METHOD AND APPARATUS FOR MANUFACTURING POROUS ARTICLES

• US 20090047439A1
• Filed: 08/11/2008
• Published: 02/19/2009
• Est. Priority Date: 08/16/2007
• Status: Abandoned Application

• Current Assignee: Materials and Electrochemical Research Corporation
• Original Assignee: Materials and Electrochemical Research Corporation
• Inventors: Shapovalov, Vladimir, Withers, James C.
• Application Number:
  US12/189,658
• Publication Number:
  US 20090047439A1
• Time in Patent Office: Days
• US Class Current: 427/448
• CPC Class Codes: B22D 23/003 Moulding by spraying metal on a surface
• CPC Class Codes: B22F 10/22 Direct deposition of molten metal
• CPC Class Codes: B22F 10/25 Direct deposition of metal particles, e.g. direct metal deposition [DMD] or laser engineered net shaping [LENS]
• CPC Class Codes: B22F 10/32 of the atmosphere, e.g. composition or pressure in a building chamber
• CPC Class Codes: B22F 10/36 of energy beam parameters
• CPC Class Codes: B22F 10/368 Temperature or temperature gradient, e.g. temperature of the melt pool
• CPC Class Codes: B22F 10/38 to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures
• CPC Class Codes: B22F 2201/013 Hydrogen
• CPC Class Codes: B22F 2202/01 Use of vibrations
• CPC Class Codes: B22F 2202/05 Use of magnetic field
• CPC Class Codes: B22F 2202/13 Use of plasma
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/003 Apparatus, e.g. furnaces in general F27B
• CPC Class Codes: B22F 3/11 Making porous workpieces or articles
• CPC Class Codes: B22F 3/115 by spraying molten metal, i.e. spray sintering, spray casting
• CPC Class Codes: C23C 24/10 with intermediate formation of a liquid phase in the layer
• CPC Class Codes: C23C 4/134 Plasma spraying
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A method for producing porous materials which comprises directing a plasma stream containing particles of a base material in liquid or solid/liquid form onto a substrate under controlled conditions in which the particles spot weld to the substrate or to one another without full fusion, and establishing relative movement between the plasma stream and the substrate whereby the material is deposited as a porous structure of desired porosity and shape.

Claims

1. A method for producing porous materials which comprises directing a plasma stream containing particles of a base material in liquid or solid/liquid form onto a substrate under controlled conditions in which the particles spot weld to the substrate or to one another without full fusion, and establishing relative movement between the plasma stream and the substrate whereby the material is deposited as a porous structure of desired porosity and shape.

2. The method of claim 1, wherein the base material comprises a metal and the plasma stream is formed in a plasma torch or a laser.

3. The method of claim 1, wherein relative movement between the plasma stream and the substrate is controlled to yield a porous structure having a pre-determined structure and pre-determined porosity.

4. The method of claim 1, including the step of injecting a gas into the plasma to increase porosity of the resulting structure.

5. The method of claim 4, wherein the gas comprises hydrogen.

23. The method claim 1, wherein the base material is a metal selected from the group consisting of W, Cu, Mo, Ni, Al, Fe, Mg, Zr, Co, Be, Cr, Ti, Ta, Mn, Ag, Au, Bi, Cd, Ce, Cs, Hg, In, Ir, La, Li, Nb, Pb, Pd, Pt, Re, Sb, Sc, Se, Si, Sn, Sr, U, V, Y and Zn a metal alloy, a ceramic, and a metal-ceramic composition.

32. The method of claim 1, including the step of subjecting the substrate to a magnetic or electromagnet field to increase porosity or produce a more uniform macro and micro-structure.

41. The method of claim 1, including the step of subjecting the substrate to an ultrasonic field to produce a higher porosity and more uniform solid structure.

50. The method of claim 1, including the step of feeding a gas to the jet device in a pulsating manner.

6. A method for forming a porous article or porous coatings comprising the steps of:

providing a base material in powder form having predetermined particle size;

feeding the base material particles to a high energy jet device such as a plasma torch, heating the base material particles to reach a surface temperature around the melting point, and directing the heated particles onto a target area on a heated substrate under conditions where the particles spot weld to the substrate surface and between themselves without full fusion;

controlling heating speed, plasma torch temperature, and heating time to cause said particles to spot-weld on the substrate with a predetermined structure and predetermined porosity;

cooling the deposited material to cause local liquid spot solidification and form a gas-solid rigid structure in layer form; and

after forming a first porous layer depositing additional layers of particles, while controlling thermal, feeding and scanning parameters to produce a desired article shape, microstructure, physico-mechanical properties and pore-solid ratio.

14. The method of claim 6, wherein amount of porosity in the porous article is controlled by controlling one or more operating parameters selected from the group consisting of controlling energy density inside the jet, controlling jet temperature, controlling substrate temperature, controlling jet or substrate motion parameters, controlling speed, acceleration, oscillation and motion trajectory of the jet or substrate, controlling orientation of gravity acting on the process, controlling relative scanning direction, controlling direction of movement of the high energy jet, controlling amount of gravitational force acting on the process, controlling vibration, and controlling total gas pressure inside the jet.

24. The method of claim 6, wherein the base material is a metal selected from the group consisting of W, Cu, Mo, Ni, Al, Fe, Mg, Zr, Co, Be, Cr, Ti, Ta, Mn, Ag, Au, Bi, Cd, Ce, Cs, Hg, In, Ir, La, Li, Nb, Pb, Pd, Pt, Re, Sb, Sc, Se, Si, Sn, Sr, U, V, Y and Zn a metal alloy, a ceramic, and a metal-ceramic composition.

33. The method of claim 6, including the step of subjecting the substrate to a magnetic or electromagnet field to increase porosity or produce a more uniform micro and micro-structure.

42. The method of claim 6, including the step of subjecting the substrate to an ultrasonic field to produce a higher porosity and more uniform solid structure.

51. The method of claim 6, including the step of feeding a gas to the jet device in a pulsating manner.

7. A method for forming a porous solid article or porous coatings comprising the steps of:

providing a base material in wire form having a predetermined diameter;

feeding the material to a high energy jet device such as a plasma torch and heating the material to cause said material to melt and form molten drops, directing the molten drops onto a target area on a substrate, and depositing the drops on the substrate under conditions where the drops spot weld to the substrate surface and between themselves without full fusion;

controlling heating speed, plasma torch temperature, and heating time to cause said particles and the substrate to produce a structure of predetermined porosity;

cooling the deposited material to cause local liquid drops to solidify and form a gas/solid rigid structure in layer form;

after forming a first porous layer depositing additional layers to form layer-by-layer a three dimensional shaped article; and

controlling thermal, feeding, and scanning parameters to produce a desired article shape, microstructure, physico-mechanical properties and pore/solid ratio.

15. The method of claim 7, wherein amount of porosity in the porous article is controlled by controlling one or more operating parameters selected from the group consisting of controlling energy density inside the jet, controlling jet temperature, controlling substrate temperature, controlling jet or substrate motion parameters, controlling speed, acceleration, oscillation and motion trajectory of the jet or substrate, controlling orientation of gravity acting on the process, controlling relative scanning direction, controlling direction of movement of the high energy jet, controlling amount of gravitational force acting on the process, controlling vibration, and controlling total gas pressure inside the jet.

25. The method of claim 7, wherein the base material is a metal selected from the group consisting of W, Cu, Mo, Ni, Al, Fe, Mg, Zr, Co, Be, Cr, Ti, Ta, Mn, Ag, Au, Bi, Cd, Ce, Cs, Hg, In, Ir, La, Li, Nb, Pb, Pd, Pt, Re, Sb, Sc, Se, Si, Sn, Sr, U, V, Y and Zn a metal alloy, a ceramic, and a metal-ceramic composition.

34. The method of claim 7, including the step of subjecting the substrate to a magnetic or electromagnet field to increase porosity or produce a more uniform macro and micro-structure.

43. The method of claim 7, including the step of subjecting the substrate to an ultrasonic field to produce a higher porosity and more uniform solid structure.

52. The method of claim 7, including the step of feeding a gas to the jet device in a pulsating manner.

8. A method for forming a porous solid article or porous coatings comprising the steps of:

feeding a base material in wire or powder form having predetermined size to a high energy scanning jet device such as a scanning plasma torch and heating the material to molten state;

exposing the molten material to an active gas in the plasma torch and dissolving the gas in the molten material;

depositing the gas containing base material on a substrate to form a liquid pool;

controlling heating speed, plasma torch temperature, and heating time to cause the liquid pool to reach predetermined active gas concentration and predetermined temperature;

cooling the local liquid pool causing said melt to solidify;

controlling gas pressure, cooling speed and cooling direction during said cooling step to cause the gas to precipitate within the solidifying base material thereby forming pores in the base material and thereby forming a gas/solid structure in layer form having predetermined porosity; and

after forming a first porous layer repeating scanning of the scanning jet while controlling oscillation parameters, linear motions parameters;

powder or wire feeding parameters to form layer-by-layer a three dimensional shaped article.

16. The method of claim 8, wherein amount of porosity in the porous article is controlled by controlling one or more operating parameters selected from the group consisting of controlling energy density inside the jet, controlling jet temperature, controlling substrate temperature, controlling jet or substrate motion parameters, controlling speed, acceleration, oscillation and motion trajectory of the jet or substrate, controlling orientation of gravity acting on the process, controlling relative scanning direction, controlling direction of movement of the high energy jet, controlling amount of gravitational force acting on the process, controlling vibration, and controlling total gas pressure inside the jet.

26. The method of claim 8, wherein the base material is a metal selected from the group consisting of W, Cu, Mo, Ni, Al, Fe, Mg, Zr, Co, Be, Cr, Ti, Ta, Mn, Ag, Au, Bi, Cd, Ce, Cs, Hg, In, Ir, La, Li, Nb, Pb, Pd, Pt, Re, Sb, Sc, Se, Si, Sn, Sr, U, V, Y and Zn a metal alloy, a ceramic, and a metal-ceramic composition.

35. The method of claim 8, including the step of subjecting the substrate to a magnetic or electromagnet field to increase porosity or produce a more uniform macro and micro-structure.

44. The method of claim 8, including the step of subjecting the substrate to an ultrasonic field to produce a higher porosity and more uniform solid structure.

53. The method of claim 8, including the step of feeding a gas to the jet device in a pulsating manner.

9. A method for forming a porous solid article or porous coatings comprising the steps of:

feeding a base material in wire or particle form to a high energy oscillating jet device such as a plasma torch together with an active gas generating solid substance of a predetermined mass ratio and heating the base material and solid substance to cause the material to melt and to cause the substrate to generate the active gas, whereupon the melted base material absorbs the active gas;

depositing the melted base material with absorbed gas on the substrate to cause the base material to form a local liquid pool;

controlling heating speed, plasma torch temperature and heating time to cause the liquid pool to reach predetermined active gas concentration and predetermined temperature;

cooling the local liquid pool causing the melt to solidify;

controlling total gas pressure, cooling speed and cooling direction during the cooling step to cause the gas to precipitate within the solidifying base material thereby forming pores in the base material and thereby form a gas/solid structure in layer form having predetermined porosity; and

after forming a first porous layer repeating to form layer-by-layer a three dimensional shaped article;

while controlling the oscillation parameters, linear motions parameters and/or powder or wire feeding parameters.

17. The method of claim 9, wherein the amount of amount of porosity in the porous article is controlled by controlling one or more operating parameters selected from the group consisting of controlling energy density inside the jet, controlling jet temperature, controlling substrate temperature, controlling jet or substrate motion parameters, controlling speed, acceleration, oscillation and motion trajectory of the jet or substrate, controlling orientation of gravity acting on the process, controlling relative scanning direction, controlling direction of movement of the high energy jet, controlling amount of gravitational force acting on the process, controlling vibration, and controlling total gas pressure inside the jet.

27. The method of claim 9, wherein the base material is a metal selected from the group consisting of W, Cu, Mo, Ni, Al, Fe, Mg, Zr, Co, Be, Cr, Ti, Ta, Mn, Ag, Au, Bi, Cd, Cc, Cs, Hg, In, Ir, La, Li, Nb, Pb, Pd, Pt, Re, Sb, Sc, Se, Si, Sn, Sr, U, V, Y and Zn a metal alloy, a ceramic, and a metal-ceramic composition.

36. The method of claim 9, including the step of subjecting the substrate to a magnetic or electromagnet field to increase porosity or produce a more uniform macro and micro-structure.

45. The method of claim 9, including the step of subjecting the substrate to an ultrasonic field to produce a higher porosity and more uniform solid structure.

54. The method of claim 9, including the step of feeding a gas to the jet device in a pulsating manner.

10. A method for forming a porous solid article or porous coatings comprising the steps of:

depositing a layer of a base material in wire or particle form and a hydrogen gas generating material such as a metal hydride, e.g. of Ti, Cr, V, La, Li, Ta, Nb, Pd, U or Y, in particle form, on a substrate;

directing a high energy jet such as a plasma torch onto the substrate to heat the base material and the hydrogen generating material on the substrate to cause the base material to form a local liquid pool, and cause the hydrogen generating material to decompose to release hydrogen gas and form a liquid/gas foam, controlling heating speed, energy jet temperature, and heating time to cause the liquid pool to reach predetermined hydrogen content and predetermined temperature, cooling the local liquid pool causing said foam to solidify;

controlling gas pressure, cooling speed and cooling direction during the cause the foam to form a gas/solid structure in layer form having a predetermined porosity;

after forming a first porous layer forming additional layers of base material and hydrogen gas generating material and heating the additional layer as before to form layer-by-layer a three dimensional shaped article, while controlling the oscillation parameters, linear motion parameters and/or powder or wire feeding parameters.

18. The method of claim 10, wherein the amount of amount of porosity in the porous article is controlled by controlling one or more operating parameters selected from the group consisting of controlling energy density inside the jet, controlling jet temperature, controlling substrate temperature, controlling jet or substrate motion parameters, controlling speed, acceleration, oscillation and motion trajectory of the jet or substrate, controlling orientation of gravity acting on the process, controlling relative scanning direction, controlling direction of movement of the high energy jet, controlling amount of gravitational force acting on the process, controlling vibration, and controlling total gas pressure inside the jet.

28. The method of claim 10, wherein the base material is a metal selected from the group consisting of W, Cu, Mo, Ni, Al, Fe, Mg, Zr, Co, Be, Cr, Ti, Ta, Mn, Ag, Au, Bi, Cd, Ce, Cs, Hg, In, Ir, La, Li, Nb, Pb, Pd, Pt, Re, Sb, Sc, Se, Si, Sn, Sr, U, V, Y and Zn a metal alloy, a ceramic, and a metal-ceramic composition.

37. The method of claim 10, including the step of subjecting the substrate to a magnetic or electromagnet field to increase porosity or produce a more uniform macro and micro-structure.

46. The method of claim 10, including the step of subjecting the substrate to an ultrasonic field to produce a higher porosity and more uniform solid structure.

55. The method of claim 10, including the step of feeding a gas to the jet device in a pulsating manner.

11. A method for forming a porous coating comprising the steps of:

feeding a base material in form of solid to a high energy jet device such as a plasma torch and heating the material to molten state;

feeding an active gas, preferably hydrogen, to the high energy jet device where it is absorbed in the molten base material;

controlling heating speed, jet temperature, and heating time to cause said molten material to achieve a predetermined active gas concentration and predetermined temperature;

scan depositing the molten material onto a target substrate, while controlling gas pressure, cooling speed and cooling direction to cause the gas to precipitate within solidifying base material and form pores in the base material and thereby form a gas/solid structure in layer form having predetermined porosity; and

controlling scanning to build up the material on the substrate.

19. The method of claim 11, wherein the amount of amount of porosity in the porous article is controlled by controlling one or more operating parameters selected from the group consisting of controlling energy density inside the jet, controlling jet temperature, controlling substrate temperature, controlling jet or substrate motion parameters, controlling speed, acceleration, oscillation and motion trajectory of the jet or substrate, controlling orientation of gravity acting on the process, controlling relative scanning direction, controlling direction of movement of the high energy jet, controlling amount of gravitational force acting on the process, controlling vibration, and controlling total gas pressure inside the jet.

22. The method of claim 11, wherein the active gas is selected from the group of consisting of argon, nitrogen, hydrogen, helium, air, oxygen, carbon monoxide, carbonic gas, water and water steam, a gaseous hydrocarbon/steam, ammonia/steam, methane, and a combination thereof.

29. The method of claim 11, wherein the base material is a metal selected from the group consisting of W, Cu, Mo, Ni, Al, Fe, Mg, Zr, Co, Be, Cr, Ti, Ta, Mn, Ag, Au, Bi, Cd, Ce, Cs, Hg, In, Ir, La, Li, Nb, Pb, Pd, Pt, Re, Sb, Sc, Se, Si, Sn, Sr, U, V, Y and Zn a metal alloy, a ceramic, and a metal-ceramic composition.

38. The method of claim 11, including the step of subjecting the substrate to a magnetic or electromagnet field to increase porosity or produce a more uniform macro and micro-structure.

47. The method of claim 11, including the step of subjecting the substrate to an ultrasonic field to produce a higher porosity and more uniform solid structure.

56. The method of claim 11, including the step of feeding a gas to the jet device in a pulsating manner.

12. A method for forming a solid skin on porous articles comprising the steps of:

providing an initial porous solid base or solid substrate;

locally heating selected areas of the porous substrate using a high energy jet device such as a plasma torch, to raise the temperature of the porous substrate surface to a temperature higher than its melting point whereby to form a local liquid pool;

controlling heating speed, jet temperature, and heating time to cause the liquid pool to reach predetermined temperature and size; and

controlling scanning of the jet and cooling speed and cooling direction of the local liquid pool to form a solid skin on the porous substrate.

20. The method of claim 12, wherein the amount of amount of porosity in the porous article is controlled by controlling one or more operating parameters selected from the group consisting of controlling energy density inside the jet, controlling jet temperature, controlling substrate temperature, controlling jet or substrate motion parameters, controlling speed, acceleration, oscillation and motion trajectory of the jet or substrate, controlling orientation of gravity acting on the process, controlling relative scanning direction, controlling direction of movement of the high energy jet, controlling amount of gravitational force acting on the process, controlling vibration, and controlling total gas pressure inside the jet.

30. The method of claim 12, wherein the base material is a metal selected from the group consisting of W, Cu, Mo, Ni, Al, Fe, Mg, Zr, Co, Be, Cr, Ti, Ta, Mn, Ag, Au, Bi, Cd, Ce, Cs, Hg, In, Ir, La, Li, Nb, Pb, Pd, Pt, Re, Sb, Sc, Se, Si, Sn, Sr, U, V, Y and Zn a metal alloy, a ceramic, and a metal-ceramic composition.

39. The method of claim 12, including the step of subjecting the substrate to a magnetic or electromagnet field to increase porosity or produce a more uniform macro and micro-structure.

48. The method of claim 12, including the step of subjecting the substrate to an ultrasonic field to produce a higher porosity and more uniform solid structure.

57. The method of claim 12, including the step of feeding a gas to the jet device in a pulsating manner.

13. A method for forming a solid skin on a porous article comprising the steps of:

providing an initial porous solid base or porous substrate;

feeding a skin forming material in powder or wire form having predetermined size and having a same or different chemical composition as the porous solid base or substrate, to a high energy jet device such as a plasma torch;

heating the skin forming material in the jet to melting and directing the melted skin forming material onto the substrate to raise the surface temperature of the porous substrate to a temperature higher than its melting point and to form local liquid pool;

controlling heating speed, jet temperature, and heating time to cause the liquid pool to reach a predetermined temperature and size; and

, cooling the local liquid pool under controlled cooling speed and cooling direction, to form a solid skin on said porous substrate.

21. The method of claim 13, wherein the amount of amount of porosity in the porous article is controlled by controlling one or more operating parameters selected from the group consisting of controlling energy density inside the jet, controlling jet temperature, controlling substrate temperature, controlling jet or substrate motion parameters, controlling speed, acceleration, oscillation and motion trajectory of the jet or substrate, controlling orientation of gravity acting on the process, controlling relative scanning direction, controlling direction of movement of the high energy jet, controlling amount of gravitational force acting on the process, controlling vibration, and controlling total gas pressure inside the jet.

31. The method of claim 13, wherein the base material is a metal selected from the group consisting of W, Cu, Mo, Ni, Al, Fe, Mg, Zr, Co, Be, Cr, Ti, Ta, Mn, Ag, Au, Bi, Cd, Ce, Cs, Hg, In, Ir, La, Li, Nb, Pb, Pd, Pt, Re, Sb, Sc, Se, Si, Sn, Sr, U, V, Y and Zn a metal alloy, a ceramic, and a metal-ceramic composition.

40. The method of claim 13, including the step of subjecting the substrate to a magnetic or electromagnet field to increase porosity or produce a more uniform macro and micro-structure.

49. The method of claim 13, including the step of subjecting the substrate to an ultrasonic field to produce a higher porosity and more uniform solid structure.

58. The method of claim 13, including the step of feeding a gas to the jet device in a pulsating manner.

59. An apparatus for producing a porous metal, comprising

a high energy, high-density jet;

a feed for feeding a base material in powder or wire form to the jet;

a substrate onto which the base material is deposited;

a controller for controlling movement of the jet and/or the substrate in three dimensions;

a controller for controlling heating of the jet and for controlling deposition of material on the substrate; and

a controller for controlling cooling of substrate.

60. The apparatus of claim 59, further including a feed for active and/or inert gases to the jet.

61. The apparatus according to claim 59, further including magnetic and electromagnetic fields around the jet.

62. The apparatus according to claim 59, further including an ultrasonic generator.

63. The apparatus according to claim 59, further including a computer for controlling operating parameters.

64. The apparatus according to claim 59, wherein the jet comprises a plasma torch, a laser, a concentrated solar light or an electric arc device.