Method for surface treatment and / or manufacture of medical products and medical products

Abstract

The invention relates to a method for surface treatment and / or production of a medical product, wherein the medical product comprises or consists of a metal or an alloy, characterized in that the method comprises the following step: a) electrochemically etching the medical product. Furthermore, the invention relates to a medical product comprising or consisting of a metal or an alloy, wherein the medical product is produced or producible by the above-mentioned method and / or has at least one of the following characteristics: - a pitting potential of 100 mV to 1200 mV, in particular 200 mV to 800 mV, preferably 400 mV to 500 mV, and / or - a contact angle of 90° to 140°, in particular 100° to 130°, preferably 110° to 130°, and / or - a passivation layer, in particular made of chromium oxide, having a thickness of 1 nm to 10 nm, in particular 3 nm to 10 nm, preferably 5 nm to 10 nm, which at least partially coats the surface of the medical product.

Description

[0001] Application areas and existing technologies This invention relates to methods for surface treatment or processing and / or manufacturing of medical products, and to medical products themselves.

[0002] Medical products, such as surgical instruments in particular, are typically surface-treated before completion. This can be done, for example, by sliding grinding and / or belt grinding. This eliminates defects in the raw materials and / or forging-related defects, such as decarburized areas, or surface defects such as porosity, scars, or cracks, which would otherwise adversely affect the product's corrosion resistance.

[0003] However, belt grinding creates tiny notches or bumps on the product surface. These can be flipped or flattened in subsequent processing steps. This results in material overlap. Furthermore, individual material transfers, such as from silica particles from the grinding belt, may occur on the product surface. This material transfer, along with the stresses associated with machining on medical products, can in turn create or increase inherent stresses within the product. Another issue is that surface defects not eliminated or generated during grinding can only be eliminated to a limited extent in subsequent processing steps.

[0004] To abrade medical products, spherical shot peening agents, such as glass beads, can be used. This causes plastic deformation of the product surface, increasing its size and roughening. Because glass beads are typically very hard (Mohs hardness 6) and also brittle, the shot peening agent will break to some extent over time. As a result, both spherical and broken glass beads impact the product surface during the abrasion process. Broken glass beads create sharp notches on the product surface, while unbroken glass beads leave spherical indentations. Through the impact of broken and unbroken glass beads, there is an interaction between the product surface indented by the broken glass beads and the surface smoothed by the unbroken glass beads. This also leads to material overlap. In addition to plastic deformation and the associated inherent stress generation, material transfer from the shot peening agent can also occur on the product surface. This material transfer is particularly noticeable in the notched areas, where material accumulation from the glass beads may remain.

[0005] As an alternative to the shot peening treatment using glass beads as an example, the surface of medical products can be brushed. For this purpose, a brush can be used to treat the product surface, for example, with a disc-shaped abrasive cloth or nylon fibers arranged in a disc shape with abrasive particles. Alumina and / or silica particles are typically applied to the brush. While brushing increases the corrosion resistance of the product surface compared to abrasive surfaces, a disadvantage is that brushed surfaces exhibit more pronounced reflective properties than abrasive surfaces.

[0006] It is also known that microstructures or notches formed by material overlap on the product surface, as well as the generation or increase of associated inherent stresses in the product, have an adverse effect on its corrosion resistance. In cases of material transfer, such as during belt grinding and / or abrasive finishing, the transferred material also creates additional microstructures and may weaken the passivation layer.

[0007] Purpose and Implementation The object of this invention is to provide a method for surface treatment or processing and / or manufacturing of medical products, which at least partially avoids the disadvantages that occur in general types of methods, and in particular produces medical products with improved corrosion resistance and reduced reflectivity.

[0008] Another objective of this invention is to provide corresponding medical products.

[0009] According to the present invention, the above-mentioned objective is achieved by a method having the features of independent claim 1 and a medical product as described in claim 14. Preferred embodiments of the method and the medical product are the subject of the dependent claims and the specification. The wording of all claims is expressly taken into account with reference to the contents of the specification.

[0010] In a first aspect, the present invention relates to a method for surface treatment or processing and / or manufacturing a medical product, wherein the medical product comprises or is composed of a metal or alloy. The method includes the following steps: a) Electrochemical etching of the medical product or the surface of the medical product.

[0011] This method may include, in particular, the steps described above in a direct and continuous manner.

[0012] In the context of this invention, the term "medical product" may refer to a medical end product, preferably a surgical instrument, or a medical end product, preferably a precursor to a surgical instrument, especially a semi-finished product, blank, or semi-finished product, or a medical end product, preferably a component of a surgical instrument.

[0013] In the context of this invention, the term "alloy" should be understood as a macroscopically homogeneous metallic material composed of at least two elements (components), wherein at least one element is a metal. Therefore, in the context of this invention, "alloy" can refer to a macroscopically homogeneous metallic material composed of at least two different metals. Alternatively, in the context of this invention, "alloy" can refer to a macroscopically homogeneous metallic material composed of at least one metal and at least one nonmetal, such as carbon.

[0014] Surprisingly, it has been found that the drawbacks of conventional surface treatments for medical products, as described at the beginning, can be partially or even completely avoided through electrochemical etching. For example, with surgical instruments, it can be demonstrated that electrochemical etching results in reduced light reflection on the product surface, as well as increased corrosion resistance. In the case of medical products made of chromium-containing or chromium alloy stainless steel, the improved corrosion resistance is particularly attributed to the entry of hexavalent chromium ions into the solution due to the electrochemical etching operation. As a result, the chromium-rich oxide layer on the surface of the medical product is removed, allowing the acid used in the electrochemical etching operation to directly attack the chemical and physical inhomogeneities on the surface of the medical product, such as chromium carbide-containing areas around chromium carbide. This creates microstructures on the surface of the medical product, especially at the locations of previous chromium carbide areas, which in particular take the form of etch pits, especially open ones. Furthermore, boundary regions, especially lath and sub-block boundaries, can be advantageously broken down, which in particular leads to the protrusion of individual martensitic laths. The result is a roughened product surface on which incident light can be scattered. Consequently, the surface of the medical product appears frosted, which is particularly advantageous for users by simplifying the handling of the medical product. For example, this can prevent eye strain for surgeons in the operating room. Reducing the chromium-depleted areas on the surface of medical products also helps to lower the risk of nucleation sites for pitting corrosion.

[0015] Another advantage is that the electrochemical etching process can promote the formation of a passivation layer, especially a thicker passivation layer compared to existing technologies. As a result, the corrosion resistance of medical products can also be increased.

[0016] Another advantage of electrochemical etching is that it can largely or completely avoid compressive and tensile stresses and / or material overlap and / or material matting on the surface of medical products. This can further reduce the risk of corrosion.

[0017] Furthermore, electrochemical etching can advantageously reduce potential corrosion-inducing material defects on the surface of medical products.

[0018] Furthermore, compared to conventional methods, the method of the present invention advantageously results in comparable or better cleanability of the surface of the medical product and / or comparable or better scratch resistance and / or comparable or better mechanical stability and / or comparable or better tactile feel, especially smoothness, of the medical product.

[0019] In one embodiment of the invention, prior to step a), the surface of the medical product is ground, preferably by sliding grinding and / or belt grinding.

[0020] For sliding abrasives, the medical product is preferably introduced into a container along with a sliding abrasive, preferably loosely packed material, or along with an aqueous solution containing the sliding abrasive and optional additives. Optional additives may be selected from corrosion inhibitors, degreasing agents, pickling agents, separating agents (e.g., plastic balls with a diameter <1 mm), and mixtures thereof. Such a solution advantageously absorbs and removes abrasive material and product stripping material generated by the sliding abrasive. Depending on the additives used in each case, other effects such as corrosion prevention, degreasing, and anti-adhesion may also be achieved.

[0021] The relative motion between the medical product and the sliding abrasive media is generated by the oscillating or rotating motion of the container. This results in material stripping from the medical product, especially at its edges. The surface profile, roughness, material stripping, and deburring performance of the medical product can be advantageously and specifically influenced by the machine used for sliding abrasive grinding, the abrasive media, and optional additives.

[0022] The sliding grinding media may contain or consist of a material selected from ceramics, plastics, natural products such as walnut shells, steel, and combinations thereof.

[0023] In principle, the sliding grinding media can be in regular and / or irregular shapes.

[0024] The sliding grinding body can be cornerless and / or edgeless, for example, elliptical, annular or spherical.

[0025] Alternatively or in combination, sliding grinding bodies may have corners and / or edges. In particular, sliding grinding bodies may be polyhedral, such as cubes, cuboids, prisms, pyramids, or crystals. Furthermore, sliding grinding bodies may especially be right prisms and / or oblique prisms.

[0026] Alternatively or in combination, the sliding grinding body may be conical and / or truncated conical.

[0027] Furthermore, mixtures of sliding abrasives of different shapes can be used for sliding abrasive applications in medical products. For example, angular and / or edgeless sliding abrasives and polyhedral sliding abrasives can be used. Alternatively or in combination, angular and / or edgeless sliding abrasives of different shapes and / or different polyhedral sliding abrasives can be used. For considerations regarding possible constructions and shapes, refer fully to the constructions and shapes of sliding abrasives described in the preceding paragraphs.

[0028] The sliding grinding head may also have at least one dimension, particularly at least one average dimension, such as diameter, particularly average diameter, and / or height, particularly average height, and / or length, particularly average length, which is from 1 mm to 80 mm. In the context of this invention, the diameter of a spherical sliding grinding head should be understood as twice the radius of a single spherical sliding grinding head. Conversely, in the context of this invention, the diameter of a non-spherical sliding grinding head should be understood as the maximum possible distance between two points, which can be taken relative to each other along the circumference of a single non-spherical sliding grinding head. The average dimension mentioned in this paragraph can be determined, for example, by bulk density and / or optical measurements. Sliding grinding can also be performed in the form of drum sliding grinding, vibratory sliding grinding, immersion sliding cutting, drag grinding, centrifugal sliding cutting, or pressure flow grinding.

[0029] For belt grinding of medical products, an abrasive belt is preferred. For this purpose, an abrasive belt running on at least two rollers is particularly suitable. The abrasive belt preferably has a particle size of 150 to 1200. The number of particle sizes depends on the unit of measurement, mesh, i.e., the number of meshes per inch (25.4 mm). Thus, for example, an abrasive with a particle size of 150 will pass precisely through a sieve with a mesh size of 150 per inch.

[0030] According to the invention, sliding grinding can be performed first, for example, before step a), followed by belt grinding. Belt grinding may be particularly advantageous for treating so-called shaded areas of medical products, and also advantageous outside such areas. Shaded areas define the region of the medical product in which sliding grinding media are ineffective or have only limited effect on the surface, especially due to the geometry and / or construction of the medical product.

[0031] Alternatively, prior to step a), the surface of the medical product can be polished solely by sliding grinding. This avoids the formation of notches and / or bumps on the product surface caused by belt grinding, thus further improving the corrosion resistance of the medical product.

[0032] Alternatively, the surface of the medical product may be polished by belt grinding only before step a).

[0033] In another embodiment of the invention, the surface of the medical product is not treated with shot peening. As already mentioned, the etching step according to the invention advantageously sands the surface of the medical product, thus eliminating the need for sanding with shot peening. In this way, the processing / manufacturing time and / or cost of the medical product can be significantly reduced, which is particularly advantageous. Furthermore, this method avoids the risk of material transfer from the shot peening agent onto the medical product, which can further improve its corrosion resistance.

[0034] Alternatively, the surface of the medical product can be treated with a shot peening agent, preferably before step a), particularly between the grinding of the medical product surface, especially sliding grinding and / or belt grinding, and step a). The shot peening agent used can be particularly ductile, i.e., non-brittle. The use of such a shot peening agent can particularly advantageously prevent or at least reduce the formation of notches and / or microstructures, especially microcracks, on the surface of the medical product. This can thereby avoid or at least reduce the occurrence of localized stress peaks in the medical product, particularly by further improving the corrosion resistance of the medical product. Most importantly, the scratch resistance of the medical product can be advantageously improved by using such a shot peening agent. Regarding the grinding of the medical product surface mentioned in this paragraph, particularly sliding grinding and / or belt grinding, refer fully to the corresponding statements given to date in the specification.

[0035] In principle, shot peening agents may contain or consist of a material selected from metals, metal oxides, alloys, ceramics, plastics, plant materials, sand, and combinations thereof.

[0036] Metals, especially aluminum.

[0037] The metal oxide can be aluminum oxide (Al2O3), preferably of the corundum type.

[0038] Plastics can be, in particular, urea resins, phenolic resins, polyester resins, or melamine resins.

[0039] Ceramics, in particular, can be glass or composite ceramics.

[0040] The alloy can be, for example, steel, especially stainless steel. Preferably, it is a rust-resistant steel, especially a rust-resistant stainless steel. For a description of suitable stainless steel, see below.

[0041] Sand, in particular, can be garnet sand.

[0042] The shot peening agent preferably contains a metal or alloy, or is preferably composed of a metal or alloy. This shot peening agent has the particular advantage of not breaking apart, thus preventing dents on the surface of medical products. Furthermore, it can reduce or even completely prevent material transfer to the product surface. Overall, this can further improve the corrosion resistance of medical products and avoid unwanted inherent stresses within the product. In addition, this shot peening agent is particularly suitable for improving the scratch resistance of medical products.

[0043] Preferably, the shot peening agent comprises steel, especially stainless steel, or is preferably composed of steel, especially stainless steel. With such a shot peening agent, the advantages mentioned in the previous paragraph can be particularly evident.

[0044] In principle, shot peening agents can have regular and / or irregular shapes, especially in the form of shot peening agent bodies with regular and / or irregular shapes.

[0045] Furthermore, it is preferable that the shot peening agent is free of corners and / or edges, especially in the form of a shot peening agent body without corners and / or edges. This avoids the formation of notches on the surface of medical products, thereby further improving their corrosion resistance.

[0046] In principle, shot peening agents can be in the form of elliptical, ring-shaped, spherical, or bead-shaped shot peening agents, or in the form of shot peening agent bodies of the corresponding shape.

[0047] The shot peening agent is preferably spherical and / or bead-shaped, or in the form of a spherical and / or bead-shaped shot peening agent body.

[0048] Alternatively or in combination, the shot peening agent may have corners and / or edges. In particular, the shot peening agent may be a polyhedron, such as a cube, cuboid, prism, pyramid, or crystal, or in the form of a shot peening agent body of the corresponding shape. The shot peening agent may also have the shape of a right prism or oblique prism, or in the form of a shot peening agent body of the corresponding shape.

[0049] Alternatively or in combination, the shot peening agent may be conical and / or truncated conical, or in the form of a conical and / or truncated conical shot peening agent body.

[0050] Alternatively or in combination, the shot peening agent may be in spherical form, such as in the form of filaments, or in the form of shot peening agent bodies of the corresponding shape.

[0051] Alternatively or in combination, shot peening agents can be in fragmented form, especially in the form of fragmented shot peening agent bodies.

[0052] Furthermore, the shot peening agent or shot peening agent body may have at least one dimension, particularly at least one average dimension, such as diameter, particularly average diameter, and / or height, particularly average height, and / or length, particularly average length, which is from 40 µm to 2000 µm. In the context of this invention, the diameter of a spherical shot peening agent or spherical shot peening agent body should be understood as twice the radius of the spherical shot peening agent or a single spherical shot peening agent body. Conversely, in the context of this invention, the diameter of a non-spherical shot peening agent or non-spherical shot peening agent body should be understood as referring to the maximum possible distance between two points, which can be taken relative to each other along the circumference of the non-spherical shot peening agent or a single non-spherical shot peening agent. The average dimension mentioned in this paragraph can be determined by, for example, laser diffraction or sieve analysis.

[0053] To accelerate the shot blasting agent or shot blasting mass onto the surface of a medical product, pressure jetting equipment, jetting equipment, or impeller equipment can be used, for example. If pressure jetting equipment or jetting equipment is used, pressures from 1 bar to 6 bar can be used.

[0054] In another embodiment of the invention, the surface of the medical product is not electropolished.

[0055] Alternatively, the surface of the medical product can be electropolished, particularly before step a), particularly between grinding on the surface of the medical product, particularly sliding grinding and / or belt grinding, and step a), particularly between treating the surface of the medical product with shot peening and performing step a), and / or after performing step a), particularly between performing step a) and treating the surface of the medical product with a passivating acid or a solution containing a passivating acid. Electropolishing is typically performed using an aqueous electrolyte solution. The aqueous electrolyte solution preferably contains an inorganic acid or mixture of inorganic acids, particularly selected from phosphoric acid, sulfuric acid, and mixtures thereof. The phosphoric acid content of the aqueous electrolyte solution can also be 20% to 70% by weight, particularly 30% to 60% by weight, preferably 40% to 50% by weight, based on the total weight of the aqueous electrolyte solution, and / or the sulfuric acid content can be 10% to 70% by weight, particularly 20% to 60% by weight, preferably 30% to 50% by weight, based on the total weight of the aqueous electrolyte solution. More preferably, the surface of the medical product is electropolished at a voltage of 2V to 10V, particularly a DC voltage. Here, the voltage can be kept constant or varied during electropolishing. More preferably at 5 A / dm 2 Up to 50 A / dm 2 The surface of the medical product is electropolished at a current density of [insert current density here]. It may be further preferred that the surface of the medical product be electropolished at a temperature of 50°C to 65°C. Regarding the grinding of the medical product surface mentioned in this paragraph, especially sliding grinding and / or belt grinding, and the treatment of the medical product surface with shot peening agents, please refer fully to the corresponding statements given to date in this specification. Regarding the treatment of the medical product surface with passivating acid or a solution containing passivating acid mentioned in this paragraph, please refer fully to the corresponding statements given in the following specification.

[0056] Typically, in order to perform step a), the surface of the medical product is anoly stripped in an electrolyte solution, i.e., the medical product forms the anode in the electrochemical cell.

[0057] In another embodiment of the invention, step a) is performed multiple times, particularly two, three, or four times.

[0058] This allows for particularly advantageous uniform treatment of the geometric characteristics of medical products, such as the closure of the medical product, without creating associated shadows. The closure of the medical product can be treated at two locations so that only a small amount of shadow is formed. Alternatively, it may be preferable to manufacture the medical product slowly during step a).

[0059] Alternatively, step a) can be performed only once.

[0060] In another embodiment of the invention, in order to perform step a), an acidic electrolyte aqueous solution is used, which in particular contains an inorganic acid or a mixture of inorganic acids.

[0061] In another embodiment of the invention, the inorganic acid is selected from phosphoric acid, sulfuric acid, and mixtures thereof. It has been found that aqueous solutions of electrolytes containing phosphoric acid and / or sulfuric acid are particularly advantageous for the electrochemical etching of surfaces of medical products made of stainless steel, especially corrosion-resistant stainless steel.

[0062] The acidic electrolyte aqueous solution can also be an aged acidic electrolyte aqueous solution.

[0063] Furthermore, the inorganic acid content of the acidic electrolyte aqueous solution can be from 50% to 95% by weight, particularly 60% to 95% by weight, preferably 75% to 95% by weight, based on the total weight of the acidic electrolyte aqueous solution. In particular, the phosphoric acid content of the acidic electrolyte aqueous solution can be from 10% to 70% by weight, particularly 20% to 70% by weight, especially 30% to 60% by weight, preferably 40% to 50% by weight, and / or the sulfuric acid content can be from 10% to 70% by weight, particularly 20% to 60% by weight, preferably 30% to 50% by weight, each based on the total weight of the acidic electrolyte aqueous solution.

[0064] Acidic electrolyte solutions may also contain additives, such as surfactants.

[0065] Advantageously, the corrosiveness of acidic electrolyte aqueous solutions can be specifically controlled by their water content. For example, the water content of the acidic electrolyte aqueous solution can be from 5% to 25% by weight, particularly from 5% to 15% by weight, preferably from 5% to 10% by weight, based on the total weight of the acidic electrolyte aqueous solution.

[0066] In another embodiment of the invention, step a) is performed for 6 to 14 minutes, particularly 8 to 12 minutes, preferably 10 minutes.

[0067] In another embodiment of the invention, step a) is performed at / at a voltage of <2V, particularly 1.2V to 1.8V, preferably 1.4V to 1.7V, more preferably 1.4V to 1.5V or 1.45V to 1.65V, especially a DC voltage, which is preferably measured at the anode (at the medical product to be surface treated or processed and / or manufactured). In this embodiment of the invention, the advantages of the invention are particularly evident. The voltage is preferably measured at the anode (at the medical product to be surface treated or processed and / or manufactured) using a silver-silver chloride electrode. The determined voltage is then converted to a standard hydrogen electrode. Typically, the voltage is set at the current source when it is unknown which portion of the voltage is applied to the anode and how much is applied to the residual resistance (e.g., wires, electrolyte, etc.). In this invention, accurate voltage at the anode is preferably crucial.

[0068] Furthermore, step a) can be performed with a constant or varying voltage, especially a DC voltage. Refer to the voltages disclosed in the preceding paragraphs for a suitable voltage range / value.

[0069] In another embodiment of the invention, step a) at / at 1.4 A / dm 2 Up to 2.4 A / dm 2 Especially 1.6A / dm 2 Up to 2.2 A / dm 2 1.8 A / dm is preferred. 2 Up to 2.0 A / dm 2 The current density is used. The (low) current density disclosed in this paragraph allows for particularly effective control of the etching of the surface of medical products over time.

[0070] In another embodiment of the invention, step a) is carried out at a temperature of 20°C to 90°C, especially 50°C to 80°C, preferably 70°C to 80°C.

[0071] In another embodiment of the invention, the surface of the medical product is not treated with a passivating acid or a solution containing a passivating acid, especially after step a). As already mentioned, this is because the etching step (step a) provided according to the invention can particularly advantageously promote the formation of a passivation layer on the surface of the medical product and thus lead to improved corrosion resistance of the medical product. This configuration of the invention also has the advantage of significantly reducing the processing / manufacturing time and / or cost of the medical product.

[0072] Alternatively, the surface of the medical product may be treated with a passivating acid or a solution containing a passivating acid, especially an aqueous solution containing a passivating acid, particularly after step a), and especially after electropolishing the surface of the medical product. For details regarding electropolishing of the medical product surface mentioned in this paragraph, please refer to the corresponding statements in the specification to date.

[0073] In this way, the formation of a passivation layer on the surface of medical products can be further enhanced or promoted, thus further improving the corrosion resistance of the medical products. In the case of medical products made of stainless steel containing chromium or chromium alloys, an enhanced chromium oxide layer can be formed on the surface of the medical product, for example, through a passivation step.

[0074] The passivating acid used can be, for example, citric acid and / or nitric acid. The solution containing the passivating acid used can be, for example, an aqueous solution containing citric acid, particularly having a citric acid content of 5% to 60% by weight, based on the total weight of the aqueous solution containing citric acid. Alternatively, the solution containing the passivating acid used can be an aqueous solution containing nitric acid, particularly having a nitric acid content of 5% to 60% by weight, based on the total weight of the aqueous solution containing nitric acid.

[0075] Citric acid is superior to nitric acid from both a health and operational safety perspective. Furthermore, citric acid allows for a thicker chromium oxide layer on medical products made of chromium-containing or chromium alloy stainless steel compared to nitric acid, because nitric acid also reduces the content of other alloying components in the case of such stainless steel.

[0076] For passivation, the medical product can be immersed in, for example, a passivating acid or a solution containing a passivating acid. Alternatively, the passivating acid or a solution containing a passivating acid can be sprayed or poured onto the surface of the medical product.

[0077] In addition, the surface of medical products can be treated with passivating acid or a solution containing passivating acid for 2 to 120 minutes, especially 5 to 60 minutes, preferably 10 to 30 minutes.

[0078] In addition, the surface of medical products can be treated with passivating acid or a solution containing passivating acid at a temperature of 20°C to 80°C, especially 30°C to 65°C, preferably 50°C to 60°C.

[0079] In addition, the surface of the medical product may be cleaned and / or degreased between step a) and treatment with a passivating acid or a solution containing a passivating acid, particularly between electropolishing the surface of the medical product and treatment with a passivating acid or a solution containing a passivating acid. For information on electropolishing of the medical product surface mentioned in this paragraph, please refer fully to the corresponding statements in the specification to date.

[0080] In another embodiment of the invention, step b) is performed after step a), particularly after electropolishing the surface of the medical product, and particularly after treating the surface of the medical product with a passivating acid or a solution containing a passivating acid. Specifically, the medical product is packaged and / or marked, particularly labeled. Preferably, step ab) is performed between steps a) and b), particularly between electropolishing the surface of the medical product and step b), particularly between treating the surface of the medical product with a passivating acid or a solution containing a passivating acid. Specifically, the medical product is sterilized, particularly steam sterilized. Alternatively, it may be preferred to perform step c) after step b), i.e., sterilize the medical product, particularly steam sterilize. For details regarding the electropolishing of the medical product surface and the treatment of the medical product surface with a passivating acid or a solution containing a passivating acid mentioned in this paragraph, please refer fully to the corresponding details given to date in the specification.

[0081] In another embodiment of the invention, the medical product comprises steel, preferably stainless steel, or the medical product is composed of steel, preferably stainless steel.

[0082] In the context of this invention, the term "stainless steel" (in accordance with EN 10020) is understood to mean alloy or non-alloy steel having a specific purity level, for example having a sulfur and / or phosphorus content of ≤ 0.025%, particularly < 0.025%.

[0083] Stainless steel may contain at least one alloying element selected from chromium, nickel, molybdenum, titanium, niobium, tungsten, vanadium, cobalt, and combinations thereof.

[0084] In particular, stainless steel can have a chromium content of 10% to 25% by mass.

[0085] More preferably, the stainless steel is a rust-free or corrosion-resistant stainless steel.

[0086] More preferably, the stainless steel is chromium-containing or chromium alloy-containing stainless steel. More preferably, the stainless steel is chromium-containing corrosion-resistant stainless steel or chromium alloy corrosion-resistant stainless steel.

[0087] In addition, stainless steel can be martensitic, ferritic or austenitic stainless steel.

[0088] Preferably, the stainless steel is a martensitic corrosion-resistant stainless steel, particularly so-called carbon martensitic stainless steel, i.e., corrosion-resistant stainless steel with chromium and carbon as the main alloying components, or so-called nickel martensitic stainless steel, i.e., corrosion-resistant stainless steel with nickel as the main alloying component, according to ISO 7153-1.

[0089] Specifically, the stainless steel can be a martensitic stainless steel with a chromium content of 10.5% to 13% by mass and / or a carbon content of 0.2% to 1% by mass.

[0090] Alternatively, the stainless steel may be, in particular, austenitic stainless steel with a chromium content of 16% to 21% by mass and / or a carbon content of 0.02% to 0.12% by mass.

[0091] Alternatively, stainless steel may be ferritic stainless steel, particularly having a chromium content of 12% to 18% by mass and / or a carbon content of <0.2% by mass.

[0092] For example, stainless steel can be stainless steel with the material abbreviation X12Cr13 (material number 1.4006). This is a martensitic stainless steel with a carbon content of 0.08% to 0.15% by mass, a chromium content of 11.5% to 13.5% by mass, and a nickel content of ≤0.75% by mass.

[0093] Alternatively, the stainless steel may be a martensitic corrosion-resistant stainless steel with the material abbreviation X12CrS13 (material number 1.4005). This stainless steel has a carbon content of 0.08% to 0.15% by mass, a chromium content of 12.0% to 14.0% by mass, a molybdenum content of ≤0.60% by mass, and an optional sulfur content of 0.15% to 0.35% by mass.

[0094] Alternatively, the stainless steel may be a martensitic corrosion-resistant stainless steel with the material abbreviation X20Cr13 (material number: 1.4021). This stainless steel has a carbon content of 0.16% to 0.25% by mass and a chromium content of 12.0% to 14.0% by mass.

[0095] Alternatively, the stainless steel may be a martensitic corrosion-resistant stainless steel with the material abbreviation X15Cr13 (material number: 1.4024). This stainless steel has a carbon content of 0.12% to 0.17% by mass and a chromium content of 12.0% to 14.0% by mass.

[0096] Alternatively, the stainless steel may be a martensitic corrosion-resistant stainless steel with the material abbreviation X30Cr13 (material number: 1.4028). This stainless steel has a carbon content of 0.26% to 0.35% by mass and a chromium content of 12.0% to 14.0% by mass.

[0097] Alternatively, the stainless steel can be a martensitic corrosion-resistant stainless steel with the material abbreviation X46Cr13 (material number: 1.4034). This stainless steel has a carbon content of 0.43% to 0.50% by mass and a chromium content of 12.5% ​​to 14.5% by mass.

[0098] Alternatively, the stainless steel may be a martensitic corrosion-resistant stainless steel with the material abbreviation X50CrMoV15 (material number: 1.4116). This stainless steel has a carbon content of 0.45% to 0.55% by mass, a chromium content of 14.0% to 15.0% by mass, a molybdenum content of 0.50% to 0.80% by mass, and a vanadium content of 0.10% to 0.20% by mass.

[0099] Alternatively, the stainless steel may be a martensitic corrosion-resistant stainless steel with the material abbreviation X17CrNi16-2 (material number: 1.4057). This stainless steel has a carbon content of 0.12% to 0.22% by mass, a chromium content of 15.0% to 17.0% by mass, and a nickel content of 1.5% to 2.5% by mass.

[0100] Alternatively, the stainless steel may be a martensitic corrosion-resistant stainless steel with the material abbreviation X39CrMo17-1 (material number: 1.4122). This stainless steel has a carbon content of 0.33% to 0.45% by mass, a chromium content of 15.5% to 17.5% by mass, a molybdenum content of 0.8% to 1.3% by mass, and a nickel content of ≤ 1.0% by mass.

[0101] Alternatively, the stainless steel can be a martensitic corrosion-resistant stainless steel with the material abbreviation X14CrMoS17 (material number: 1.4104). This stainless steel has a carbon content of 0.10% to 0.17% by mass, a chromium content of 15.5% to 17.5% by mass, a molybdenum content of 0.20% to 0.60% by mass, and a sulfur content of 0.15% to 0.35% by mass.

[0102] Alternatively, the stainless steel may be a martensitic corrosion-resistant stainless steel with the material abbreviation X3CrNiMo13-4 (material number: 1.4313). This stainless steel has a carbon content of ≤0.05% by mass, a chromium content of 12.0% to 14.0% by mass, a molybdenum content of 0.3% to 0.7% by mass, and a nickel content of 3.5% to 4.5% by mass.

[0103] Alternatively, the stainless steel may be a martensitic corrosion-resistant stainless steel with the material abbreviation X4CrNiMo16-5-1 (material number: 1.4418). This stainless steel has a carbon content of ≤0.06% by mass, a chromium content of 15.0% to 17.0% by mass, a molybdenum content of 0.80% to 1.50% by mass, and a nickel content of 4.0% to 6.0% by mass.

[0104] Alternatively, the stainless steel can be martensitic stainless steel with the material abbreviation X65Cr13. This stainless steel has a carbon content of 0.58% to 0.70% by mass, a chromium content of 12.5% ​​to 14.5% by mass, a manganese content of ≤1.00% by mass, a silicon content of ≤1.00% by mass, a phosphorus content of 0.04% by mass, and a sulfur content of 0.015% by mass.

[0105] Alternatively, the stainless steel may be a martensitic stainless steel with the material abbreviation X30CrMoN15-1 (material number: 1.4108). This stainless steel has a carbon content of 0.25% to 0.35% by mass, a chromium content of 14.0% to 16.0% by mass, a molybdenum content of 0.85% to 1.10% by mass, a nickel content of 0.50% by mass, a manganese content of 1.00% by mass, a silicon content of 1.00% by mass, and a nitrogen content of 0.03% to 0.50% by mass.

[0106] Alternatively, the stainless steel can be a martensitic stainless steel with the material abbreviation X70CrMo15 (material number: 1.4109). This stainless steel has a carbon content of 0.60% to 0.75% by mass, a chromium content of 14.0% to 16.0% by mass, a molybdenum content of 0.40% to 0.80% by mass, a manganese content of ≤1.00% by mass, a silicon content of ≤0.70% by mass, a phosphorus content of 0.04% by mass, and a sulfur content of 0.015% by mass.

[0107] Alternatively, the stainless steel can be a martensitic stainless steel with the material abbreviation X90CrMoV18 (material number: 1.4112). This stainless steel has a carbon content of 0.90%, a chromium content of 17% to 19%, and a molybdenum content of 0.90% by mass.

[0108] Alternatively, the stainless steel can be a martensitic stainless steel with the material abbreviation X38CrMoV15 (material number: 1.4117). This stainless steel has a carbon content of 0.38% by mass, a chromium content of 14% to 15% by mass, and a molybdenum content of 0.50% by mass.

[0109] Alternatively, the stainless steel can be a martensitic stainless steel with the material abbreviation X150CrMo17 (material number: 1.4125). This stainless steel has a carbon content of 1.10%, a chromium content of 17%, and a molybdenum content of 0.60% by mass.

[0110] Alternatively, the stainless steel may be a martensitic stainless steel with the material abbreviation X22CrMoNiS13-1 (material number: 1.4121). This stainless steel has a carbon content of 0.20% to 0.25% by mass, a chromium content of 12.0% to 14.0% by mass, a molybdenum content of 1.00% to 1.50% by mass, a nickel content of 0.80% to 1.20% by mass, a manganese content of 1.00% to 1.50% by mass, a silicon content ≤1.00% by mass, a phosphorus content of 0.045% by mass, and a sulfur content of 0.15% to 0.25% by mass.

[0111] Alternatively, the stainless steel can be a martensitic stainless steel with the material abbreviation X40CrMoVN16-2 (material number: 1.4123). This stainless steel has a carbon content of 0.35% to 0.50% by mass, a chromium content of 14.0% to 16.0% by mass, a molybdenum content of 1.00% to 2.50% by mass, a nickel content of 0.5% by mass, a manganese content of ≤1.00% by mass, a silicon content of ≤1.00% by mass, a phosphorus content of 0.04% by mass, and a sulfur content of 0.015% by mass.

[0112] Alternatively, the stainless steel may be a martensitic stainless steel with the material abbreviation X105CrMo17 (material number: 1.4125). This stainless steel has a carbon content of 0.95% to 1.20% by mass, a chromium content of 16.0% to 18.0% by mass, a molybdenum content of 0.04% to 0.80% by mass, a manganese content of up to 1.00% by mass, a silicon content of up to 1.00% by mass, a phosphorus content of up to 0.040% by mass, and a sulfur content of up to 0.015% by mass.

[0113] Alternatively, the stainless steel can be a precipitation-hardening corrosion-resistant stainless steel with the material abbreviation X5CrNiCuNb16-4 (material number: 1.4542). This stainless steel has a carbon content of ≤0.07% by mass, a chromium content of 15.0% to 17.0% by mass, a molybdenum content of ≤0.60% by mass, a nickel content of 3.0% to 5.0% by mass, a copper content of 3.0% to 5.0% by mass, and a niobium content of up to 0.45% by mass.

[0114] Alternatively, the stainless steel may be a precipitation-hardening corrosion-resistant stainless steel with the material abbreviation X7CrNiAl17-7 (material number: 1.4568). This stainless steel has a carbon content of ≤0.09%, a chromium content of 16.0% to 18.0%, a nickel content of 6.5% to 7.8%, and an aluminum content of 0.70% to 1.50%.

[0115] Alternatively, the stainless steel can be a precipitation-hardening corrosion-resistant stainless steel with the material abbreviation X5CrNiMoCuNb14-5 (material number: 1.4594). This stainless steel has a carbon content of ≤0.07% by mass, a chromium content of 13.0% to 15.0% by mass, a molybdenum content of 1.20% to 2.00% by mass, a nickel content of 5.0% to 6.0% by mass, a copper content of 1.20% to 2.00% by mass, and a niobium content of 0.15% to 0.60% by mass.

[0116] Alternatively, the stainless steel can be a precipitation-hardening corrosion-resistant stainless steel with the material abbreviation X3CrNiTiMb12-9 (material number: 1.4543). This stainless steel has the following mass content: carbon ≤0.03%, chromium 11.0% to 12.5%, molybdenum ≤0.50%, nickel 3.00% to 5.00%, titanium ≤0.90% to 1.40%, copper 1.50% to 2.50%, niobium 0.10% to 0.50%, manganese 0.50%, silicon 0.50%, phosphorus ≤0.02%, and sulfur ≤0.015%.

[0117] Alternatively, the stainless steel may be a ferritic corrosion-resistant stainless steel with the material abbreviation X2CrNi12 (material number: 1.4003). This stainless steel has a carbon content of ≤0.03% by mass, a chromium content of 10.5% to 12.5% ​​by mass, a nickel content of 0.3% to 1.00% by mass, and a nitrogen content of ≤0.03% by mass.

[0118] Alternatively, the stainless steel may be a ferritic corrosion-resistant stainless steel with the material abbreviation X2CrNi12 (material number: 1.4512). This stainless steel has a carbon content of ≤0.03% by mass, a chromium content of 10.5% to 12.5% ​​by mass, and a titanium content of up to 0.65% by mass.

[0119] Alternatively, the stainless steel can be a ferritic corrosion-resistant stainless steel with the material abbreviation X6Cr17 (material number: 1.4016). This stainless steel has a carbon content of ≤0.08% by mass and a chromium content of 16.0% to 18.0% by mass.

[0120] Alternatively, the stainless steel may be a ferritic corrosion-resistant stainless steel with the material abbreviation X3CrTi17 (material number: 1.4510). This stainless steel has a carbon content of ≤0.05% by mass, a chromium content of 16.0% to 18.0% by mass, and a titanium content of up to 0.80% by mass.

[0121] Alternatively, the stainless steel may be a ferritic corrosion-resistant stainless steel with the material abbreviation X6CrMoS17 (material number: 1.4105). This stainless steel has a carbon content of ≤0.08% by mass, a chromium content of 16.0% to 18.0% by mass, a molybdenum content of 0.20% to 0.60% by mass, and a sulfur content of 0.15% to 0.35% by mass.

[0122] Alternatively, the stainless steel may be a ferritic corrosion-resistant stainless steel with the material abbreviation X3CrNb17 (material number: 1.4511). This stainless steel has a carbon content of ≤0.05% by mass, a chromium content of 16.0% to 18.0% by mass, and a niobium content of up to 1.00% by mass.

[0123] Alternatively, the stainless steel may be a ferritic corrosion-resistant stainless steel with the material abbreviation X2CrTiNb18 (material number: 1.4509). This stainless steel has a carbon content of ≤0.03% by mass, a chromium content of 17.5% to 18.5% by mass, a niobium content of up to 1.00% by mass, and a titanium content of 0.10% to 0.60% by mass.

[0124] Alternatively, the stainless steel can be a ferritic corrosion-resistant stainless steel with the material abbreviation X6CrMo17-1 (material number: 1.4113). This steel has a carbon content of ≤0.08% by mass, a chromium content of 16.0% to 18.0% by mass, and a molybdenum content of 0.90% to 1.40% by mass.

[0125] Alternatively, the stainless steel may be a ferritic corrosion-resistant stainless steel with the material abbreviation X2CrMoTi18-2 (material number: 1.4521). This stainless steel has a carbon content of ≤0.025% by mass, a chromium content of 17.0% to 20.0% by mass, a molybdenum content of 1.80% to 2.50% by mass, and a titanium content of up to 0.80% by mass.

[0126] Alternatively, the stainless steel can be an austenitic-ferritic corrosion-resistant stainless steel with the material abbreviation X2CrNi22-2 (material number: 1.4062). This stainless steel has a carbon content of ≤0.03% by mass, a chromium content of 21.5% to 24.0% by mass, a molybdenum content of ≤0.45% by mass, a nickel content of 1.00% to 2.90% by mass, and a nitrogen content of 0.16% to 0.28% by mass.

[0127] Alternatively, the stainless steel may be an austenitic-ferritic corrosion-resistant stainless steel with the material abbreviation X2CrMnNiN21-5-1 (material number: 1.4162). This stainless steel has a carbon content of ≤0.04%, a chromium content of 21.0% to 22.0%, a molybdenum content of 0.10% to 0.80%, a nickel content of 1.35% to 1.70%, a manganese content of 4.0% to 6.0%, a nitrogen content of 0.20% to 0.25%, and a copper content of 0.10% to 0.80%.

[0128] Alternatively, the stainless steel can be an austenitic-ferritic corrosion-resistant stainless steel with the material abbreviation X2CrNiN23-4 (material number: 1.4362). This stainless steel has a carbon content of ≤0.03% by mass, a chromium content of 22.0% to 24.0% by mass, a molybdenum content of 0.10% to 0.60% by mass, a nickel content of 3.5% to 5.5% by mass, and a copper content of 0.10% to 0.60% by mass.

[0129] Alternatively, the stainless steel may be an austenitic-ferritic corrosion-resistant stainless steel with the material abbreviation X2CrNiMoN22-5-3 (material number: 1.4462). This stainless steel has a carbon content of ≤0.03% by mass, a chromium content of 21.0% to 23.0% by mass, a molybdenum content of 2.5% to 3.5% by mass, a nickel content of 4.5% to 6.5% by mass, and a nitrogen content of 0.10% to 0.22% by mass.

[0130] Alternatively, the stainless steel can be an austenitic-ferritic corrosion-resistant stainless steel with the material abbreviation X2CrNiMnMoCuN24-4-3-2 (material number: 1.4662). This stainless steel has a carbon content of ≤0.03%, a chromium content of 23.0% to 25.0%, a molybdenum content of 1.00% to 2.00%, a nickel content of 3.0% to 4.5%, a manganese content of 2.5% to 4.0%, and a copper content of 0.10% to 0.80%.

[0131] Alternatively, the stainless steel can be an austenitic-ferritic corrosion-resistant stainless steel with the material abbreviation X2CrNiMoN25-7-4 (material number: 1.4410). This stainless steel has a carbon content of ≤0.03% by mass, a chromium content of 24.0% to 26.0% by mass, a molybdenum content of 3.0% to 4.5% by mass, a nickel content of 6.0% to 8.0% by mass, and a nitrogen content of 0.24% to 0.35% by mass.

[0132] Alternatively, the stainless steel may be an austenitic-ferritic corrosion-resistant stainless steel with the material abbreviation X2CrNiMoCuWN25-7-4 (material number: 1.4501). This stainless steel has a carbon content of ≤0.03% by mass, a chromium content of 24.0% to 26.0% by mass, a molybdenum content of 3.0% to 4.0% by mass, a nickel content of 6.0% to 8.0% by mass, a copper content of 0.50% to 1.00% by mass, a tungsten content of 0.50% to 1.00% by mass, and a nitrogen content of 0.20% to 0.30% by mass.

[0133] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X2CrNiMo18-15-3 (material number: 1.4441). This stainless steel has a carbon content of up to 0.030% by mass, a chromium content of 17.0% to 19.0% by mass, a molybdenum content of 2.7% to 3.0% by mass, a nickel content of 13.0% to 15.0% by mass, a manganese content of up to 2.00% by mass, a copper content of up to 0.50% by mass, a silicon content of up to 0.75% by mass, a phosphorus content of up to 0.025% by mass, a sulfur content of up to 0.003% by mass, and a nitrogen content of up to 0.10% by mass.

[0134] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X5CrNi18-10 (material number: 1.4301). This stainless steel has a carbon content of ≤0.07% by mass, a chromium content of 17.5% to 19.5% by mass, a nickel content of 8.0% to 10.5% by mass, and a nitrogen content of ≤0.11% by mass.

[0135] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X4CrNi18-12 (material number: 1.4303). This stainless steel has a carbon content of ≤0.06% by mass, a chromium content of 17.0% to 19.0% by mass, a nickel content of 11.0% to 13.0% by mass, and a nitrogen content of ≤0.11% by mass.

[0136] Alternatively, the stainless steel can be an austenitic corrosion-resistant stainless steel with the material abbreviation X8CrNiS18-9 (material number: 1.4305). This stainless steel has a carbon content of ≤0.10%, a chromium content of 17.0% to 19.0%, a nickel content of 8.0% to 10.0%, a sulfur content of 0.15% to 0.35%, and a copper content of ≤1.00%.

[0137] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X2CrNi19-11 (material number: 1.4306). This stainless steel has a carbon content of ≤0.030%, a chromium content of 18.0% to 20.0%, a nickel content of 10.0% to 12.0%, and a nitrogen content of ≤0.11%.

[0138] Alternatively, the stainless steel can be an austenitic corrosion-resistant stainless steel with the material abbreviation X2CrNi18-9 (material number: 1.4307). This stainless steel has a carbon content of ≤0.030%, a chromium content of 17.5% to 19.5%, a nickel content of 8.0% to 10.5%, and a nitrogen content of ≤0.11%.

[0139] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X2CrNi18-10 (material number: 1.4311). This stainless steel has a carbon content of ≤0.030% by mass, a chromium content of 17.5% to 19.5% by mass, a nickel content of 8.5% to 11.5% by mass, and a nitrogen content of 0.12% to 0.22% by mass.

[0140] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X6CrNiTi18-10 (material number: 1.4541). This stainless steel has a carbon content of ≤0.08% by mass, a chromium content of 17.0% to 19.0% by mass, a nickel content of 9.0% to 12.0% by mass, and a titanium content of up to 0.70% by mass.

[0141] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X6CrNiNb18-10 (material number: 1.4550). This stainless steel has a carbon content of ≤0.08% by mass, a chromium content of 17.0% to 19.0% by mass, a nickel content of 9.0% to 12.0% by mass, and a niobium content of up to 1.00% by mass.

[0142] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X3CrNiCu18-9-4 (material number: 1.4567). This stainless steel has a carbon content of ≤0.04% by mass, a chromium content of 17.0% to 19.0% by mass, a nickel content of 8.5% to 10.5% by mass, and a copper content of 3.0% to 4.0% by mass.

[0143] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X10CrNi18-8 (material number: 1.4310). This stainless steel has a carbon content of 0.05% to 0.15% by mass, a chromium content of 16.0% to 19.0% by mass, a molybdenum content of ≤0.80% by mass, and a nickel content of 6.0% to 9.5% by mass.

[0144] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X5CrNiMo17-12-2 (material number: 1.4401). This stainless steel has a carbon content of ≤0.07%, a chromium content of 16.5% to 18.5%, a molybdenum content of 2.00% to 2.50%, a nickel content of 10.0% to 13.0%, and a nitrogen content of ≤0.10%.

[0145] Alternatively, the stainless steel can be an austenitic corrosion-resistant stainless steel with the material abbreviation X2CrNiMo17-12-2 (material number: 1.4404). This stainless steel has a carbon content of ≤0.030%, a chromium content of 16.5% to 18.5%, a molybdenum content of 2.00% to 2.50%, a nickel content of 10.0% to 13.0%, and a nitrogen content of ≤0.10%.

[0146] Alternatively, the stainless steel can be an austenitic corrosion-resistant stainless steel with the material abbreviation X6CrNiMoTi17-12-2 (material number: 1.4571). This stainless steel has a carbon content of ≤0.08% by mass, a chromium content of 16.5% to 18.5% by mass, a molybdenum content of 2.00% to 2.50% by mass, a nickel content of 10.5% to 13.5% by mass, and a titanium content of up to 0.70% by mass.

[0147] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X2CrNiMoN17-13-3 (material number: 1.4429). This stainless steel has a carbon content of ≤0.030%, a chromium content of 16.5% to 18.5%, a molybdenum content of 2.5% to 3.0%, a nickel content of 11.0% to 14.0%, and a nitrogen content of 0.12% to 0.22%.

[0148] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X2CrNiMo18-14-3 (material number: 1.4435). This stainless steel has a carbon content of ≤0.030%, a chromium content of 17.0% to 19.0%, a molybdenum content of 2.5% to 3.0%, a nickel content of 12.5% ​​to 15.0%, and a nitrogen content of ≤0.10%.

[0149] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X3CrNiMo17-13-3 (material number: 1.4436). This stainless steel has a carbon content of ≤0.05% by mass, a chromium content of 16.5% to 18.5% by mass, a molybdenum content of 2.5% to 3.0% by mass, a nickel content of 10.5% to 13.0% by mass, and a nitrogen content of ≤0.10% by mass.

[0150] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X2CrNiMoN17-13-5 (material number: 1.4439). This stainless steel has a carbon content of ≤0.030%, a chromium content of 16.5% to 18.5%, a molybdenum content of 4.0% to 5.0%, a nickel content of 12.5% ​​to 14.5%, and a nitrogen content of 0.12% to 0.22%.

[0151] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X1NiCrMoCu25-20-5 (material number: 1.4539). This stainless steel has a carbon content of ≤0.020%, a chromium content of 19.0% to 21.0%, a molybdenum content of 4.0% to 5.0%, a nickel content of 24.0% to 26.0%, a copper content of 1.20% to 2.00%, and a nitrogen content of ≤0.15%.

[0152] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X2CrNiMnMoNbN25-18-5-4 (material number: 1.4565). This stainless steel has a carbon content ≤0.030%, a chromium content of 24.0% to 26.0%, a molybdenum content of 4.0% to 5.0%, a nickel content of 16.0% to 19.0%, a manganese content of 5.0% to 7.0%, a nitrogen content of 0.30% to 0.60%, and a niobium content ≤0.15%.

[0153] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X1NiCrMoCuN25-20-7 (material number: 1.4529). This stainless steel has a carbon content of ≤0.020%, a chromium content of 19.0% to 21.0%, a molybdenum content of 6.0% to 7.0%, a nickel content of 24.0% to 26.0%, a copper content of 0.50% to 1.50%, and a nitrogen content of 0.15% to 0.25%.

[0154] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X1CrNiMoCuN20-18-7 (material number: 1.4547). This stainless steel has a carbon content of ≤0.020%, a chromium content of 19.5% to 20.5%, a molybdenum content of 6.0% to 7.0%, a nickel content of 17.5% to 18.5%, a copper content of 0.50% to 1.00%, and a nitrogen content of 0.18% to 0.25%.

[0155] Alternatively, the stainless steel may be an austenitic corrosion-resistant stainless steel with the material abbreviation X1CrNiMoCuN24-22-8 (material number: 1.4652). This stainless steel has a carbon content of ≤0.020%, a chromium content of 23.0% to 25.0%, a molybdenum content of 7.0% to 8.0%, a nickel content of 21.0% to 23.0%, a manganese content of 2.0% to 4.0%, and a nitrogen content of 0.45% to 0.55%.

[0156] In another embodiment of the invention, the medical product is a medical device, preferably a surgical instrument. The device may be a reusable device or a disposable device (“disposable device”).

[0157] In addition, the device can be a minimally invasive device, that is, a device that can be used for minimally invasive surgery.

[0158] Surgical instruments can be selected in particular from dilators, clamping instruments, clamping instruments, cutting instruments, suturing devices, endoscopes, and combination instruments.

[0159] For example, dilators can be wound hooks, retractors, wound dilators, sternal dilators, wound retractors, endoscopes, or cannulas.

[0160] For example, the clamping device can be tweezers, clamps, needle holders, or clamping forceps.

[0161] For example, clamping devices can be soft clamps, especially for temporary occlusion of the intestine and capillaries, or preparatory clamps.

[0162] For example, cutting instruments can be scalpels, knives, scissors, branch forceps, bone splitting forceps, ring forceps, electrocautery, nasal turbinate knife, cauterizers, or ultrasonic scalpels.

[0163] The suturing device may in particular be a stapler (suture device) or a stapler remover.

[0164] Combined instruments can be, for example, internal anastomotic staples or staples that clamp and simultaneously and precisely cut hollow organs. Alternatively, combined instruments can be combined needle holders that serve as universal suturing devices, capable of both clamping and cutting.

[0165] In addition, surgical instruments can be hammers.

[0166] In addition, surgical instruments can be chisels, especially flat or hollow chisels, such as bone hollow chisels, or curettes, especially bone curettes.

[0167] In addition, surgical instruments can be probes.

[0168] In addition, surgical instruments can be bone punchers.

[0169] In addition, surgical instruments can be joysticks, lifts, or respirators.

[0170] In a second aspect, the present invention relates to medical products comprising or composed of metals or alloys, wherein the medical products are manufactured or can be manufactured by a method according to a first aspect of the invention and / or have at least one of the following characteristics: - Pitting potentials of 100 mV to 1200 mV, especially 200 mV to 800 mV, preferably 400 mV to 500 mV (measured relative to a standard hydrogen electrode), and / or - A contact angle of 90° to 140°, especially 100° to 130°, preferably 110° to 130°, and / or - A passivation layer, which is made of chromium oxide in particular, has a thickness of 1 nm to 10 nm, especially 3 nm to 10 nm, preferably 5 nm to 10 nm, which at least partially, especially only partially or completely coats the surface of the medical product.

[0171] In terms of corrosion resistance of medical products, the aforementioned pitting potential and contact angle are particularly advantageous.

[0172] In the context of this invention, the term "pitting potential" is understood to refer to an electrochemical potential, which can be determined using an electrochemical cell with a three-electrode arrangement. The pitting potential is characterized by a rapid rise in current and describes the collapse of the passivation layer as pitting occurs. An increase in pitting potential improves corrosion resistance by reducing the tendency for pitting.

[0173] Pitting potential can be measured according to ASTM G5-13-1 or DIN EN ISO 10993-15.

[0174] In the context of this invention, the term "contact angle" should be understood as the angle formed by a droplet on the surface of a medical product relative to that surface. A reduced contact angle relates to reduced contact between the droplet and the surface of the medical product. A reduced contact angle is particularly advantageous in producing improvements in the corrosion resistance and cleanability of the medical product.

[0175] Contact angles can be measured according to ASTM D 7334-08. Alternatively, contact angle measurements can be performed using a contact angle measuring instrument from dataPhysics (Contact Angle System OCA 15 Plus) and a 0.9% sodium chloride solution (B. Braun) with a droplet volume of 1 µl. For contact angle measurements, samples in this case can be cleaned during the standard manufacturing process and then cleaned in softened water in an ultrasonic bath for 5 minutes prior to measurement, with the sample rinsed with softened water and dried with oil-free compressed air just before measurement.

[0176] Medical products are preferred, especially surgical instruments.

[0177] To avoid repetition, further features and advantages of the medical product are described entirely in the context of the first aspect of the invention. The features and advantages described therein relating to the method and the medical product are also applicable by analogy to the medical product according to the second aspect of the invention.

[0178] Other features and advantages of the invention will become apparent from the following description of preferred embodiments of the claims and reference examples. Here, the features of the invention may be implemented individually or in combination with each other. The embodiments described below are intended to further illustrate the invention and not to limit it thereto.

[0179] Example Section 1. Surface treatment of surgical instruments or representative specimens according to the method of the present invention. The specimens and surgical instruments used were all made of the same martensitic stainless steel (X20Cr13) and with the same manufacturing steps and parameters.

[0180] The instrument and sample sheet were subjected to SEM / EDX analysis (foreign material and material overlap).

[0181] Similarly, potentiodynamic testing (pitting potential) was performed on the instrument and sample sheet.

[0182] Contact angle measurements (contact angle) are performed on a sample sheet (a flat surface without shadows).

[0183] Gloss measurement (gloss level) is performed on a sample sheet (a flat surface without shadows).

[0184] 3D laser confocal microscopy (roughness depth) is performed on a sample slide (a plane without shadows).

[0185] Prior to surface treatment, surgical instruments, corrosion specimens, and sample sheets are shaped and heat-treated according to the current surgical instrument production chain.

[0186] For subsequent surface treatment, the surgical instruments (clamp BH110R), etched specimens, and sample pieces were polished by gliding and grinding in an acidic solution for four hours, followed by gliding and grinding in an aqueous solution for one hour.

[0187] Subsequently, the surgical instruments, etched specimens, and sample pieces were subjected to electrochemical etching. For this, the components were immersed in an acidic electrolyte solution heated to 40 °C, containing 11 wt% phosphoric acid and 61 wt% sulfuric acid, and a DC voltage was applied for 10 minutes to generate a voltage of 1.5 V at the anode. The current density was set to 2.0 A / dm².

[0188] Finally, the surgical instruments, corroded specimens, and sample pieces were passivated. For this, the components were immersed in a 10% wt% citric acid solution at 60°C for 10 minutes. Afterward, the components were acid-washed and cleaned in ethanol.

[0189] After fabrication, the formation on the instrument and sample surfaces was examined using scanning electron microscopy and energy-dispersive X-ray spectroscopy. SEM studies showed that the etch pits were almost randomly distributed on the surface, with slight localization at grain boundaries. These were on the order of approximately 5 µm. The chemical composition was homogeneous and contained approximately 0.1% less chromium by weight compared to the starting material. This is due to chromium carbide dissolved from the surface.

[0190] Furthermore, the surface morphology of the instruments and sample pieces was evaluated using 3D laser confocal microscopy and metallographic specimens. The average roughness depth of 0.5 µm was determined using 3D laser confocal measurements. This is attributed to the depth of the etch pits, which, according to metallographic studies, ranges from 1 to 3 µm.

[0191] Changes in reflectance properties were examined by measuring the gloss of the test pieces. A significant decrease in gloss was observed, with values ​​of 3.7 gloss units (20°) and 21.6 gloss units (60°). The reflectance properties were therefore determined to be strongly matte.

[0192] Wetting analysis of the liquid was performed by measuring the contact angle on the test piece. The average contact angle determined here was 116.3°.

[0193] Finally, the electrochemical / corrosion characteristics of the formed surface were examined and the pitting potential was determined by potentiodynamic polarization measurements on the corroded samples. To compare whether the measurements on the samples were instrument-dependent, the pitting potential was measured on laboratory instruments. The results for the samples were confirmed here. A pitting potential of 475 mV could be recorded here.

[0194] 2. Surface treatment of surgical instruments according to general methods. First, the surgical instruments (clamped with BH110R), the corroded specimen, and the sample piece were subjected to sliding grinding for four hours. Afterward, the surgical instruments and sample piece were allowed to brighten for one hour.

[0195] Subsequently, the surgical instruments and specimens are treated by spraying. For this purpose, glass beads with an average diameter of 40 μm to 70 μm are used. The spraying is carried out in a spraying device at a pressure of 4 bar.

[0196] Subsequently, the surgical instruments and specimens were passivated. For this purpose, a 10% citric acid solution was used. Passivation was performed at 55°C for 10 minutes.

[0197] After surface treatment of the surgical instruments and specimens, numerous material overlaps or mattings were observed. Furthermore, 1.4% foreign material transfer was detected. The roughness depth was approximately 0.151 µm. Additionally, the contact angle of the sample sheet was 66.0°. The gloss levels were determined to be 41.9 gloss units (20°) and 159.8 gloss units (60°), thus describing it as slightly frosted. The pitting potential of the corroded specimen was 386 mV.

[0198] 3. Conclusion The above comparison between the method of the present invention and general methods shows that the method of the present invention produces a more corrosion-resistant product with very little reflection (gloss).

Claims

1. A method of manufacturing a surgical instrument or a component of a surgical instrument, wherein the surgical instrument or a component of a surgical instrument comprises or is composed of chromium-containing stainless steel, wherein the method includes the following steps: a) Electrochemical etching of the surgical instrument or a component of the surgical instrument, characterized in that step a) is performed at 1.6 A / dm 2 Up to 2.2A / dm 2 The experiment was conducted at a current density. In this process, after step a), the surface of the surgical instrument or a component of the surgical instrument is treated with a passivating acid or a solution containing a passivating acid. Prior to step a), sliding grinding is performed on the surface of the surgical instrument or a component of the surgical instrument.

2. The method according to claim 1, characterized in that, Prior to step a), belt grinding is performed on the surface of the surgical instrument or a component of the surgical instrument.

3. The method according to claim 1 or 2, characterized in that, The surface of the surgical instrument or its components was not treated with shot blasting and / or not electropolished.

4. The method according to claim 1 or 2, characterized in that, Step a) is performed multiple times.

5. The method according to claim 1 or 2, characterized in that, Step a) can be performed two, three, or four times.

6. The method according to claim 1 or 2, characterized in that, To perform step a), an acidic electrolyte aqueous solution is used.

7. The method according to claim 6, characterized in that, The acidic electrolyte aqueous solution contains inorganic acids or mixtures of inorganic acids.

8. The method according to claim 7, characterized in that, The inorganic acid is selected from phosphoric acid, sulfuric acid, and mixtures thereof.

9. The method according to claim 1 or 2, characterized in that, Step a) lasts for 6 to 14 minutes.

10. The method according to claim 1 or 2, characterized in that, Step a) last for 8 to 12 minutes.

11. The method of claim 1 or 2, wherein, Step a) lasts for 10 minutes.

12. The method of claim 1 or 2, wherein, Step a) at 1.8 A / dm 2 Up to 2.0 A / dm 2 The experiment was conducted at a current density of [specific value].

13. The method of claim 1 or 2, wherein, Step a) is performed at a temperature between 20°C and 90°C.

14. The method of claim 1 or 2, wherein, Step a) is performed at a temperature of 50°C to 80°C.

15. The method of claim 1 or 2, wherein, Step a) is performed at a temperature of 70°C to 80°C.

16. The method of claim 1 or 2, wherein, Step b) is performed after step a), i.e., packaging the surgical instrument or components of the surgical instrument, and step ab) is performed between steps a) and b), i.e., sterilizing the surgical instrument or components of the surgical instrument, or step c) is performed after step b), i.e., sterilizing the surgical instrument or components of the surgical instrument.

17. The method of claim 1 or 2, wherein, The surgical instruments or components thereof are made of chromium-containing corrosion-resistant stainless steel.

18. The method of claim 1 or 2, wherein, The surgical instruments or components thereof are made of martensitic corrosion-resistant stainless steel.