Generation of nanoparticles in the concentrated energy (laser beam) and gas flow

The method of generation and selection of small nanoparticles in the airflow is considered in this paper. To melt the material (stainless steel), a concentrated energy flow – a pulsed solid‐state laser beam – was used. Using the Mossbauer spectroscopy method, the particle sizes and their chemical composition at various distances from the melting place were determined. The influence of parameters of the laser beam power and the airflow on the size of particles and their chemical composition was investigated. First Published Online: 14 Oct 201

Study of fe based nanoparticles for tribosuspensions

Nanoparticles can be used to make tribosuspensions mixing them with oils or other liquids. Tribosuspension are widely applied in industry, transportation and etc. having aim to cool the contacting surfaces and reduce friction improving longevity of the surfaces. In the study the methods that are cheap and can generated large amount of nanoparticles were chosen. Nanoparticles were obtained by laser cutting (Fig. 1) and the selection of the nanoparticles in the gas flow [1]. Mechano-synthesis using iron and other metal salt were also applied to obtain large amount of Fe mixed different metal (Co, Fe, Mn, Ti) oxide (oxyhydroxide) nanoparticles [2, 3]Fizikos institutasVytauto Didžiojo universitetasŽemės ūkio akademij

Influence of finishing laser cutting on the wear of the friction pair surface

Vytauto Didžiojo universitetasŽemės ūkio akademij

Magnetic nanomaterials in the use of friction problems

Nanocrystalline materials are finding increasing application everyday. One possible application is modification of surfaces or oils with magnetic nanoparticles. Two aspects are used in serial production. Firstly, oils are enriched with iron oxide nanoparticles and form suspension - so called ferrofluid. Structural defects on the steel surface form magnetic field gradients, which attract particles from oil. At defected place collections of nanoparticles are formed and they cover defects. Being very small particles can fill even tiniest splits (up to 0,01 pm) and prevent further cracking. Secondly, external magnetic field can change viscosity of oil. These properties allow creation of dampers with controllable resilience or control of the rotation speed of shaft. The use of nanocrystalline particles is very perspective and requires more research in order to investigate magnetic properties of nanoparticles, and how these properties depend on the particle size and mobility (Brownian motion)Vytauto Didžiojo universitetasŽemės ūkio akademij

Influence of fluor-oligomeric coat to the surface of steel

Vytauto Didžiojo universitetasŽemės ūkio akademij

Tribological behavior of steel (iron) - Foleox system

The paper describes results of the study of tribological characteristics of the steel - fluoroligomer (Foleox) system and regularities of interaction between fluoroligomer and iron. It is found that the fluoroligomer film reduces the friction torque and wear of seal members that favors the cyclic delivery of fuel pumps. The effect of fluoroligomer on the pair tribological behavior is explained by the formation of carbides on the surface of iron and changes in its structureFizikos institutasVytauto Didžiojo universitetasŽemės ūkio akademij

The properties and interactions in the system steel (iron) – FOLEOX

Vytauto Didžiojo universitetasŽemės ūkio akademij

The properties and physicochemical interactions in iron-fluor-oligomer systems

We explore the efficiency of fuel pumps by modifying the friction surfaces with fluor-oligomeric films, analyze the peculiarities of interaction between the fluor-oligomer and iron, and investigate the influence of fluor-oligomer on the corrosive properties of iron. After processing the surfaces of precise friction pairs with fluor-oligomer, the average cyclic delivery of fuel pumps increases by up to 18%, and the elevated efficiency persists for 40 hours of operation. The fluor-oligomer lowers wear as compared with the control version, especially at higher rotation speeds. The positive effect is explained by the chemical interaction between iron and the fluoroligomer film as follows from the data obtained by the Mössbauer spectroscopy, the X-ray diffraction analysis, and electrochemical technique. Even extremely thin fluor-oligomeric films (down to 2 μg.cm–2) may sufficiently improve the corrosion resistance of ironVytauto Didžiojo universitetasŽemės ūkio akademij

Influence of fluor-oligomers on the structural and tribological properties of steel surface at the rolling friction

Purpose - The purpose of this paper is to investigate the influence of fluor-oligomeric coat on the mechanical properties of steel surface, as well as the chemical interaction of fluor-oligomeric films with surface and theoretical-phenomenological interpretation of structural processes in friction surface. Design/methodology/approach - Four groups of specimens were studied: two groups of specimens without any wear tests - initial steel specimen as control version and a specimen which was ten times coated by fluor-oligomer, and two groups of specimens, which were tribologically tested for one miilion cycles - without any coating and coated specimens. Closed kinematical profile scheme roller-roller of steel 45 was chosen for tribological tests. Wear of friction surface after those tests was investigated. The interaction between fluor-oligomer and iron was studied by means of Mossbauer spectroscopy. The micro-hardness of matrix was also measured. Findings - Affecting the surface of steel by the fluor-oligomer and friction produces the complicated processes of carbide decay and formation occur. The mechanisms are found which are related to the weakening of chemical bond in steel during the absorption, to the generation of microscopic ruptures, to the decrease (30-50 per cent) of the amount of carbides and its increase during the friction (up to 50 per cent). The mechanical effect which causes the regeneration of carbides during friction is revealed. Tribological efficiency of fluor-oligomeric coats (five times lower wear of coated specimens) is explained by the balance of three processes - the softening of matrix during adsorption, the detention of dislocations, and formation of hard particles in the matrix. Originality/value - The complex mechanism of the increase of wear resistance is explained by filling of ductile matrix with carbide particlesVytauto Didžiojo universitetasŽemės ūkio akademij