Method of confirmation of exhaustion of protective properties of heat-resistant diffusive coatings
FIELD: measurement equipment.
SUBSTANCE: invention relates to nondestructive examination, to study of metal properties and is intended for confirmation of exhaustion of protective properties of heat-resistant diffusive coatings on details made of carboniferous heat-resistant alloys. The method of confirmation of exhaustion of protective properties of heat-resistant diffusive coatings on details made of carboniferous heat-resistant alloys by change of physical and chemical properties of the surface layer of heat-resistant diffusive coatings during operation in conditions of high temperature, comprises application of reagent on the coating surface, and the fact of exhaustion of protective properties of the heat-resistant diffusive covering is witnessed visually by change of colour of the surface of heat-resistant diffusive coating with formation of carbon and black oxides during the process of chemical reaction between carbide phases, forming in the surface layer of the heat-resistant diffusive coating at the late stages of operation, and reagent.
EFFECT: simplicity, reliability and reliability of tests is achieved.
1 ex, 5 tbl, 10 dwg
The invention relates to nondestructive testing, to investigate the properties of metals and is intended to confirm the exhaustion of the protective properties of heat-resistant diffusion coatings on parts made of carbon-containing superalloys.
The known method of determining the developed part of the resource, which is measured by changes in the physical properties of the material of the sensor attached to the surface of the test details [Sahm K.-F., M. Natter Dornier-fatique measuring system. "Dornier Post", 1978, No. 3, p.48-49].
The disadvantage of this method is that developed about the resource is judged by the change in reflectivity of the sensor, glued on its surface, which does not guarantee reliability of the definition elaborated by the resource due to differences in the properties of materials parts and the sensor.
The closest technical solution is a method of assessment developed resource [RF Patent №1769069 from 04.12.1990 G. / Method of evaluating the degree of fatigue damage of materials // Voropaev V. S., J. A. Svirsky, Vorobyova L. A.], namely that the sample material is subjected to cyclic loading, and determine the change in the chemical composition of the surface layer of the material from cyclic loading, which are judged on the proportion of generated resource.
The disadvantage of this method is the high complexity it is basically�Oh implement due to the necessity of special preparation of the polished test surface area of the details and complexity of the technique of electron probe x-ray analysis, requiring the creation of a high vacuum.
The problem to be solved by the claimed invention is the development of reliable and simple way of confirming the exhaustion of the protective properties of heat-resistant diffusion coatings on carbon-based heat-resistant alloys.
The technical result that can be achieved by carrying out the invention, is the possibility of transition from the operation of parts made of heat-resistant carbon-containing alloys coated with heat-resistant diffusion coatings under the assigned resource to the system operation on the technical condition.
This technical result is achieved in that in the method of confirmation of the exhaustion of the protective properties of heat-resistant diffusion coatings on parts made of carbon-containing heat-resistant alloys, the change of physico-chemical properties of the surface layer of heat-resistant diffusion coatings in the process of operation at elevated temperatures, including the application of the reagent on the surface of the heat-resistant diffusion coatings, the fact of the exhaustion of the protective properties of heat-resistant diffusion coatings are judged visually on the basis of color change of the surface heat-resistant diffusion coatings with formation of carbon oxides and black color in the course of chemical re�functions between the carbide phases, formed in the surface layer of heat-resistant diffusion coatings in the later stages of operation, and a reagent.
The inventive method is explained in Fig. 1-10 and table. 1-5, where a given phase composition of heat-resistant alloy IS (Fig. 1, tab. 1) deposited on the alloy heat-resistant diffusion coatings (Fig. 2, table. 2), the change of phase composition of the surface layer of the coating during operation at elevated temperatures (Fig. 3, 4 and 5, tab. 3, 4 and 5); the appearance of the samples coated in the process of operation at an elevated temperature until the coating protective properties (Fig. 6), at the time of exhaustion of the coating protective properties (Fig. 7) and after the coating has exhausted protective properties (Fig. 8); coating the surface of a drop of liquid reagent solution to the exhaustion of protective coating properties does not cause a chemical reaction (Fig. 9), whereas at the time of exhaustion of the coating protective properties, there are signs of a chemical reaction (Fig. 10).
Simultaneously with the exhaustion of the coating protective properties, as it follows from Fig. 4 and table. 4, in the surface coating layer formed of the carbide phase Cr23C6and'alni3C0,5. To detect them on the surface was applied an aqueous solution of sodium hypochlorite NaOCl. As a result of redox reactions between the carb�DNAME phases and sodium hypochlorite
are the reaction products (e.g., carbon and oxides of chromium and Nickel black color) that can be detected visually (Fig. 10).
Operation of parts made of heat-resistant alloys at elevated temperatures after the exhaustion of heat-resistant diffusion coating protective properties inevitably leads to burnout coatings, the development of the process of oxidation of heat-resistant alloy and substantial violation of part geometry (Fig. 8). This fact makes non-repairable parts, which eliminates the possibility of re-use and lead to significant material losses. However, the timely withdrawal of the parts from operation to onset of burnout coating allows repeatedly to carry out the refurbishment and return the item for re-use, thus saving material. To prevent burnout of the coating, typically use a system of exploitation assigned to a resource that does not allow full use of the protective properties of heat-resistant coatings. The existence of simple objects and�guidance criterion of exhaustion of heat-resistant coating protective properties allows you to navigate to the system operation on the technical condition, that gives the opportunity to use reserves of heat-resistant coatings without the risk of burnout.
An example of a specific implementation method
Experimental cylindrical samples with a diameter of 14 mm and a height of 5 mm made of heat-resistant alloy grades GS. According to the spectral analysis conducted on the spectrograph brand PMI Master PRO, was determined the chemical composition of the alloy (weight %): C - 0,17; Cr - 5,0; With 9.2 per; W - 9,1; Mo - 1,2; Al - 5,9; Nb - 1,5; TA - 4,1; Re - 3,9; Hf - 0,03; 0,014; Y - 0,004; CE - a 0.02; Si - 0,24; Ni - basis.
Heat treatment alloy: quenching under vacuum to 1280°C after annealing for 4 hours at the same temperature.
The phase composition of the alloy and coatings as in the initial state and at different stages of operation at elevated temperatures, was determined by x-ray diffraction diffractometer brand DRON-3 using the standard software of the diffractometer; before removing the diffraction pattern of the surface of the samples was cleaned from oxide films using soft abrasive-liquid processing.
The diffraction pattern of the surface layer of the sample after heat treatment of the alloy prior to coating shown in Fig. 1; phase composition of the alloy IS after heat treatment before coating are shown in table. 1.
The samples were deposited heat-resistant diffusion coating (�Ravalomanana in vacuum, the residual pressure of 1.33·10-1PA). The coating was carried out in a powder mixture of the following composition (weight %): aluminium powder brand ASD-4 - 10%; chromium powder brand PHS - 40%; powder of aluminum oxide of the brand of the sur - 50%; ammonium chloride NH4Cl (qualification "analytical grade") of 0.5%. The temperature of formation of the coating was 1000°C, duration - 5 hours.
After coating, the samples were subjected to thermal treatment at a temperature of 1210°C for 1 hour and 15 minutes at a residual pressure of 1.33·10-1PA to relieve internal stresses and removal of gases from the surface layers.
The diffraction pattern of the surface layer of the coating before use at elevated temperatures is shown in Fig. 2; the phase composition of the surface layer of the coating before use at elevated temperatures are presented in table. 2. The carbide phase in the surface coating layer is not detected.
After coating, the samples were kept in a muffle furnace at a temperature of 1080°C.
The diffraction pattern of the surface layer of the coating after 300 hours in a muffle furnace at a temperature of 1080°C is shown in Fig. 3; phase composition of the surface layer of the same coating is shown in table. 3.
The diffraction pattern of the surface layer of the coating after 400 hours in a muffle furnace at tempera�ur 1080°C is shown in Fig. 4; phase composition of the surface layer of the same coating is shown in table. 4.
The diffraction pattern of the surface layer of the coating after 500 hours in a muffle furnace at a temperature of 1080°C is shown in Fig. 5; the phase composition of the surface layer of the same coating is shown in table. 5.
Fig. 6 shows the appearance of samples after 300 hours in a muffle furnace at a temperature of 1080°C. a Uniform gray color of the solid oxide film suggests that the coating has not exhausted its protective properties. The result of the analysis of the phase composition of the surface layer of the coating (Fig. 3, tab. 3) indicate the absence of carbide phases. Applying drops of a 4% aqueous solution of sodium hypochlorite to clean oxide films from the surface of this coating does not lead to chemical reactions (Fig. 9).
Fig. 7 shows the appearance of samples after 400 hours in a muffle furnace at a temperature of 1080°C. Uneven gray color of the oxide film caused by the appearance in its structure complex oxide NiCrO4that indicates that coverage has exhausted its protective properties and has begun the oxidation of heat-resistant alloy. The results of the analysis of the phase composition of the surface layer of the coating (Fig. 4, tab. 4) indicate the appearance of a carbide phases. Applying drops of a 4% aqueous solution� of sodium hypochlorite to clean oxide films from the surface of this sample led to the chemical reactions of type (1, 2) with the formation of carbon, chromium oxide and Nickel oxide black, which can easily be detected visually (Fig. 10).
Fig. 8 shows the appearance of samples after 500 hours in a muffle furnace at a temperature of 1080°C. On the sample surface, there are clear signs of burnout coating, which is indicative of the intensive development of the process of oxidation of heat-resistant alloy. The results of the analysis of the phase composition of the surface layer of suitable cover (Fig. 5, tab. 5) indicate the presence of carbide phases and a significant amount of various oxides.
Compared with the prior art the use of this reliable and simple method allows, without resorting to the use of expensive equipment, visually confirm the fact of exhaustion of the protective properties of heat-resistant diffusion coatings on carbon-based heat-resistant alloys.
Confirmation method of exhaustion of the protective properties of heat-resistant diffusion coatings on parts made of carbon-containing heat-resistant alloys, the change of physico-chemical properties of the surface layer of heat-resistant diffusion coatings in the process of operation �ri elevated temperature, including the application of the reagent to the surface of the coating, characterized in that on the fact of exhaustion of the protective properties of heat-resistant diffusion coatings are judged visually on the basis of color change of the surface heat-resistant diffusion coatings with formation of carbon oxides and black color in the course of chemical reaction between the carbide phases formed in the surface layer of heat-resistant diffusion coatings in the later stages of operation, and reagent.
SUBSTANCE: invention refers to medicine and describes using resorufin and/or toluidine blue used as an organic oxidation-reduction colouring agent, one or more polyols, glycerol, and water introduced into gelatine and/or hydroxyethylstarch, and/or methlcellulose used as additives, as an oxygen indicator. The indicator is configured so that an oxygen-sensitive product stays visible.
EFFECT: declared invention provides the light- and heat-sensitive visibly discolouring oxygen indicator.
19 cl, 6 tbl, 10 ex
FIELD: measurement equipment.
SUBSTANCE: invention relates to ecology, namely to sanitary-chemical control of the state of environment and can be used for solution of tasks for detection and measurement of harmful substance concentrations in the air. A device for detection of harmful substances in the air includes an air flow booster and the primary chemical transducer; with that, the air flow booster includes the following: a control unit providing setting of parameters of bleed air, operation and control of the device; an air path for transportation of an air flow; an air pump connected to the control unit for pumping of air through the air path; a self-contained power source, and the primary chemical transducer is connected to the air path. With that, the device includes flow and temperature sensors of the pumped air, which are arranged in the air path, as well as sensors of atmospheric pressure and relative humidity of the pumped air, which are arranged outside the air path, and the control unit includes an information display device; at least one control button and an electronic circuit providing the following: recording of data from sensors; determination of air density; control of volumetric flow of the pumped air; adjustment of air sampling time, and analogue-to-digital conversion of the obtained and transmitted data.
EFFECT: improving accuracy of taken air volumes; increasing quick action of operation of the device; control and fixation of parameters of the taken air (volumetric air flow rate, atmospheric pressure, temperature and humidity); increasing ease of use; improving accuracy of readout of information from the primary chemical transducer; providing technical control and fixation of colorimetric changes of the primary chemical transducer; reducing overall dimensions and the weight of the device; enlarging functional capabilities.
24 cl, 1 dwg
SUBSTANCE: invention relates to analytical chemistry, namely to photometric determination of small concentrations of iron (III) in solutions of pure salts. The method includes conversion of iron (III) in a complex compound with an organic reagent and a surface-active substance in a mildly acidic medium by heating the above on water bath with following photometry of the obtained solution, and to a solution of iron (III) with pH 3.9-.5.2 added is 50-fold quantity of an organic reagent, represented by xylenol orange, 1.8-2.2 ml of a surface-active substance in the form of a 2% solution of ETHAL LA-7, and water to 10 ml of the volume with the following heating on water bath at a temperature of 60-80°C for 15 min and addition of 1 ml of acetone into the obtained solution.
EFFECT: invention makes it possible to increase the analysis sensitivity.
SUBSTANCE: invention relates to the field of gases identification and refers to a spectral analysis system for gases identification using a treated tape. The system includes a treated tape, an adjustable colour source, a photodiode, a colour identification sensor and a microprocessor. The adjustable colour source emits radiation in the direction of the treated tape with multiple varied wavelengths. The photodiode measures the radiation reflected from the treated tape. The microprocessor analyses the measurement results and, proceeding from the colour identified and the colour spot intensity, identifies the type and concentration of the gas the treated tape has been exposed to. Additionally, the microprocessor, with the help of the colour identification sensor, controls the radiation wavelength of the adjustable colour source and, whenever required, corrects the colour source radiation.
EFFECT: technical effect consists in increased sensitivity and ensuring the possibility of different type gases detection.
13 cl, 2 dwg
FIELD: oil and gas industry.
SUBSTANCE: at first sample of tested oil product with fixed volume is passed through water-coagulating agent placed between turns of a flat spiral mounted in a cavity of the element having shape of a truncated cone. When the sample is passed along the spiral the time for coagulation of free water microdrops in the sample is extended. Then the sample of the tested oil product is passed through a filter membrane with a deposited layer of water-sensitive chemical agent. At that by means of the hollow element having shape of a truncated cone this sample is localised at the surface of this water-sensitive chemical agent and water availability or concentration is evaluated by its colour changing. Additionally water concentration in the sample of the tested oil product is evaluated against decrease of the sample fixed volume before the water-sensitive chemical agent changes its colour.
EFFECT: improved accuracy of the analysis.
SUBSTANCE: invention relates to field of analytical chemistry, namely to photocolorimetric method of analysis, and can be used for determination of iron (II) content in extract of spruce needles, containing iron (II) in very low concentration. Method includes its transfer into complex compound with organic reagent, with addition of 150-200-fold amount of organic reagent to solution of iron (II) with pH 3, as reagent used is Congo red, 0.2-0.4 ml solution of surface-active substance in form of 0.2% solution of 6-aminocapronic acid, and water to 10 ml with further heating on water bath at temperature 80-98°C for 10-15 min.
EFFECT: increased analysis sensitivity.
SUBSTANCE: invention describes a method of determining aluminium (III), which involves preparing a sorbent, an aluminium (III) solution, extracting aluminium (III) from the solution using the sorbent and conversion thereof into a complex on the surface of the sorbent, separating the sorbent from the solution, measuring luminescent intensity of the surface aluminium (III) complex and determining content of aluminium from a calibration curve. The sorbent used is silica gel which is successively modified with polyhexamethylene guanidine and 7-iodo-8-hydroxyquinoline-5-sulphonic acid, and luminescent intensity is measured at 495 nm.
EFFECT: low threshold of detecting aluminium, wider range of determined content, low consumption of the organic complexing agent.
4 ex, 2 tbl
SUBSTANCE: invention can be used to determine content of iron (II) in solutions of pure salts containing iron (II) in very low concentrations. The method involves converting iron (III) into a complex compound with an organic reagent in a weakly acidic medium. The iron (II) solution with pH 2-5 is mixed with 200-300 times the amount of the organic reagent which is Congo red, 0.2-0.4 ml surfactant solution in form of a 0.2% solution of monoalkyphenyl ester of polyethylene glycol based on a polymer distillate and 10 ml water, followed by heating on a water bath at temperature of 80-98°C for 10-15 minutes.
EFFECT: high sensitivity of analysis.
5 dwg, 1 ex
SUBSTANCE: method of determining tin (IV) in an aqueous solution involves extraction of tin (IV) ions. Extraction is carried out by adding antipyrine, sulphosalicylic acid and calcium chloride with concentration of 0.60, 0.35 and 2 mol/l, respectively, to the solution. After phase separation, morin solution is added to the extract to form a fluorescent tin and morin complex, followed by measurement of fluorescence of the obtained solution using liquid analyser Fluorat2-3M to determine concentration of tin (IV).
EFFECT: quantitative detection of tin ions and simple analysis.
1 dwg, 1 ex
SUBSTANCE: invention describes a method for quantitative determination of organic compounds in binary mixtures by measuring thermal effects of polymorphic transitions occurring during decomposition of products of saturating tert-butylcalixarene with compounds of a binary mixture selected from: cyclohexane, chloroform, dimethyl sulphoxide, pyridine and from: benzene, tetrachloromethane, acetonitrile, acetone, dichloromethane, toluene. Quantitative analysis of content of organic compounds in binary mixtures is carried out based on a calibration curve of thermal effects of processes of decomposition of products of saturating tert-butylcalixarene with said mixtures versus content of components in the mixture.
EFFECT: method enables to conduct quantitative analysis of binary mixtures of a known composition or mixtures where the component which does not induce phase transition of calixarene is known, wherein the analysed components can have similar physical and chemical properties.
42 ex, 4 tbl, 3 dwg
FIELD: analytical methods.
SUBSTANCE: group of inventions is directed on detecting and quantitatively determining hydrogen radicals present in water or in aqueous solution and is characterized by adding sodium 3,5-dibromo-4-nitrosobenzenesulfonate to sample to detect hydrogen radicals from coloration appearing as a result of their absorption characteristics, and additionally characterized by blowing gaseous hydrogen through 1,1-diphenyl-2-picrylhydrazide solution absorbing near 517 nm and sodium 3,5-dibromo-4-nitrosobenzenesulfonate solution at constant velocity in presence of platinum black in order to quantitatively evaluate hydrogen radical concentration using calibration curve based on correlation between coefficient of absorption near 450 nm for azo compound of sodium 3,5-dibromo-4-nitrosobenzenesulfonate and concentration of hydrogen radicals appeared.
EFFECT: increased determination accuracy and enabled analysis of hydrogen radicals in various media.
6 cl, 15 dwg, 1 tbl, 5 ex
FIELD: analytical methods in environmental monitoring.
SUBSTANCE: method comprises: sampling, acidifying samples with HCl/H2SO4 mixture, adding Ce(SO4)2 as oxidant and removing its excess with reducing agent NH2OH·HCl, adding rhodamine C as organic reagent, extracting resulting complex, separating organic phase from aqueous phase, and measuring optical density. Extraction is performed with carbon tetrachloride/methyl isobutyl ketone mixture at 5:1 volume ratio and extractant-to-sample volume ratio 1:1 under dynamic conditions by way of washing away complex with extractant. Content of antimony is judged of from difference of optical densities of extractant and mixture.
EFFECT: lowered measurement threshold to values comparable with allowable limits, increased reliability, reduced analysis time, and automated analytical procedure.
3 cl, 1 dwg, 3 tbl, 3 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to preparing analytical reagents eliciting selectivity and high sensitivity with respect to transient metal cations. Method involves interaction of 2-hydroxythiobenzoyl hydrazone with aromatic aldehydes that results to synthesis of 2-(2'-hydroxyphenyl)-5-(R'-phenyl)-1,3,4-thiadiazolines-2 that have been tested as analytical reagents with metal cation salts of s-, p- and d-elements. Obtained results of investigations have been applied for analysis of medicinal agents containing transient metal cations. Invention provides expanding assortment of analytical reagents used for detection of metal cations of s-, p- and d-elements that can be used in analytical, pharmaceutical and chemical-toxicological practice.
EFFECT: valuable properties of reagents.
1 cl, 2 tbl, 3 ex
FIELD: pharmaceutical chemistry.
SUBSTANCE: the present innovation deals with identifying isoniazide, pyridine derivative, applied to control the quality of production manufactured by pharmaceutical enterprises and prepared by drug stores. One should detect by treating the sample under investigation with freshly prepared 10%-hydroxylamine hydrochloride alkaline solution at obtaining the color. The method creates minimal duration for detection.
EFFECT: higher sensitivity and specificity of the method.
1 ex, 2 tbl
FIELD: analytic chemistry (indicating compositions).
SUBSTANCE: claimed composition contains (mass %): sorbent (anionite, modified with organic reagent) 0.4; hydrochloric acid 0.0011-0.0015; and balance: water. Composition of present invention is useful in determination of Mo(VI) content in natural water and wastewater.
EFFECT: improved sensitivity, increased analysis velocity and decreased effort.
FIELD: analytical chemistry of elements.
SUBSTANCE: the invention is pertaining to the field of analytical chemistry of elements, in particular, to methods of detection of silver availability, that may be used at detection of silver availability in the natural waters and technological solutions. The method of detection of silver availability provides for preparation of a silver solution (1), its transformation into a complex compound and measurement of the luminescent emission intensity. Silver is separated from solutions using a silica gel chemically modified with the help of mercaptogroups and intensity of the silver complex compound luminescent emission (1) is measured with the help of mercaptogroups on the surface of silica gel at 77К at ultraviolet irradiation light. The technical result is simplification of the technological process, decrease of a relative limit of detection, extension of the range of defined concentrations.
EFFECT: the invention ensures simplification of the technological process, decrease of a relative limit of detection, extension of the range of defined concentrations.
FIELD: analytical methods.
SUBSTANCE: indicator composition, which is used two-step analytical procedure, contains 0.6% anionite AN-31 in sulfate form (as sorbent), 0.05% 4-(2-pyridylazo)resorcinol (reagent), 0.098-0.1% sulfuric acid as pH-creating reagent in the first step, which is neutralized in the second step with excess (0.0035-0.004%) aqueous ammonia to pH 9. Method can be, in particular, used for assaying waste waters and industrial solutions.
EFFECT: enabled joint determination of the two ions, improved selectivity of analysis, and accelerated analytical procedure.
FIELD: analytical chemistry.
SUBSTANCE: method can be used for determining content of bismuth in copper-based alloys. Bismuth solution (III) is prepared, transferred into complex compound and diffuse reflection factor is measured. Bismuth is selected due to transferring it into complex compound from 0,5-3 M solution of hydrochloric acid by means of sorbent - silica, chemically modified N-allyl-N'-propylthiocarbamide. Diffuse reflection factor of bismuth (iii) complex is measured when taking N-allyl-N'-propylthiocarbamide on the surface of silica.
EFFECT: simplified procedure of measurement; widened range of concentrations to me measured.
4 ex, 1 tbl
FIELD: analytical chemistry, indicating composition for gold (iii) assay in aqueous solutions, in particular in waste water and processing solutions.
SUBSTANCE: claimed composition contains (mass %): anionite as sorbent 0.8; hydrochloric acid 5.8; tin(II) chloride 0.8 and balance: water. Method of present invention makes it possible to detect Au(III) in acidic solutions (pH<2).
EFFECT: method with improved sensitivity and selectivity.
FIELD: analytical methods.
SUBSTANCE: in indicator composition for determining manganese(II), in particular, in waste waters and production solutions, containing 0.6% of sorbent, 0.05% of reagent, medium pH adjusting substance, and water, said sorbent is sulfate-form anionite (AN-31), said reagent is 4-(2-pyridylazo)resorcinol, and pH of medium is adjusted with 0.0035-0.004% of ammonia. Concentration of Mn2+ ions is measured spectrophotometrically in presence of above-defined indicator.
EFFECT: increased determination selectivity and accelerated analytical procedure.