GB2187478A - Producing diffusion layers on metals by glow discharge - Google Patents
Producing diffusion layers on metals by glow discharge Download PDFInfo
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- GB2187478A GB2187478A GB08704831A GB8704831A GB2187478A GB 2187478 A GB2187478 A GB 2187478A GB 08704831 A GB08704831 A GB 08704831A GB 8704831 A GB8704831 A GB 8704831A GB 2187478 A GB2187478 A GB 2187478A
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- generator
- gaseous medium
- glow discharge
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/36—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases using ionised gases, e.g. ionitriding
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- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Chemical Vapour Deposition (AREA)
Abstract
An apparatus and method is disclosed for the production of a superficial diffusion layer, in which a gaseous medium is introduced into a generator (7) for generating reactive gaseous medium, mounted in a lower portion of a working chamber (3), the generator (7), after having been heated in a glow discharge, or by electric resistance, activates thermally the said medium, thus producing a reactive gaseous medium, which, in turn, after having passed close to the object (5) to be treated is activated electrically, thus producing a superficial diffusion layer on the object (5). In an alternative arrangement (Fig. 4) the working chamber is situated in a resistance furnace and is provided with a water cooled cover, a tube for feeding the gaseous medium being situated in the cover and having an outlet situated below the object being treated to provide an upward flow of the gaseous medium. <IMAGE>
Description
SPECIFICATION
Method and apparatus for forming of a diffusion superficial layer on a material
This invention relates to the method of production of diffusion superficial layers on metals by thermo-chemical treatment, as well as and apparatus for production of diffusion superficial layers, particularly for production of layers, such as nitride, carbide, silicide, and composite layers on various materials.
The known method of production of diffusion superficial layers on metal in glow discharge consists of the steps of introducing a definite chemical mixture into a working chamber under a pressure of 3 to 13 nPa, (such a mixture may be, for example, boron chloride mixed with hydrogen during the plasma boriding process, or, nitrogen and hydrogen or ammonia during the plasma nitriding process), whereupon a potential difference between the cathode, being the object to be treated, and anode, being the working chamber wall and an inner shield, of up to 1600 V is applied.
Under these conditions an abnormal glow discharge is produced characterised by, among other things, the existence of a potential drop zone in the neighbourhood of the cathode. In that very zone active ions are produced, which are then accelerated toward the cathode, heat it and chemically react with it.
Another known method of production of diffusion superficial layers on metals by glow discharge requires that the temperature of the object to be treated be sufficient for the process of chemical reaction on its surface, necessary for production of a diffusion layer.
So for instance in the case of production of titanium nitride layers in a gaseous medium consisting of TiCI4 vapours, hydrogen and nitrogen, the temperature of the object to be treated should be at least 800 degress Centigrade.
Such a method ensures activation of the gaseous medium and heating of the parts to the required temperatures due to the glow discharge phenomenon, the temperature range during a titanizing, or boriding, process of the object being from 800 up to 1000 degres
Centigrade. Those skilled in Art know from the Polish Patent Specification N 112 135 an apparatus for producing diffusion superficial layers on metals consisting of a working chamber with water-cooled walls, said chamber being suited to being filled with reactive gas and provided with a constant voltage power supply unit. Inside said working chamber there is located a cylindrical metal jacket provided with a tube for supplying reactive gas, the object to be treated being situated in the space surrounded by the jacket, the jacket being the anode, and the object, the cathode.
Still another apparatus known from the Polish
Patents Specification No P-250 262 for thermo-chemical treatment at a reduced pressure consists of a vacuum chamber accommodating a flow reactor which has the shape of a container with the object to be treated.
Glow discharge is maintained around the inner surface of the flow reactor.
According to the invention in a first aspect there is provided a method of forming a diffusion superficial layer on a metal in glow discharge comprising the steps of:
introducing reactants into a reactive gas generator adjacently coupled to a chamber containing an object to be treated,
thermally activating the reactants in the generator to form a reactive gas medium; and
passing the reactive gas medium adjacent to the object under glow discharge whereby a superficial diffusion layer is formed on the object.
According to the method in a second aspect there is provided a method of producing superficial diffusion layers on metals in glow discharge comprising the steps of:
introducing a first gaseous medium into a working chamber and activating the medium during glow discharge to form a first diffusion layer; and
introducing a second gaseous medium into the working chamber, after said first medium, and activating the second medium during glow discharge to form a successive diffusion layer.
According to the invention in a third aspect there is provided apparatus for the production of superficial diffusion layers on a metal object in glow discharge comprising:
a working chamber arranged to receive the object and
a generator arranged thermally to activate a gaseous medium therein to form the reactive gaseous medium, said generator being adjacently connected to the chamber.
The method according to the invention consists in that the gaseous medium is introduced into the generator of the reactive gaseous medium accommodated in the bottom part of the working chamber, said generator being heated by glow discharge or by taking advantage of electric resistance and thus activates thermally the gaseous medium and produces a reactive gaseous medium, which, in turn, after having passed close enough to the object to be treated is activated electrically in glow discharge and forms a superficial diffusion layer.
The first still another method according to the invention consists in that in the reaction generator of the gaseous medium accommodated in the bottom part of the working chamber there are placed in reactants, one of them being introduced into the generator being heated either due to glow discharge, or in effect of electric resistance, thus forming a reactive medium, which after thermaly activation in that generator is next brought close to the object to be treated, thus forming a superficial diffusion layer.
Still another second method according to the invention consists in that a combined superficial diffusion layer on the object being treated is produced by changing successively the reaction gaseous medium being brought close to the object being treated.
In the another second method as least one gaseous atmospheres of the medium is ther mally activated in the generator of a reactive gaseous medium accommodated in the bottom portion of the working chamber by heating the generator, either in glow discharge, or by electric resistance, and a reactive gaseous medium is produced which after having passed close to the object to be treated is being activated electrically in glow discharge, together with the surface of the object being treated, thus forming at least one diffusion layer. The successive gaseous layers of the medium are introduced in close proximity to the object being treated, thus forming successive diffusion layers.
Successive gaseous media are also activated thermally in the generator of a reactive gaseous medium accommodated in the bottom region of the working chamber, either by heating in glow discharge, or by electric resistance, thus forming a gaseous reactive medium, which after having passed close to the object being treated is activated electrically in a glow discharge, together with the surface of the object being treated, thus forming the successive diffusion layers. It is advantageous, if in the method, and in the first and the second method the objects being treated are heated under glow discharge conditions to a temperature lower than that in the generator of the gaseous reactive medium.
Characteristic feature of the apparatus according to the invention is the presence of a generator of a reacrive gaseous medium in the bottom portion of the space surrounded by the shield, said generator having the shape of a container provided with an outlet of the reactive gaseous medium and an inlet of the gaseous medium. Moreover, said generator is heated either by glow discharge, or by electric resistance. Still another apparatus according to the invention is characterised by that it has a flow reactor and a generator of the reactive gaseous medium permanently connected to each other (the external surface) mass of said generator being greater than the external surface mass ratio of the reactor. The value of pressure in the connected spaces of the said generator and reactor is greater than that in the working chamber.
The second apparatus according to the invention in characterised by that the working chamber is provided with a heating jacket situated at the height of the said chamber, said heating shield having a controlled and stabilised temperature and a common electric potential with the working chamber being the anode. Heating elements are situated in a tight-manner in the heating shield.
The third apparatus according to the invention is characterised by that the working chamber is situated at its height in a resistance furnace having a controlled constant temperature and is provided with a watercooled cover. In the cover there is situated a tube for feeding the gaseous medium whose outlet is situated below the object being treated, thus compelling the upward flow of the gaseous medium.
According to the inventions, preliminary thermal activation in the generator has made possible lowering of temperature during the process of production of superficial diffusion layer. Owing to this, the whole process can be effected on ready-made products without changing the mechanical properties of the cores. Moreover, the described methods make possible the reactive gaseous medium to be produced in a controlled way directly in the working chamber.
According to still another invention, the degree of filling the flow reactor with the parts to be treated has been increased. Moreover, due to possible heating of the reactor and generator by glow discharge, the consumption of electric power has been reduced.
According to the second and third another invention, control of the course of chemical reactions taking place during the process of production of diffusion superficial layers under glow discharge conditions has been obtained which makes possible supply of active particles of the element of the layer by elimination of deposition of some products of the reaction on the cooling surfaces of the working chamber. Moreover, said apparatuses enable the active particles of the gaseous medium to be better utilised during the production of the layers and it also facilitate proper circulation of the reactive gas in the working chamber.
Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a diagrammatic representation of a first embodiment of the invention.
Figure 2 is a diagrammatic representation of a second embodiment of apparatus according to the invention.
Figure 3 is a diagrammatic representation of a third embodiment of the invention, and;
Figure 4 is a diagrammatic representation of a fourth embodiment of the invention.
As shown in Fig. 1 a first embodiment of the apparatus of the invention includes a water-cooled working chamber 1 provide with a gaseous medium outlet 2 in a cover of the chamber 1. Inside the water-cooled chamber 1 there is situated a cylindrical shield 3 ensuring proper circulation of the reactive gaseous medium. Shield 3 has, in its upper porton, a coaxial hole.
A gaseous medium is supplied directly through inlet 4 into the space surrounded by the shield 3. An object 5 to be treated is to be placed inside the shield 3 space and forms an cathode, whereas the shield 3 and the working chamber 1 form an anode. The anode and cathode, via current leadthrough 13, are connected to constant current power supply unit 6. In the space surrounded by shield 3 in the bottom portion of the chamber 1 there is situated a generator 7 of the reactive gaseous medium having at the top a reactive gaseous medium outlet 8. The bottom part of the generator 7 is provided with a gaseous medium inlet 9. If the generator 7 is heated by glow discharge it has an inlet 10, for supply of hydrogen, or argon. Moreover, generator 7 has an outlet 11, which is connected to a vacuum pump (not shown in the drawing).
A second embodiment of the apparatus of the invention is shown in Fig. 2. The apparatus includes a working chamber 1 with watercooled walls which can be filled with gaseous medium at a desired pressure via inlet 4 and outlet 2, as well as a generator a reactive gaseous medium 7 and flow reactor 12 accommodating the object being treated 5. Generator 7 and reactor 12 are permanently connected to each other and the external surface mass ratio of the generator 7 is greater than that of the reactor 12. Generator 7 and reactor 12 form the cathode, whereas the working chamber 1 is the anode, supplied through current leadthrough 13, 13' by power supply unit 6.The dimensions of the generator 7 and the reactor 12 have been so suited that use of one power supply unit enables temperature T1 to be obtained in the generator 7 and temperature T2 to be obtained in the reactor 12, the value of temperature T1 being greater than the value of temperature T2.
Generator 7 and reactor 12 is connected to the metering system 14 for the gaseous reactive medium and pumping-out unit 15 which ensures the same pressure P1 is maintained in the generator 7 and reactor 12. Inlet 4 enables gas to be metered into the working chamber whereas outlet 2 enables gas to be pumped-out from the chamber 1, thus ensuring in it pressure P2, the pressure P1 being greater than the pressure P2, or equal to it.
The principle of operation of this apparatus is the following:
Current leadthroughs 13.13' are connected to the supply unit pole of negative polarity, the working chamber 1 being connected to the pole of positive polarity and earthed. The treated objects 5 to be titanized are placed in the reactor 12, and next the air is pumped-out through the outlet 2 from chamber 1 and generator 7 and reactor 12 through outlet 15.
Simultaneously, proper pressure is stabilised in the working chamber 1 equal to 15 hPa by metering argon through inlet 4. Next the generator 7 and the reactor 12 are heated in glow discharge. When the generator 7 has reached a temperature of 1000 degress Centigrade and the reactor 12 has reached a temperature of 900 degress Centigrade the reactive gaseous medium consisting of TiCI4 vapours and hydrogen H2 is metered through proportioning system 14 and current leadthrough 13' at a constant pressure of 30 hPa.
The reactive gaseous medium is pumped-out through current leadthrough-13 by pumpingout system 15. After three hours a titanium carbide TiC layer, 12 microns thicks is produced.
Fig. 3 of the drawing shows a third embodiment of the apparatus, which consists of a working chamber 1 provided with an upper cover 16 and a lower cover 17 with watercooled side chamber walls 1 which protect against damaging of the chamber 1, in combination with covers 16 and 17. At the height of the chamber 1 there is mounted an external heating shield 18 with tightly mounted resistant heating elements 19 protecting against influence of the gaseous medium. Shield 18 has common electric potential with the chamber 1 and forms the anode, the heating elements 19, in turn, being connected to the supply and temperature stabilising system 20.
In the upper cover 16 there is provided an outlet 2 for the gaseous medium, and in the bottom cover 17 there is an inlet 4 for supplying the gaseous medium directly close to the space encircled by the shield 18. An object to be treated 5 is located inside said space of the shield 18 and forms the cathode connected via current leadthrough 13 to the negative pole of power supply unit 6, the positive pole of which is connected to the working chamber 1 and shield 18 which form the anode.
In the space encircled by the shield 18 in the bottom portion of the chamber 1 there is situated a generator of the reactive gaseous medium 7, which includes, in the upper portion, thereof, an outlet 8 for the reactive gaseous medium. In the lower portion of the generator 7 with electric resistance heating or by glow discharge there is an inlet 9 for the gaseous medium.Moreover, generator 7 is equipped with an outlet 11 which is connected to a vacuum pump not shown in the drawing The apparatus shown in Fig. 3-operates in the following way:
Gaseous medium containing titanium chloride vapours TiCI4 mixed with hydrogen H2 and nitrogen N4 is thermally activated in the generator 7 which after having been heated by electric resistance heaters or by glow discharge has a temperature of 920 degress Centigrade, the reactive gaseous medium being introduced through the outlet 8 close to the object 5 being treated for example carbon steel (0.45%
C).
The object 5 is heated under glow discharge conditions, the anode and cathode be ing supplied from power supply unit 20 up to a temperature of about 600 degress Centigrade, the value of pressure in chamber 1 ranging up to 13 hPa and the heating shield 18 forming the anode heated by electric resistance up to a temperature of 700 degress
Centigrade which protects against deposition of titanium chlorides, such and TiCI3 and TiCI2 on the walls of the shield 18 and ensures simultaneously an effective utilization of the reactive gas. The system 20 ensures a constant temperature of the jacket.
In Fig. 4 a fourth embodiment of the invention is shown which includes a working chamber 1 provided with the upper water-cooled cover 16. A metering tube 21 for the gaseous medium passes through the cover 16, the tube 21 having an outlet 22 which is mounted below the object 5. The cover 16 is further provided with an outlet 2 for the gaseous medium. The treated object 5 is located inside the working chamber 1 and forms a cathode connected through current leadthrough 13 to the negative pole of a power supply unit 6, whose positive pole is connected to the working chamber 1 which forms the anode.
Working chamber 1 is situated at an appropriate height in a resistance furnace 23 to which the power supply and temperature stabilising system 20 is electrically connected.
The apparatus shown in Fig. 4 of the drawing operates as described below:
Gaseous medium containing titanium chloride vapours TiCI4 mixed with hydrogen H4 is supplied through tube 21, for feeding the gaseous medium, into the chamber 1. Outlet 22 is situated below the object being treated 5, thus forcing an upward flow of the gaseous medium, which when passing through the pipe 21 is being preliminarily heated. Next, in the chamber 1 there is produced a working pressure of 7 hPA, whereas the walls of the chamber 1 being the anode are heated in a resistance furnace 23 to a temperature of 800 degress Centigrade. Power supply system 20 ensures a constant temperature in the chamber 1. The object 5 treated, being the cathode, is heated in a glow discharge produced by means of the power supply unit 6 to a temperature of 900 degress Centigrade.During the heating of the walls of the chamber 1, as well as during titanizing, the cover 16 is water-cooled for which reason the sealing connection of the cover 16 with the chamber 1 and with tube 21 and outlet 2 must be secured. After three hours of treatment of titanium carbide layer about 6 microns thick is obtained on the workpiece being treated, made of instrumental steel (NC 6).
The following are examples of diffusion superficial layers obtained in accordance with aspects of the invention:
Example I
A gaseous medium containing TiCI4 vapours in a mixture with hydrogen H2 and nitrogen N2 is thermally activated in a generator of reactive gaseous medium 7, which after having been heated by electric resistance has a temperature of 920 degrees Centigrade, wherein the reactive gaseous medium is introduced through outlet 8 in close proximity to the object 5 being treated made of carbon steel (0.45% C), which is heated under glow discharging conditions to a temperature of 600 degress Centigrade at a pressure up to 13 hPa. After three hours a superficial layer of titanium nitride 3 microns thick is obtained.
Example II
In the generator of a reactive gaseous medium 7 chromium chips are placed and heated up to a temperature of about 900 degress
Centigrade. Next a gaseous medium containing chlorine compunds is to be introduced into the generator 7 through inlet. The produced Cry12 compound in an amount controlled by passing strictly determined amounts of volatile chlorine compounds through the generator 7 is the reactive gaseous medium, which is to be introduced to the object 5 being treated made of
N9 (instrumental) steel.
The object 5 is to be heated to a temperature of about 850 degrees Centigrade under glow discharge conditions in an atmosphere of hydrogen H2 and argon. The value of pressure in the working chamber 1 ranges up to 10 hPa. After three hours of thermochemical treatment a superficial layer of chromium carbide Cr7C3 about 10 microns thick is obtained.
Example 111
A composited superficial diffusion layer is produced by activation of gaseous atmosphere in the form of TICI4 vapours in a mixture with hydrogen H2 in a generator of reactive gaseous medium 7 heated to a temperature of 950 degrees Centigrade and next, after thermal activation, the obtained reactive gaseous medium is introduced in direct proximity to the object 5 treated, made of stainless steel.
The object being treated 5 is preliminarily heated under glow discharge conditions for five hours at a temperature of 700 degress
Centigrade in a gaseous medium consisting of
H2 hydrogen and N2 nitrogen, the hydrogen/nitrogen ratio being equal to 3:1, introduced directly into the working chamber through inlet 4. The value of pressure in the working chamber 1 ranges within the limits from 3 up to 10 hPa. Next after two hours of treatment at a temperature of 700 degress Centigrade a composite layer is obtained consisting of a diffusion layer, that is a nitrided layer 60 microns thick made of stainless steel and superficial layer of titanium nitride 3 microns thick on the object 5 being treated.
Applications of the apparatus described are not limited to the presented examples of embodiment, but they can be also used for heat and thermochemical treatment in processes such as nitriding, carbo-nitriding, siliconizing as well as for production of other layers depending upon the gaseous medium applied to the working chamber.
Claims (31)
1. A method of forming a superficial diffusion layer on a metal in a glow discharge comprising the steps of:
introducing reactants into a reactive gas generator adjacently coupled to a chamber containing an object to be treated,
thermally activating the reactants in the generator to form a reactive gas medium; and
passing the reactive gas medium adjacent to the object under glow discharge whereby a superficial diffusion layer is formed on the object.
2. A method as claimed in claim 1 wherein the gaseous medium is thermally activated in the generator by means of a glow discharge.
3. A method as claimed in claim 1 wherein the gaseous medium is thermally activated in the generator by means of electrical resistance heating.
4. A method as claimed in any one of the preceding claims wherein the generator is disposed at a lower zone of the chamber.
5. A method as claimed in any one of the preceding claims wherein the object is treated under glow discharge conditions at a temperature lower than that of the generator.
6. A method as claimed in any one of the preceding claims wherein the reactants comprise a first reactant which is heated in said generator and a second reactant introduced into the generator after said heating of the first reactant whereby said reactive gas medium is formed from said first and second reactants.
7. A method of producing diffusion layers on metals in glow discharge comprising the steps of:
introducing a first gaseous medium into a working chamber and activating the medium during glow discharge to form a first diffusion layer; and
introducing a second gaseous medium into the working chamber, after said first medium, and activating the medium during glow discharge to form a successive diffusion layer.
8. A method as claimed in claim 7 wherein at least one of the gaseous atmospheres of the medium is thermally activated in a generator coupled to the chamber, the resulting reactive gaseous medium being passed adjacent to the object under said glow discharge to form the first diffusion layer.
9. A method as claimed in claim 8 wherein the successive gaseous media are thermally activated in a generator coupled to the chamber thus producing reactive gaseous media which having being brought adjacent to the object being treated are electrically activated by glow discharge together with a surface of the object to be treated, thus producing the successive diffusion layers.
10. A method as claimed in any one of claims 5 to 7 wherein the object being treated is heated under glow discharge conditions to a temperature lower than that of the reactive gaseous medium.
11. Apparatus for forming superficial diffusion layers on a metal object in glow discharge comprising:
a working chamber arranged to receive the object and to be filled with a reactive gaseous medium and
a generator arranged thermally to activate a gaseous medium therein, to form the reactive gaseous medium said generator being adjacently connected to the chamber.
12. Apparatus as claimed in claim 11 wherein the working chamber has watercooled walls and said generator and a flow reactor accommodating the object to be treated are disposed within the chamber, the generator and reactor forming a cathode and the working chamber forming an anode, the anode and cathode being supplied by current from a constant current supply unit and wherein the external surface to mass ratio of the generator is greater than the external surface to mass ratio of the reactor, the value of pressure P1 in the combined spaces of the generator and the reactor being greater than the value of pressure in the working chamber.
13. Apparatus as claimed in claim 11 wherein the working chamber is provided with an internal heating shield with a controlled and stabilised temperature situated in said chamber, the screen having a common electrical potential with the chamber and defining an anode, the object being arranged to be connected to a cathode.
14. Apparatus as claimed in claim 13 wherein heating elements are mounted in the heating shield.
15. Apparatus for forming superficial diffusion layers on metals comprising a watercooled working chamber for receiving therein an object to be treated, the object forming a cathode connectable to a constant current power supply unit, the working chamber defining an anode connectable to said unit and wherein the working chamber is situated in a resistance furnace with a controlled and stabilised temperature and is provided with means for supplying said gaseous medium below the object being treated, to provide an upward flow of said medium adjacent to said object.
16. Apparatus as claimed in claim 15 wherein said means comprises a tube the outlet of which is mounted below the object being treated and wherein the chamber is provided with a water-cooled cover through which the tube enters the chamber.
17. A method of production of diffusion superficial layers on metals in glow discharge, wherein a gaseous medium is produced in a working chamber, or supplied to said working chamber from outside, where it is electrically ativated during the glow discharge process, characterised by that the gaseous medium is introduced into the generator of the reactive gaseous medium mounted in the lower zone of the working chamber, wherein the heating of the generator effected either by means of a glow discharge, or by electric resistance, activated thermally the said medium, thus forming the reactive gaseous medium which, in turn, after having passed close to the object being treated is activated electrically in glow discharge, thus forming a superficial diffusion layer.
18. A method as claimed in claim 17 wherein the objects being treated are heated under glow discharge conditions to a temperature lower than that in the generator of the reactive gaseous medium.
19. A method of production of superficial diffusion layers on metals in glow discharge, in which gaseous medium is introduced into a working chamber, where it is electrically activated during a glow discharge process, wherein the reactants are placed in a generator of the reactive gaseous medium mounted in the bottom portion of the working chamber, one of said reactants being introduced into said generator heated by means of a glow discharge, or by electric resistance, thus forming a gaseous medium, which after having been activated thermally in said generator is brought close to the object being treated, thus forming superficial diffusion layer.
20. A method as claimed in claim 19 wherein the objects being treated are heated under glow discharge conditions to a temperature lower than that in the generator of the reactive gaseous medium.
21. A method of production of superficial diffusion layers on metals in glow discharge, wherein the gaseous mdeium is introduced into a working chamber, where it is electrically activated during a glow discharge process, wherein a composite superficial diffusion layer is produced on the object being treated, before the successive change of the reactive gaseous medium, which is supplied close to the object being treated.
22. A method as claimed in claim 21 wherein at least one of the gaseous atmospheres of the medium is thermally activated in a generator of the reactive gaseous medium mounted in the lower portion of the working chamber by heating the generator either by a glow discharge process, or by means of electric resistance, which after having passed close to the object being treated is activated electrically in a glow discharge, together with the surface of the object being treated, thus forming at least one diffusion layer, the successive gaseous atmospheres of the medium being introduced close to the object being treated, thus producing the successive diffusion layers.
23. A method as claimed in claim 21 wherein the successive gaseous media are thermally activated in a generator of reactive gaseous medium mounted in the lower portion of working chamber by heating the generator, either in a glow discharge or by means of electric resistance, and thus producing reactive gaseous media, which after having been brought close to the object being treated are electrically activated by a glow discharge, together with the surface of the object treated, thus producing the successive diffusion layers.
24. A method as claimed in claim 21 wherein the objects being treated are heated up under glow discharge conditions to a temperature lower than that of the reactive gaseous medium.
25. Apparatus for production of diffusion superficial layers in a glow discharge on the objects being treated, consisting of a working chamber with water-cooled walls, suited to being filled with gaseous medium, including a cylindrical jacket located inside and provided with a pipe for supplying the gaseous medium, wherein the object being treated is the cathode and is located in a space encircled by a jacket, which together with the working chamber is the anode supplied from a constant current powder supply unit wherein in the bottom of the space surrounded by the jacket portion there is located a generator of the reactive gaseous medium having the shape of a container provided with an outlet of the reactive gaseous medium and an inlet of the gaseous medium, said generator being heated either by a glow discharge, or by means of electric resistance.
26. Apparatus for production of superficial diffusion layers on metals forming a working chamber with water-cooled walls, suited to being filled with gaseous medium at the required pressure, said working chamber being provided with a generator of the reactive gaseous medium and a flow reactor accommodating the object being treated, said generator and reactor being the cathode, and said working chamber being the anode, supplied by current ieadthrough from constant current power supply unit wherein the flow reactor and the generator of the reactive medium are permanently connected to each other, the external surface to mass ratio of the said generator being greater than the external surface to mass ratio of the said reactor, the value of pressure P1 in the combined spaces of the said generator and the said reactor being greater than the value of pressure in the working chamber.
27. Apparatus for production of superficial layers on metals in a glow discharge of the objects being treated, being a working chamber provided with an upper and lower cover suited to being filled with a gaseous medium, wherein the object being treated, mounted inside the said working chamber, is the cathode connectable through a current leadthrough to a voltage power supply unit wherein the working chamber is provided with an internal heating shield with a controlled and stabilised temperature, situated at the height of the said chamber, said screen having common electric potential with the chamber being the anode.
28. Apparatus as claimed in claim 27 wherein heating elements are mounted in an tight manner in the heating shield.
29. Apparatus for production of superficial diffusion layers on metals in a glow discharge of the objects being treated, said apparatus being a water-cooled working chamber provided with an upper cover, suited to be filled with gaseous medium, wherein the object being treated mounted inside the said working chamber is the cathode which is connected electrically by the leadthrough to a constant current power supply unit, the said working chamber being the anode being connected to the other pole of the said power supply unit, wherein the working chamber is situated at appropriate height in a resistance furnace with a controlled and stabilised temperature and is provided with a water-cooled cover in which tube for proportioning gaseous medium is accommodated, the outlet of said tube being mounted below the object being treated, thus forcing the gaseous medium to flow upwards.
30. Apparatus for the production of diffusion superficial layers on materials substantially as hereinbefore described with reference to any one of Figs. 1 to 4 of the accompanying drawings.
31. A method of forming diffusion superficial layers on materials substantially as hereinbefore described and, optionally, illustrated with reference to any one of the accompanying drawings.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PL25818186A PL147847B1 (en) | 1986-02-28 | 1986-02-28 | Method of and apparatus for producing cases on metal surfaces |
| PL25991986A PL147600B1 (en) | 1986-06-06 | 1986-06-06 | Method of producing superficial diffusion layers |
| PL26367187A PL150288B1 (en) | 1987-01-16 | 1987-01-16 | Apparatus for producing cases on metal surfaces |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8704831D0 GB8704831D0 (en) | 1987-04-08 |
| GB2187478A true GB2187478A (en) | 1987-09-09 |
Family
ID=27354064
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08704831A Withdrawn GB2187478A (en) | 1986-02-28 | 1987-03-02 | Producing diffusion layers on metals by glow discharge |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE3706482A1 (en) |
| GB (1) | GB2187478A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1990004044A1 (en) * | 1988-10-08 | 1990-04-19 | Tecvac Limited | Surface treatment of metals and alloys |
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| EP0095887A1 (en) * | 1982-05-28 | 1983-12-07 | Fujitsu Limited | Apparatus for plasma chemical vapour deposition |
| EP0118643A1 (en) * | 1982-12-22 | 1984-09-19 | Energy Conversion Devices, Inc. | Cathode assembly for glow discharge deposition apparatus |
| EP0118644A1 (en) * | 1982-12-22 | 1984-09-19 | Energy Conversion Devices, Inc. | Cathode assembly for glow discharge deposition apparatus |
| GB2148328A (en) * | 1983-08-16 | 1985-05-30 | Canon Kk | Chemical vapour deposition process |
-
1987
- 1987-02-27 DE DE19873706482 patent/DE3706482A1/en not_active Withdrawn
- 1987-03-02 GB GB08704831A patent/GB2187478A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0074212A1 (en) * | 1981-08-24 | 1983-03-16 | Kabushiki Kaisha Toshiba | Apparatus for forming thin film |
| EP0095887A1 (en) * | 1982-05-28 | 1983-12-07 | Fujitsu Limited | Apparatus for plasma chemical vapour deposition |
| EP0118643A1 (en) * | 1982-12-22 | 1984-09-19 | Energy Conversion Devices, Inc. | Cathode assembly for glow discharge deposition apparatus |
| EP0118644A1 (en) * | 1982-12-22 | 1984-09-19 | Energy Conversion Devices, Inc. | Cathode assembly for glow discharge deposition apparatus |
| GB2148328A (en) * | 1983-08-16 | 1985-05-30 | Canon Kk | Chemical vapour deposition process |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1990004044A1 (en) * | 1988-10-08 | 1990-04-19 | Tecvac Limited | Surface treatment of metals and alloys |
| GB2245601A (en) * | 1988-10-08 | 1992-01-08 | Tecvac Ltd | Surface treatment of metals and alloys |
| GB2245601B (en) * | 1988-10-08 | 1992-10-07 | Tecvac Ltd | Surface treatment of metals and alloys |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8704831D0 (en) | 1987-04-08 |
| DE3706482A1 (en) | 1987-09-03 |
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| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |