Shock wave nano-technology method

Abstract

The patent described the advantages of detonation plasma spraying, laser pyrolysis technologies, etc., being optimized by pulses with common parameters, like duration, slope for all mentioned above technologies.

For example, in some high temperature processes, using pulsed plasma or laser technology, plays vital important role the efficiency of plasma chemical processes. Since the plasma chemical reaction process efficiency is 20-30%, its value could be increased up to the thermodynamically feasible level of 60%.

The Shock waves created by electrical pulses disintegrates liquid particles up to Nano size fragments, accelerate them and finally formatted a coating with superior characteristics.

The influence of the pulses of radiation, detonation, electro impulse plasma can be generated by the same single pulse parameters of duration, slope, etc.

Claims

I. A method of increasing chemical reaction efficiency from 20-30% up to theoretical feasible 60% comprising the steps of: (a) set up duration of infrared laser radiation of a pulse of around 10.sup.4 s (10.sup.2 s) and slop of the pulse 10.sup.6-10.sup.9 A/s; (b) set up a resin in a hermetical chamber with transparent wall which located along his pulse's shot; (c) is being measuring gas products because of interaction of a resin with the pulse to calculate Chemical reaction efficiency.

II. A method of increasing a bond strength of coatings with substrate in 4-5-fold comprising the steps of: (a) into a Plasma torch which is operated by Air is being inserting Hydrocarbons to create the detonation process; (b) set up the duration of detonation pulse is being around 10.sup.4 s (10.sup.2 s) at the slop of a pulse's front is 10.sup.6-10.sup.9 A/s.

III. A method of producing a Nano-particles which is in turn formatting Nano coatings comprising the steps of; (a) igniting DC/AC plasma arc in plasma forming gas; (b) imposing on the plasma arc the pulses I in direct/reverse or both polarity plasma current I; (c) set up the slope of the front of pulses 10.sup.6-10.sup.9 A/s at amplitude I/I.sub.plasma current4-5, duration of them for subtraction range is 10.sup.2 s25 s, frequency range F.sub.modulation20 kHz which is necessary to control length L.sub.arc and accordingly V-I characteristics of DC/AC arc of plasma torch, generating a shock waves disintegration some liquid particles up to Nano size fragments and accelerating them.

IV. The method as define in claim I, II, III, the common time duration of pulse of a different nature: laser initiated chemical reaction, detonation spraying process, pulses of current for spraying (claims #I, II, III) must be set up the same duration around 10.sup.2 s under slope of the pulses 10.sup.6-10.sup.6 A/s.

V. To exclude of oxygen from Air plasma and increase an enthalpy of plasmashould be inserting in the plasma a hydrocarbon which increase a coefficient of spraying efficiency and, in turn, convert the torch with a vorticial stabilization of an arc into high effective pseudo-laminar plasma.

VI. The point of material feeding in the torch must be in an area where a plasma arc is attached to the anode.

VII. The method as define in claim III to decrease nonmetallic contaminations (Me-metal, MeO, MeN, MeC) contents in 3-4-fold in spraying product.

VI. The method as define in claim III wherein to control a porosity of coatings in the range 0-40% should be variating the frequency of pulse modulation and an anode length within 60%.

VII. The method as define in claim III wherein to convert plasma spraying torch operation to the regime of Nano particles generation up to size 0.1-5 nmshould increase the enthalpy of plasma jet to disintegrate and accelerate them by shock waves created by pulse modulation.

VIII. The method as define in claim III wherein to change the L.sub.arc relatively to the point of powder feeding for spraying which occur impact on parameters of spraying, torch characteristics, etc., should be set up a velocity arc's electrons close to the phase velocity of wave which is creating by pulse modulator: these resonant electrons gain energy from the wave that led to control the L.sub.arc and moreover is raising heat efficiency of the torch up to 30%.

IX. The method as define in claim III wherein by changing the frequency modulation can be find the value corresponding to a minimal average current I vs. maximal voltage V and Larc.

X. The method as define in claim III wherein suitable time const of a type of plasma forming gas should be lower than 30 s to create a high effective shock wave.

XI. The method as define in claim III wherein when the pulses are applied to an arc in the reverse polarity, the integral characteristic of disintegrating of the particles reaches 100% at frequency corresponding to the growth of large-scale shunting of the arc at the spraying wire-anode.

XII. The method as define in claim III wherein the minimum size of the sprayed particles is determined by a number of shock waves interacting with the particle during its flight.

XIII. The method as define in claim III; the use of current modulation makes the process of spraying less sensitive to the initial dimensions of a spraying particles than in traditional technology.

XIV. The method as define in claim III wherein a plasma deposition of coatings in a regime of superimposing current pulses in a reverse polarity to the arc leads to an increase in an adhesion of the coatings to the substrate up to the detonation level and reduces the gas permeability of the coatings by an order of magnitude.

XV. Plasma cutting speed can be increased by30% with rise of pulse amplitude in the direct polarity to the arc and upper limit of cutting speed is restricted by a cathode failure.

Description

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0083] The influence of the plasma/laser/detonation disturbances created by means of pulses of the different nature and the influence of these disturbances on above mentioned processes were subject of the present invention.

[0084] It is shown that inserting hydrocarbons into the air plasma jet is a contributing factor for the transition of the torch to the laminar spraying mode (with vortex stabilization of the arc), with a high coefficient use of powder. The physical estimations obtained have made understandable the mechanisms of the formation of the sprayed coatings. The results of interaction between the pulse-modulated plasma jet and the wire and powdery material being sprayed have been scrutinized in the given invention.

[0085] When plasma spraying is performed with DC current pulses superimposed in a reverse and direct polarity to the arc, the through-gas permeability of the coating is reduced by the order of magnitude. The most important explanation behind the phenomena is the disintegration of particles sprayed specific to the modulation process. By modulating the plasma arc current, sequential plasma shock waves disintegrate the spray particles, up to the size of the Nano-particles, and accelerate them toward the target substrate. The plasma arc current is precisely controlled to assure short time constant in the plasma, so that rapid changes in the plasma arc current form the plasma shock waves that strongly impact the spray particles.

[0086] The experimental data indicates the fact that of pulse pyrolysis will be more responsive to energy-E than to pulse duration- and eventually is approximated to the thermodynamically feasible value of 60%, which is 2-3 times more than continuous plasma chemical pyrolysis.

[0087] The pulse modulated plasma jet initiate disintegration process of being sprayed powder, wire, etc. The flux of plasma following a shock wave will interact with a droplet, thereby increasing the vibration amplitude which in turn causes the disintegration of droplets into large-size fragments.

[0088] In case of the sack-like breakdown, a spherical droplet would be reshaped into an ellipsoidal, where latter being blown out into a growing sack to be disintegrated into larger and smaller droplets. The larger ones were formed due to fragmentation of the sack rim.

[0089] The decreased through gas permeability A and increased tensile bond strength a of coating with substrate accordingly, can be accounted for among other things, by the fact that the modulation gives rise to the formation of plasma coatings which is assembled from the fine particles (of 0.05 to 5 m) moving with high velocity and penetrating deeply to crystal lattice of substrate.

[0090] The experimental results show the area of external change of V, I, La under 100 s.sub.sub25 s under I/I>1.66 and smooth character of change I and V at .sub.sub<25 s vs. frequency modulation. It is the way to control the DC plasma torch parameters.

[0091] It was shown that by a variation of the enthalpy and modulation parameters for any type of DC arc torches, it is possible to control the particle's purity, size and consequently the quality of coatings (porosity, micro-hardness, tensile bond strength and so on) with deposition efficiency approaching to 100%.

[0092] To increase the bond strength of NiTi coatings with substrate from 50 MPa (7200 psi, without modulation) up to 200 MPa (29000 psi) because of the collision the particle with the substrate by detonation waves.

[0093] While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.

[0094] It was shown the effect of modulation of the plasma arc on the cutting process [12], greatly improves cutting characteristics, mainly because of an increase in length of the free arc, which in turn increasing cutting speed, thickness of cutting material.

BRIEF DESCRIPTION OF DRAWING

[0095] FIG. 1a. The experimentally obtained experimental data for (), (E)

[0096] FIG. 1b. The experimentally obtained experimental data for (E).

[0097] Experimentally found chemical reaction efficiency of resin pyrolysis vs. reaction temperature and energy of laser pulse radiation

[0098] FIG. 2. The stage of nascent, the growing sack of sprayed particle, formation stage of a growing sack of sprayed particle with thick rim.

[0099] It is shown, how is formed growing sack of sprayed particle during melting them in plasma jet spraying process

[0100] FIG. 3. Initial NiTi powder (size range is: 5-200 m).

[0101] It is shown how looks like the powder before penetrating the plasma jet

[0102] FIG. 4. An example of powder aggregation

[0103] The melted particles may join each other

[0104] FIG. 5. Particle size distribution after plasma spraying with modulation as per subtraction pattern

[0105] It is shown, the experimental distribution of the particles vs. their sizes after spraying by DC plasma current with pulses opposite polarity to this current.

[0106] FIG. 6. Distribution of particles after spraying as per adding pattern: I=0.8 kA

[0107] It is shown experimental distribution of the particles vs. their sizes after spraying by pulses of amplitude 0.8 kA of the same polarity to this current.

[0108] FIG. 7. The decreased through gas permeability vs frequency of modulation.

[0109] It was shown how the through gas permeability of coating depended on the frequency of modulation of DC arc.

[0110] FIG. 8. increased tensile bond strength of coating with substrate vs. frequency of modulation

[0111] Experimental data of dependence bond strength of coating with substrate vs. frequency of modulation

[0112] FIG. 9. versus .sub.m and I in subtraction modulation

[0113] Integral characteristic of processed by plasma of powder shown in dependence of current and frequency pulse modulated plasma in reverse polarity to the DC arc.

[0114] FIG. 10. versus I in adding modulation (=200 s)

[0115] Integral characteristic of processed by plasma of powder shown in dependence of current and frequency pulse modulated plasma in direct polarity to the DC arc.

[0116] FIG. 11. Particle diameter versus modulation frequency (asubtraction and badding pattern) for Ni, Stainless steel, Tungsten wires.

[0117] It is shown the sizes of sprayed particles in dependence of the types of modulation and for different materials like stainless steel, Tungsten, Nickel.

[0118] FIG. 12. Arc length vs. frequency of modulation

[0119] It was shown the dependence of the length of plasma arc in the anode channel of Plasma torch vs. the frequency of modulation

[0120] FIG. 13. The DC arc voltage V, current I versus .sub.m at

.sub.sub=20 s (I/I<1.66B), .sub.sub=70 s (I/I>1.66A).

[0121] It is shown the change of DC plasma arc voltage and current, in dependence of modulation frequency and the duration of each pulse imposed onto the DC arc.

[0122] FIG. 14a. EM images of particles sprayed under the low modulation modes.

[0123] FIG. 14b. EM images of particles sprayed under the high modulation modes

[0124] At this image shown significant change fraction composition of sprayed materials in dependence of different types of modulation modes.

[0125] FIG. 15a(Upper). Generations of Nano-particles with modulation

[0126] FIG. 15b. Generations of Nano-particles without modulation

[0127] Comparison of the fraction composition of the sprayed materials in dependence of the enthalpy of DC plasma torch at the modulation and without.

[0128] FIG. 16. Microstructure of coating from Al.sub.2O.sub.3 sprayed without modulation: micro-hardness is 1066 HVO.3, porosity is 2.0%.

[0129] At this microstructure was shown that without modulation in coating revealed the significant porosity.

[0130] FIG. 17. Microstructure of coating from Al.sub.2O.sub.3 sprayed with modulation under frequency20.5 kHz: micro-hardness is 1200 HVO.3, porosity is 0.5%

[0131] At this microstructure was shown that without modulation in coating the porosity. Is almost absent.

REFERENCES (NEW)

[0132] 1. B. E. Gutman, Shock degassing as a method for increasing process efficiency, Fizika Goreniya i Vzryva, Vol. 25, No 2, pp 142-144, 198. [0133] 2. B. Gutman, Shock wave atomization: physical mechanisms of a modulated DC Plasma torch during spray coatings, Atomization and Spraying, Journal, Vol. 16, Issue 3, pp. 279-298, 2005. [0134] 3. Boris Gutman, Pulsed plasma and laser technologies and their business aspects, Cambridge international Science publishing, England, ISBN 1898326967, pp. 203, September 2000. (book with all USSR's-Israel's Patent, Publications, up to 2000, translated to English, could be received from Author B. Gutman: boris.gutman@gmail.com). [0135] 4. B. Gutman-Goodman, Plasma spraying Arc current Modulation method U.S. Pat. No. 5,900,272, PCT/US98/22011, October 1997, May 1999. [0136] 5. B. Gutman, Nano Plasma Technology Production for tiles against piercing weaponry, [0137] Open Materials Science Journal, 3, pp. 40-46, 2009. [0138] 6. B. Gutman, Thermal nucleus fusion torch method, U.S. Pat. No. 8,436,271, 2013. [0139] 7. B. Gutman, Experimental base for Introduction to Non-magnetically Fusion engine development, Journal of Electrical and Electronic Engineering, 2017. [0140] 8. B. Gutman, Testing Results of Plasma Spraying Ceramics Coatings by Pulse Plasma Modulation Technology, American Journal of Nano Research and Applications, pp. 49-60, September 2017. [0141] 9. B. Gutman, Mechanisms influencing on the parameters of plasma coatings in a modulated plasma arc, Proceeding of ITSC, Kobe, May 1995. [0142] 10. B. Gutman-Goodman, Shock wave physical mechanisms of modulated arc as applied to dusted plasma flows to form the coatings, Proceedings of ITSC 2005, Basel, Switzerland [0143] 11. B. Gutman-Goodman, The development of novel technologies for plasma spraying of coatings, Proceedings of the 5.sup.th national thermal spray conference, June 7Anaheim, Calif., 1993. [0144] 12. B. E. Gutman, Effect of modulation on the plasma arc on the cutting process, Svar. proiz., No. 7, 1985 (Welding production, July 1985). [0145] 13. B. E. Gutman, Effect of modulation of the plasma arc on spraying parameters, Welding production, September 1984. [0146] 14. B. Goodman-Gutman, Investigation of dispersion processes of sprayed particles by means of torch modulation, Proceedings of the 7.sup.th national spray conference, Boston, Mass., 20-24 Jun. 1994.