Composition for coating and method of applying
(57) Abstract:The invention relates to the field of application of anti-friction coatings on the contact and friction surfaces. Proposed composition and method spray composition consisting of components of different hardness, one of which is a polymer with a particle size not exceeding 10 microns at its effective content of not more than 10 wt.%. The method allows to receive anti-friction coatings with low friction coefficient, which has both high mechanical strength and thermal conductivity. 2 S. and 2 C.p. f-crystals. The invention relates to mechanical engineering and can be used for the application of anti-friction coatings on the contact and friction surfaces.Known powder coating consisting of copper powder and 10 to 90% zinc (P. RF 2062820).Known material for coating, a mixture of at least two components: ductile metals or their alloys and the material, the hardness of which is not less than three times the hardness of the first component (Z. N 9305207, op. BI N 1, 97 g).However, these compositions are a mixture of different metals, so based pokr is stew, have large coefficients of friction.Known polymeric coating, such as PTFE coating on aluminium (p. RF N2068037, publ. 20.10.96, and.C JP N 63-35817, publ. 25.08.89 year).However, polymer coatings have low mechanical strength, low thermal conductivity and high thermal expansion coefficient.Closest to the claimed is a coating material composed of a mixture of powders containing at least two components: a metal or alloy and 20 to 80% by weight of the powder material, the hardness of which is not less than three times the hardness of the first component and the particles of which have a shape close to spherical, and the transverse size of an average of at least 30 μm (n RF N 2109842, op. 27.04.98 g). However, like any metal coating, it is subject to corrosion, has a high electrical conductivity and thermal conductivity, has a large coefficient of friction.There are many methods of coating on the friction surfaces. For example, there is a method of coating by placing between the friction surfaces of the mechanically activated mixture obrazovvatelnogo substances, such as quartz, particle size of 0.1 - 5 μm.with. USSR N 1 is estlat in a ball mill. The known method results in films with low technological properties. They are short-lived, fragile and lack continuity.A known method of applying ultradispersed polytetrafluoroethylene (EPTFE) with a particle size of 5 microns on pre-anodized aluminum surface by mechanical polishing followed by heating the surface to 280 - 340oC (n, RF N 2068037, publ. 20.10.96,)
However, this method does not allow to achieve a uniform coating, and therefore, leads to the fact that the mechanical properties of the surface when the work is not stable.Known methods for impregnation of PTFE aluminum film galvanic coating by anodic oxidation in an acidic solution, containing suspended particles of polytetrafluoroethylene (and. C. Japan N 63-35817, publ. 25.08.89; and.with. USSR N 1708943, publ. 30.01.92). The method is complex, inefficient and barely acceptable for coating large areas.Closest to the claimed is the method of coating the surface accelerated gas flow of powdered material composed of a mixture of powders containing at least two of comicy which have the form, close to spherical, and the transverse size of which an average of at least 30 μm (N RF N 2109842). The method is suitable for surface hardening, and the resulting coating has a high coefficient of friction.The task, which directed the claimed composition and the method of its application, is receiving anti-friction coating that has both a low coefficient of friction in vacuum and high mechanical strength and thermal conductivity, and low thermal expansion coefficient and good adhesion when the thickness of the coating.The problem is solved proposed composition composed of a mixture of powders comprising at least two components of different hardness, provided that the component with the lesser hardness is a polymeric material with a particle size not exceeding 10 microns at its effective amount in the composition is not more than 10 wt.%, and the method of coating the accelerated gas stream of the specified structure, previously subjected to mechanical activation.The proposed composition and method of applying reduce the coefficient of friction of 0.05 while increasing the thickness of the coating and firmly the ptx2">As one of the components of the composition can be used materials having high heat conductivity and mechanical strength, such as copper, aluminum, Nickel, iron, zinc, oxides or alloys, graphite, and so on, with an average particle size up to 20 microns. The increase in dispersion leads to spotty coverage and reduces its strength.The second component of the inventive composition is a polymer with a particle size up to 10 microns and a hardness less than the hardness of the first component, for example ultradispersed polytetrafluoroethylene (EPTFE) (Flower A. K., Matveenko L. A., Ignat'eva, L. N., Buznik C. M. Thermodynamic method of recycling of polytetrafluoroethylene as a way to create new highly dispersed fluoropolymer. International Symposium "Chemistry and chemical education, APR XXI century: proc. Dokl. -Vladivostok. -1997. -S. 192.)
The use of the composition for coating as one of the components of the polymer with a hardness lower than the hardness of another component leads to "enveloping" of solid particles softer, which helps to protect the particles of the main component, and hence the surface from corrosion, reduces friction and wear of the coating, leading to simplified above 10 μm does not fully "encapsulating particles of the main component, that leads to a significant deterioration in the quality of the coating, and when the content of polymer in the mixture is greater than 10 wt.% the coating is not formed.The composition is prepared by mixing the inventive components either mechanically or with the use of designated equipment, for example in ball mills or mills activators, and is applied to the surface either by rubbing or by the surface finishing process, or gas-dynamic spraying.The best result is achieved when using the method of gas-dynamic spraying, allowing you to use the advantages of the proposed structure. The method is as follows.A powder mixture consisting of a main component and a polymer is subjected to mechanical activation by known methods, for example in a mill-activator. Preliminary mechanical activation of the mixture enables you to evenly apply the polymer to the surface of the base component. Then through the nozzle of the gas installation air flow with supersonic speed powder applied to the surface.Upon impact, the particles of the main component driven into the surface of the material, increasing its mechanical strength, conductivity and Elasti the polymer layer, significantly reduces the coefficient of friction of the coating, the value of which is close to the coefficient of friction PTFE coating.The coating can be applied on a variety of surfaces both in size and shape, and substrate material (metal, alloys, ceramics, glass, stone, etc)
Depending on the purpose of the coating thickness can vary from tenths to several millimeters.When measuring the coefficient of friction (KTr) scheme was used sliding cylinder on a plane (K. K. Folders, N. A. Rogozin "Dictionary of fuels, lubricants, additives and special liquids. M, Chemistry, 1975, S. 170-171). The coefficient of friction of the samples coated with two-component layer of the inventive coating was measured in a pair of hardened steel SHKH15 in the absence of lubrication.Coating adhesion was measured by the method of lattice cuts on GOST 15140-78. Evaluation of the coating adhesion was performed on a 4-point system. In all cases, the adhesion was 1 point, which means that the cut edges are completely smooth, there are no signs of exfoliation in any square of the grid.An example implementation of the method
of 21.6 G. of copper powder with an average of DISM/s2. The masses of the balls 60 g (the ratio of balls: download 100:40). Processing time 3 minutes the thus Treated mixture is placed in the infeed gas installation made in the Institute SB RAS. The pressure at the inlet of the supersonic pneumothoraces is 15 to 18 ATM. In the air flow whose velocity is 2.6 Mach, injections particles of the mixture through the nozzle (critical section 3x3 mm, the cross section of the slice 3x10 mm) are bonded to the surface of the aluminum alloy D16T. When interacting particles mix with the surface temperature rises to 350-380oC. the Resulting coating has a coefficient of friction of 0.05. 1. Composition for coating composed of a mixture of powders comprising at least two components of different hardness, characterized in that as component with a lower hardness using a polymeric material with a particle size not exceeding 10 microns at its effective amount in the mixture is not more than 10 wt.%.2. Composition under item 1, characterized in that as one of the components using powder selected from the group comprising copper, aluminum, Nickel, iron, zinc, oxides or alloys, graphite with particle size up to 20 microns.3. Composition under item 1, characterized in that Senia coatings, comprising coating the surface of the accelerated gas stream composition composed of a mixture of powders comprising at least two components of different hardness, wherein as part of a mixture of powders, specified in paragraph 1, previously subjected to mechanical activation.
FIELD: portable apparatuses for applying coatings of powder materials by gasodynamic deposition.
SUBSTANCE: apparatus includes compressed gas source, powder meter, deposition unit in the form of portable manual tool with remote control having supersonic nozzle and gas heater rigidly connected with it. Gas heater includes metallic body inside which electric and heat insulation having through mutually parallel pneumatic ducts with inserted in them heating members. Apparatus also includes pneumatic duct for feeding powder from powder meter to supersonic nozzle, locking devices and unit for controlling deposition process, said units are mutually connected through flexible pneumatic ducts and electric connection wires. According to invention electric and heat insulation of gas heater includes inner and outer cylinders coaxially arranged one inside other. Inner cylinder has central through passage for placing pneumatic duct for feeding powder from meter to supersonic nozzle. Pneumatic ducts along its periphery are in the form of grooves. Inner and outer cylinders of electric heat insulation of gas heater are made of heat resistant material having electric and heat insulated coating on surfaces restricting pneumatic ducts.
EFFECT: enlarged manufacturing possibilities, simplified design, lowered mass, improved capability for repairing works, enhanced operational efficiency.
2 cl, 3 dwg