The method of applying a chromium coating
(57) Abstract:The invention can be used to protect the surface of the moving parts of mechanisms. The method comprises the deposition on a substrate chrome plating electrolytic method of chrome-containing solutions in the presence of a catalyst, on the first layer additionally precipitated chromium thermal dissociation of hexacarbonyl chromium, the thickness of the additional layer is 5 to 15% of the thickness of the first coating layer. table 1. The invention relates to mechanical engineering and can be used to protect the surface of the moving parts of mechanisms.A known method of applying to the surface of the product (substrate) chrome coatings by thermal dissociation vapor hexacarbonyl chromium . The method is carried out at a temperature of the substrate from 350 to 800oC in a vacuum of about 1 to 10-1mm RT. Art. when continuous pumping system. The number of carbonyl vapor fed to the reactor is governed by the temperature of the crystal hexacarbonyl chrome sublimator and typically is in the range from 40 to 80oC. Under these conditions, the rate of coating is from 20 to 150 μm/hCharacteristic of the">However, when the deposition of such coatings in these modes, the adhesive strength of their steel substrate is insufficient, and in the machining of parts is observed the formation of cracks in the coating and partial detachment from the substrate.Known electrolytic method of applying a chromium coating and, in particular, with the use of high-speed self-regulating chromium electrolytes . The method is carried out on the basis of catalytic anions in the form of sparingly soluble compounds of the following composition , g/l:
1) 250 chromic anhydride, 5-6 sulfate strontium, 8-10 calcium fluoride, sulfate-fluoride electrolyte (SF);
2) 230-250 chromic anhydride, 18-20 potassium silicofluoride, 8-10 calcium fluoride, fluoride-crematories electrolyte (FCF).The process is carried out at a temperature of electrolyte 40 to 70oC and a cathode current density of 30-70 A/DM2. In these conditions get shiny chrome coating with a small internal stresses characterizing the high strength of the coating to the substrate. However, the maximum microhardness of such coatings does not exceed 800-900 kg/mm2.The task of the invention to provide coatings. This problem is solved by the proposed method, the coating of the self-regulating chromium electrolytes, followed by additional deposition of chromium thermal dissociation of carbonyl vapor of chromium, the thickness of the additional layer is 5-15% of the thickness of the first layer.The method is as follows. Sample as the cathode is placed in hromsoderzhashchej electrolyte specific composition comprising catalyst. The deposition of chromium is carried out at 50-60oC, current density And 60-70/DM2. The sample after leaching is placed in a vacuum chamber on a graphite heater. The vacuum chamber, the sample is heated up to 350-500oC and is supplied from the pre-heated sublimator pair of hexacarbonyl chromium. Duration of 7-10 minutes On the surface of the heated sample pairs hexacarbonyl chromium decompose with the formation of additional chrome plating, the thickness of the additional coating layer is 5-15% of the thickness of the first layer.Example 1. A sample of Art. 3 is placed as a cathode in sulfate-fluoride (SF) electrolyte composition: 250 g/l of chromic anhydride, 6 g/l of strontium sulfate and 8 g/l of calcium fluoride. The deposition of chromium CR is C is removed from the electrolyte, washed with distilled water, dried, wipe the inner side moistened with ethyl alcohol, and put the camera on a graphite heater. Then the vacuum system until sufficient pressure 5 10-2mm RT. Art. the Sample is heated to 350oC and served from preheated to 40oC sublimator pair of hexacarbonyl chrome with vacuum. On the surface of the heated sample pairs hexacarbonyl chromium decompose with the formation of additional coverage. The residual pressure in the apparatus is reduced to 1 to 10-1mm RT. senior process Duration 7-10 minutesThe thickness (a) primary and secondary layers is determined by calculation on the weight gain of the sample. The thickness of the layers is respectively 40 and 3 μm. Microhardness (Hcdetermine the device PMT-3. The microhardness of the first layer 750 kg/mm2the second layer 1400 kg/mm2. Other examples are given in the table.As seen from the examples 1-3, the proposed method obtained the chrome coating with high microhardness while maintaining strong adhesion of the coating to the substrate.This invention involves an inventive step, since it was not known that when applied to pervia, since experimentally it was shown that the coating system Cr-Cr (in the case of a chromium substrate and Cr-carbonyl coating layer) does not possess the strength of coupling, as evidenced by the example 4.In example 4, the coating only the carbonyl method on a substrate of chromium, obtained by a metallurgical method. There is cracking of the coating and its partial detachment from the chrome substrate. Microhardness preserved the chrome coating is quite high and is 1250 kg/mm2.Sources of information
1. Syrkin Century, Carbonyl metals. - M.: Metallurgy, 1978.2. Borisov, A. the process of chrome plating spools of valves in high-speed self-regulating electrolytes /Sat. The improvement of means of mechanization of agriculture non-Chernozem zone. - Chelyabinsk, CHUMASH, 1981, S. 46.3. Yuriev L. I., Kozlov, I. P., Borisov, A. Physico-mechanical properties of electrolytic chromium obtained from self-regulating electrolytes /Sat. Repair of machines and technical metal. - M.: MYISP, 1975, S. 43. The method of applying a chromium coating on a substrate by electrolytic deposition of chromium is niteline deposition of chromium thermal dissociation vapor hexacarbonyl chromium, the thickness of the additional layer is 5 to 15% of the thickness of the first coating layer.
FIELD: technological processes.
SUBSTANCE: wood is modified by means of introduction of metal into its porous structure during thermal decomposition of nickel tetracarbonyl vapours inside wood, vapours of nickel tetracarbonyl are supplied into bottom part of wood stock with the speed of not more than 20 l/hr per 1 cm2 of cross section area in process of heating zone displacement downright with the speed of 12-15 cm/hr, at that for modification wood is used with humidity of not more than 2 wt %.
EFFECT: increase of wood heat conductivity and increase of resource of its operation in friction units.
2 cl, 1 dwg, 2 tbl, 7 ex
SUBSTANCE: invention relates to manufacturing method of supersmall metallic shot by method of chemical deposition from the gaseous phase and decomposition and can be used in manufacturing of miniaturised details and subassembly. It is used vertically oriented reactor, containing top and bottom parts. Introduction of metal-containing process gas is implemented into the bottom part of reactor. It is taken place advancement of metal-containing process gas in reactor along the ascending lines, initiation of metal-containing process gas decomposition inside the reactor, creation of conditions for formation of metal particles from the process gas, and extrusion of particles from top part of reactor.
EFFECT: at usage of upstream gas it is achieved more accurate approximation of velocity profile to theoretical "piston flow" and with this it is created required more "narrow" particle size distribution by dimension, excluding or reducing necessity of the following assortment.
17 cl, 7 dwg, 3 tbl
SUBSTANCE: invention refers to method of fabrication of metal coating, adhesion of which to material of pad exceeds 10 MPa and up to 18.6 MPa; method is characterised by metals, carbon and oxygen contents in composition of coating; method can be implemented in mechanical engineering, automobile industry, aircraft industry, powder metallurgy and other branches of industry. Coating is produced by means of chemical sedimentation of metals at decomposition of metals carbonyl sorbed onto pad out of gas phase. Sedimentation is performed in a reactor with forced cyclic displacement of pad from the zone of reagent sorption to the zone of its decomposition and reverse by means of fluidisation and mechanical of vibration mixing.
EFFECT: considerably improved characteristics of coatings, production of row of new materials possessing upgraded physic-chemical and mechanical properties of surface; also coatings are ecologically compatible and low in cost compared with analogs, as these coatings are produced in completely closed for reagents cycle.
9 cl, 2 dwg, 1 tbl, 13 ex
SUBSTANCE: invention refers to fabrication of metal coating, particularly, molybdenum on metal powders by thermal decomposition of hexa-carbonyl of molybdenum in medium of hydrogen sulphide and can be used for fabrication of anti-friction disperse-strengthened composite materials on base of polymer particles. The procedure for application of molybdenum particles on metal powders consists in application of coating by thermal dissociation of vapours of molybdenum hexa-carbonyl. Also, the main layer of applied coating consists of mixture of hexa-carbonyl of molybdenum and mono-oxide of carbon in volume ratio of vapours 1: 5 at 200°C, whereupon produced layer is saturated with disulphide of molybdenum made of mixture of products of thermal dissociation of hexa-carbonyl of molybdenum and hydrogen sulphide in volume ratio of vapours 1: 2 at temperature 400°C.
EFFECT: fabrication of molybdenum coating on metal powders efficient in optimal operational combination of values of hardness, wear resistance and heat resistance of composite materials facilitating increased service life of parts of friction pairs made out of given composites.
2 tbl, 1 ex
SUBSTANCE: invention relates to thermochemistry and electrochemistry, particularly, to improvement of electrolytic and carbonyl deposition of continuous-strip foil from iron group, and to devices to this end. Then, refining with decomposition of ferromagnetic material sublimated halide or evaporated carbonyl, or soluble ferromagnetic material compound with deposition either on titanium drum, or titanium drum cathode, are performed. Simultaneously with above refining, refining is performed using permanent magnetic field by arranging magnetic system inside titanium drum comprising either permanent magnets, ferromagnetic tubes and ferromagnetic discs connected in series in magnetic circuit, or ferromagnetic tube and ferromagnetic discs connected in series in magnetic circuit. Ferromagnetic tube is surrounded by permanent magnetic field excitation windings with high-temperature insulation. Note here that said permanent magnetic field is closed on titanium oxide surface made on titanium drum or titanium drum cathode.
EFFECT: high-efficiency production of foil strip of higher operating properties.
9 cl, 7 dwg
FIELD: power engineering.
SUBSTANCE: method includes creation of the specified gas medium, heating of a substrate, supply of an organometallic compound to the substrate, its decomposition with generation of a layer of tungsten on the substrate and removal of decomposition products. The organometallic compound is supplied to the centre of the rotary substrate in the medium of assist gas, and direction of substrate rotation during formation of layers is varied. Supply, decomposition of the organometallic compound and removal of decomposition products is carried out cyclically. The device comprises a reactor with a tight vessel, an electric furnace and a substrate placed in the reactor, systems of creation and maintenance of the required gas medium coupled with the reactor, as well as the system of creation and maintenance of the specified pressure and the system of organometallic compound supply. The system of organometallic compound supply is placed oppositely to the substrate for its supply in the centre of the substrate and is equipped with a system of assist gas supply.
EFFECT: invention provides for production of tungsten layers with high extent of purity and thickness from hundreds of nanometers to dozens of microns with a homogeneous nanosize structure.
5 cl, 3 dwg, 1 tbl, 9 ex
SUBSTANCE: device for application of coatings onto small-sized products includes a reactor with a cylindrical housing, which can be swayed in a vertical plane, on one end of which a cover plate with a branch pipe and a heater is installed, and on the other end a temperature-controlled casing with a branch pipe is installed; a corrugated ruler is installed inside the reactor with its long side along a generatrix of the cylindrical housing. The device is equipped with a flat plate-like bending spring rigidly attached to the corrugated ruler and provided with cantilever end sections projecting beyond the limits of the ruler as to its width with possibility of being pressed down to the inner surface of the cylindrical housing.
EFFECT: providing multiple use of an application device of coatings onto small-sized products of different shapes due to possibility of quick and easy replacement of the corrugated ruler.
FIELD: technological processes.
SUBSTANCE: invention relates to application of double-layer metal coatings and can be used for production of wear-resistant coatings when repairing parts by surfacing and spraying. Method of applying iron-tungsten coating on powder technical ceramics by thermal decomposition of vapors, containing iron pentacarbonyl and tungsten hexacarbonyl, is characterised by sequential application on powder particles of adhesion layer from mixture of iron pentacarbonyl and carbon monoxide in volume ratio of vapours 1:5 at temperature of their thermal decomposition of 250 °C, and then surface layer from mixture of tungsten hexacarbonyl and carbon monoxide in volume ratio of vapours 1:5 at temperature of their thermal decomposition of 800 °C.
EFFECT: coating, efficient in optimal operation of combination of values of hardness and strength of adhesion, which improves wear resistance of parts, reconditioned by sputtering and deposition of produced powders.
1 cl, 1 tbl, 1 ex
SUBSTANCE: method of applying the anti-corrosive coating on the detonating elongated charge metal shell contains the thermostating of the elongated detonating charge disposed in the working chamber and its depositing on the metal surface by decomposition of the initial metal compound of carbonyl group vapour in the gas-carrier flow. The thermostating is carried out at the temperature of 80-85°C during 3-5 minutes. The metal carbonyl is used as the initial metal compounds of the carbonyl group, the acoustic stiffness of which is greater or not less than the stiffness of the detonating elongated charge shell metal, and the hydrogen sulfide is used as the gas-carrier. The metal carbonyl vapour and hydrogen sulphide are supplied simultaneously at the rate of 1.0-1.5 g/h and 0.1-0.2 g/h, respectively, at the residual pressure in the working chamber of 10-1-10 Pa.
EFFECT: increasing of gas, vapour, water resistance of the protective coating, its adhesion with the metal shell of the detonating elongated charge, increasing the productivity of work, the expansion of functionality and the application scope of corrosion resistant, protective coating.
FIELD: metallurgy, namely processes for applying wear resistant chrome carbide coatings, protection of surface of articles of titanium and its alloys against action of aggressive media, abrasive wear and high temperature influence.
SUBSTANCE: method comprises steps of applying sub-layer of metal and further applying of wear resistant chrome carbide layer by pyrolysis of chrome-organic compounds of bis-arene. Before applying wear resistant layer of chrome carbide, sub-layer of nickel or its alloys with thickness 0.1 - 10 micrometers is applied.
EFFECT: possibility for applying on titanium and its alloys wear resistant coating with enhanced adhesion degree of coating and substrate and with improved strength against crumpling at elimination of cracking.
4 cl, 1 tbl, 4 ex
FIELD: mechanical engineering; methods of depositing of the chromium coatings on steel details.
SUBSTANCE: the invention is pertaining to the field of mechanical engineering, in particular, to the method of depositing of the chromium coating on the steel details and may be used for restoration and hardening of surfaces of the friction components of machines. The method includes an electrolytic deposition on a substrate of a chromium coating out of chromium-containing solutions at presence of a catalytic agent. Then conduct an anodic etching in the same electrolyte keeping to the following modes: a current density of 40-50 A/dc2, the temperature of the electrolyte - 50-65°C. After the anodic etching they exercise deposition of an additional layer of the chromium coating from a gas phase of chromium hexacarbonyl by a thermal dissociation. In the particular cases of the invention realization the depth of the galvanic chromium layer makes 5-15 microns, and the increase of the coating thickness up to a required value is gained with the help of a thermal dissociation of the chromium hexacarbonyl vapors from the gaseous medium. The technical result of the invention is an increased adhesive strength of the coating with the substrate and an increased productivity of the process.
EFFECT: the invention ensures an increased adhesive strength of the coating with the substrate and a raise of the process productivity.
2 cl, 1 tbl, 3 ex
FIELD: galvanoplastics; methods of production of art articles.
SUBSTANCE: the invention is pertaining to the field of galvanoplastics and may be used at manufacture of the art articles. The method provides for sensitization of the surfaces of the model in the solution of stannum chloride (II) with addition of hydrochloric acid, chemical metallization and galvanic copper coating. At that before the sensitization the surface of the model wetted with solution of stannum chloride stannum (II), then the model is coated with the layer of the acrylic lacquer, and after sensitizations conduct hydrolysis. At that the chemical metallization is conducted in the solution of silvering in the following composition of components (in g/l): silver nitrate - 2; 25 % ammonia water solution - 10; 10 % caustic potassium water solution - 18; and at galvanic copper coating apply a current of the low cathode density of 0.5 A/dm2. The technical result: the invention allows to realize metallization of the ill- wettable surfaces of plants and insects, to improved quality of metallization of insects and plants.
EFFECT: the invention allows to realize metallization of the ill- wettable surfaces of plants and insects, to improved quality of metallization of insects and plants.