutions ◽  
Wear Volume ◽  
Oxide Coatings ◽  
Porous Ti ◽  
The Coefficient Of Friction ◽  
Dry Conditions ◽  
Anodic Oxidation Method ◽  
Tribological Characterization ◽  
Scratch Tests

In this work, the resistance to scratch and wear (pin-on-flat) tests of five different porous TiO2 films were compared. Such tribological tests were carried out under dry conditions. The coatings were electrodeposited on commercially pure-Ti by anodic oxidation method in different electrolyte solutions at constant voltages. The scratch tests were conducted by applying increasing normal loads up to 400 mN. The coefficient of friction (COF) varied from 0.2 up to 0.5, and increased at larger penetrations depths. When the electrolyte concentration was changed from 0.5 into 1.0M H2SO4, the COF slightly decreased. Scanning electron microscopy indicated that the coatings produced in H2SO4/150V and Na2SO4/100V did not have their substrates revealed. In addition, the samples anodized in H2SO4/150V had the highest elastic recoveries. Therefore, such coatings seem to be more resistant to scratch tests than the others. The wear tests were carried out with Berkovich tip as counter-face under constant normal loads of 10 mN in 10 forward-backward cycles. The coatings deposited in H2SO4/150V had the lowest wear volume rates. The findings suggest that the porous Ti oxide coatings electrodeposited above their rupture voltages are more suitable to both scratch- and wear-resistance compared to those prepared at the lowest voltage (H2SO4/100V).

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