EP0758407B1 - Cermet and process for producing it - Google Patents

Abstract

PCT No. PCT/DE95/00434 Sec. 371 Date Sep. 30, 1996 Sec. 102(e) Date Sep. 30, 1996 PCT Filed Mar. 29, 1995 PCT Pub. No. WO95/30030 PCT Pub. Date Nov. 9, 1995A cermet including a cermet core zone in which the content of a binder amounts to at most 90% by mass in relationship to a cermet hard phase is formed with a 0.01 to 3 um deep surface layer having an increased resistance to wear compare to the cermet core zone.

Description

The invention relates to a cermet with a hard material content of 95 to 75% by mass and 5 to 25% by mass of binder as the balance Cobalt and / or nickel, the hard material phase consisting of carbonitrides with a cubic B1 crystal structure and 30 to 60 mass% Ti, 5 to 25 mass% W, 5 to 15 mass% Ta, of which up to 70% by mass can be replaced by Nb, 0 to 12 mass% Mo, 0 to 5 mass% V, 0 to 2 mass% Cr, 0 to Contains 1% by mass of Hf and / or Zr, the (C + N) content in the carbonitride phase > 80 mol%, the nitrogen content N / (C + N) is between 0.15 and 0.7 and in the binder phase up to 2% Al and / or metallic W, Ti, Mo, V and / or Cr dissolved are. The hard material phases essentially have a core-edge structure.

The invention further relates to a method of manufacture of such a cermet by mixing, grinding, granulating and Pressing a starting mixture containing corresponding constituents and then sintering.

EP 0 344 421 A1 proposes a cermet that either an average grain size of the hard material phase in the surface layer compared to a core with a penetration depth of 0.05 mm, which is between 0.8 to 1.2 times the average grain size of the hard material phase in the cermet core is or in the same penetration depth affects a binder phase that is 0.7 up to 1.2 times the average binder content of the cermet core or where the hardness in the aforementioned penetration depth between 0.95 and 1.1 times the average hardness of the Cermet core lies. The starting mixture is used to produce this cermet sintered after grinding, mixing and pre-pressing, in a first stage up to 1300 ° C or below is sintered under vacuum or an inert gas atmosphere while in a second stage above 1300 ° C at a nitrogen pressure is sintered from 0.1 to 20 torr, and wherein the Nitrogen pressure also increases with increasing temperature should. The cooling is also in the presence of nitrogen performed.

EP 0 368 336 B1 describes a cermet substrate with a hard surface layer in which the region with the maximum Hardness at a depth between 5 µm and 50 µm from the substrate surface is present, and the substrate surface has a hardness of 20 to 90% of the maximum hardness. To make this Cermets becomes the pre-pressed mixture of an initial temperature increase to 1100 ° C in a vacuum, followed by an increase in temperature from 1100 ° C to a temperature range between 1400 ° C and 1500 ° C in a nitrogen atmosphere and one finally subjected to sintering in a vacuum.

EP 0 374 358 B1 describes a process for producing a cermet with 7 to 20% by weight binder phase and a hard phase made of titanium carbide, titanium nitride and / or titanium carbonitride with 35 to 59% by weight Ti, 9 to 29% by weight W, 0.4 to 3.5% by weight Mo, 4 to 24% by weight of at least one metal from Ta, Nb, V and zirconium, 5.5 to 9.5% by weight N ₂ and 4, 5 to 12 wt .-% C. The formulated mixed, dried and pre-pressed mass is sintered in such a way that the temperature is raised to 1350 ° C. in vacuo, the nitrogen atmosphere being set to 1 Torr at 1350 ° C., the nitrogen partial pressure together with the temperature increase from 1350 ° C. to the sintering temperature is gradually increased, the nitrogen atmosphere being set to 5 torr at the sintering temperature.

EP 0 492 059 A3 describes a cermet body whose hardness is at a penetration depth of not less than 1 mm higher than in the interior of the cermet, wherein the binder content can be minimized in a layer thickness of 0.5 to 3 μm compared to the core substrate. The cermet should have a hard material coating in a thickness of 0.5 to 20 μm made of carbides, nitrides, oxides and borides of titanium and Al ₂ O ₃ . To produce this body, a green compact is first heated to a temperature between 1100 ° C. and 1400 ° C. under vacuum, then nitrogen gas is admitted to a pressure at which the partial nitrogen pressure is between 5 and 10 torr, so that the substrate surface is denitrified. The sintering and the final cooling are carried out under a non-oxidizing atmosphere, such as a vacuum or an inert gas atmosphere. Finally, the body is coated using CVD or PVD.

To produce a high-viscosity cermet, EP 0 499 223 A1 proposes that the relative concentration of the binder in a 10 μm thick layer near the surface be 5 to 50% of the average mean content of binder in the cermet core and in the layer below it from 10 μm to 100 μm Penetration depth to set the binder content to 70 to 100% relative to the cermet core, whereby compressive stresses of 30 kgf / mm ² and more exist on the surface. In the process used for this purpose, the sintering is carried out under nitrogen gas at a constant pressure of 5 to 30 torr and the cooling under vacuum at a cooling rate of 10 to 20 ° C./min.

EP 0 515 340 A3, however, describes a cermet with one Binder-enriched zone near the surface.

EP 0 519 895 A1 discloses a cermet with a three-layered edge zone, in which the first layer is TiN-rich to a depth of 50 μm, the next layer from 50 to 150 μm penetration depth with a binder enrichment and the next layer from 150 μm to 400 µm is formed with a binder depletion relative to the interior of the cermet core. For this purpose, the sintered body is in an atmosphere of N ₂ and / or NH ₃ , possibly in combination with CH ₄ , CO, CO ₂ at 1100 ° C to 1350 ° C for one to 25 hours under atmospheric pressure or a pressure above 1.1 bar treated.

The cermets known from the prior art have the surface either different binder levels what is recognizable by spotty appearance, or tend to stick of the binder with the sinter pad, what because of that related reactions to changes in composition in the Contact zone leads. Other disadvantages of the previous one Cermets known in the prior art are sometimes high Surface roughness as well as with increased binder metal contents in poor adhesion to the surface from there Wear protection layers. If nickel content in the Surface is increased, is not a CVD coating at all possible. The disadvantages mentioned speak in particular against the use of the cermet as a cutting insert for cutting Editing.

It is therefore an object of the invention, the cermet mentioned by influencing the near-surface zone to improve that it is more suitable for cutting operations regardless of whether it is uncoated or with a single or multi-layer coating is to be used.

This object is achieved by the cermet mentioned in claim 1 solved. Apart from the extreme defined in claim 1 thin edge zone, the cermet lies in a homogeneous Structure before what the presence of core-edge structures of the Hard phase should not rule out.

The object is further described by that described in claim 2 Solved cermet.

Further developments of the invention are in the subclaims 3 to 7 described.

The core areas under the surface layer mentioned have at least essentially one hard material phase a core edge structure. In contrast, the hard phase in the surface layer only homogeneously or with the core edge structure intended for the core may also be partially available.

According to a further embodiment of the invention Cermet up a zone just below the surface layer to a depth of at least 50 µm, maximum 600 µm, the one Porosity according to IS04505 of ≤A02 and <B02 and below Core <A08 and <B04.

Particularly when the cermets are used for cutting operations, the further preferably low roughness depths R _T 6 6 μm or R _Z 5 5 μm have an effect. The hardness HV30 is preferably constant in the surface area.

According to an alternative embodiment, the cermet in the surface layer with a depth between 0.01 and 3 µm a Co and / or Ni binder content <90 mass% in one Ti content between 100% and 120% relative to the core area and the sum of the contents of W, Ta and possibly Mo, Nb, V, Cr is 80 to 100 mass%.

The cermet can have one or more wear protection layers, which consist of titanium carbide or nitride and / or Al ₂ O ₃ , preferably applied by the CVD method.

The cermet described is produced by the method set out in claim 8. Thereafter, a mixture containing the constituents determined according to claim 1 or 3 to 7 is ground, granulated and pre-pressed and then sintered, preferably in sintering furnaces with graphite heating conductors. After pressing, the green body is first heated to the melting temperature of the binder phase under vacuum with a pressure ≤ 10 ^-1 mbar, then further heated to the sintering temperature, which is between 1450 to 1530 ° C, where the temperature is 0.2 to 2 hours held and then the body is cooled to 1200 ° C. The last heating, holding and cooling is carried out in a gas mixture of N ₂ and CO with an N ₂ / (N ₂ + CO) ratio between 0.1 and 0.9 under an average pressure of 10% to 80% of the mean alternately in a period between 40 and 240 sec, preferably 40 to 180 sec. The N ₂ / (N ₂ + CO) ratio is determined by the equation
y = (16/11 x - 0.12) ± 10%, where x = N / (C + N) in mass% in the cermet and y =% By mass of the ratio of nitrogen to the total amount of nitrogen and carbon monoxide in the gas mixture and then the finished sintered bodies are cooled under inert gas, such as argon, nitrogen or a vacuum atmosphere.

The mean pressure is determined by the linear relationship y = (7/10 x + 2.5) ± 10%, where y is the mean pressure (mbar) and x is the binding content in mass%. This means for one Binder content of 5 mass% a pressure of 6 mbar ± 0.6 mbar as pressure average and at 25 mass% a pressure of 20 mbar ± 2 mbar.

The procedure described above is to be understood such that a pressure average over the entire heating process the melting point of the binding phase, sintering and cooling to 1200 ° C remains constant, but around this pressure average Pressure fluctuates periodically, especially due to a uniform one Deflection to higher and lower values. The fluctuation amplitude can be sinusoidal or sawtoothed or have forms derived from them. In contrast to the after state of the art pressure treatments only lead the pressure fluctuations described to a thin uniform Surface layer influence of the type described above.

According to a variant for the production of a cermet according to one of claims 2, 3, 5, 6 or 7, the sintered Body after sintering under a hot isostatic press Argon at temperatures close to the sintering temperature and pressures be subjected to above 30 bar. During that without that Subsequent hot isostatic presses produced a body significantly reduced binder content of less than 30% by mass in the surface layer up to a maximum penetration depth 3 µm shows, then has the hot isostatically pressed Body partially higher binder content, but still below 90% relative to the binder content in the cermet core.

Fig. 1

den linearen Zusammenhang zwischen dem Verhältnis N/(C+N) im Cermet und der Einstellung des Gehaltes N₂/(N₂+CO) im Gasgemisch und

Fig. 2

die Abhängigkeit der Einstellung des mittleren Druckes vom Bindemetallgehalt in der Ausgangsmischung bzw. im Cermet.

In a first embodiment variant, cermet bodies are only subjected to sintering. The setting of the gas atmosphere during sintering can be seen in FIGS. 1 and 2. Show it

Fig. 1

the linear relationship between the ratio N / (C + N) in the cermet and the setting of the content N ₂ / (N ₂ + CO) in the gas mixture and

Fig. 2

the dependence of the setting of the mean pressure on the binder metal content in the starting mixture or in the cermet.

As can be seen from Fig. 1, the respective value x represents the relative nitrogen content in the cermet, namely the ratio N / (C + N) and the value y the setting of the gas mixture N ₂ / (N ₂ + CO). The limit values are specified by cermet nitrogen contents between 0.15 and 0.7, to which settings of the gas mixture of 0.1 and 0.9 are assigned. All values in between can be seen in the graphical representation, whereby fluctuations up or down of 10% are permitted. The same applies to the representation according to FIG. 2, where the ordinate y represents the mean pressure in bar and the abscissa represents the binder content x in mass%. With a binder content of 25% by mass, the mean pressure to be set is 20 mbar, with a binder content of 5% by mass 6 mbar, with deviations from the mean value of up to 10% being permitted here as well. The pressures set in the sintering furnace then fluctuate around a constant mean pressure, alternating upwards and downwards at least 10%.

In a first exemplary embodiment of the invention, the following starting mixture was used (data in mass%): 35.2 TiC 9.0 TaC 15.1 TiN 1.0 NbC 19.2 WC 4.8 Ni 7.1 MO ₂ C 8.6 Co

1. Entwachsen bis 500°C

2. Aufheizen von 500 bis 1300°C unter Vakuum mit einer Aufheizgeschwindigkeit von 400°C/h

3. Aufheizen von 1300 bis 1480°C unter einem Gasgemisch aus N₂ und CO, bei dem das Verhältnis N₂/(N₂+CO) = 0,27 betrug. Nach Erreichen der Sintertemperatur wurde die Temperatur und die nachfolgend noch beschriebene Druckbehandlung eine Stunde gehalten, anschließend wurde der Sinterkörper von 1480°C auf 1200°C mit einer Abkühlgeschwindigkeit von 250°C/h abgekühlt. Das Aufheizen von 1300°C auf 1480°, das Halten der Temperatur sowie das anschließende Abkühlen sind bei einem mittleren Druck von 10 mbar durchgeführt worden, wobei der Druck periodisch bei einer Periodendauer von 150 sec um 3 mbar zu höheren und zu niedrigeren Werten (13 mbar und 7 mbar) schwankte.

4. Als letzter Verfahrensschritt schloß sich das weitere Abkühlen unter Argon an.

The powder particle diameters were between 1 and 2 µm. This results in a nitrogen content of 3.4 mass% and a carbon content of 9.3 mass%, so that the ratio N / (N + C) = 0.27. The total binder content is 13.4% by mass. The starting mixture was ground, mixed and pre-pressed as is known in the art. The following process steps were then applied:

1. Dewax up to 500 ° C

2. Heating from 500 to 1300 ° C under vacuum with a heating rate of 400 ° C / h

3. Heating from 1300 to 1480 ° C under a gas mixture of N ₂ and CO, in which the ratio N ₂ / (N ₂ + CO) = 0.27. After the sintering temperature had been reached, the temperature and the pressure treatment described below were held for one hour, and then the sintered body was cooled from 1480 ° C. to 1200 ° C. at a cooling rate of 250 ° C./h. The heating from 1300 ° C to 1480 °, the maintenance of the temperature and the subsequent cooling have been carried out at an average pressure of 10 mbar, the pressure periodically at a period of 150 seconds by 3 mbar to higher and lower values (13 mbar and 7 mbar) fluctuated.

4. The last step in the process was followed by further cooling under argon.

The same process steps 1, 2 and 4 were carried out for a reference body, but step 3 with the proviso that no CO was blown in and the set N ₂ pressure was constant at 20 mbar.

The following values were found in the analysis of the surface layers after sintering: Example 1: Cermet according to the invention Comparative cermet Ti (surface layer) / Ti (core): 1.3 1.4 Binder (surface layer) / Binder (core) 0.12 0.6 Total (W, Mo, Ta, Nb) (surface) / Total (W, Mo, Ta, Nb) (core) 0.9 0.6 Edge layer thickness 0.5 µm 10 µm Zone below the surface layer with a porosity ≤A02 and <B02 200 µm 250 µm and a porosity in the core <A06 and <B02 surface roughness R _T 5 µm 15 µm R _Z 3.8 µm 11 µm

The corresponding analyzes of the surface layer after hot isostatic pressing gave the following values: Example 2: Cermet according to the invention Comparative cermet Ti (surface layer) / Ti (core) 1.23 1.00 Binder (surface layer) / Binder (core) 0.15 1.20 Total (W, Mo, Ta, Nb) (surface) / Total (W, Mo, Ta, Nb) (core) 0.98 0.8 Porosity throughout ≤A02 and <B02 all other values as in example 1.

In a further example of the invention, the following starting mixture was assumed (data in mass%): 26.1 TiC 1.1 NbC 27.1 TiN 8.2 Ni 20.1 WC 8.7 Co 8.7 TaC

1. Entwachsen bis 500°C

2. Aufheizen von 500 bis 1320°C unter Vakuum mit einer Aufheizgeschwindigkeit von 400°C/h

3. Aufheizen von 1320 bis 1480°C unter einem Gasgemisch aus N₂ und CO, bei dem das Verhältnis N₂/(N₂+CO) = 0,54 betrug. Nach Erreichen der Sintertemperatur wurde die Temperatur und die nachfolgend noch beschriebene Druckbehandlung eine Stunde gehalten, anschließend wurde der Sinterkörper von 1480°C auf 1200°C mit einer Abkühlgeschwindigkeit von 250°C/h abgekühlt. Das Aufheizen von 1320°C auf 1480°, das Halten der Temperatur sowie das anschließende Abkühlen sind bei einem mittleren Druck von 15 mbar durchgeführt worden, wobei der Druck periodisch bei einer Periodendauer von 120 sec um 5mbar zu höheren und zu niedrigeren Werten (20 mbar und 10 mbar) schwankte.

4. Als letzter Verfahrensschritt schloß sich das weitere Abkühlen unter Argon an.

The powder particle diameters were between 1 and 2 µm. This results in a nitrogen content of 6.1 mass% and a carbon content of 7.2 mass%, so that the ratio N / (N + C) = 0.46. The total binder content is 16.9% by mass. The starting mixture was ground, mixed and pre-pressed as is known in the art. The following process steps were then applied:

1. Dewax up to 500 ° C

2. Heating from 500 to 1320 ° C under vacuum with a heating rate of 400 ° C / h

3. Heating from 1320 to 1480 ° C under a gas mixture of N ₂ and CO, in which the ratio N ₂ / (N ₂ + CO) = 0.54. After the sintering temperature had been reached, the temperature and the pressure treatment described below were held for one hour, and then the sintered body was cooled from 1480 ° C. to 1200 ° C. at a cooling rate of 250 ° C./h. The heating from 1320 ° C to 1480 °, the maintenance of the temperature and the subsequent cooling were carried out at an average pressure of 15 mbar, the pressure periodically at a period of 120 sec by 5 mbar to higher and lower values (20 mbar and 10 mbar) fluctuated.

4. The last step in the process was followed by further cooling under argon.

A comparison body was subjected to the same process steps 1, 2 and 4, but process step 3 with the proviso that no CO was blown in and the N ₂ pressure was constant at 20 mbar.

The following values were found in the analysis of the surface layers after sintering: Example 3: Cermet according to the invention Comparative cermet Ti (surface layer) / Ti (core) 1.32 1.00 Binder (surface layer) / Binder (core) 0.27 0.50 Total (W, Ta, Nb) (surface) / Total (W, Ta, Nb) (core) 0.82 1.5 Edge layer thickness 0.3 µm 5 µm Zone below the surface layer with a porosity ≤A02 and <B02 100 µm 120 µm Porosity in the core <A08 and <B02 roughness depth R _T 3.5 µm 13 µm R _Z 2.8 µm 9 µm

The corresponding analyzes of the surface layer after hot isostatic pressing gave the following values: Example 4: Cermet according to the invention Comparative cermet Ti surface layer / Ti core 1.21 1.00 Binder surface layer / binder core 0.69 1.60 Total amount (W, Ta, Nb) surface / total amount (W, Ta, Nb) core 0.78 0.4 Porosity throughout ≤A02 and <B02 all other values as in example 3.

Werkstückstoff: 42 CrMo4V

Wendeschneidplatten-Form: CnMG 120408-22

Schneidkantenverrundung: 30 - 50 µm

Schnittbedingungen:
Schnittgeschwindigkeit V_c = 140 m/min
Schnittiefe a_p = 2 mm
Vorschub f = 0,3 mm Beispiel Standzeit (min) erfindungsgemäßer Cermet Vergleichs-Cermet 1 16 5 2 18 9 3 25 12 4 32 13

Schnittzeitkriterium: Plastische Deformation

The cermets produced according to the above examples have been subjected to the following machining tests:
Turning in a smooth cut, dry

Workpiece material: 42 CrMo4V

Insert shape: CnMG 120408-22

Rounding of cutting edges: 30 - 50 µm

Cutting conditions:
Cutting speed V _c = 140 m / min
Depth of cut a _p = 2 mm
Feed f = 0.3 mm example Tool life (min) Cermet according to the invention Comparative cermet 1 16 5 2nd 18th 9 3rd 25th 12th 4th 32 13

Cutting time criterion: plastic deformation

Claims (10)

1. Cermet with a hard material content of 95 to 75 % by mass and 5 to 25 % by mass Co- and/or Ni-binder, whereby the hard material phase consists of carbonitrides with cubic B1 crystalline structure and contains 30 to 60 % by mass Ti, 5 to 25 % by mass W, 5 to 15 % by mass Ta, of which up to 70 % by mass can be replaced by Nb, 0 to 12 % by mass Mo, 0 to 5 % by mass V, 0 to 2 % by mass Cr, 0 to 1 % by mass Hf and/or Zr, the (C+N) content in the carbonitride phase is >80 mol %, the nitrogen content N/(C+N) ranges between 0.15 and 0.7 and in the binder phase up to 2 % by mass Al is contained and/or metallic W, Ti, Mo, V and/or Cr are dissolved, whereby only in a surface layer defined by a penetration depth of 0.01 to 3 µm, measurable through an energy dispersive microanalysis on a measuring surface >(0.5 x 0.5)mm²,

   1. the content of Co- and/or Ni-binder in relation to the underlying cermet core zones amounts to ≤30 % by mass

   2. the Ti-content amounts to 110 to 130 % in relation to the underlying cermet core zones, whereby each time in the cermet core on the one hand and in the surface layer on the other hand an even distribution of the binder metal exists and

   3. the sum of contents in W, Ta, as well as possible contents of Mo, Nb, V and/or Cr in the surface layer with a thickness of 0.01 to 3 µm amounts to 70 to 100 % by mass in relation to the underlying cermet core zones.
2. Cermet with a hard material content of 95 to 75 % by mass and 5 to 25 % by mass Co- and/or Ni-binder, whereby the hard material phase consists of carbonitrides with cubic B1 crystalline structure and contains 30 to 60 % by mass Ti, 5 to 25 % by mass W, 5 to 15 % by mass Ta, 70 % by mass of which can be replaced by Nb, 0 to 12 % by mass Mo, 0 to 5 % by mass V, 0 to 2 % by mass Cr, 0 to 1 % by mass Hf and/or Zr, the (C+N) content in the carbonitride phase amounts to > 80 mol %, the nitrogen content N/(C+N) ranges between 0.15 and 0.7 and in the binder phase up to 2 % by mass Al is contained and/or metallic W, Ti, Mo, V and/or Cr are dissolved, whereby the Co- and/or Ni-binder content in the surface layer with a penetration depth of 0.01 to 3 µm, measurable by an energy dispersive microanalysis, in relation to the underlying layers <90 % by masss at a Ti-content between 100 % to 120 % in relation to the core zone and the sum of the contents of W, Ta, as well as optionally Mo, Nb, V, Cr ranges between 80 % by mass and 110 % by mass.
3. Cermet according to claim 1 or 2, characterized in that the core zones underlying the surface layer have at least in essence a hard material phase with a core-rim structure and/or that in the surface layer the hard material phase is exclusively homogeneous.
4. Cermet according to one of claims 1 or 3, characterized in that the zone immediately under the surface layer down to a depth of al least 50 µm, maximum 600 µm, has a porosity ≤A02 and <B02 (according to ISO4505) and <A08 and <B04 in the underlying core.
5. Cermet according to claim 2 or 2, characterized in that throughout the body the porosity is ≤A02 and <B02.
6. Cermet according to one of claim 1 to 5, characterized in that the depth of surface roughness equals R_T ≤6 µm or R_Z ≤5 µm and/or that the hardness HV 30 is constant in the surface area.
7. Cermet according to one of claims 1 to 6, characterized by a single or multiple layer coating of carbides or nitrides of Ti and/or Al₂O₃, preferably applied through the CVD process.
8. Process for the production of a cermet according to one of claims 1 or 3 to 7, by blending, grinding, granulating and compressing a corresponding initial mixture containing the ingredients and sintering it afterwards, preferably in sintering furnaces with graphite heat conductors,
   characterized by a heating up to the melting point of the binder phase under vacuum with a pressure of ≤10^-1 mbar, a further heating from the melting temperature of the binder phase up to the sintering temperature and holding the sintering temperature for 0.2 - 2 hours and a subsequent cooling down to 1220°C, whereby the further heating, holding and cooling takes place in a gas mixture of N₂ and CO with a N₂/(N₂+CO) ratio between 0.1 and 0.9 under a average pressure alternating by 10 % to 80 % about the middle pressure in a period of time between 40 and 240 seconds, preferably 40 to 180 seconds, with an average pressure which is determined by the linear relation
   y = ( 7 / 10 x + 2,5) ± 10 %, whereby y = the average pressure (mbar) and x = the binder content in % by mass, and a N₂/(N₂ + CO) ratio y, which is determined by
   y = ( 16 / 11 x - 0,12) ± 10 % with x = N/(C+N) in the cermet, and subsequent cooling under inert gas, such as argon, nitrogen or under vacuum.
9. Process according to claim 8, characterized in that during the heating within the melting point range (T_S ± 80°C) with the introduction of nitrogen a pressure of 0.2 mbar is set, whereby preferably the compressed body is at first heated up to 1020°C under vacuum with a pressure of ≤0.1 mbar, before a pressure of 0.2 mbar is set during the heating from 1020°C to 1370°C with the introduction of nitrogen.
10. Precess for the production of a cermet according to one of claims 2, 3, 5 or 6 or 8, 9, characterized in that after sintering a hot isostatic compression under argon is performed, at temperatures close to the sintering temperature and pressure and pressure above 30 bar.

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