Surface coating of a carbide or a nitride

1. A surface coating comprising at least one carbide layer having the general formula MQC, wherein

M is an element from the group consisting of Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta or any mixture thereof, and

Q is an element from the group consisting of Mn, Cr, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag, Re, W, Os, Ir, Pt, Au, Al or any mixture thereof, characterised in that the layer comprises at least two different crystal structures or parts of such structures, and that the relative amounts of M and Q in the layer are within a range in which the energy required for forming a crystal structure of said carbide is generally equal for said at least two structures.

2. A surface coating according to claim 1 , characterised in that the carbide has the general formula MxQ(1−x)C, wherein 0<x<1 , and x is selected such that the valence electron concentration (VEC) for said carbide is in the range of 9.30-9.90.

3. A surface coating according to claim 2 , wherein M is an element from the group consisting of Sc, Ti, V or any mixture thereof, and Q is an element from the group consisting of Mn, Cr, Fe, Co, Ni, Cu or any mixture thereof, characterised in that, x is selected such that the valence electron concentration (VEC) for said carbide is in the range of 9.50-9.90.

4. A surface coating according to claim 2 , wherein M is an element from the group consisting of Y, Nb, Zr or a mixture thereof, and Q is an element from the group consisting of Mo, Tc, Ru, Rh, Pd, Ag or a mixture thereof, characterised in that x is selected such that the valence electron concentration (VEC) for said carbide is in the range of 9.40-9.80.

5. A surface coating according to claim 2 , wherein M is an element from the group consisting of La, Hf, Ta and mixtures therein, and Q is an element from the group consisting of Re, W, Os, Ir, Pt, Au and mixtures therein, characterised in that x is selected such that the valence electron concentration (VEC) for said carbide is in the range of 9.30-9.70.

6. A surface coating according to claim 1 , characterised in that M is an element from one row of the periodic table and Q is from another row of the periodic table.

7. A surface coating according to claim 1 , characterised in that the relative amounts of M and Q is generally constant across the thickness of the deposited layer.

8. A surface coating according to claim 1 , characterised in that M and Q belong to adjacent columns in the periodic table, i.e the number of valence electrons differs by one.

9. A cutting tool, characterised in that it comprises a coating according to claim 1 .

10. A surface coating comprising at least one nitride layer having the general formula MQN, wherein

M is an element from the group consisting of Sc, Y, La, Ti, Zr, Hf or any mixture thereof, and

Q is an element from the group consisting of V, Nb, Ta, Mn, Cr, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag, Re, W, Os, Ir, Pt, Au, Al or any mixture thereof, characterised in that the layer comprises at least two different crystal structures or parts of such structures, and that the relative amounts of M and Q in the layer are within a range in which the energy required for forming a crystal structure of said nitride is generally equal for said at least two structures.

11. A surface coating according to claim 10 , characterised in that the nitride has the general formula MxQ(1−x)N, wherein 0<x<1 , and x is selected such that the valence electron concentration (VEC) for said nitride is in the range of 9.30-9.90.

12. A surface coating according to claim 11 , wherein M is an element from the group consisting of Sc, Ti or any mixture thereof, and Q is an element from the group consisting of V, Mn, Cr, Fe, Co, Ni, Cu or any mixture thereof, characterised in that, x is selected such that the valence electron concentration (VEC) for said nitride is in the range of 9.5-9.90.

13. A surface coating according to claim 11 , wherein M is an element from the group consisting of Y and Zr or a mixture thereof, and Q is an element from the group consisting of Nb, Mo, Tc, Ru, Rh, Pd, Ag or a mixture thereof, characterised in that x is selected such that the valence electron concentration (VEC) for said nitride is in the range of 9.40-9.80.

14. A surface coating according to claim 11 , wherein M is an element from the group consisting of La and Hf and mixtures therein, and Q is an element from the group consisting of Ta, Re, W, Os, Ir, Pt, Au and mixtures therein, characterised in that x is selected such that the valence electron concentration (VEC) for said nitride is in the range of 9.30-9.70.

15. A method of producing a surface coating comprising at least one carbide layer having the general formula MQC, wherein

M is an element from the group consisting of Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta or any mixture thereof, and

Q is an element from the group consisting of Mn, Cr, Fe, Co, Ni, Cu Mo, Tc, Ru, Rh, Pd, Ag W, Re, Os, Ir, Pt, Au, Al or any mixture thereof, characterised in that a substrate is subjected to a simultaneous flow of atoms of M and Q under such conditions that the carbide layer is deposited on the substrate, and that at least two different carbide layer structures or parts of such structures are deposited on the substrate, the relative amounts of M and Q directed towards the substrate being chosen such that the energy required for forming a crystal structure of said carbide is generally equal f or said at least two carbide structures.

16. A method of producing a surface coating comprising at least one nitride layer having the general formula MQN, wherein

M is an element from the group consisting of Sc, Y, La, Ti, Zr, Hf, or any mixture thereof, and

Q is an element from the group consisting of V, Nb, Ta, Mn, Cr, Fe, Co, Ni, Cu, Mo, To, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, Au, Al or any mixture thereof, characterised in that a substrate is subjected to a simultaneous flow of atoms of M and Q under such conditions that the nitride is deposited on the substrate, and that at least two different nitride layer structures or parts of such structures are deposited on the substrate, the relative amounts of M and Q directed towards the substrate being chosen such that the energy required for forming a crystal structure of said nitride is generally equal for said at least two nitride structures.

17. A method according to claim 15 , or 16 characterised in that the relative amounts of M and Q directed towards the substrate are such that any differences in forming-energy between said at least two structures is small enough to permit a random transition from the formation of one of said structures to the formation of a second or other structure under the prevailing production conditions.

18. A method according to claim 17 , characterised in that the carbide or nitride is deposited onto the substrate under generally constant production conditions, at least two structures thereby being randomly formed in the carbide or nitride layer.

19. A method according to claim 15 , or 16 characterised in that, during the deposition of the carbide or nitride onto the substrate, at least one production parameter is adjusted such that the formation of one of said at least two structures is at least temporarily promoted.

20. A method according to claim 19 , characterised in that said parameter is the amount of M or Q directed towards the substrate.

21. A method according to claim 15 , characterised in that the carbide or nitride layer is deposited by means of vapor deposition method.

22. A method according to claim 15 , characterised in that the carbide or nitride is deposited by means of a sputtering technique.