Process monitoring method with use of gaseous reagent containing one or more gaseous hydrocarbons
FIELD: processes of chemical infiltration or chemical deposition from vapor phase, case hardening in furnace.
SUBSTANCE: method is used for monitoring process realized in furnace with use of gas reagent containing at least one gaseous hydrocarbon. Method comprises steps of adjusting working parameters of furnace; adding into furnace gas-reagent containing at least one gaseous hydrocarbon; discharging from furnace exhaust gases that contain by-products of gas-reagent reaction; washing out exhaust gases by means of oil that absorbs resins present in exhaust gases; receiving information related to process according to measured quantity of resins absorbed by oil. It is possible to change working parameters of furnace such as temperature, pressure in furnace, gas-reagent consumption and composition.
EFFECT: possibility for monitoring process in furnace without special apparatus of infiltration furnace.
14 cl, 1 dwg, 1 ex
The technical FIELD
The present invention relates to processes using gas-reagent containing one or more gaseous hydrocarbons, in particular the process of cementation details, education coating of pyrolytic carbon on the substrate by deposition of vapor phase or seals porous substrates using a matrix of pyrolytic carbon formed by chemical vapor phase infiltration.
Private, but not exclusive application of the invention is the manufacture of parts made of composite material containing substrate with a fiber reinforcement or preformed billet, reinforced by a matrix of pyrolytic carbon, in particular of parts from composite material such as carbon/carbon (C/C).
The sealing substrate is placed in a furnace, in which under reduced pressure injected gas-reagent containing one or more carbon sources. This carbon source consists of one or more gaseous hydrocarbons, typically methane, propane or their mixtures. The operating parameters of the furnace is positioned so that upon contact of the gas source with the substrate to obtain by its decomposition (cracking) matrix of pyrolytic carbon. Exhaust gases containing by-products of the reaction is AI, removed from the furnace by a method of pumping.
Typically, the operating parameters of the furnace, in particular the temperature in the furnace, the pressure in the furnace, the flow rate of a reagent gas in the furnace, the composition of a reagent gas, constant throughout the compaction process. However, conditions infiltration gradually changed during the process, gradually fill the source of the pores of the substrate. The selected values of the parameters are therefore the result of the search of the best compromise between optimal conditions at the beginning of the densification process and at the end of it, and there is the risk of changes in the microstructure of deposited matrix due to the change in porosity of the substrate, i.e. the geometrical characteristics of the porous structure. The adaptation of the operating parameters of the furnace during the process of compaction could provide the opportunity to optimize the entire process and reduce the time required to obtain the desired degree of compaction and the formation of matrix material with the desired microstructure.
Thus, the applicant of this application proposed in patent document WO 96/31447 to change the operating parameters of the furnace to optimize the densification process with simultaneous control of the microstructure of the matrix material. However, this change is made at a predetermined model and does not account for real progress.
Patentno document US 5348774 it was also suggested to continuously measure the weight change of the substrate to monitor the progress of the compaction process. In accordance with the measured value changes can affect some parameters, in particular the power supplied to the inductor, which in combination with the current collector, the bounding side wall of the furnace, provides its heat. Monitoring the weight change of the substrate also allows you to define the end of the densification process. This requires a special furnace device to continuously measure the mass of the substrate at high temperatures prevailing inside the furnace. Such a device can, in addition, to reduce the possible number of substrates loaded into the useful internal volume of the furnace.
The task, which directed the present invention is the method of continuous monitoring of process the compaction of the substrate matrix of pyrolytic carbon without requiring the use of special devices infiltration oven.
More generally the invention is directed to offer a method that provides the possibility of continuous monitoring of the process taking place in the oven and using gas-reagent containing one or more gaseous hydrocarbons at relatively high temperatures, leading to the presence of resins in the exhaust from the furnace gases.
To solve the same tasks in accordance with the invention proposes a method, whereby the output from the furnace exhaust gases are subjected to the flushing oil absorbent resin contained in the exhaust gas, and measuring the amount of resin absorbed by the oil, in the best case scenario - the value corresponding to the change with time of the amount of resin absorbed by the oil, get information about the process.
With this purpose it is possible to carry out the circulation of the oil in the closed circuit and to measure the increase in the volume or weight of the oil. Thus, according to one of the embodiments of this method the oil is continuously removed from the tank and injected into the stream of exhaust gases, oil, rich in resins, returned to the reservoir, and information about the progress of the process is obtained from measurements of the change of the oil level in the tank. The oil can be ejected into the flow of exhaust gases circulating in the spray column, for example, containing the Venturi.
This oil is preferably aromatic oil, which is able to absorb polycyclic aromatic hydrocarbons contained in the exhaust gas. In particular, as the oil may be one selected from mineral oils, such as oils-based xylenes.
Received information about the process can be used to determine when the end of this process.
You can also control the work process, changing, if necessary, on the basis of the obtained information about the process, at least one of the following operating parameters of the furnace: the furnace temperature, furnace pressure, the flow rate of a reagent gas and the composition of a reagent gas.
The method according to the invention applies, in particular, for monitoring processes of cementation, chemical deposition from the gas (vapor) phase, or sealing by chemical vapor phase infiltration.
The principle of monitoring of chemical or physico-chemical process by analyzing adverse reaction products in the waste furnace or reactor is well known. In the particular case of chemical vapor phase infiltration with the use of a reagent gas containing gaseous hydrocarbons such as methane and/or propane, may be provided for the analysis of exhaust gases withdrawn from the furnace, with the aim of measuring the amount of a particular by-product formed in the reaction, such as benzene, which is a good indicator of progress. However, this measure is complicated by the fact that the exhaust gases contain very numerous light and heavy hydrocarbons, a relatively significant number of resins which can quickly clog the flow channels and equipment.
The applicant of this application stated that a simple monitoring of a number of resins, absorbed by the wash oil from waste gases, can serve as a source of reliable information about the progress of the process without the use of complex equipment and with the possibility of integration in the installation of off-gas treatment. Indeed, treatment of exhaust gases is highly desirable in order to avoid clogging of the channels and to meet environmental requirements. The removal of the resin by washing is an effective method of treatment. The present invention may benefit from the use of such a processing method for implementing simple and cost-effective continuous monitoring process.
A BRIEF DESCRIPTION of GRAPHIC MATERIALS
Other features and advantages of the present invention will become apparent from the following detailed description, given with reference to the sole accompanying drawing, which shows an industrial plant chemical vapor phase infiltration, allowing the use of the method according to the invention.
INFORMATION CONFIRMING the POSSIBILITY of carrying out the INVENTION
The drawing schematically shows an installation for chemical infiltration gaseous phase, designed to seal porous substrates using a matrix of pyrolytic carbon. The process of infiltration of vapor phase can be isothermal and Isobaric type, i.e. it may be changed without the I temperature and pressure in the substrate, with a temperature gradient, i.e. by uneven heating of the substrate, or pressure gradient, i.e. with two opposite sides of the substrates of different pressure.
In furnace 10, which is surrounded by a casing 12, is placed the sealed porous substrate 14, for example fibrous parts made of composite materials based on carbon matrix. For example, as a fibrous billet parts can be used billet grilles, or parts of the diffuser pipes rocket engines, or billet brake discs composite type With a/C. Furnace 10 is limited to the side wall 16, forming a current collector made of, for example, of graphite, a bottom 18 and a lid 20, also made of graphite. The current collector 16 is connected with its surrounding winding 22 of the inductance. The heating furnace is caused mainly by the emission of a current collector, the heating due to inductive coupling with the winding inductance.
Gas-reagent is injected through the channel 24, passing, for example, through the inlet hole 19 provided in the bottom 18 of the furnace. Reactive gas contains one or more substances-carbon sources and, possibly, a catalytic additive. In the depicted example, the gas-reagent is formed from two components, coming from sources 25A, 25b connected to the channel 24, through the valves 26a 26b and the flow meter 27. Exhaust gases withdrawn from the furnace through the hole 21 provided in the cover 20, channel 28, is connected to the device 60 pumping, which provides circulation of a reagent gas in the furnace and supports inside the specified level of reduced pressure.
As the gaseous source of pyrolytic carbon is used, in particular alkanes, alkali and alkenes, mainly methane, propane or their mixtures, of which the decomposition (cracking) in contact with the sealing substrate is obtained carbon. Possible catalytic additive is considered here to be a component of a reagent gas, providing for the activation of carbon deposition of sediment from a source or sources of carbon in the selected operating conditions. Catalytic additive can also be a source of carbon. So, in gas-reagent containing a mixture of methane and propane (both of which are sources of carbon), coming from sources 25A and 25b, propane at specific values of temperature and pressure may play a role catalyzing additives.
The final degree of compaction of the substrate and the microstructure of pyrolytic carbon are determined, in particular, the operating parameters of the furnace, namely:
the temperature of the furnace,
- pressure in the furnace,
- the consumption of a reagent gas in the furnace,
- composition of a reagent gas, i.e. in particular with the holding in gas-reagent source or sources of carbon content and possible catalytic additives.
The exhaust gases contain by-products of reactions (cracking) of the source or sources of pyrolytic carbon, unreacted part of the source or sources of carbon and gaseous hydrogen (H2), resulting from cracking of the source or sources of carbon. The reaction by-products contain unsaturated hydrocarbons, light aromatic hydrocarbons (benzene, monocyclic hydrocarbons and polycyclic aromatic hydrocarbons such as naphthalene, pyrene, anthracene and acenaphthylen deposited in the form of resins.
According to the invention the monitoring of the compaction process of the substrates is carried out by washing the flue gases of oil, these absorbent resin, and processing value corresponding to the amount of resin absorbed by the oil.
This flushing oil additionally helps to eliminate resin, which otherwise might clog the output channels of the furnace and to be used in the pumping device, for example, in the oil of the vacuum pump or condensate ejector condenser.
On the accompanying drawing shows one of the embodiments of the device 30 flushing oil located between the hole of the output of the exhaust gases from the furnace 10 and the device 60 pumping. Such a device is also described in published international application WO 03/047725 filed simultaneously with the present application and entitled "Method and installation for the treatment of exhaust gases, containing hydrocarbons".
The washing device oil is preferably located near the outlet of the furnace 10 in order to avoid sedimentation of the resin in the channel connecting the outlet of the furnace with a washing device, since the cooling of the exhaust gases contributes to deposition.
The device 30 flushing oil spray contains the column 32, the upper part of which is connected to the channel 28. Column 32 may, for example, contain a tube 34 of the Venturi formed by reducing the cross-section of the opening through which gases pass. The lower part of the column 32 is connected with a hole 42 for input gases, located in the upper wall of the tank 40 recycling oil near its edges. Also in the top wall of the tank 40, near the other of its edges, there is a hole 44 for outputting gas, United channel 62 of the device 60 pumping.
Hole o oil is in the lower part of the tank 40 and is connected to the pump 50, which extracts the oil from the reservoir 40 and forces it through the heat exchanger 52 in the nozzle 36, 38 located essentially on the axis of the column 32. In the tank 40 can be located more nozzles 46a, 46b, in which the oil after the heat exchanger 52 in parallel with the nozzles 36, 38.
For cooling of the oil coming from the reservoir 40, through the heat exchanger 52 is leaking coolant, e.g. the cold water. The cooling water also passes through the heat exchanger 54, having, for example, the shape of the plates, connected in series with the heat exchanger 52 and located within the tank 40.
The heat exchanger 54, as well as nozzles 46a, 46b, is located inside the tank between the hole 42 of the gas inlet and the bore 44 of the output of the gas above the oil level. In the hole 44 of the output gas from the reservoir 40 may be installed keplerlaan 48.
The device 30 flushing oil works as follows. The oil fed to the nozzles 36, 38, is sprayed into the stream of exhaust gases passing through the tube 32, and an increase in the rate of flow of gases through the Venturi 34 contributes to this spray. One of the nozzles 36 may be installed in the upper part of the column 32, above the Venturi, and the other nozzle 38 is near the throat of the Venturi. You can also use one of the nozzles 36 or 38.
Spattered oil absorbs a significant portion of the resin, portable flue gases, in particular polycyclic aromatic hydrocarbons, which are transferred to an oil bath, located in the tank 40.
The vapor pressure of the used oil must be low enough not to cause evaporation at the pressure existing at the outlet of the furnace 10, and the pollution of exhaust gases vapors of oil. For example, the pressure is in the oven 10 during the classical process of sealing a porous substrate matrix of pyrolytic carbon is usually less of 10.1 kPa. The oil must have a viscosity sufficient to ensure its circulation and formation of oil mist from nozzles.
Therefore, in the preferred embodiment, used mineral oil aromatic type having a vapor pressure less than 100 PA at a temperature of 0°C.
Preferably use oil-based xylenes, for example, a synthetic oil, manufactured by the French company Elf Atochem under the trademark "Jaritherm AX 320" and consisting of 85% by weight of monosilicide and 15% by weight of disilicide. This oil has a viscosity equal to 60 centipoises at a temperature of 0°and a vapor pressure lower than 100 PA at a temperature of 0°C.
In the heat exchangers 52 and 54, cold water enters at a temperature of approximately 0°for cooling the maximum amount of oil sprayed by the nozzles 36, 38 and nozzles 46a, 46b, between putting gas in the tank 40 and the output from it.
The heat exchanger 54 promotes condensation resins remaining in the exhaust gases after they exit the column 32.
Keplerlaan 48 comprising, for example, from partitions, helps to "break in" oil mist, available at the outlet from the tank 40, with the aim of separating drops of oil, mergers and return in an oil bath.
Capture using the device 30 flushing oil allows you to delete the maximum number is the number of resins, such as polycyclic aromatic hydrocarbons. In the washed flue gases can only stay lighter aromatic hydrocarbons (benzene and monocyclic hydrocarbons), but they do not create the danger of clogging of the channels due to the higher vapor pressure.
The device 60 contains pumping ejector condenser 64 or more similar ejector condensers arranged in series (the drawing shows only one ejector condenser), and can be used and other pumping device, such as rotary pumps.
Ejector condenser 64 contains the ejector 66, which receives water vapor from the heater 80, and the capacitor 68 which is located behind the ejector. The capacitor 68 is a refrigerator with external cooling, in which the gases emerging from the ejector, come into contact with the channels through which flows a coolant, such as cold water.
After passing through the condenser 68 water flows into the cooling column 70, after which it can be collected in the reservoir 72 and is returned to the condenser 68 by pump 74.
The condensate in the output channel 76 of the capacitor contains hydrocarbons, for example benzene, toluene, xylene, and possibly the remains of polycyclic aromatic hydrocarbons, dissolved enter formed by the condensation of steam coming from the ejector 66. The condensate can be treated by adsorption on charcoal.
At the outlet of the condenser exhaust gases pass through the pump 78. There can be used the liquid ring pump, cooled by heat exchanger so that the gases leaving the installation, had a temperature close to ambient temperature.
The extracted gas contains mainly unsaturated hydrocarbons, as well as the remains of the reactive gas and hydrogen gas H2coming from the furnace 10. It can be directed through the channel 79 to the torch and at least partially used as fuel for the heater 80. In this case, it is mixed in the buffer tank 82 with a combustible gas such as natural gas flowing through the channel 84. From the buffer tank 82 fuel enters the burner 86 of the heater 80.
In the illustrated example, the estimate of the amount of resin absorbed with washing oil, is carried out by measuring the oil level in the reservoir 40. The sensor 58 sends to the circuit 90 processing the signal corresponding to the oil level, with the aim of forming information I used to monitor the compaction process. The sensor 58 may be of any known type, for example using a vibrating plate or radar signal is found in this case, the distance between the upper wall of the tank, where is the sensor and the surface of the oil.
Information I contains, for example, the time derivative of the signal corresponding to the oil level, and reports, thus, changes in time of the tar in the exhaust gas.
The first possibility is to monitor the information I to determine the end of the densification process. The compaction process can be considered complete when the change in oil level, i.e. the change in the content of resin in the exhaust gas increases over a certain limit, for example, increases by more than 2% over a certain observation period. This observation period may last several hours, since the duration of cycles seals are normally very high.
Another possibility, which may be used in addition to the first, is to monitor the operating parameters of the furnace, depending on the value of information I. So:
- if the change in oil level, measured over a certain period of observations decreases to a limit S1for example about 0.1%, it is possible to influence the parameters of the seal (e.g., temperature, composition of the gas-reagent) in order to enhance sealing;
- if the change oil level increases over a certain limit S1for example of the order of 1%, it is possible to influence the parameters of the UE is othenia to slow seals.
For example, for a nominal flow rate of a reagent gas (a mixture of methane and propane) at the entrance to the furnace, equal to 500 l/min, the threshold S1may correspond to the reduction of the change in mass of the resin with 0.5 to 2 g/h, and the threshold S2- increase the change in mass of the resin with 5 to 8 g/H.
At the end of the process can be carried out at least partial drainage of the oil from the reservoir 40 at the outlet of the pump 50 by closing valve 51 mounted on the channel connecting the pump 50 with the heat exchanger 52, the opening of the valve 53 mounted on the channel that connects the output of pump 50 with the channel 56 o used oil. Collected used oil may be destroyed by the method of combustion, and in the reservoir 40 add clean oil.
Of course, for monitoring the amount of resin absorbed with wash oil may be provided with means that differ from the measurements increase the level or volume in the tank recirculation, for example measuring the increase in weight of oil.
It should also be noted that changes in the level or weight of oil in the tank 40 may be converted to a value corresponding to the process seal, for example expressing the content of the equivalent of benzene in the exhaust gas.
As already mentioned, the method according to the invention can be applied for monitoring processes, otlichnikom sealing by chemical vapor phase infiltration, processes carried out in a furnace using gas-reagent containing gaseous hydrocarbons, in particular methane and/or propane, at a relatively high temperature, and related to education in the exhaust gas resins. These other processes include, in particular, chemical vapor deposition for formation on substrates coating of pyrolytic carbon is usually carried out at a temperature of approximately 1000°With or higher, and cementation of the parts in the furnace, which can be used a mixture of methane and propane at a temperature of approximately 900°C.
1. Method of monitoring the progress of a process performed in a furnace using gas-reagent containing at least one gaseous hydrocarbon, comprising setting the operating parameters of the furnace, the introduction into the furnace of a reagent gas containing at least one gaseous hydrocarbon, and removing from the furnace off-gases containing by-products of the reaction of a reagent gas, wherein the exhaust gases are subjected to the flushing oil absorbent resin contained in the exhaust gas, and the quantity of the resin is absorbed by the oil, get information about the process for setting the operating parameters.
2. The method according to claim 1, characterized in that information about the progress of the process is obtained from the value corresponding to the change of time and the number of resins, the absorbed oil.
3. The method according to claim 1 or 2, characterized in that provide oil circulation in a closed circuit and measure the increase in oil volume.
4. The method according to claim 3, characterized in that the oil is continuously removed from the tank and Inuktitut in the flow of exhaust gases, oil, rich in resins, return to the reservoir, and information about the progress of the process is obtained from measurements of changes in the level of oil in it.
5. The method according to claim 1 or 2, characterized in that provide oil circulation in a closed circuit and measure the increase in weight of oil.
6. The method according to claim 1, characterized in that the oil Inuktitut in the waste gas stream circulating in a spray column.
7. The method according to claim 6, characterized in that the exhaust gases circulating in the column with the Venturi tube.
8. The method according to claim 1, characterized in that said oil is oil that is able to absorb polycyclic aromatic hydrocarbons contained in the exhaust gas.
9. The method according to claim 8, characterized in that the said mineral oil is an aromatic oil.
10. The method according to claim 1, wherein the received information about the process used to determine the end of the process.
11. The method according to claim 1, wherein the received information about the process used for process control, ISM the latter, if necessary, on the basis of the obtained information about the process, at least one of the following operating parameters of the furnace: the furnace temperature, furnace pressure, the flow rate of a reagent gas and the composition of a reagent gas.
12. Application of the method according to claim 1 for monitoring process seals porous substrates matrix of pyrolytic carbon formed by chemical vapor phase infiltration.
13. Application of the method according to claim 1 for monitoring of educational process on the substrate coating of pyrolytic carbon by chemical deposition from the vapor phase.
14. Application of the method according to claim 1 for monitoring the cementation process details.
FIELD: microelectronics; methods of manufacture of microcircuit chips.
SUBSTANCE: the offered invention is pertaining to the field of microelectronics, in particular, to the methods of manufacture of microcircuit chips. The offered method includes a loading of semiconductor slices in a reactor having hot walls perpendicularly to a gas stream, pumping-out of the reactor air up to the ultimate vacuum, introduction of monosilane for deposition of layers of polycrystalline silicon, silane supply cutoff, pumping-out of the reactor air up to the ultimate vacuum, delivery of a noble gas into the reactor up to atmospheric air pressure, unloading of the semiconductor slices from the reactor. After introduction of the noble gas into the reactor conduct an additional thermal annealing of layers of polycrystalline silicon at the temperature of no less than 1323K, then keep the slices at this temperature during 40-60 minutes in a stream of noble gas and reduce the temperature down to the temperature of the polycrystalline silicon layers growth. The technical result of the invention is a decrease of heterogeneity of resistance of the polycrystalline silicon layers.
EFFECT: the invention ensures a decrease of heterogeneity of resistance of the polycrystalline silicon layers.
1 dwg, 2 tbl, 1 ex
FIELD: luminescent materials.
SUBSTANCE: nitride coating precursor, in particular aluminum-, gallium-, or tin-containing metalloorganic nitride, is charged into reaction vessel 10a filled with electroluminescent phosphor, e.g. ZuS-Cu, and surrounded by heating means 30a using nitrogen as inert gas carrier. Precursor is passed through pipeline 32 open all over its length. Co-reagent, e.g. anhydrous ammonia is fed into lower part of vessel 12a through porous glass disk 12a. When vessel 10a is heated to 150-225°C, nitride coating precipitates on phosphor particles being in fluidized state. Phosphor bearing nonoxide coating is characterized by high brightness after 100 h use at high humidity.
EFFECT: enabled large-scale manufacture of phosphors.
3 cl, 2 dwg
FIELD: radio and electric engineering.
SUBSTANCE: method includes applying oxide dielectric film on heat-resistant board and making electric-conductive circuit imprint by photo-lithography method, after applying film, metallic film is applied with specific resistance ρ≤1 Ohm•sm with thickness 15-25 mcm, then protective, well-soldering, metal-resistant nickel or cobalt cover is applied with thickness 4-5 mcm, as dielectric oxide film chromium-oxide film of black color is used with thickness not less than 8 mcm with specific resistance ρ≥1x109 Ohm•sm. In certain cases of method realization, applying said dielectric oxide and then metallic with specific resistance ρ≤1 Ohm•sm and protective metal-resistant well-soldering films is performed on both sides of heat-resilient board and onto inner surface of technological apertures; as heat-resilient board titan or copper, or aluminum plates are used, as metallic cover with specific resistance ρ≤1 Ohm•sm copper or aluminum, or molybdenum are precipitated.
EFFECT: higher efficiency.
4 cl, 4 ex
FIELD: the invention refers to application of covers in a liquefying layer particular to an arrangement for settling covers in a liquefying layer.
SUBSTANCE: the arrangement for settling covers in a liquefying layer has a chemical reactor of a cylindrical form and a system of feeding with liquefiable gas, the inner surface of the cylindrical reactor is provided with vertical grooves located on ribs of regular polygons inscribed into the inner diameter of the reactor. At that the number of grooves is chosen in the limits 3-20, the grooves in the section have a form of an equilateral triangle and for a reactor with a diameter of 20-100 mm the relation of squares of transversal sections of the reactor and of all grooves is in the limits 100-200.
EFFECT: the invention provides stability of a liquefying layer at essential increasing of the particles' mass in the process of applying a cover.
1 cl, 1 dwg
FIELD: metal science; protection of materials against external and corrosive attacks.
SUBSTANCE: proposed method for producing diamond-like films designed for encapsulating solar photocells to protect them against chemical, radiation, and mechanical damage includes variation of ion kinetic energy, plasma discharge current, and spatial density distribution of plasma incorporating C+, H+, N+, and Ar+ ions by acting upon ion current from radial source with electric field built up by stop-down, neutralizing, and accelerating electrodes. Spatial plasma distribution is checked for uniformity by measuring plasma current density on solar photocell surface whose temperature is maintained not to exceed 80 oC. In the process substrate holder makes complex axial movement in three directions within vacuum chamber. Diamond-like films produced in the process on solar photocell surface area over 110 cm2 are noted for uniformity, difference in their optical parameters variable within desired range is not over 5%.
EFFECT: enhanced adhesive property, microhardness, and resistance of films to corrosive attacks.
5 cl, 12 dwg, 2 tbl