Wear and Tear Resistance of Coupling Fits with Clearance Restored by Porous Epoxy Polyamide coatings

2020 ◽  
pp. 182-188
Author(s):  
Veaceslav Tapu ◽  
◽  
Vladimir Gorobet ◽  
Keyword(s):  
Surface Layer ◽  
Wear Rate ◽  
Friction Pair ◽  
Polymeric Materials ◽  
Porous Polymer ◽  
Surface Layers ◽  
Running Water ◽  
Friction Zone ◽  
Metal Polymer ◽  
Lubrication Conditions

The using of polymeric materials as coatings for the restoration of worn–out machine parts has found application in the industry of repairment. Their wider use is hampered because of poor adhesion strength, shrinkage, ageing, low wetting ability and other properties of polymeric materials. To improve the physical and mechanical properties of polyamide P12, it is advisable to add to the composition of various substances that help to reduce shrinkage, ageing, increase wear resistance. It is proposed to increase the oil absorption of the surface layers of polymer composite coatings by introducing 5...10% of sodium chloride (NaCl) into the composition. The obtained porous coatings were further subjected to wear tests under various lubrication conditions. The wear rate of the composite material under different lubrication conditions is different, so after 240 hours of testing, friction wear without lubrication was 18.8 ±2 μm, when using water – 16.8 ±2 μm, and when using LITOL 24 grease – 10±1 μm ... When using LITOL 24, a positive gradient of interfacial resistance of molecular bonds and surface layers is provided. Abrasion of the latter, as a rule, is not abrasive, but frictional and manifests itself in the separation of different, configurations of particles from the surface layer. Also, the lubricant is in the friction zone for longer because it is retained in the artificially formed pores of the surface layer of the coating. The presence of grease in the friction zone reduces the wear rate of the metal counter body. In those cases when there was no lubrication or there was water, the wear rate of the metal counter body was higher and practically had the same character. So, after 240 hours of testing, the following results were obtained: with friction and without lubrication In.l.=14 ±1 µm; friction in the presence of running water Iwater=13±1 µm; friction when using Litol 24, I=9±1 μm. Based on the results obtained, it can be stated that for a metal–porous polymer composite sliding friction pair, the types of lubricants affect the intensity of their wear. It should be noted that during the first hundred hours of testing, the evolution of the wear of the friction pair with different types of lubricant is practically the same and has a tendency to increase smoothly. This type of wear can be explained by the transfer of the composite material to the metal counter body. After removing this layer from the metal counter body, the process of its wear is different and depends on the type of lubricant. Metal counter bodies practically do not change the nature of wear when using water as a lubricant, as well as when friction without lubrication, but when using LITOL 24 lubricant, the wear rate is much less. The durability of friction pairs largely depends on the size of the gap. Thus, for the friction pairs studied with friction without lubrication, the linear intensity of the change in the gap value for 240 hours of testing will be 6.03 ∙ 10–8, for the condition of friction in running water and with Litol 24 lubricant, respectively 5.5 ∙ 10–8 and 3.6 • 10–8. In other words, we can say that in the studied area of 240 hours, the gap in friction pairs with friction without lubrication increased by 60 μm per 1 km of the distance travelled, when using water at 55 μm/km and 36 μm/km when using Litol 24 lubricant. It was found that the intensity of the increase in the gap in the friction pair when using a porous polymer coating based on a polyamide epoxy composition as a counter body in a metal–polymer friction pair, under lubrication conditions with Litol, is 1.64 times less than when using such coatings without pores. The obtained porous coatings showed higher wear resistance when using water as a lubricant (1.1 times less than that of the base one). The results obtained confirm that the creation of a porous surface layer in the coating of the polymer composition will contribute to an increase in the service life of the recovered friction pairs by replacing the usual metal–metal pair with a metal–polymer one.

INFLUENCE OF THE DYNAMICS OF FORCED MOTION ON THE STATIC FRICTION IN METAL-POLYMER SLIDING PAIRS

Tribologia ◽  
2021 ◽  
Vol 295 (1) ◽  
pp. 21-26
Author(s):  
Mariusz Opałka ◽  
Wojciech Wieleba ◽  
Angelika Radzińska
Keyword(s):  
Relative Motion ◽  
Friction Pair ◽  
Polymeric Materials ◽  
Static Friction ◽  
Metallic Materials ◽  
Test Results ◽  
Friction Resistance ◽  
Rate Of Increase ◽  
Polymer Metal ◽  
Metal Polymer

The resistance during the frictional interaction of polymeric materials with metallic materials is characterized by a significant dependence on the dynamics of the motion inputs. In a metal-polymer friction pair, the static friction resistance during standstill under load depends on the rate of growth of the force causing the relative motion. Tribological tests of selected (polymer-metal) sliding pairs were carried out. The selected polymers were polyurethane (TPU), polysulfone (PSU), and silicone rubber (SI). They interacted with a pin made of normalized C45 steel under unitary pressure p = 0.5 MPa in dry friction conditions at different gradients of the force driving the relative motion (dF/dt = 0.1-20 [N/s]). The static friction coefficient of the selected sliding pairs was determined on the basis of the recorded static friction force values. The test results show a significant influence of the rate of increase in the motion driving force on the values of static friction resistance. This is mainly due to the viscoelastic properties of polymers.

scholarly journals The influence of technologically boron-modification surface layer on the friction processes in sliding pairs of combustion engine

2010 ◽  
Vol 140 (1) ◽  
pp. 50-56
Author(s):  
Kazimierz LEJDA ◽  
Janusz LUBAS
Keyword(s):  
Surface Layer ◽  
Combustion Engine ◽  
Friction Pair ◽  
Important Influence ◽  
Surface Layers ◽  
Boron Modification ◽  
Friction Parameter

The aim of the present work is to determine the influence of borided surface layers on the friction parameter in the work of sliding pairs in the I.C. engine. The tribological evaluation included pack-borided and laser-borided surface layers deposited on rocker arm, piston pin and pin of crankshaft. The tests were performed in the generator set equipped with one-cylinder 4-stroke carburettor Robin Subaru engine. The wear of the elements of the combustion engine demonstrated that the process of boronizing has an important influence on the decrease of wear of the borided element of the friction pair.

Methods of Decreasing Wear in Metal-Polymer Contacts

1978 ◽  
Vol 100 (2) ◽  
pp. 185-188 ◽  
Author(s):  
V. A. Belyi ◽  
I. V. Kragelskii ◽  
V. G. Savkin ◽  
A. I. Sviridyonok
Keyword(s):  
Friction And Wear ◽  
Wear Behavior ◽  
Polymeric Materials ◽  
Material Surface ◽  
Surface Layers ◽  
Frictional Properties ◽  
Special Surface ◽  
The One ◽  
Metal Polymer ◽  
Selective Mechanism

In metal-polymer contacts, wear can be decreased either by developing materials which have the required frictional properties before rubbing, or by additives which revise the material surface properties during sliding. Two methods of each type are described. Several polymers were prepared by solidification against other solids which produced special surface structures. Other specimens were prepared by irradiation to change the structure of the polymer. In other experiments, two kinds of additives were incorporated into the surface layers of the polymer. The one is a complex compound which decomposes during sliding and alters the frictional properties. The other is an additive which influenced the transfer by a ‘selective’ mechanism. All of these methods widen the safe range of load and speed for the polymers. In the development of polymeric materials for improving friction and wear behavior, a polymer may be specially prepared before use, or may incorporate additives which alter the surfaces during sliding. Two modifications of polymers of each type are described below and follow upon preliminary work on these products [1–5].

Electrokinetics, Adsorption and Colloid Study of Simulated Nuclear Waste Glasses Leached in Aqueous Solutions

1984 ◽  
Vol 44 ◽  
Author(s):  
Cheng T. Lee ◽  
D. E. Clark
Keyword(s):  
Surface Layer ◽  
Nuclear Waste ◽  
Glass Surface ◽  
Charged Particles ◽  
Electrostatic Repulsion ◽  
Surface Layers ◽  
Short Term ◽  
Chloride Solutions ◽  
Zeta Potentials ◽  
Glass Surfaces

AbstractZeta potentials of SRL-131-29.8% TOS simulated nuclear waste glasses leached in D.I. water, Al, Ca, Mg, and Zn chloride solutions at 90°C were measured as a function of leaching time. For short term leaching, the adsorption of Ca, Mg, Zn and Al reverses the glass surface potential from negative to positive. Colloids were found to be stable in D.I. water and AICl3 solutions after leaching, presumably due to the electrostatic repulsion between the glass surface and similarly charged particles. Colloids were not found in Mg, Zn or Ca chloride solutions after leaching; instead, a relatively thick metasilicate surface layer was formed on glass surfaces leached in these solutions. The concentration of Si in solution is reduced by the formation of these surface layers.

Stresses in the Surface Layer and Hydrogen Absorption and Diffusion in Cavitation Condition

2014 ◽  
Vol 225 ◽  
pp. 131-138
Author(s):  
Jarosław Chmiel ◽  
Jolanta Baranowska ◽  
Roman Jędrzejewski ◽  
Arkadiusz Rzeczycki
Keyword(s):  
Surface Layer ◽  
Stress State ◽  
Hydrogen Absorption ◽  
Surface Layers ◽  
Fem Modeling ◽  
And Diffusion

Cavitation attack in liquids generated a various states of stresses in surface layers of metals. Differences in stress state effects on hydrogen absorption activated by the cavitation implosion. Results of XRD investigation and FEM modeling shows on inhomogenity of process.

scholarly journals Elemental composition of the surface layers formed on titanium at the cathodic treatment in chitosan-containing aqueous-dimethyl sulfoxide solutions of phosphate-molybdate electrolyte

2021 ◽  
Vol 21 (1) ◽  
pp. 32-48
Author(s):  
Svetlana S. Popova ◽  
◽  
Hussein Ali Hussein ◽  
Lyubov’ N. Olshanskaya ◽  
Sergei V. Arzamastsev ◽  
...  
Keyword(s):  
Surface Layer ◽  
Phosphoric Acid ◽  
Organic Solvent ◽  
Dimethyl Sulfoxide ◽  
Electrolyte Solution ◽  
Aqueous Electrolyte ◽  
Sodium Molybdate ◽  
Volume Ratio ◽  
Surface Layers ◽  
Potentiostatic Mode

It was established that at the cathodic treatment of titanium in aqueous dimethyl sulfoxide solutions of sodium molybdate, containing phosphoric acid, at the potential of the cathodic incorporation of sodium (Ec = −2.6 V) in the potentiostatic mode, the composition formed on the electrode surface layer depended not only on the composition of the solution, but also on the volume ratio of the aqueous electrolyte solution and the organic solvent (dimethyl sulfoxide).

scholarly journals About the mechanism for reducing the adhesion wear of the copper friction pair in the inert atmosphere by the nitrogen ions implantation method

2020 ◽  
pp. 72-79
Author(s):  
V.P. Sergeev ◽  
◽  
M.P. Kalashnikov ◽  
A.R. Sungatulin ◽  
O.V. Sergeev ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Surface Layer ◽  
Friction Pair ◽  
High Energy ◽  
Inert Atmosphere ◽  
Solid Solution Hardening ◽  
Internal Stresses ◽  
Maximum Increase ◽  
Energy Beam ◽  
Nitrogen Ions

The mechanisms of increasing the resistance of copper samples treated with a high-energy beam of nitrogen ions to adhesive wear during friction together with a copper counterbody in an argon atmosphere are studied. It was shown that the increase in wear resistance is complex and is associated with the action of mechanisms such as solid-solution hardening, grinding of copper grains, precipitation of the finely dispersed CuN3 phase, increase in the density of dislocations and internal stresses of the second kind in the surface layer . The maximum increase in wear resistance and microhardness (~ 4 and ~ 2.6 times, respectively, compared with the original copper) is observed about ion fluence of ~ 9×1017 ion/cm2. A further increase in fluencies leads to a decrease in wear resistance and microhardness due to the enlargement of the pores formed in the surface layer of copper as a result of implantation of nitrogen ions.

Features of damage and modification of surface layers of Al and its alloys by powerful energy flows in a plasma focus device

2021 ◽  
Vol 9 ◽  
pp. 34-52
Author(s):  
V. N. Pimenov ◽  
◽  
S.A. Maslyaev ◽  
Keyword(s):  
Surface Layer ◽  
Plasma Focus ◽  
Phase State ◽  
Structural Phase ◽  
Pulsed Laser ◽  
Plasma Focus Device ◽  
Deuterium Plasma ◽  
Surface Layers ◽  
Pulsed Laser Radiation ◽  
Structural Phase State

The results of the analysis of damageability and modification of the structural-phase state of the surface layers of aluminum and its alloys by powerful flows of fast high-energy ions and high-temperature plasma in Plasma focus devices, as well as using pulsed laser radiation. Pure Al, an alloy of the Al – Mg – Li system, a duralumin alloy, and a composition of a ceramic coating Al2O3 on an Al substrate are considered. It is shown that in the regime of Al irradiation with a power density of q ≈ 106 – 107 W/cm2 in the nano- and microsecond range of pulse durations, ultrafast crystallization of melted surface layer occurs with the formation of a wavy surface relief and the structural fragments of sub-microcrystalline and nanoscale size. After the action of deuterium plasma flows on a duralumin alloy tube located along the axis of the Plasma focus device a modification of the structural-phase state of the alloy is observed: the initial two-phase state of an αAl-solid solution of copper in aluminum and inclusions of the second phase of CuAl2 became fine-grained and single-phase due to the dissolution of CuAl2 particles in the melt. Irradiation of an alloy of the Al – Mg – Li system containing (wt %) 2 % Li and 5 % Mg at q = 5·106 W/cm2, t = 50 – 100 ns after four pulsed impacts of fast ions and deuterium plasma led to the modification the structural-phase state of the surface layer of the alloy, associated with an increase in the content of magnesium oxide and a decrease in the crystal lattice parameter of the Al-based solid solution. The formation of spherical cavities due to the evaporation of lithium into the internal micropores of the surface layer was also found. The low damage and structural stability of Al2O3 ceramics on an Al substrate under beam-plasma impacts in plasma focus device with a radiation power density q ≤ 108 – 109 W/cm2 in the nano- and microsecond range of pulse duration is noted. At the same time, the Al2O3/Al composition was unstable to pulsed laser radiation in the free-running mode (q = 105 – 106 W/cm2, t = 0.7 ms) and Q-switch mode (q = 107 – 108 W/cm2, t = 80 ns). In both cases the coating peeled off from the substrate.

Structure of the freshened surface layer in the Eastern Arctic during ice-free periods

2021 ◽  
Author(s):  
Alexander Osadchiev ◽  
Dmitry Frey
Keyword(s):  
Surface Layer ◽  
Sea Water ◽  
Discharge Rate ◽  
World Ocean ◽  
Kara Sea ◽  
Surface Layers ◽  
Narrow Channels ◽  
Lena River ◽  
Annual Variability ◽  
The World

<p><span>Discharges from the largest rivers of the World to coastal sea form sea-wide freshened surface layers which areas have order of hundred thousands of square kilometers. Large freshened surface layers (which are among the largest in the World Ocean) are located in the Kara, Laptev, and East-Siberian seas in the Eastern Arctic. </span><span>This work is focused on the structure and inter-annual variability of these freshened water masses during ice-free periods. The freshened surface layer in the Laptev and East-Siberian seas is formed mainly by deltaic rives among which the Lena River contributes about two thirds of the inflowing freshwater volume. Based on in situ measurements, we show that the area of this freshened surface layer is much greater than the area of the freshened surface layer in the neighboring Kara Sea, while the total annual freshwater discharge to the Laptev and East-Siberian seas is 1.5 times less than to the Kara Sea (mainly from the estuaries of the Ob and Yenisei rivers). This feature is caused by differences in morphology of the estuaries and deltas. Shallow and narrow channels of the Lena Delta are limitedly affected by sea water. As a result, undiluted Lena discharge inflows to sea from multiple channels and forms relatively shallow plume, as compared to the Ob-Yenisei plumes which mix with subjacent saline sea water in deep and wide estuaries. The shallow Lena plume spreads over wide area (up to 500 000 km<sup>2</sup>) in the Laptev and East-Siberian seas during and shortly after freshet period in summer and then transforms to the Laptev/East-Siberian ROFI in autumn. Area and position of the relatively shallow freshened surface layer in the Laptev and East-Siberian seas have large inter-annual variability governed by local wind forcing conditions, however, do not show any dependence on significant variability of the annual volume of discharge rate from the Lena River. The deep freshened surface layer in the Kara Sea also has distinct seasonal varability of area and position, however, is stable on inter-annual time scale.<br></span></p>

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