Method for joining diamonds

Abstract

A method of joining diamonds together is disclosed. The method includes placing two or more diamond pieces together, each diamond piece having at least one mating surface. The two or more diamonds are placed such that the mating surface of one diamond piece is in contact with the mating surface of at least one other diamond piece. The two or more diamonds are joined together by welding along their mating surfaces by a laser source selected from a group consisting of a femtosecond laser, a picosecond laser, or a combination thereof. A diamond material comprising two or more diamond pieces joined together by said method is also disclosed.

Description

METHOD FOR JOINING DIAMONDSTechnical Field

[0001] The present disclosure relates to manufacturing larger diamonds by a welding process. More particularly, the present disclosure relates to a method of manufacturing a diamond material by joining two or more diamonds together by a welding process.Background

[0002] While diamonds are highly valued for their exceptional properties, such as toughness, chemical inertness, etc., there is generally a limit on the size of naturally occurring diamonds. There is also a limit on the size of the diamonds that can be artificially produced using various techniques. However, various applications require diamonds of a larger size to unlock their full potential. For example, advanced scientific research equipment and applications such as electrodes, etc., benefit from larger diamonds.Summary of the Invention

[0003] In an aspect, the present disclosure relates to a method of joining diamonds together. The method includes placing two or more diamond pieces together, each diamond piece having at least one mating surface. The two or more diamonds are placed such that the mating surface of one diamond piece is in contact with the mating surface of at least one other diamond piece. The two or more diamonds are joined together by welding along their mating surfaces. The welding is done by a laser source selected from a group consisting of a femtosecond laser and a picosecond laser.

[0004] In another aspect, the present disclosure also relates to a diamond material comprising two or more diamond pieces joined together by said method.Brief Description of Drawings

[0005] FIG. 1 is a perspective view of a diamond piece, in accordance with an embodiment of the present disclosure;

[0006] FIG. 2 is a diamond material formed by joining multiple diamond pieces of FIG. 1, in accordance with an embodiment of the present disclosure;

[0007] FIG. 3 is a perspective view of a diamond piece, in accordance with another embodiment of the present disclosure;

[0008] FIG 4 is a diamond material formed by joining multiple diamond pieces of FIG. 3, in accordance with another embodiment of the present disclosure;

[0009] FIGS. 5A-5C are exemplary illustrations of a diamond piece, in accordance with various embodiments of the present disclosure;

[0010] FIGS 6A-6B are side views of a diamond material, in accordance with various embodiments of the present disclosure; and

[0011] FIGS. 7A-7C are exemplary illustrations of a diamond piece, in accordance with various embodiments of the present disclosure.Detailed Description

[0012] Reference will now be made in detail to embodiments of the present disclosure. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilised in conjunction with a detailed description of certain specific embodiments of the invention. Furthermore, embodiments of the invention may include several features, no single one of which is solely responsible for its desirable attributes or which is essential to practising the inventions herein described.

[0013] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the invention and are not intended to be restrictive thereof.

[0014] The terms “a”, “an”, and “the” are used to refer to “one or more” (i.e., to at least one) of the grammatical object of the article.

[0015] Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristicdescribed in connection with the embodiment is included in at least one embodiment of the present invention.

[0016] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion and are not intended to be construed as “consists of only”, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method.

[0017] Likewise, the terms “having” and “including” and their grammatical variants are intended to be non-limiting, such that recitations of said items in a list are not to the exclusion of other items that can be substituted or added to the listed items.

[0018] Also, any numerical range recited herein is intended to include all subranges subsumed therein. For example, a range of "1 to 10" is intended to include any and all subranges between and including the recited minimum value of 1 and the recited maximum value of 10, that is, all subranges beginning with a minimum value equal to or greater than 1 and ending with a maximum value equal to or less than 10, and all subranges in between.

[0019] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0020] Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods and materials are now described. A method of joining diamonds together is disclosed. In its broadest scope, the method includes welding two or more diamond pieces together by an ultrashort-pulse laser, wherein the resulting welded interface exhibits a reduced heat-affected zone and substantially uniform mechanical and / or thermal properties.

[0021] The two or more diamond pieces that can be joined together can have varied sizes and shapes. Each of the two or more diamond pieces has at least one mating surface which allows it to be welded to at least one mating surface of another diamond piece. The at least one mating surface of each engineered diamond piecemay be integrally formed thereon and is of the same material as the engineered diamond piece. Referring to FIGS. 1 and 2 in an exemplary embodiment, each of the two or more diamond pieces 100 has a rectangular cuboidal shape having a total of six side surfaces - for example, six planar side surfaces, as shown - and may correspondingly resemble tiles. Referring again to FIG. 1, each of the two or more diamond pieces 100 defines a first side 102 and a second side 104. Each of the one or more diamond pieces 100 also defines a series of lateral faces 106, e.g., a first lateral face 106a, a second lateral face 106b, a third lateral face 106c, and a fourth lateral face 106d, each extending from the first side 102 to the second side 104. The first side 102 may be disposed oppositely to the second side 104. Further, the first lateral face 106a may be located oppositely to the second lateral face 106b, and the third lateral face 106c may be located oppositely to the fourth lateral face 106d. One or more of the lateral faces 106a, 106b, 106c, 106d defines the mating surface of the diamond piece 100. For example, referring to FIG. 2, three diamond pieces, 100, 200 and 300, are joined together to form a diamond material, 500. In such an embodiment, in the diamond piece 200 that is in the middle, the third lateral surface 206c and the fourth lateral surface 206d that lie opposite to each other are the mating surfaces of said diamond piece 200, while in the diamond piece 100, the fourth lateral surface 106d is the mating surface of said diamond piece, and in the diamond piece 300, the third lateral surface 106c is the mating surface of said diamond piece 300, which are welded together to form a diamond material 500. Each of the two or more diamond pieces 100, 200, 300 may have the same dimensions, as is suggested in the illustration provided in FIG. 2. However, in some other embodiments, each of the two or more diamond pieces 100, 200, 300 may have a different dimension.

[0022] In some embodiments, each of the two or more diamond pieces 100 includes at least one alignment feature enabling a precise fit and facilitating laser welding. In an exemplary embodiment, the alignment feature includes at least one protrusion 110 and at least one complementary recess 108. FIG. 3 illustrates the diamond piece 100’, wherein the lateral surface 106d (of the diamond piece 100’) includes the protrusion 110 and the lateral surface 106b (of the diamond piece 100’) includes the recess 108. FIG. 4 illustrates the diamond material 500’ having fourdiamond pieces 100’, 200’, 300’, and 400’ aligned and joined together. As illustrated in FIG. 4, the protrusion 110 of the diamond piece 100’ fits into a complementary recess 208 of the diamond piece 200’. Similarly, a protrusion 210 of the diamond piece 200’ fits into a complementary recess 308 of the diamond piece 300’; a protrusion 310 of the diamond piece 300’ fits into a complementary recess 408 of the diamond piece 400’, and a protrusion 410 of the diamond piece 400’ fits into the complementary recess 108 of the diamond piece 100. In some embodiments, such alignment features increase surface contact area and minimise stress concentrations.

[0023] In some embodiments, the mating surface of each of the two or more diamond pieces 100 is provided with at least one chamfered surface. In an example, as shown in FIG. 5A, each of the mating surfaces 106a- 106d of the diamond piece 100 is provided with a chamfered surface. In other embodiments, the diamond piece 100 may have mating surfaces 106a- 106d that are a combination of chamfered, flat or fillet or any other suitable shape. FIG. 5B and 5C illustrate the diamond piece 100 with a combination of flat and chamfered mating surfaces 106a- 106d. In an exemplary joining of the diamond pieces 100” and 200”, first and second chamfered surfaces 112, 114, formed at the mating surface 106d, of the diamond piece 100” may be aligned and abutted against first and second chamfered surfaces 212, 214, formed at the mating surface 206c, of the diamond piece 200”, as shown in FIG. 6A.

[0024] In some other embodiments, the mating surface of each of the two or more diamond pieces 100, 200 is provided with at least one fillet surface. In an exemplary joining of the diamond pieces 100’ ’ ’ and 200’ ’ ’ , first and second fillet surfaces 116, 118, formed at the mating surface 106d, of the diamond piece 100’ ’ ’ may be aligned and abutted against first and second fillet surfaces 216, 218, formed at the mating surface 206c, of the diamond piece 200’”, as shown in FIG. 6B.

[0025] In some other embodiments, depending on the shape and size of the diamond material 500, or 500’ to be formed, the diamond pieces 100 may be formed to have different radius of curvature (e.g., Rl, or R2, or R3). In an example, as shown in FIG. 7A, the diamond piece 100 may have a large radius of curvature Rl.In another example, as shown in FIG. 7B, the diamond piece 100 may have a radius of curvature R2 different (e.g., relatively smaller) than the radius of curvature Rl. In yet another example, as shown in FIG. 7C, the diamond piece 100 may have a radius of curvature R3 different (e.g., relatively smaller) than the radius of curvatures Rl and R2.

[0026] The diamond piece may be a natural diamond, or an artificial diamond manufactured using any known method. The artificial diamonds may be undoped or doped. In some embodiments, the diamond pieces are doped with nitrogen, boron, phosphorus or a combination thereof. In some embodiments, the diamond piece has gradient doping. In some embodiments, the gradient doping is such that the doping is greater at the mating surface of the diamond piece 100 than at the centre of the diamond piece. In some embodiments, diamond piece having a higher doping at the mating surface, allows optimisation of the electrical or thermal conduction across a weld seam. In some embodiments, at least one of the two or more diamond pieces has a doping profile that is different than the doping profile of the other diamond pieces.

[0027] In some embodiments, at least one of the two or more diamond pieces has at least one textured surface. Such a textured surface includes a nanotextured surface, a microtextured surface or a combination thereof. The textured surface is provided on at least one surface other than the mating surface of the diamond piece. The microtextured or nanotextured surface may be provided for specific functions, for example, for enhancing bonding strength, electrode reactivity, etc.

[0028] In some embodiments, each of the two or more diamond pieces may have a different textured surface. In some other embodiments, one of the diamond pieces of the two or more diamond pieces may have a textured surface, while one or more of the other diamond pieces may be doped. Texturing of the diamond pieces includes forming wave form structures (sin waves), zig zag or serrated structures, patterned structures, mortise and tenon structures, keys and key slots, notches, spacers, guide rails and ridges and combinations thereof. In an embodiment, the texturing may be done at the mating surface of the diamond pieces. Thus, themethod allows joining of diamond pieces with various properties together, which is not possible otherwise.

[0029] In the first step of the method, two or more diamond pieces 100 are placed together such that the mating surface 106 of one diamond piece is in contact with the mating surface of at least one other diamond piece 100. Once placed together, the two or more diamond pieces 100 are joined together by welding along their mating surfaces.

[0030] In accordance with an embodiment, the welding is done by a femtosecond laser. The femtosecond laser has at least one pulse width in the range from 50 femtoseconds to 500 femtoseconds depending on the thickness of the two or more diamond pieces that are to be joined. Preferably, the femtosecond laser has at least one pulse width in the range from 80 femtoseconds to 200 femtoseconds. In accordance with an aspect, the femtosecond laser has a pulse repetition rate from50 kHz to a few MHz. Preferably, the femtosecond laser has a pulse repetition rate from 50 kHz to 2 MHz, and more preferably, the femtosecond laser has a pulse repetition rate from 50 kHz to 1 MHz. The pulse repetition rate of the femtosecond laser is selected such that it maintains sufficient average power while preventing excessive heat accumulation. In accordance with an aspect, the average power of the femtosecond laser that is used is of the order of a few watts (W) to tens of watts, depending on the thickness of the two or more diamond pieces that to be joined and desired weld depth. In some embodiments, the average power of the femtosecond laser is in the range from 0.5 W to 50 W. Preferably, the average power of the femtosecond laser is in the range from 1 W to 20 W.

[0031] In an alternate embodiment, the welding is done by a picosecond laser. In an aspect, the picosecond laser has at least one pulse width in the range from 1 picosecond to 100 picoseconds. Preferably, the picosecond laser has at least one pulse width in the range from 2 picoseconds to 50 picoseconds. In an aspect, the picosecond laser has a pulse repetition rate of at least 50 kHz, depending on required processing speed and thermal management. Preferably, the pulse repetition rate is in a range from 50 kHz to 1 MHz. More preferably, the pulse repetition rate is in a range from 100 kHz to 500 kHz. The energy per pulse is in a range from microjoules(pj) to millijoules (mJ), ensuring localised melting / fusion without over-penetration. Preferably, the energy per pulse is in a range from 5 p J to 2 mJ and more preferably in a range from 20 p J to 1 mJ.

[0032] In some embodiments, precise control of power and pulse energy is done to avoid crack formation or thermal damage. Short pulse durations (fs-ps range) reduce heat-affected zones and enable high-quality weld seams.

[0033] In accordance with an aspect, the welding is carried out with a tightly focused beam having a spot size in the range from a few micrometres to tens of micrometres to ensure high-intensity interaction at an interface of the mating surfaces 106, enabling localised melting and fusion of the diamond pieces 100. In an aspect, the spot size is in a range from 1 pm to 100 pm. Preferably, the spot size is in a range from 5 pm to 30 pm.

[0034] The short pulse duration inherently minimises thermal diffusion, reducing graphitisation or microcracking. The pulse energy is carefully tuned so that local melting / fusion occurs at the interface of the mating surfaces 106 without overpenetration or damaging the diamond pieces 100.

[0035] In some embodiments, the welding is carried out with overlapping passes to ensure full coverage and minimise porosity. In some embodiments, the welding is carried out with an overlap of 50 % to 90%. In some other embodiments, the welding of the mating surfaces comprises passing the laser at least two times over the mating surfaces of the diamond pieces. In some embodiments, passing the laser two or more times over the mating surfaces of the diamond pieces ensures consistent bonding and allows for filling of any minor voids or cracks. In some additional embodiments, the process further comprises forming at least one additional diamond layer over the welded together mating surfaces of the diamond pieces.

[0036] In some embodiments, the process further comprises smoothening the mating surface of the diamond pieces prior to welding to reduce surface roughness and improve contact. The smoothening is done by processes such as polishing, chemical-mechanical planarisation, laser ablation or reactive plasma etching. The smoothening of the mating surface may be done by polishing (e.g., mechanicallapping with diamond-based slurries) or chemical-mechanical planarisation (CMP). Other suitable techniques may include laser ablation (using ultrafast lasers to selectively remove micro-roughness) or reactive plasma etching (to isotropically remove surface irregularities). In some embodiments, the smoothening of the mating surface before welding allows for precision alignment of the diamond pieces.

[0037] In an aspect, the diamond pieces are precisely aligned so that their mating surfaces contact each other with minimal gaps. In some embodiments, tools such as optical alignment or micrometre-stage fixtures may be used to precisely align the diamond pieces.

[0038] In an aspect, the welding is carried out in a controlled atmosphere. The controller atmosphere under which the welding is carried out includes but is not limited to a vacuum or inert gas atmosphere, including a nitrogen atmosphere, to minimise oxidation or contamination at high temperatures. Certain embodiments require slight overpressure of inert gas to help expel debris or molten material.

[0039] In some embodiments, the process further comprises depositing an intermediate carbide-forming layer on the mating surface of the diamond pieces prior to welding. The carbide-forming layer is deposited in extremely thin films of less than 500 nanometres prior to laser welding. The carbide-forming layer includes carbide-forming metals, including but not limited to titanium (Ti), tungsten (W) and chromium (Cr).

[0040] In accordance with an aspect, the welding is carried out under real-time sensors (e.g., pyrometers, optical sensors) for detection of weld pool formation and temperature to dynamically adjust laser parameters. Closed-loop feedback helps avoid defects such as cracks, voids or insufficient weld penetration.

[0041] In some embodiments, stress or thermal sensors are provided near the interface of the mating surface 106a, 106b, 106c, 106d to monitor weld integrity over time. Data from these sensors can feed into a predictive maintenance algorithm, alerting users if cracks or thermal hotspots develop.

[0042] In some embodiments, at least one sensor is provided within or adjacent to the mating surface of the at least one diamond piece prior to welding. In someexemplary embodiments, the sensor includes a solid-state sensor chip, such as a diamond-based microelectromechanical system (MEMS).

[0043] In some embodiments, the two or more diamond pieces that include a boron or nitrogen-doped region near the mating surface are joined such that at least one sensor is formed at or adjacent to the mating surface of the at least one diamond piece. In such embodiments, variation in thermal conductivity or photoluminescence can indicate stress or temperature changes.

[0044] In some embodiments, the at least one sensor at or adjacent to the mating surface of the at least one diamond piece is formed by ultrafast laser writing of optical waveguides. In such embodiments, the optical waveguides allow routing a monitoring laser beam. The optical signals, for example, Raman or Brillouin scattering, detect microcracks or thermal gradients.

[0045] In some embodiments, the sensors may be located within 50 to 200 micrometres of the mating surface of the at least one diamond piece.

[0046] A diamond material comprising two or more diamond pieces joined together is also disclosed. In some embodiments, the diamond material is such that at least one of the diamond pieces that forms the diamond material has at least one surface that is textured. The surface of at least one of the diamond pieces includes a microtexture, nanotexture or a combination thereof. In some embodiments, each of the two or more diamond pieces may have a different textured surface. In some embodiments, the diamond material is such that at least one of the diamond pieces 100 is doped. In some embodiments the diamond pieces may be doped with any known dopant, including but not limited to boron, nitrogen, phosphorus or a combination thereof. In some embodiments, the diamond pieces may have gradient doping. In some embodiments, the gradient doping is such that the doping is greater at the mating surface, allowing for optimisation of the electrical or thermal conduction across the weld seam. In yet another embodiment, at least one of the two or more diamond pieces may have a different doping profile than the other diamond pieces that form the diamond material. In some embodiments, one diamond piece of the two or more diamond pieces may have a textured surface, while another diamond piece of the two or more diamond pieces may be doped.

[0047] In some embodiments, the diamond material has a thermal conductivity of at least 90% of the thermal conductivity of each of the two or more diamond pieces. In yet other embodiments, the diamond material has a thermal conductivity of at least 95% of the thermal conductivity of each of the two or more diamond pieces.

[0048] In some embodiments, the diamond material has a tensile or flexural strength of at least 80% of the tensile or flexural strength of the two or more diamond pieces. In yet other embodiments, the diamond material has a tensile or flexural strength of at least 90% of the tensile or flexural strength of the two or more diamond pieces.

[0049] In some embodiments, one or more sensors are provided at or near the mating surface of at least one of the two or more diamond pieces, enabling realtime stress or temperature monitoring and predictive maintenance of the weld seam. The sensor includes a solid-state sensor chip, such as a diamond-based microelectromechanical system (MEMS). In some embodiments, at least one sensor is defined by one or more doped regions at or adjacent to the mating surface of the diamond piece. In some embodiments, the sensor is defined by laser-written optical waveguides.Industrial Applicability

[0050] The size of diamonds often restricts their use in various applications. While scaling diamond size is challenging, joining smaller diamond pieces (tiles) to create a larger diamond material provides an alternative route to achieve the desired dimensions. The key challenge is to realise robust, crack-free, and high- conductivity joints that preserve the diamond’s mechanical, thermal, and electrical properties across interfaces. Such diamond material is valuable in high-power electronics cooling, optical windows, electrochemical electrodes, and advanced research tools.

[0051] The disclosed method enables the creation of diamond material that surpasses the size of individual diamonds. In particular, the method enables the formation of multi-centimetre or larger diamond assemblies beyond single-crystalgrowth limits. For example, the two or more diamond pieces, similar to the diamond pieces 100, 100’, 100”, 100’”, may be welded together to form a shape selected from a group comprising of spherical, semi-spherical, cuboidal, cubical, planar, prismatic, pyramidal, cylindrical, frustoconical, conical, ellipsoidal, toroidal, and frustopyramidal. Although the diamond material of various exemplary shapes, as mentioned above, may be formed by joining (e.g., welding) the set of diamond pieces together, it should be noted that the shape of the diamond material should not be limited to these exemplary shapes only. Further, the types and choice of mating surfaces of the engineered diamond pieces allow the engineered diamond pieces to be manufactured in standard shapes and sizes and to be used as modular building blocks to form size and shapes of the diamond materials or the diamond components as desired.

[0052] Moreover, the method as disclosed allows for the formation of diamond material (larger diamond) with distinct sections, a feat not achievable with manufactured diamonds. For example, different sections of the diamond material obtained from the method disclosed can have distinct properties — for instance, a heavily boron-doped section for electrochemical activity and a lightly doped section for optical clarity, or a section having a nanotextured surface and the other a microtextured surface. Thus, the method allows for various permutations and combinations in a simple and efficient manner and allows for the formation of a composite structure suitable for combined electrochemical and optical applications. Moreover, robust, near-seamless interfaces obtained using the disclosed method expand the operational envelope of the diamond material that is obtained, allowing higher power loads, longer lifespans, and improved uniformity across the assembled component.

[0053] The diamond material so obtained may exhibit tensile strength or fracture toughness of at least 80% of the tensile strength or fracture toughness of the two or more diamond pieces. Although diamond exhibits extremely high strength, any interface can introduce local stress concentrations. The laser-welding method that includes welding with multiple passes, smoothing and overlappingscans can significantly reduce microcracks, enabling the diamond so made to approach such tensile strength or fracture toughness.

[0054] Moreover, the diamond material so obtained may exhibit a thermal conductivity of at least 90% of the thermal conductivity of the two or more diamond pieces. In some cases, with highly optimised doping gradients, minimal seal voids and perfect alignment, the diamond material may exhibit a thermal conductivity of at least 95% of the thermal conductivity of the two or more diamond pieces.

[0055] It will be apparent to those skilled in the art that various modifications and variations can be made to the method and / or system of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the method and / or system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalent.List of Elements diamond piece first side second side lateral face a first lateral face b second lateral face c third lateral face d fourth lateral face at least one complementary recess at least one protrusion first chamfered surface second chamfered surface first fillet surface second fillet surface diamond piece c third lateral surface d fourth lateral surface complementary recess protrusion first chamfered surface second chamfered surface first fillet surface second fillet surface diamond piece complementary recess protrusion diamond piece complementary recess protrusion500 diamond material

Claims

We Claim:

1. A method of joining diamonds together, the method comprising: placing two or more diamond pieces together, each diamond piece having at least one mating surface, the two or more diamond pieces placed such that the mating surface of one diamond piece is in contact with the mating surface of at least one other diamond piece; and joining the two or more diamond pieces by welding along their mating surfaces, wherein the welding is done by a laser source selected from a group consisting of a femtosecond laser and a picosecond laser, or a combination thereof.

2. The method of claim 1, wherein the femtosecond laser has at least one pulse width in the range from 50 femtoseconds to 500 femtoseconds.

3. The method of claim 1, wherein the femtosecond laser has a pulse repetition rate in the range from 50 kHz to 2 MHz.

4. The method of claim 1, wherein the femtosecond laser has an average power in the range from 0.5W to 50W.

5. The method of claim 1, wherein the picosecond laser has at least one pulse width in the range from 1 picosecond to 100 picoseconds.

6. The method of claim 1, wherein the picosecond laser has a pulse repetition rate in the range from 50 kHz to 1 MHz.

7. The method of claim 1, wherein the picosecond laser has an energy per pulse in the range from 5 microjoules (p J) to 2 millijoules (mJ).

8. The method of claim 1, wherein the laser has a spot size in a range from 1 micrometre to 100 micrometres.

9. The method of claim 1, wherein at least one diamond piece has at least one mating surface that includes a protrusion, and at least one other diamond piece has at least one mating surface that includes a complementary recess, such that when the mating surfaces are placed in contact, the protrusion of one diamond piece fits into the complementary recess of the other diamond piece to align the diamond pieces together.

10. The method of claim 1, wherein one or more mating surfaces of at least one diamond piece has at least one chamfer surface or at least one fillet surface.

11. The method of claim 1, wherein at least one diamond piece is doped.

12. The method of claim 1, wherein at least one diamond piece has at least one textured surface.

13. The method of claim 1, further comprising smoothening the mating surface of the diamond pieces by a process selected from a group consisting of polishing, chemical-mechanical planarisation, laser ablation and reactive plasma etching.

14. The method of claim 1, further comprising depositing an intermediate carbide-forming layer on the mating surface of at least one diamond piece prior to the welding.

15. The method of claim 1, wherein the welding is carried out in a controlled atmosphere selected from a group consisting of a vacuum, a nitrogen atmosphere, and an argon atmosphere.

16. The method of claim 1, wherein the laser is passed at least two times over the mating surfaces of the two or more diamond pieces.

17. The method of claim 1, further comprising providing at least one sensor within or adjacent to the mating surface of at least one diamond piece prior to the welding.

18. The method of claim 17, wherein the at least one sensor is a solid-state sensor chip.

19. The method of claim 17, wherein the two or more diamond pieces are joined such that the at least one sensor is formed at or adjacent to the mating surface of the at least one diamond piece, wherein each of said diamond pieces is doped.

20. The method of claim 17, further comprising forming at least one sensor at or adjacent to the mating surface of the at least one diamond piece by ultrafast laser writing of optical waveguides.

21. The method of claim 1 , wherein the diamond pieces are engineered diamonds.

22. The method of claim 1 wherein the two or more diamond pieces are welded together to form a shape selected from a group comprising of spherical, semi- spherical, cuboidal, cubical, planar, prismatic, pyramidal, cylindrical, frustoconical, conical, ellipsoidal, toroidal, frustopyramidal, or combinations thereof.

23. The method of claim 1 further comprising forming at least one additional diamond layer over the welded together mating surfaces of the diamond pieces.

24. A diamond material comprising two or more diamond pieces joined together by a method of any of claims 1 to 23.

25. The diamond material of claim 24, having a thermal conductivity of at least 90% of the thermal conductivity of each of the two or more diamond pieces.

26. The diamond material of claim 24, having a tensile or flexural strength of at least 80% of the tensile or flexural strength of each of the two or more diamond pieces.

27. The diamond material of claim 24, wherein at least one of the two or more diamond pieces has at least one textured surface.

28. The diamond material of claim 24, wherein at least one of the two or more diamond pieces is doped.

29. The diamond material of claim 24, wherein the diamond pieces are welded together to form a shape selected from a group comprising of spherical, semi- spherical, cuboidal, cubical, planar, prismatic, pyramidal, cylindrical, frustoconical, conical, ellipsoidal, toroidal, frustopyramidal, or combinations thereof.

30. A set of engineered diamond pieces comprising: at least two engineered diamond pieces, each engineered diamond piece defining at least one mating surface integrally formed thereon of the same material as the engineered diamond piece, the at least one mating surface of one of the at least two engineered diamond pieces configured for joining with at least one mating surface of the other of the at least two engineered diamond pieces by welding to form a diamond component.

31. The set of engineered diamond pieces of claim 30, wherein at least one engineered diamond piece of the at least two engineered diamond pieces has a plurality of mating surfaces.

32. The set of engineered diamond pieces of claim 30, wherein the at least one mating surface of the engineered diamond piece has a chamfer surface, or a fillet surface, or a combination thereof.

33. The set of engineered diamond pieces of claim 30, wherein the at least one mating surface includes alignment features selected from a group comprising interlocking protrusions and recesses, guide rails, guide ridges, reference notches, reference markers, integrally formed spacers, and combinations thereof, wherein each of the alignment features is configured to facilitate alignment of the engineered diamond pieces prior to the welding.

34. The set of engineered diamond pieces of claim 30, wherein the engineered diamond pieces are of same shape and equal size with the at least two engineered diamond pieces having at least one mating surface having a chamfer.

35. The set of engineered diamond pieces of claim 30, wherein at least one engineered diamond piece is provided with at least one sensor, and wherein the at least one sensor is provided within or adjacent to the at least one mating surface of the at least one engineered diamond piece prior to the welding.

36. The set of engineered diamond pieces of claim 35, wherein each of the at least two engineered diamond pieces include a doped region near the mating surface such that the at least one sensor is formed at or adjacent to the mating surface of the at least one engineered diamond piece when the at least two engineered diamond pieces are joined.

37. The set of engineered diamond pieces of claim 36, wherein the doped region may include at least one of boron-doped region, nitrogen-doped region, or a combination thereof.

38. The set of engineered diamond pieces of claim 30, wherein at least two of the engineered diamond pieces have different thermal conductivity.

39. The set of engineered diamond pieces of claim 30, wherein shape of at least one diamond piece is selected from a group comprising of spherical, semi- spherical, cuboidal, cubical, planar, prismatic, pyramidal, cylindrical, frustoconical, conical, ellipsoidal, toroidal, frustopyramidal, or combinations thereof.

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