scholarly journals Experimental Studies on Fretting Wear Behavior of PVDF Piezoelectric Thin Films

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 734
Author(s):  
Yuanjie Shu ◽  
Liaoliang Ke ◽  
Jie Su ◽  
Fei Shen

This paper discusses an in-depth experimental study on the fretting wear behavior of PVDF (polyvinylidene fluoride) piezoelectric thin film against a Si3N4 ceramic sphere under air conditions. A fretting wear device with a ball-on-plate contact configuration was applied. The changes of displacement amplitude, normal force, and applied voltage were taken into account. The friction logs were used to determine the contact state of the PVDF thin film during the fretting test. The 3D topography instrument and scanning electron microscope (SEM) were used to measure the details of the surface morphology and wear volume. The test results of PVDF thin films under different normal force, displacement amplitude, and applied voltage are summarized through the collection and analysis of experimental data. It is shown that the creep and plastic deformation lead to obvious winkles at the contact surface, which may decrease the specific wear rate of PVDF thin films.

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2153
Author(s):  
Tengfei Zhang ◽  
Jie Su ◽  
Yuanjie Shu ◽  
Fei Shen ◽  
Liaoliang Ke

Rubbers are widely used in various fields as the important sealing materials, such as window seal, door seal, valve, pump seal, etc. The fretting wear behavior of rubbers has an important effect on their sealing performance. This paper presents an experimental study on the fretting wear behavior of rubbers against the steel ball under air conditions (room temperature at 20 ± 2 °C and humidity at 40%). Three kinds of rubbers, including EPDM (ethylene propylene diene monomer), FPM (fluororubber), and NBR (nitrile–butadiene rubber), are considered in experiments. The sphere-on-flat contact pattern is used as the contact model. The influences of the displacement amplitude, normal force, frequency, and rubber hardness on the fretting wear behavior are discussed in detail. White light profiler and scanning electron microscope (SEM) are used to analyze the wear mechanism of the rubber surface. The fretting wear performances of three rubbers are compared by considering the effect of the displacement amplitude, normal force, frequency, and rubber hardness. The results show that NBR has the most stable friction coefficient and the best wear resistance among the three rubbers.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5778
Author(s):  
Long Xin ◽  
Lanzheng Kang ◽  
Weiwei Bian ◽  
Mengyang Zhang ◽  
Qinglei Jiang ◽  
...  

The effect of displacement amplitude on fretting wear behavior and damage mechanisms of alloy 690 in air and nitrogen atmospheres was investigated in detail. The results showed that in air, the friction coefficient gradually increased with the increase in displacement amplitude which conformed to the universal law. In nitrogen, however, it had the highest point at the displacement amplitude of 60 μm due to very strong adhesion. Whether in air or nitrogen, the wear volume gradually increased with the increase in displacement amplitude. The wear volume in air was larger than that in nitrogen except at 30 μm. At 30 μm, the wear volume in air was slightly smaller. With an increase in displacement amplitude, a transformation of fretting running status between partial slip, mixed stick-slip, and final gross slip occurred along with the change of Ft-D curves from linear, to elliptic, to, finally, parallelogrammical. Correspondingly, the fretting regime changed from a partial slip regime to a mixed regime to a gross slip regime. With the increase in displacement amplitude, the transition from partial slip to gross slip in nitrogen was delayed as compared with in air due to the strong adhesion actuated by low oxygen content in a reducing environment. Whether in air or nitrogen, the competitive relation between fretting-induced fatigue and fretting-induced wear was prominent. The cracking velocity was more rapid than the wear. Fretting-induced fatigue dominated at 30 μm in air but at 30–60 μm in nitrogen. Fretting-induced wear won the competition at 45–90 μm in air but at 75–90 μm in nitrogen.


Author(s):  
Tsali Cross ◽  
Somuri Prasad ◽  
Rishi Raj

Polymer derived ceramics (PDC’s) are processed from liquid organometallic precursors by cross-linking the polymers into infusible solids, followed by controlled pyrolysis. No previous work regarding their tribology has been reported. Further, the synthesis of PDC’s as thin films, and the role that the nanostructure plays on the mechanical properties has not been reported. The objective of this research was to evaluate the fundamental tribological behavior of polymer derived SiCN in both bulk and thin film form. Friction and wear evaluations were made on bulk materials and thin films using a Si3N4 ballon-disk linear wear tester at various contact pressures and in different environments that contained various amounts of humidity. The micro/nanostructure was characterized by FTIR, microRaman, and scanning electron microscopy. Bulk SiCN gave a low friction coefficient and good wear resistance in humid environments but showed significant fracture and gouging in dry environments at higher contact pressures. Although there is ambiguity regarding the tribology of the thin films there seems to be a dependence upon the nitrogen content within the materials derived from the polymeric stage. The future work will focus on optimizing processing conditions of thin films and investigating the role that nitrogen plays in both bulk and thin film SiCN materials.


1995 ◽  
Vol 403 ◽  
Author(s):  
K. Barmak ◽  
C. Michaelsent ◽  
J. Rickman ◽  
M. Dahmstt

AbstractIt is a well known fact that the properties and performance of polycrystalline materials, including polycrystalline thin films, are strongly affected by the grain structure. Therefore, in treating reactive phase formation in these films, it is (or it will inevitably be) necessary to quantify the grain structure of reactant and product phases and its evolution during the course of the reaction. Theoretical models and the conventional view of thin film reactions, however, have been largely extensions, to small and finite dimensions, of theories and descriptions developed for bulk diffusion couples. These models and descriptions primarily focus on the growth stage and to a much lesser extent on the nucleation stage. Consequently, these models and descriptions are not able to treat the development of product phase grain structure. Recent calorimetric investigations of several thin film systems demonstrate the importance of nucleation kinetics (and hence nucleation barriers) in product phase formation and provide quantitative measures of the thermodynamics and kinetics of formation of the product phases, thereby allowing some degree of comparison with reaction models. Furthermore, microstructural investigations of thin-film reactions demonstrate the non-planarity of the growth front and highlight the role of reactant-phase grain boundaries. In this paper, a summary of these experimental studies and recent theoretical treatments, which combine nucleation and growth in an integrated manner, is presented, with particular emphasis on the Nb/Al system. These experiments and models lead to a new view of reactive phase formation and grain structure evolution as one in which the latter is an integral part of the former. Based on this view, directions for future research are discussed.


2020 ◽  
Vol 979 ◽  
pp. 180-184
Author(s):  
I. Karuppusamy ◽  
K. Ramachandran ◽  
S. Karuppuchamy

The CuI thin film has been successfully prepared by using cathodic electrodeposition method. The synthesized film was characterized using advanced techniques such as XRD, SEM-EDX and UV measurements. The films are crystallized in face centered cubic structure. The crystallinity is increasing for the applied potential of-0.3 V and the crystallinity deteriorates on increasing the potential above - 0.3 V. It was also observed that the applied voltage plays an important role. Homogeneously distributed triangular faceted morphology was observed from SEM. This is consistent with the result of XRD that electrodeposited CuI thin films grow preferential orientation along the (111) crystal plane.


2012 ◽  
Vol 562-564 ◽  
pp. 179-183 ◽  
Author(s):  
Jiu Wang ◽  
Bo Shui Chen ◽  
Jian Hua Fang ◽  
Jiang Wu

First the fretting wear behavior of CuS nanoparticles additives in grease were studied. The results show that the fretting wear volume reduce significantly when CuS nanoparticles additives add to grease. At the same time the existence of sulfid nanoparticles can reduce friction coefficient at the latter fretting time. The results of XPS tests show that Cu, Zn, Ni, S and B elements were founded in the film of wear scar. Secondly the effect of antiwear and oiliness additives on fretting wear behavior of nanoparticles additives in Grease were studied. It was found that when some antiwear, oiliness additives (such as T203, T322, stearyl alcohol or stearic acid) and sulfide nanoparticles were added to urea grease, a synergy effect between the two types of additives made fretting wear volume more small than that of either additive. Based on the results of contrast experiment and some analysis of fretting wear scars, we present the idea that two additives react with friction surface step by step. That is to say, the high chemical activity of CuS nanoparticles decompose first and form protective layer, the heat converted from chemical reaction of CuS decomposition and mechanical motion promote composition of common oil additives, thus protective layer is formed once again and wear volume further decrease.


2016 ◽  
Vol 872 ◽  
pp. 147-151
Author(s):  
Chayangkoon Mangkornkarn ◽  
Benjarong Samransuksamer ◽  
Mati Horprathum ◽  
Pitak Eiamchai ◽  
Apiluck Eiad-Ua ◽  
...  

We reported on the influence of applied voltage on the surface morphology of anodic titanium dioxide (ATO) thin films. At first, titanium (Ti) thin films were prepared by DC-magnetron sputtering for use as a base material in the anodization process. The titanium dioxide (TiO2) nanoporous ATO was fabricated by the anodization process from the Ti thin film, with different applied voltages from 20 V to 60 V in an electrolyte based on an ethylene glycol containing NH4F. Pore size distribution of ATO thin films can be varied from 20-50 nm by increasing the applied voltage, while the thickness of the film also increases. In addition, to observe the effect of time, the optimal condition of anodizing voltage was studied by increasing the anodizing time. The results clearly showed the nanoporous ATO over the films and the thickness of the nanoporous ATO is approximately 260 nm.


1992 ◽  
Vol 280 ◽  
Author(s):  
Qiuming Yu ◽  
Paulette Clancy

ABSTRACTThe equilibrium structure of a variety of Si1−xGex/Si heterostructures have been simulated by Molecular Dynamics, modeled by the Stillinger-Weber potential, to investigate the effect of strain on the surfaces of SiGe thin Alms. It was found that the strain in SiGe/Si(100) thin films was relaxed by the segregation of Ge to the surface. Rebonding of sub-surface atoms into dimers in the presence of a vacancy or cluster of vacancies above them was observed in the ensuing surface reconstruction. For SiGe/Si, the amount of “re-bonded missing dimers” in the top two layers increased with increasing Ge composition. But for Ge/Si(100), a V-shaped twinning defect was observed in the Ge thin film. To further investigate the effect of strain on surface reconstruction, bulk Si and Ge structures were also studied. For bulk Si, several rebonded missing dimers were found at the surface, while for bulk Ge(100), the surface showed a typical 2×1 reconstruction. All these findings corroborate recent experimental studies and theoretical predictions.


2004 ◽  
Vol 835 ◽  
Author(s):  
T. H. Lee ◽  
B. J. Harder ◽  
C. Zuo ◽  
S. E. Dorris ◽  
U. Balachandran

ABSTRACTThin films of BaCe0.8Y0.2O3-δ (BCY) were prepared by colloidal spray deposition. Dense, crack-free BCY films having a grain size of 2–7 μm were successfully deposited on NiO/BCY substrates. Electrochemical hydrogen pumping with the BCY films showed that the maximum current density increased with temperature. The maximum current density was sensitive to the moisture in the cathode gas; the value obtained with a dry cathode gas was only half that with a wet cathode gas. A very high hydrogen-pumping current density of 3.4 A/cm2 was measured at 700°C with an applied voltage of 1.5 V.


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