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This invention involves the application of dense, metallurgically bonded deposits of tungsten and tungsten rhenium coatings onto preformed based x-ray anodes to be used as focal tracks. The coatings are applied by low pressure DC plasma spraying. The invention also includes heat treatments that furt

This invention involves the application of dense, metallurgically bonded deposits of tungsten and tungsten rhenium coatings onto preformed based x-ray anodes to be used as focal tracks. The coatings are applied by low pressure DC plasma spraying. The invention also includes heat treatments that further densify the as-applied coatings improving their suitability for use as focal tracks.

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What is claimed is: 1. A method for the production of a rotary anode for X-ray tubes, comprising: providing a base; pre-heating the base; using low pressure plasma to spray material as a focal track layer on to the base, including use of at least one plasma gun and one or more auxiliary heating sou

What is claimed is: 1. A method for the production of a rotary anode for X-ray tubes, comprising: providing a base; pre-heating the base; using low pressure plasma to spray material as a focal track layer on to the base, including use of at least one plasma gun and one or more auxiliary heating sources to maintain even heating of the base and to retain a desired temperature of the base during the low pressure plasma spray. 2. The method for production of a rotary anode for X-ray tubes as set forth in claim 1, wherein: the material is selected from the group consisting of tungsten, tungsten alloys, and combinations thereof. 3. The method for production of a rotary anode for X-ray tubes as set forth in claim 2, wherein: tungsten alloy is comprised of tungsten rhenium alloys comprising of rhenium from 3.5 wt % up to a solubility limit in the tungsten. 4. The method for production of a rotary anode for X-ray tubes as set forth in claim 3, wherein: the rhenium content is 5 to 10 wt %. 5. The method for production of a rotary anode for X-ray tubes as set forth in claim 2, wherein: the tungsten and the tungsten alloy are comprised of a de-agglomerated tungsten powder, with a mean powder particle size ranging from approximately 2 micrometers to about 15 micrometers, with a D50 of 8 to 10 micrometers. 6. The method for production of a rotary anode for X-ray tubes as set forth in claim 5, wherein: the one or more auxiliary heating sources are comprised of plasma guns. 7. The method for production of a rotary anode for X-ray tubes as set forth in claim 6, wherein: the low pressure plasma spraying of tungsten alloy as a focal track layer onto the base is comprised of: placing the base within a chamber; masking areas of the base adjacent the focal track to shield the areas from tungsten alloy spray deposits; a first lowering of the chamber pressure for removal of gases; introducing a low pressure inert gas into the chamber for forming a protective environment; igniting the plasma guns inside the chamber; cleaning the base for removal of oxides and dirt; further de-agglomerating the de-agglomerated tungsten alloy powder; preheating the base for commencing a low pressure plasma spraying coating cycle; pouring the further de-agglomerated tungsten alloy powder into one of the plasma guns for depositing thereof onto the base; commencing the low pressure plasma spraying coating cycle of the base to desired coating thickness using one of the plasma guns, and maintaining even heating of the base using one of other plasma gun and heat source; a second lowering of the chamber pressure upon completion of the low pressure plasma spraying coating cycle, cooling the base, filling the chamber with gas to atmospheric pressure, and removing the base. 8. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: the base is placed onto a self-aligning fixture that aligns the base with an axial centerline of a turntable that is located within the chamber, with the turntable effecting an axial rotation and translational movement of the base via computer control within the chamber. 9. The method for production of a rotary anode for X-ray tubes as set forth in claim 8, wherein: the self-aligning fixture is comprised of high temperature molybdenum alloys, having three independent components locked and centered by the use of molybdenum eccentric pin that lock in the base alloy thereon, and align base with the central axis of the turntable; the turntable is comprised of an insulating platform allowing the base to rest thereon, and preventing heat conduction from the anode into the turntable; and the rotation is effected by a drive mechanism, and the axial translation is effected by servo control of a shaft that moves turntable. 10. The method for production of a rotary anode for X-ray tubes as set forth in claim 8, wherein: the mask is coupled with the self-aligning fixture by a locking mechanism for quickly and easily locking and releasing the base and preventing the base from wobbling when locked. 11. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: a movement of the plasma guns inside the chamber is vertical in relation to the base. 12. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: the control of pressure of the chamber, motion of the plasma guns, and a rotary and translational axis of the base alloy are controlled by a computer. 13. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: the inert gases introduced into the chamber is comprised of argon and helium, and is set to increase the chamber pressure to an approximate pressure of 5 to 60 torr. 14. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: the cleaning of the base includes using negative reverse transferred arc using one or more plasma guns. 15. The method for production of a rotary anode for X-ray tubes as set forth in claim 14, wherein: negative reverse transferred arc further comprises: providing a supplemental power supply coupled with at least one of the plasma guns to form a bias from an anode of the selected plasma gun to the base alloy, which when ignited, creates arcing and removes and pulls off surface oxides and dirt from a surface of the base. 16. The method for production of a rotary anode for X-ray tubes as set forth in claim 15, wherein: a duration of cleaning lasts approximately from about 60 to 90 seconds, with a power input of approximately 20 KW. 17. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: further de-agglomerating process, includes: heating the de-agglomerated tungsten alloy powder to an approximate temperature of about 38° C. to remove moisture. 18. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: further de-agglomerating process, includes: vibrating the de-agglomerated tungsten alloy powder for time to eliminate electrostatic charges, preventing static agglomeration of the particles. 19. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: the duration of preheating the base to a minimum of 1300° C. and higher is approximately 3 to about 4 minutes, which allows for re-crystallization of equiaxed grain of the tungsten alloy particles deposited onto the base as the focal track using the plasma guns. 20. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: the duration of the coating cycle is approximately 16 minutes, and is comprised of moving the base under the plasma guns through the rotational and translational motion of the base. 21. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: the base is cooled to an approximate temperature of about 150° C. 22. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: cooling the base includes using a cooling chamber, with the cooling chamber filled with an inert gas and the base moved therein for faster cooling. 23. The method for production of a rotary anode for X-ray tubes as set forth in claim 22, wherein: the inert gas is comprised of argon. 24. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, further comprising: a post-coating beat treatment to stabilize grain structure and provide relief of residual stress. 25. The method for production of a rotary anode for X-ray tubes as set forth in claim 24, wherein: post-coating heat treatment includes: placing the formed anode within a vacuum chamber and reducing a pressure of the vacuum chamber to de-gas the formed anode, and commencing a heat treatment process of the formed anode therein within the vacuum chamber, which allows the void pores therein the focal track to consolidate. 26. The method for production of a rotary anode for X-ray tubes as set forth in claim 23, wherein: the vacuum chamber is a vacuum heat treatment furnace. 27. The method for production of a rotary anode for X-ray tubes as set forth in claim 25, wherein: the duration and intensity of the heat treatment is approximately 30 minutes to 2 hours at an approximately temperature of 1600° C., which further dense the focal track by an additional 1 to 1.5% of as sprayed density. 28. The method for production of a rotary anode for X-ray tubes as set forth in claim 25, further comprising: further densification of the formed anode by commencing one of hot isostatic pressing, hot forging, and pseudo hot isostatic pressing of the anode. 29. The method for production of a rotary anode for X-ray tubes as set forth in claim 28, wherein: the hot isostatic pressing includes: heat treatment of the formed anode under an increased chamber pressure by introducing an inert gas therein while maintain the heat treatment process. 30. The method for production of a rotary anode for X-ray tubes as set forth in claim 29, wherein: the inert gas is comprised of argon to form a protective environment, with the duration of the hot isostatic pressing lasting from approximately 1 to about 2 hours, under approximate pressure of about 15,000 psi to 28,000 psi, at a temperature of approximately 1500° C. to 1800° C., which results in an anode having a theoretical density of 98% of theoretical and upwards. 31. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, further comprising; grinding the focal track layer using diamond grinding wheel to form an appropriate angle of focal track layer; and application of a super finishing process using diamond belts to achieve finishes of approximately 4 micro-inches and less. 32. The method for production of a rotary anode for X-ray tubes as set forth in claim 31, wherein: the super finish process includes vibratory polishing the grinded-off anode to polish off the grind marks. 33. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: the particle velocity is approximately 200 m/sec or more within the plasma flow prior to impingement onto the base. 34. The method for production of a rotary anode for X-ray tubes as set forth in claim 7, wherein: the pressure within the chamber is modified by pumps. 35. The method for the production of a rotary anode for X-ray tubes as set forth in claim 1, wherein: the base is comprised of an alloy with primary constituent comprised of molybdenum. 36. The method for the production of a rotary anode for X-ray tubes as set forth in claim 35, wherein: the base alloy is comprised of one of Titanium-Zirconium-Molybdenum (TZM) alloy, Oxide dispersion strengthen Molybdenum alloy, Carbide dispersion strengthen Molybdenum alloy, Boride dispersion strengthen Molybdenum, and Niobium-tungsten Molybdenum alloy. 37. The method for the production of a rotary anode for X-ray tubes as set forth in claim 35, wherein: the base alloy is manufactured using one of a powder metallurgical techniques and arc melting, followed by one of forging and rolling.