Medical device and its manufacturing method

Abstract

The present invention relates to a method of manufacturing a medical device comprising at least one distal jaw portion having a hardened gripping and / or cutting surface, the method comprising the steps of providing at least one jaw portion and hardening at least one region of the jaw portion, the hardening being carried out by providing a thermal spray device configured for high velocity oxy-fuel thermal spraying, feeding a coating material through the thermal spray device to generate particles of the coating material, and impinging the generated particles of coating material on at least one region of the jaw portion to generate a layer of the coating material, thereby forming a hardened gripping and / or cutting surface.

Description

[Technical field]

[0001] The present invention relates to medical instruments having at least one distal jaw portion having a hardened gripping and / or cutting surface, and methods of making such medical instruments. [Background technology]

[0002] Medical instruments having at least one distal jaw having a gripping and / or cutting surface are used to grasp, hold, clamp and / or cut medical material or body tissue and are available in the form of forceps, clamps, surgical needle holders, scissors, etc. To ensure sufficient durability and efficient handling of the medical instrument, the gripping and / or cutting surface of the at least one jaw must be sufficiently hard.

[0003] It is well known to mount jaw inserts on the inside of the jaw parts in order to achieve a sufficiently hard or hardened gripping and / or cutting surface. These jaw inserts are usually preformed and made of tungsten carbide or other hard materials. Soldering, welding or other suitable joining techniques are often used to join the jaw insert to the jaw parts. For example, German Utility Model No. 202004008169 discloses a method for manufacturing a surgical needle holder with a metallic or ceramic jaw insert, which is glued to the jaw parts.

[0004] The process of soldering, welding or gluing the jaw insert to the jaw portion can involve manual operations that are prone to error, and therefore it can be difficult to achieve sufficient repeatability of the individual steps of the manufacturing process, which can lead to quality deficiencies in the medical device. Summary of the Invention [Means for solving the problem]

[0005] The object of the present invention is to provide a method for producing a medical instrument of the type mentioned at the beginning, which results in an improved production quality and in improved properties of the produced medical instrument, in particular with regard to the hardened gripping and / or cutting surfaces.

[0006] A further object of the invention is to provide a medical instrument of the type mentioned at the outset, which has improved properties, in particular with regard to the hardened gripping and / or cutting surfaces.

[0007] These objects are solved by a method having the features of claim 1 and by a medical device having the features of claim 9. Preferred embodiments are defined in the dependent claims.

[0008] According to a first aspect, there is provided a method of manufacturing a medical instrument comprising at least one distal jaw portion having a hardened gripping and / or cutting surface, the method comprising the steps of providing at least one jaw portion and hardening at least one region of the jaw portion, the hardening being carried out by providing a thermal spray apparatus configured for high velocity oxygen fuel (HVOF) thermal spraying, feeding a coating material through the thermal spray apparatus to generate particles of the coating material, and impinging the generated particles of coating material against at least one region of the jaw portion to generate a layer of the coating material, thereby forming a hardened gripping and / or cutting surface.

[0009] For ease of explanation, the term "hardened gripping and / or cutting surface" will be abbreviated below to "hardened surface."

[0010] In the present invention, it is not necessary to bond a jaw insert to the jaw portion to achieve the hardened surface. Instead, at least one region of the jaw portion is coated by high velocity oxygen fuel (HVOF) spray to form the hardened surface. The inventors have recognized that by forming a hardened surface by HVOF, superior properties can be achieved in terms of hardness, durability, surface finish, and precision.

[0011] High velocity oxy-fuel spraying (HVOF) is a thermal spraying technique. It is a coating process in which partially molten or heated material is sprayed onto a surface. Thermal spraying can produce relatively thick coatings over large areas at high deposition rates compared to other coating processes such as electroplating, physical vapor deposition, and chemical vapor deposition. Coating materials that can be used for thermal spraying include metals, alloys, ceramics, plastics, and composites. In particular, HVOF is a specialized thermal spraying technique in which a mixture of gaseous or liquid fuel and oxygen is fed into the thermal spraying device. The mixture of gaseous or liquid fuel and oxygen is ignited and burned in the thermal spraying device. The resulting hot gas stream exits the converging-diverging nozzle and passes through the straight section of the thermal spraying device. The coating material is fed into the thermal spraying device, atomized, and accelerated by the gas stream. The coating material can be fed into / through the thermal spraying device in the form of powder and / or wire, and the resulting particles of coating material are heated and / or partially melted in the hot gas stream. The flow of hot gas and particles is directed at the surface to be coated, i.e. particles of the generated coating material are caused to impinge on at least one area of ​​the jaws. By causing the particles of the generated coating material to impinge on at least one area of ​​the jaws, a layer of coating material is generated, i.e. the particles are deposited on the surface to be coated, thereby forming a hardened surface.

[0012] At least one distal jaw portion may be provided as a separate unit or as part of the medical instrument. For example, the distal jaw portion may be in the form of a separate jaw member. Alternatively, the distal jaw portion may be provided as an integral part of a component of the medical instrument, such as a branch of the instrument. In one embodiment, the medical instrument has two distal jaw portions forming an instrument mouth. The medical instruments produced may be in the form of clamps, forceps, surgical needle holders, scissors, etc. for open, endoscopic, and / or robotic surgery.

[0013] In one embodiment, the layer of coating material is produced with a thickness between 0.1 mm and 2 mm, preferably between 0.2 mm and 1.5 mm, more preferably between 0.4 mm and 0.8 mm. Compared to other surface coating techniques such as electroplating, physical vapor deposition and chemical vapor deposition, HVOF allows for the deposition of a relatively thick layer of coating material. The inventors have recognized that coating at least one distal jaw portion with a relatively thin layer of coating material may lead to drawbacks. For example, a thin coating layer may be prone to breakage during use of the medical instrument. This may pose health risks to the patient. Therefore, depositing a thick layer of coating material using HVOF may reduce such risks. A thickness between 0.1 mm and 2 mm is advantageous, in particular with regard to the required processing time. A thickness between 0.2 mm and 1.5 mm is advantageous, in particular with regard to the mechanical properties obtained. The inventors have recognized that a thickness between 0.4 mm and 0.8 mm is advantageous, in particular with regard to both the reduction of the required processing time for depositing the coating material and the achievement of excellent mechanical properties of the resulting hardened surface. In one embodiment, the thickness is less than 0.1 mm.

[0014] In one embodiment, the method further comprises pre-texturing at least one region of the jaws to provide a non-smooth surface pattern, the pre-texturing being performed by machining the material of the jaws prior to generating the layer of coating material. The non-smooth surface pattern enhances the frictional properties of the hardened surface. Preferably, the non-smooth surface pattern comprises a regular or irregular pattern of recesses, protrusions, teeth, etc. The pre-texturing is performed prior to forming the hardened surface. Thus, the at least one region is unhardened or relatively soft at this stage of the method, which can simplify machining of the material of the jaws. In one embodiment, the material of the jaws is selected from the group consisting of steel, medical grade metals and / or alloys.

[0015] In one embodiment, the step of machining the material of the jaw portion comprises at least one machining technique selected from the group consisting of grinding, milling, engraving and embossing, and combinations thereof.

[0016] In one embodiment, the method further comprises a step of post-texturing at least one region of the jaws to provide a non-smooth surface pattern or to finish a non-smooth surface pattern provided by pre-texturing, the step of post-texturing being performed by machining the layer of coating material after generating the layer of coating material. Post-texturing can be used both to create a non-smooth surface pattern for improving the frictional properties of the hardened surface or to finish an existing non-smooth surface pattern created by pre-texturing. In contrast to pre-texturing, post-texturing is performed by machining the deposited coating material. Because the coating material is relatively hard, it may be necessary to employ processing techniques different from those used for pre-texturing and subsequent coating by HVOF. Post-texturing is performed after the deposition of the coating material, so that the non-smooth surface pattern can be formed with high precision. In comparison, forming a non-smooth surface pattern by pre-texturing (without additional post-texturing) may result in less precision, since the coating material is deposited on an already existing non-smooth surface pattern. In embodiments that do not include post-texturing, preferably the thickness of the layer of coating material is adapted to the shape, form and / or size of the pre-textured non-smooth surface pattern.

[0017] In one embodiment, the step of machining the layer of coating material comprises at least one electrochemical machining technique selected from the group consisting of pulsed electrochemical machining (PECM), precision electrochemical machining (PEM) and electrochemical milling (ECM) and combinations thereof. Electrochemical machining techniques involve the removal of material by electrochemical processes and can be used to machine extremely hard materials or materials that are difficult to machine by traditional (mechanical) machining techniques. The inventors have recognized that the use of PECM, PEM and / or ECM for post-texturing is particularly advantageous and allows the creation of non-smooth surface patterns with high precision. In one embodiment, machining the layer of coating material comprises at least one mechanical machining technique, preferably milling.

[0018] In one embodiment, the coating material is selected from the group consisting of cermets, ceramics, metals, metal alloys, polymers, composites, and tungsten carbide. The term "cermet" refers to a composite material consisting of ceramic (cer) and metal (met). Cermets can combine the properties of ceramics, such as hardness, and the properties of metals, such as the ability to plastically deform. Suitable ceramics include Cr2O3, Al2O3, ZrO2, and the like. Suitable (pure) metals include nickel (Ni), copper (Cu), aluminum (Al), molybdenum (Mo), titanium (Ti), and the like. Suitable metal alloys include steel, nickel, chromium, and cobalt alloys, including NiCrSiB and MCrAlYs, and the like. Suitable polymers include polyester and nylon. Suitable composite materials include nickel graphite. The inventors have discovered that the use of tungsten carbide (WC) as a coating material is particularly advantageous.

[0019] In one embodiment, the coating material is a cermet, the cermet comprising at least one metal and at least one ceramic, the at least one metal being selected from the group consisting of cobalt (Co), chromium (Cr), nickel (Ni) and alloys thereof, and the at least one ceramic being selected from the group consisting of tungsten carbide (WC), chromium carbide (Cr3C2), silicon boron carbide (SiBC) and mixtures thereof.

[0020] In one embodiment, the cermet is a compound containing or consisting of tungsten carbide (WC) and cobalt (Co), or a compound containing or consisting of tungsten carbide (WC), cobalt (Co) and chromium (Cr). The inventors have discovered that by using any of the aforementioned compounds, a hardened surface with excellent properties can be obtained.

[0021] According to a second aspect, there is provided a medical instrument comprising at least one distal jaw part, at least one region of the at least one jaw part being provided with a layer of coating material, the layer of coating material forming a hardened surface of the at least one jaw part. The medical instrument according to the second aspect of the invention is manufactured by a method according to the first aspect of the invention. Therefore, to avoid repetition, reference is made to what has been disclosed with respect to the first aspect. Further features and embodiments of the second aspect follow the disclosure of the first aspect and its embodiments.

[0022] In the following, embodiments of the invention will be described in detail with reference to the drawings, in which like elements are provided with like reference numerals throughout. The drawings are shown in schematic form. [Brief description of the drawings]

[0023] [Figure 1]FIG. 1 is a perspective view of one embodiment of a medical device according to the present invention, with an enlarged top view of the hardened gripping surface and / or cutting surface of the medical device. [Diagram 2] 1 is a schematic diagram for explaining one embodiment of a method for manufacturing a medical device according to the present invention. [Diagram 3] FIG. 1 is a schematic diagram for explaining one embodiment of the method according to the present invention. [Figure 4] 5 is a schematic diagram for illustrating a further embodiment of the method according to the invention; FIG. [Diagram 5] 5 is a schematic diagram for illustrating a further embodiment of the method according to the invention; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] According to FIG. 1, the medical instrument 1 comprises two instrument branches 2, 2a, namely a first instrument branch 2 and a second instrument branch 2a. Each of the two instrument branches 2, 2a has a distal jaw section 3, 3a and a proximal handling section 4, 4a. The jaw sections 3, 3a can also be denoted as a first jaw section 3 and a second jaw section 3a. The handling sections 4, 4a can also be denoted as a first handling section 4 and a second handling section 4a. The two instrument branches 2, 2a are pivotally connected to each other. In the illustrated embodiment, the two instrument branches 2, 2a are pivotable relative to each other about a hinge axis 5. The distal jaw sections 3, 3a form an instrument mouse M that is movable between an open state (see FIG. 1) and a closed state (not shown). The instrument mouse M is movable by a relative pivotal movement of the two instrument branches 2, 2a about the hinge axis 5. To close the instrument mouth M, the jaw portions 3, 3a are moved inwardly towards each other. To open the instrument mouth M, the jaw portions 3, 3a are moved outwardly away from each other.

[0025] In the illustrated embodiment, the medical instrument 1 is a surgical needle holder configured to securely grasp a surgical needle between the distal jaw portions 3, 3a and / or within the instrument mouth M. In other embodiments not shown, the medical instrument is a clamp, forceps, etc. In other words, the medical instrument 1 is forceps-like or clamp-like and can grasp, grab, hold, and / or clamp medical material or body tissue between the jaw portions 3, 3a.

[0026] In a non-illustrated embodiment, the medical instrument is a surgical scissors configured to cut medical material or body tissue between the jaws. To ensure sufficient durability of the jaws 3, 3a and efficient handling of the medical instrument 1, the jaws 3, 3a are provided with hardened gripping surfaces F, Fa, respectively. The aforementioned hardened gripping surfaces F, Fa can also be denoted as a first hardened gripping surface F and a second hardened gripping surface Fa.

[0027] In the embodiment described above, not shown, each of the jaws includes a hardened cutting surface.

[0028] In order to achieve a sufficiently hard or hardened gripping surface, it is well known in the art to attach so-called jaw inserts to the inside of the jaw parts. These jaw inserts are usually separate pre-formed components made of a sufficiently hard material. To join the jaw insert to the respective jaw part, soldering, welding or other suitable joining techniques are often used. This can lead to a rather complicated structure of the medical instrument and a manufacturing method requiring manual manufacturing steps that are prone to errors.

[0029] Instead of such jaw inserts, each jaw portion 3, 3a includes a layer L of a coating material C that forms a hardened gripping surface F, Fa of the respective jaw portion 3, 3a. Forming the hardened gripping surfaces F, Fa by a coating process that will be described in more detail below can simplify design and manufacture and improve the overall quality of the medical device 1.

[0030] Various embodiments of the method for manufacturing the medical instrument 1 will now be described in more detail with reference to Figures 2-5. Hereinafter, in these figures and the corresponding following description, reference is made only to the first jaw portion 3 and the first hardened gripping surface F. However, it goes without saying that the same manufacturing steps and / or techniques can be used to form the second hardened gripping surface Fa of the second jaw portion 3a. Furthermore, the illustrated method does not only apply to the manufacture of a medical instrument having two jaw portions, but also to a medical instrument having only one jaw portion, or to a medical instrument having more than two jaw portions, and thus to a medical instrument having at least one jaw portion.

[0031] Referring to FIG. 2 , the manufacture of the medical device 1 comprises the steps of providing (at least one) jaw portion 3 and hardening at least one region R of the jaw portion 3, the hardening step being carried out by the steps of providing a thermal spraying apparatus 100 configured for high velocity oxygen fuel thermal spraying (HVOF), feeding a coating material C through the thermal spraying apparatus 100 to generate particles P of the coating material C, and impinging the generated particles P of the coating material C against at least one region R of the jaw portion 3 to generate a layer L of the coating material C, thereby forming a hardened gripping surface F.

[0032] In one embodiment, the jaw portion 3 is provided together with the (first) instrument branch 2 of the medical instrument. In other words, in one embodiment, the distal jaw portion 3 forms the distal end of the instrument branch 2 and is integral with the remainder of the instrument branch 2. In other embodiments, the jaw portion 3 is provided as a separate component and is joined to the instrument branch 2 after forming a hardened gripping surface F.

[0033] The thermal spray apparatus 100 is configured for HVOF and in the illustrated embodiment includes a combustion chamber 101, a converging-diverging nozzle 102, and a straight section 103. The converging-diverging nozzle 102 may also be referred to as a Laval nozzle and / or a supersonic nozzle. The straight section 103 may also be referred to as a barrel. The thermal spray apparatus 100 is depicted diagrammatically and in a highly simplified manner.

[0034] High Velocity Oxygen Fuel (HVOF) coating is a thermal spray technique known per se in the field of surface technology. It involves supplying gaseous or liquid fuel G and oxygen O to a combustion chamber 101. The mixture of fuel G and oxygen O is ignited by a spark plug 104 and combusted continuously. The ignition and / or combustion I ejects through a convergent-divergent nozzle 102 forming a flow S of hot gases through a straight section 103. In one embodiment, the fuel G is a gaseous fuel and is selected from the group consisting of hydrogen, methane, propane, propylene, acetylene, natural gas or mixtures thereof. In another embodiment, the fuel is a liquid fuel, for example kerosene.

[0035] In the illustrated embodiment, the coating material C is fed through the thermal spray apparatus 100 in the form of a powder. More precisely, the coating material C is injected into the flow of hot gases S just past the converging-diverging nozzle 102. The flow of hot gases S atomizes the powder and / or coating material C into particles P. The exit velocity of the particles P exceeds the speed of sound.

[0036] The outlet of the straight section 103 is directed towards the region R of the jaw section. Thus, the particles P emerging from the outlet impinge on the region R and deposit thereon by forming a layer L of said coating material C, thereby forming a hardened gripping surface F.

[0037] In the illustrated embodiment, the coating material C is a compound of tungsten carbide (WC), cobalt (Co) and chromium (Cr). Said compound is a so-called cermet, i.e. a compound of at least one ceramic (cer) and at least one metal (met). In other embodiments, the coating material is selected from the group consisting of cermets, ceramics, metals, metal alloys, polymers and composites.

[0038] In a preferred embodiment, the coating material is comprised of tungsten carbide.

[0039] HVOF can form coatings that are significantly thicker than those formed by common coating techniques such as electroplating, physical vapor deposition and / or chemical vapor deposition. Thus, layer L can also be referred to as a thick layer. The thickness T of layer L is between 0.1 mm and 2 mm. In the illustrated embodiment, the thickness is 0.6 mm.

[0040] 3, 4 and 5 show diagrammatically further embodiments.

[0041] The method according to Fig. 3 comprises the steps of providing (at least one) jaw part 3 (step a)) and hardening a region R of the jaw part 3 by the HVOF coating technique already illustrated with reference to Fig. 2 (step b). The method further comprises the step of pre-texturing the region R of the jaw part 3 (step c)) in order to provide a non-smooth surface pattern 9, this pre-texturing step being carried out by a step of processing the material of the jaw part 3 before forming the hardened gripping surface F. The non-smooth surface pattern 9 comprises a regular or irregular pattern of recesses 7 and protrusions or projections 6. Said regular or irregular pattern of recesses 7 and protrusions forms teeth 8. The teeth 8 increase friction and / or enlarge the surface for depositing the coating material C. The teeth 8 and / or the non-smooth surface pattern 9 are made by processing the material of the jaw part. Before pre-texturing, the jaw part has a smooth surface RF, which may also be called a raw surface. In the illustrated embodiment, the material of the jaw part 3 is a medical grade stainless steel material. In other embodiments, the jaw material is a medical grade metal alloy or the like.

[0042] The machining of the material of the jaw portion 3 includes at least one machining technique selected from the group consisting of grinding, milling, engraving and embossing, or a combination thereof.

[0043] The hardening by HVOF coating (step b)) is carried out after the pretexturing. Thus, particles P of the coating material C are bombarded against the non-smooth surface pattern 9 to generate a layer L of the coating material C. The layer C covers the non-smooth surface pattern 9, thereby degrading or reducing the recesses 7 and protrusions 6. This degradation at least partially preserves the non-smooth surface pattern 9 and forms a hardened gripping surface F with a reduced or degraded non-smooth surface pattern 9'. The reduced or degraded non-smooth surface pattern 9' comprises reduced or degraded recesses 7' and reduced or degraded protrusions 6'. In other words, the resulting hardened gripping surface F has slightly rounded teeth 8' compared to the teeth 8.

[0044] In the embodiment according to figure 3, the thickness T of the layer L is adapted to sufficiently preserve the non-smooth surface pattern 9, so that after application of the layer L a sufficiently rough and / or non-smooth deteriorated surface pattern 9' can be reached.

[0045] The embodiment according to Fig. 4 comprises steps a), c) and b) of the embodiment according to Fig. 3. Moreover, the embodiment according to Fig. 4 comprises a further step (step d)) of post-texturing the area R of the jaw part 3 in order to finish and / or reinforce the non-smooth surface pattern F provided by the pre-texturing and subsequent coating. This post-texturing is carried out by a step of machining the layer L of the coating material C after producing the layer L. By this post-texturing, a finished hardened gripping surface F' is obtained. The finished hardened gripping surface F' can also be described as a (frictionally) reinforced hardened gripping surface and has a reinforced or finished non-smooth surface pattern 9''. The reinforced non-smooth surface pattern 9'' is produced by machining the layer L produced in step b) to form reinforced protrusions 6'' and reinforced recesses 7'' (versus reduced or deteriorated protrusions 6' and recesses 7'). In other words, the teeth 8 produced in step c) by machining the material of the jaw part are at least partially restored by machining the layer L. Compared to the textured surface pattern 9', the finished textured surface pattern 9'' provides improved friction characteristics and improved precision.

[0046] The processing of the layer L of coating material C in step d) comprises at least one electrochemical processing technique selected from the group consisting of pulsed electrochemical processing (PECM), precision electrochemical processing (PEM) and electrochemical milling (ECM) and combinations thereof.

[0047] In the embodiment shown in Fig. 5, a layer L of coating material C is applied directly onto the raw surface RF of the jaw part to form a smooth coating surface CF. In contrast to the embodiments of Figs. 3 and 4, the embodiment shown in Fig. 5 therefore does not include a pre-texturing (step c)) of the region R of the jaw part 3. A post-texturing step (step d)) is performed by machining the layer L of coating material to provide a non-smooth surface pattern 9'''. The resulting hardened gripping surface F'' is similar to the finished or reinforced hardened gripping surface F' of the embodiment according to Fig. 4. In the embodiment according to Fig. 5, the layer L is machined by at least one electrochemical machining technique.

[0048] From the foregoing, one skilled in the art will recognize that pretexturing and posttexturing steps are advantageous in achieving improved frictional properties and improved precision of the resulting hardened gripping surface. However, the aforementioned pretexturing and / or posttexturing steps are not required to practice the present invention.

Claims

1. A method for manufacturing a medical instrument (1) comprising at least one distal jaw portion (3) having a hardened gripping and / or cutting surface (F, F', F''), comprising the steps of: providing said at least one jaw portion (3); and hardening at least one region (R) of the jaw portion (3), The curing step includes: Providing a thermal spray apparatus (100) configured for high velocity oxy-fuel thermal spraying (HVOF); feeding said coating material (C) through said thermal spray device (100) to produce particles (P) of said coating material (C); impacting said particles (P) of the generated coating material (C) against said at least one region (R) of said jaw parts (3) to generate a layer (L) of said coating material (C), thereby forming said hardened gripping and / or cutting surfaces (F, F', F''); The method according to claim 1, wherein said coating material (C) is selected from the group consisting of metals, metal alloys and cermets.

2. 2. The method according to claim 1, wherein the layer (L) of the coating material (C) is produced with a thickness (T) between 0.1 mm and 2 mm, preferably between 0.2 mm and 1.5 mm, and more preferably between 0.4 mm and 0.8 mm.

3. further comprising the step of pre-texturing said at least one region (R) of said jaw portion (3) to provide a non-smooth surface pattern (9), 3. The method according to claim 1 or 2, wherein the pre-texturing step is carried out by a step of working the material of the jaw parts (3) before producing the layer (L) of the coating material (C).

4. 4. The method according to claim 3, wherein the step of machining the material of the jaw portions (3) comprises at least one machining technique selected from the group consisting of grinding, milling, engraving and embossing and combinations thereof.

5. further comprising a step of post-texturing said at least one region (R) of said jaw part to provide a non-smooth surface pattern (9'') or to finish off said non-smooth surface pattern (9) provided by the pre-texturing step, 5. The method according to claim 1, wherein the post-texturing step is performed by processing the layer (L) of coating material (C) after producing the layer (L) of coating material (C).

6. 6. The method of claim 5, wherein the step of machining the layer (L) of the coating material (C) comprises at least one electrochemical machining technique selected from the group consisting of Pulsed Electrochemical Machining (PECM), Precision Electrochemical Machining (PEM) and Electrochemical Milling (ECM) and combinations thereof.

7. The coating material (C) is a cermet, The cermet comprises at least one metal and at least one ceramic; the at least one metal is selected from the group consisting of cobalt (Co), chromium (Cr), nickel (Ni) and alloys thereof; The at least one ceramic may be selected from the group consisting of tungsten carbide (WC), chromium carbide (Cr 3 C 2 7. The method of claim 1, wherein the metal oxide is selected from the group consisting of silicon boron carbide (SiBC) and mixtures thereof.

8. 8. The method according to claim 7, wherein the cermet is a compound containing or consisting of tungsten carbide (WC) and cobalt (Co), or a compound containing or consisting of tungsten carbide (WC), cobalt (Co) and chromium (Cr).

9. A medical instrument (1) comprising at least one distal jaw portion (3), At least one region (R) of said at least one jaw portion (3) is provided with a layer (L) of a coating material (C), The medical instrument (1), wherein said layer (L) of said coating material (C) forms a hardened gripping and / or cutting surface (F, F', F'') of said at least one jaw portion (3).

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