DE4226229A1 - Surface treatment using high energy material pulse - Google Patents

Abstract

(A) Surface treatment of a solid body with a short duration pulse of high energy and density material is carried out by (a) passing energy from an energy store to an energy converter in which it is converted to an energy carrier in the form of a gas, liq., and/or solid for acceleration towards the solid body surface, and (b) impinging the pulse on the solid body surface for interaction with the extremely thin outer surface layer to effect structural and/or compositional modifications without affecting the rest of the solid body. In a similar process, the energy carrier and/or additive, acclerated by the energy carrier, impinges on the solid body surface to create new matter which is then sepd. and recovered in isolated form. Appts. for carrying out the processes is also claimed.

Description

The invention relates to a method for applying egg ner solid surface, especially a material upper surface, for the purpose of achieving changes in the structure and / or the structure and / or the composition. Fer ner is the invention on devices for performing the this procedure.

In the course of technological progress are constantly increasing demands on components and systems of the Ma made of machinery. In particular, the increase in Zuver Liability and durability of components subject to tribological stress le is extremely important in this context. A Coating is the way to achieve this goal of component surfaces with modern high-tech hard materials fen.

It is known to use layers of high-strength materials with various to apply the most coating processes to a component. The following methods are known in particular:

• - PVD (physical vapor deposition) methods
• - CVD (chemical vapor deposition) methods
• - electrolytic (galvanic and chemical) deposition
• - thermal spraying
• - plating process
• - hot dip
• - Laser surface treatments Ion implantation, electron beam process.

The object of the invention is to achieve one in particular of particularly high quality or special properties appropriate surface layers of materials to create that versatile and using Vorrich is realizable, at least in its basic concept tion are known, but so far technically completely ver  have been used for various purposes.

According to the invention, the object is achieved in we noticeably through a procedure for applying a feast body surface, in particular a material surface, with a brief impulse of a mass of high energy and Density at which the stored in an energy store Energy directed into an energy converter and there to one to be accelerated in the direction of the solid surface Energy source in the form of a gas and / or a liquid speed and / or a solid is transferred in such a way that the impulse occurring on the solid surface with the boundary layer of the solid interacts and in this extremely thin surface layer without influencing the Base material changes in the structure and / or in the Structure and / or in the composition causes.

Particularly advantageous configurations and modifications of the method according to the invention are detailed in the Claims 1 to 24 specified.

Of particular importance is that it is the invention Process enables not only extremely hard and wear to achieve solid surfaces, but these surfaces also very specific ones, so far at least not in this way achievable properties, especially with regard to Wettability and structure, to lend, and before to achieve everything, such as material conversions play the transformation of graphite into diamond-like, ultra hard carbon structures, so-called fullerenes.

The process parameters can be adjusted to the desired one Adjust the layer properties in a targeted manner.

Devices which can be used advantageously for carrying out the inventive method and modifications of this Procedures are described in subclaims 25 to 34 ben, in the form of various plasma dynamic  Accelerator systems.

A particularly advantageous device for reali Sation of the method according to the invention consists of a coaxial plasma accelerator with compression coil. A such system delivers for a short time, that is in the micro to Millisecond range, high pressures in the kbar range with temp ratures up to 20,000 K and can therefore in a plasma flow with flow velocities of up to 70 km / sec Accelerate particles to very high speeds. The These speed ranges represent an essential sub differed from the existing coating processes because using these known surface treatment technologies such speed ranges not even close to him can be enough. The use of such a magneto- gas dynamic accelerator for performing the inventions The method according to the invention enables extremely short exposure delivery times and high power densities.

Others to implement the method according to the invention suitable and thus usable systems represent the electrothermal accelerator and the control rail accelerator. With these different loading accelerator types it is possible to meet the respective requirements in the surface treatment especially with regard to the materials to be used, the required pressures, tempera structures and flow velocities of the respective plasma to take variable and optimal account.

The invention is illustrated below using examples Reference to the pictures explained in more detail, whereby from it is emphasized that not only the content of the claims, but also the overall content of these explanatory description is part of the invention.  

The drawing shows:

Fig. 1 the functional principle of an accelerator for influencing materials,

Fig. 2 shows a schematic structure of a test facility,

Fig. 3 is a schematic diagram of a plasma dynamic accelerator,

Fig. 4 is a sectional view of a plasma dynamic accelerator with gas injection through the outer electrode and injection of additional materials through the central electrode,

Fig. 5 shows a plasma dynamic accelerator with a convergent / divergent compression coil,

Fig. 6 shows the schematic structure of an electrothermal accelerator, and

Fig. 7 is a schematic representation of a guardrail accelerator with object material.

Fig. 1 shows the principle of operation of the Accelerator gene for influencing the surface of materials for the purpose of implementing the method according to the invention.

This schematic representation shows that only the task of the energy converter at the various ver reversible accelerator systems in different ways is performed. The for the inventive method required short-term impulses of a mass of high energy and Density are by means of these different accelerator systems gene achievable, the selection of the respective system according the specific tasks at hand.  

A typical overall system is shown in Fig. 2, and it shows the accelerator system, which consists of the actual plasma accelerator, which is installed in a vacuum tank, and a capacitor bank with ignitron switches as an external energy store.

The plasma accelerator itself is owned by the two main groups pen of the coaxial accelerator and the compression coil formed, this coaxial accelerator with compresses sion coil represents the energy converter.

Fig. 3 shows a schematic diagram of a plasma dynamic accelerator with compression coil. The coaxial part consists of a rod-shaped central electrode and an outer electrode with a ring cross-section. This is followed by a tapered coil, which is attached insulated at the rear end and is conductively connected to the outer electrode via a current feedback. The entire accelerator can be regarded as an electrical resonant circuit, consisting of a capacitance, inductors and resistors. If the switch in the energy storage system is closed, a discharge current that changes over time begins to flow through the system. The conductive connection between the center electrode and the outer electrode is produced by a plasma which represents the energy source and which is generated at the start of the current discharge either by vaporization and ionization of a metal foil or by ionization of a gas. Further details of such a plasma dynamic accelerator can be found in US Patents 3,929,119 and 3,916,761.

Fig. 4 shows a schematic representation of an embodiment of a plasma dynamic accelerator with gas injection through the outer electrode and the possibility of injecting filler materials through the central electrode.

An inductive storage device or a capacitive memory can be used. The energy converter, into which the energy from the energy storage is directed, converts the supplied electrical energy into thermal and / or kinetic and / or chemical energy of one Energy carrier around. A gas is used as an energy source det, this is briefly due to the energy supply very high temperature and high pressure and density brings. In particular, the gas is ionized so that a plasma is created. This plasma is used to to serve as an energy source and / or to serve others at the same time To provide filler materials with kinetic energy and with feed and finally interact with the object bring material, with the very thin edge layer of the object material, in particular the duration of the momentum exerted on the object material, the tempe rature, density and pressure are chosen so that the Ge add and target the structure of this very thin edge layer influenced, however, the depth of the thermal action this thin boundary layer is restricted.

For this interaction, the energy storage, the energy converter and the energy source with or without broken te filler materials and the object material in a special re order to be brought to the appropriate influence solution of the object material and in particular its edge perform shift. Above all, a suitable one Arrangement of the physical parameters of the energy storage and the energy converter as well as a suitable selection of the Energy carrier and this energy carrier as well as given if added material is made, and this must again in a suitable form with the selection and with the type order of the object material in relation to the energy wall related. These considerations apply basically regardless of the type of energy used converter.  

Fig. 5 shows a modification of a plasma dynamic accelerator with a convergent / divergent designed compression coil, which makes it possible to generate a substantially parallel plasma flow on the output side, which ensures an advantageous distribution of the temperature, the density and the flow velocity in the plasma jet, so that the application of a solid surface and in particular a workpiece surface takes place in a particularly uniform manner. In particular, the uniform application of the largest possible surface is achieved. The object material can be arranged in a suitable manner inside or outside of the coaxial accelerator with compression coil, and the choice of the position of the object material is of essential importance for the solution of the particular task, since the duration, height, density and composition of the pulse differ in Ab change dependency on the respective position.

The coaxial accelerator with compression coil can in particular especially with a suitable total energy input and corresponding pulse duration are operated so that the Ero sion and ablation of the components of the accelerator avoided being a specially defined and made of foreign substances undisturbed exposure to the object material can be guaranteed.

Fig. 6 shows a half section of an electrothermal accelerator that can also be used as an energy converter. This consists of an external electrical energy storage, a high pressure chamber, which is also referred to as the explosion chamber, and the actual accelerator tube. In the explosion chamber there is an electrically conductive material between two electrodes. If the energy storage is discharged, a current begins to flow in the system, whereby energy is supplied to the material in the chamber. Due to the strong current surge, the material spontaneously evaporates (under certain circumstances, the material to be influenced by the object material), and a hot, high-pressure plasma is created that expands in the axial direction. The object material is then exposed to the plasma flow at a suitable distance from the combustion chamber in the course or outside the course of the electrothermal accelerator, the type of introduction of the object material and in particular the distance of the object material from the combustion chamber from the parameters of the energy storage device and is dependent on the electrothermal accelerator. In particular, an advantageous coating or interaction with the object material, which leads to special surface properties, can be achieved in this way as well as by the energy supplied to the electro-thermal accelerator and the directional pulse duration.

For this purpose, the object material is suitably within or arranged outside the electrothermal accelerator net. In particular, this electrothermal accelerator with a suitable total amount of energy supplied and ent speaking pulse duration are operated, so that the erosion and ablation of the components of the accelerator is avoided, being a particularly defined and unaffected by foreign substances effect on the object material becomes.

Both during the generation of the plasma and during the loading acceleration of the plasma in the axial direction can this Plasma, which is the actual energy source, still a white other material that is suitable to be added entirely special properties when influencing the object work to produce fabric.

Fig. 7 shows a guardrail accelerator that can also be used as an energy converter, as described for example in European patent application 89 900 590 for a completely different application. This guardrail NEN accelerator can either consist of a guardrail accelerator with two parallel guardrails or a guardrail accelerator with more than two guardrail pairs. In this guardrail accelerator, the energy source is generated by evaporation and ionization of a film, by gas injection or by injection of plasma using an electrothermal accelerator or by erosion of the electrodes and / or the insulators. The length of this accelerator is suitably adapted to the parameters of the energy supply in order to generate a short pulse of high density either inside the accelerator or outside the accelerator, which pulse length, pressure temperature and density are suitable for applying a solid surface or material surface , so that special properties are created there.

For all accelerator systems described above, that by the surge discharge of the capacitor bank Ionization of a gas ent a high-energy plasma stands that accelerates to high speeds and on is then compressed to high pressures in the kbar range. Then this plasma hits, which is the energy source poses, with or without additives, on the person to be treated Material, the parameters of the impulse being chosen so that only the very thin surface layer of the of the respective material and the base material - in Contrary to all previous corresponding procedures - is not influenced thermally.

The method according to the invention is accordingly distinguished by

• - a very high power density at the respective Active site,
• - high pressure, temperature and speed parity meters (approx. 50 km / sec) of the plasma flow,
• - extremely short exposure times on the workpiece surface che and thus by avoiding a thermal  Strain on the base material on surfaces treatment,
• - suitable parameter ranges for the production of new ones Material modifications, for example the ore carbon modifications such as diamond and Fullerenes,
• - very high cooling rates of the workpiece surfaces extremely short exposure times, especially in conjunction with liquid nitrogen cooling, such as
• - the possibility of generating non-equilibrium weight phases.

It is of particular importance that using the process principle according to the invention or using of modifications of this principle on a workpiece surface surface new substances can arise that differ from this let be separated and thus be isolated. By experiments carried out when bombarding an aluminum target Graphite powder in a helium plasma flow showed that the graphite powder into novel carbon molecule chains was converted to what are known as fullerenes, that is who specified diamond-like carbon molecular chains could.

It was also possible to confirm through tests that it is possible with the aid of the invention to produce defined amorphous surfaces. The bombardment of a copper material with helium plasma led to the melting of a thin surface layer, with active cooling of the material with liquid nitrogen causing rapid solidification (cooling rates in the range of 10 ⁹ K / s) of this surface layer and An amorphous surface was formed.

The bombardment of a pure iron surface sprayed with diamond powder surface with helium diamond powder plasma made the exit possible formation of a very hard surface layer, the hardness te can be further increased if high purity slide sheath powder with a correspondingly high proportion of diamond grains is used.

It should also be mentioned that it is by means of the Erfin systems provided, in particular by means of a plasma dynamic accelerator is also possible, a microver to carry out a melt flow, which leads to the fact that grain sizes not achievable with conventional processes can be aimed. Exploitation of an electrical energy giequelle as part of a plasma dynamic accelerator in conjunction with a specially designed one at the end strong axial field-indicating compression coil leads to a pronounced tearing of, for example, a Melt flow fed by means of injection, whereby through the possible field design depending on the compression coil because optimal, smallest possible grain sizes Conditions can be created. For a quick return cooling of the microparticles formed can be done accordingly cooled baffle be provided.

Claims (34)

1. Process for loading a solid surface che, in particular a material surface with a momentary impulse of a mass of high energy and you te, in which the stored in an energy storage Energy directed into an energy converter and on there one in the direction of the solid surface low energy in the form of a gas and / or a liquid and / or a solid such that is transferred to the solid surface occurring impulse with the boundary layer of the solid interacts and in this extremely thin Surface layer without influencing the base material Changes in the structure and / or in the structure and / or in the composition. 2. The method according to claim 1, characterized, that electrical energy is stored in the energy store and this electrical energy in the energy converter in ther mix and / or kinetic and / or chemical energy is transformed into an energy source. 3. The method according to claim 2, characterized, that the energy source consists of a gas that by the energy converter briefly to extremely high speeds and to very high temperatures and high temperatures Bring pressure and high density and thereby by partially se or whole ionization is converted into a plasma. 4. The method according to any one of the preceding claims, characterized, that the respective energy source to accelerate Filler materials are used with the edge  layer of the exchangeable body in a predeterminable exchange effect occur, in particular the duration of the the solid impulse, its temperature, Density and pressure are chosen so that structure and / or structure and / or composition of the a defined surface layer of the material the corresponding boundary layer is specifically influenced and ins special special properties are set, such as high wear resistance, high Corrosion resistance and special processing properties like good wetting ability to apply of melt metallizations, galvanic metallizations gene and / or for applying coatings physical coating process. 5. The method according to any one of the preceding claims, characterized, that filler materials in the area between the energy transducer and the solid body and supplied by the respective Energy carriers in the direction of the solid surface be accelerated. 6. The method according to any one of claims 1 to 4, characterized, that filler materials on the surface of the solid applied and with the edge layer of the solid by the impulse impinging on the solid Interaction. 7. The method according to any one of the preceding claims, characterized, that an impulse with itself over the length of its movement path-changing cross-sectional shape and the Ab stood between the energy converter and the solid Dependence on that required in the boundary layer Interaction is carried out variably adjustable.   8. The method according to any one of the preceding claims, characterized, that to generate the energy source carbon-containing Gases such as methane and / or nitriding nitrogenous gases used or an energy source ger are supplied. 9. The method according to any one of the preceding claims, characterized, that the energy source is supplied with a material that essentially only entrained by the energy source and accelerated and not from those occurring in the energy converter accelerating electromagnetic forces, which are preferably materials which with the plasma forming the energy carrier inclined, also liquefied or evaporated and gelled can even occasionally be ionized. 10. The method according to any one of the preceding claims, characterized, that the parameters defining the short-term pulse be chosen such that high heating speed speed and / or rapid cooling rate in structure which can be predetermined in the boundary layer of the solid tures and grain sizes set, in particular by Rapid solidification technology on the amorphous surface layers Solid bodies are generated. 11. The method according to claim 10, characterized, that to increase the cooling rate of the edge layer the material to be treated before and / or wäh rend treatment at low temperature, for example to the temperature of liquid nitrogen or liquid Helium is brought.   12. The method according to any one of the preceding claims, characterized, that to prevent surface reactions, esp especially to prevent oxidation in energy converter-generated plasma produced from an inert gas or the noble gas is added to the plasma as an additive becomes. 13. The method according to any one of the preceding claims, characterized, that in the plasma solid particles in the form of elements ten or compounds in crystalline or amorphous Form introduced and this under the short-term on effect of the plasma mechanically, preferably by the high back pressure so implanted in the peripheral layer that there is no material change in the particles follows and accordingly a mechanical alloy high-energy impulse, in particular also is caused by conventionally non-alloyable substances. 14. The method according to any one of the preceding claims, characterized, that to implant in the peripheral layer of the solid particles in particular evenly distributed a film is applied that tra the particles film of the plasma flow or the plasma pulse exposed and zer by their influence is disturbed, the particles being bombarded by the plasma nigt and in uniform distribution with or without that Plasma implanted or mechanically in the peripheral layer be alloyed. 15. The method according to any one of the preceding claims, characterized, that the parameters of the short-term pulse such ge be chosen that the solid particles in the plasma and / or when striking the solid surface a change in structure and / or composition  Experienced. 16. The method according to claim 15, characterized, that the respective energy source as filler material Carbon in the form of graphite powder and / or slide jacket powder added and when interacting with the Solid material a hard surface layer is generated and in particular new properties of the solid edge layer, for example by converting coal fabric or graphite powder in fullerene, who created the. 17. The method according to any one of the preceding claims, characterized, that before the impulse is applied, the boundary layer of the Solid body of a thermochemical treatment, in particular carburized or nitrided in order to increase the concentration of Ele like carbon and nitrogen. 18. The method according to any one of the preceding claims, characterized, that in the boundary layer of the respective solid material fe introduced with particularly reactive properties and in particular reactive metals and / or chlorides can be used that have a wetting of too metallic surfaces without the use of flux possible. 19. Process for loading a solid surface with a brief impulse of a mass of high energy and density at which stored in an energy store energy into an energy converter and there to be in the direction of the solid surface accelerating energy is transmitted in such a way that when it hits the energy source and / or additives accelerated by the energy source  New substances are created on the solid surface, which separate from it and thus win in isolation to let. 20. The method according to claim 19, characterized, that by converting carbon or graphite powder or other elements on the solid surface separable fullerenes and / or fullerene-like structure be formed from other elements. 21. Process for micro atomization of a melt stream Utilization of short-term impulses of high energy, in particular dere according to one or more of the preceding claims che, the material forming the melt stream the Energy carrier or to accelerate from the energy carrier forming additive and by the electrical Energy that is transferred to the Melt flow is transmitted in particles of extreme small grain size is torn. 22. The method according to claim 21, characterized, that the microparticles by means of a cooled, as Baffle serving wall collected and collected become. 23. The method according to claim 21 or 22, characterized, that the melt stream together with a gas plasma the coil area of a plasma dynamic acceleration gers is introduced, the coil designed so will have a strong axial field in front of it lies, causing the gas plasma in which an azimuthal electric current flows, a strong radial force is exercised, which then affects the melt flow wearing.   24. The method according to one or more of the preceding Expectations, characterized, that the individual process steps several times in succession which are carried out with the parameters unchanged remain or in successive procedures steps to achieve different treatments can be modified. 25. Device for performing the method according to a or more of claims 1 to 24, characterized by the use of a plasma dynamic accelerator according to U.S. Patents 3,929,119 and / or 3,916,761, the U.S. Pat Distance between the coaxial accelerator and the Solid surface is preferably adjustable and the shape of the compression coil used in each case Art is selected so that the for the application of the Boundary layer of the solid required short-term plasma pulse is obtained. 26. The device according to claim 25, characterized, that the compression coil towards the solid surface is tapered. 27. The apparatus according to claim 25, characterized, that the compression coil is a convergent / divergent Has shape. 28. Device according to one of claims 25 to 27, characterized, that the solid inside or outside of the coax len accelerator arranged with compression coil is, the accelerator with compression coil total energy and pulse duration can be selected are that erosion and ablation of the components of the  Accelerator avoided and thus one of foreign matter fen undisturbed exposure to the boundary layer of the solid can take place. 29. Device according to one of claims 25 to 28, characterized, that facilities are provided to the energy source Add additional material, which is preferably is about materials that through the energy carrier co-accelerating forming plasma and ver liquid or vaporized and occasionally even ionic can be siert, and that these facilities a Introduction of additional material in the area of coaxial Accelerator or the compression coil or on End or at a distance from the end of the compression coil possible, in particular an introduction to Zu material through a central electrode in the through the compression coil flowing plasma can be done. 30. Device for performing the method according to a or more of claims 1 to 24, characterized by the use an electrothermal accelerator according to the European 's patent application 89 905 663.4, which the Ener gieträger forming plasma both during its generation as well as its acceleration towards the hard a filler material if necessary is available and the solid inside or outside of the electrothermal accelerator can and the total tens supplied to the accelerator Technology and pulse duration can be selected so that erosion and ablation of the components of the accelerator avoided and thus a situation unaffected by foreign substances striking the edge layer of the solid can.   31. Device for performing the method according to a or more of claims 1 to 24, characterized by the use a guardrail accelerator with two or more Guardrail pairs according to European patent application 89 900 590.4, the energy source by evaporation and ionization of a film, by gas injection or by injecting plasma using an electrotherma len accelerator or by erosion of the electrodes and / or the isolators can be generated and the Be Accelerated total energy and pulse duration are so selectable that erosion and ablation of the construction parts of the accelerator avoided and thus one of Foreign matter undisturbed exposure to the edge layer of the solid can be done. 32. Device according to claim 31, characterized, that the required momentum of a mass of high energy and Density by choosing the length of the accelerator is aimable. 33. Device according to one or more of claims 25 up to 32, characterized, that the respective energy converter from such material there is no impairment, in particular re no influence on the foreign matter of the exposure of the material surface, taking such materials are chosen in the sense of in the energy source and / or substances contained in the additives Foreign substances are or from which in the generation of the Energy carrier and / or the introduction of additive do not contain such foreign substances stand.   34. Device according to claim 33, characterized, that the surfaces of the energy converter that with the Energy carriers interact before a Beauf impact coated with protective materials, being particularly on the surface of the energy wall materials are applied or sprayed on correspond to a component of the energy source or its addition to the energy source as an additive see is.