GB2590493A - Joining by coating components - Google Patents

Abstract

A method of making a fluid conduit 290 for high performance liquid chromatography from two components 200 & 250, each having a coating 230 & 260 on a side thereof and at least one of these sides having an indentation therein. At least one coating 230,260 is activated by means of ion bombardment, plasma treatment, corona discharge ion beam treatment, atom bombardment, etching or UV or passivation is inhibited. The coated sides of the components 200,250 are pressed together to form a body in which the conduit 290 lies either parallel to or perpendicular to the abutting sides of the components 200,250. The coatings 230,260 can be PVD or CVD deposited diamond-like carbon which can be doped (e.g. by O, Si, N or fluorinated DLC), a ceramic, a carbide (e.g. BTiC), titanium nitride, Ti2AlN or silicon. Each component 200,250 can further comprise an intermediate adhesion layer. The method can be used to coat and bond together components made from metal sheet (e.g stainless steel), polymers (e.g. PEEK) or ceramics. The indentation can be in the form of micro-channels in a microfluidic device.

Description

JOINING BY COATING COMPONENTS

BACKGROUND ART

[0001] The present invention relates to joining components in particular for providing a fluidic conduit preferably for use in a high-performance liquid chromatography application.

[0002] In high performance liquid chromatography (HPLC), a liquid has to be provided usually at a very controlled flow rate (e. g. in the range of microliters to milliliters per minute) and at high pressure (typically 20-100 MPa, 200-1000 bar, and beyond up to currently 200 MPa, 2000 bar) at which compressibility of the liquid becomes noticeable. For liquid separation in an HPLC system, a mobile phase comprising a sample fluid (e.g. a chemical or biological mixture) with compounds to be separated is driven through a stationary phase (such as a chromatographic column packing), thus separating different compounds of the sample fluid which may then be identified. The term compound, as used herein, shall cover compounds which might comprise one or more different components.

[0003] The mobile phase, for example a solvent, is pumped under high pressure typically through a chromatographic column containing packing medium (also referred to as packing material or stationary phase). As the sample is carried through the column by the liquid flow, the different compounds, each one having a different affinity to the packing medium, move through the column at different speeds. Those compounds having greater affinity for the stationary phase move more slowly through the column than those having less affinity, and this speed differential results in the compounds being separated from one another as they pass through the column. The stationary phase is subject to a mechanical force generated in particular by a hydraulic pump that pumps the mobile phase usually from an upstream connection of the column to a downstream connection of the column. As a result of flow, depending on the physical properties of the stationary phase and the mobile phase, a relatively high-pressure drop is generated across the column.

[0004] In particular in HPLC but also in other applications, there often is a need for joining components together. Further, there often is a need to provide a fluidic flow path e.g. suitable to withstand certain chemicals as well as high pressure -1 -requirements.

DISCLOSURE

[0005] It is an object of the invention to provide an improved joining of components in particular for providing a fluidic conduit preferably for use in a high-performance liquid chromatography application. The object is solved by the independent claim(s).

Further embodiments are shown by the dependent claim(s).

[0006] Diamond-like Carbon (DLC) coatings are used in many industrial and medical applications and showing excellent characteristics in aggressive environments, at high mechanical stress situations and in tribological systems.

[0007] Embodiments of the present invention provide a bonding method utilizing modifiable DLC layers to form low dispersion, flow optimized, mechanically robust and biocompatible (micro-) channels.

[0008] Embodiments of the present invention allow providing chemically resistant and mechanically stable bio-compatible surfaces preferably in high-pressure (micro- 15)channel applications, for example in combination with a strong mechanical and pressure stable bond. Also or in addition, embodiments provide higher flow velocities to enable higher throughput. Further, embodiments enable advancing certain microfluidics technologies, such as metal microfluidics (MMF) applying layered metal sheets, to a wider material spectrum and market including bio-compatible applications. Certain embodiments allow application of very high pressure and minimized dispersion in (micro-)channels in order to increase resolution and flow velocities.

[0009] Embodiments of the present invention providing DLC bonding may create a pin hole free, highly chemical resistant, mechanically strong and completely biocompatible bond-zone between two substrates. Using this bonding technique to form a (micro-)channel may enable higher flow velocities, a biocompatible flow channel in materials originally not biocompatible and a reliably strong bond between two substrates for high pressure application (such as the aforementioned MMF applications).

[0010] Embodiments of the present invention allow avoiding the need to bond (e.g. -2 -diffusion bonding) and sequentially coat the microchannels e.g. using an expansive and time-consuming ceramic coating.

[0011] Embodiments of the present invention allow providing robust bonding as well as giving the microchannel a chemically resistant, biocompatible and flow optimized coating in one process step.

[0012] Embodiments of the present invention allow providing a hydrophobic coating and properties enable higher flow velocities and reduced back-pressure.

[0013] Embodiments of the present invention allow providing a strong reduction of the sample dispersion and thus an increase of the level of detection due to low wall friction of the DLC Layer in the channels.

[0014] Embodiments of the present invention allow providing a better sample resolution and therefore enabling better overall analyses, in particular in HPLC and SEC applications.

[0015] An exemplary embodiment is provided by the process: Etching or/and micromachining (micro-)channels into metal sheet and sequentially polish the surface. Using a common plasma-enhanced chemical vapor deposition or PVD process to coat the surface of the micro-structured sheets with a DLC multi-layer. The coating surface is preferably not passivated or may be actively activated e.g. using plasma, UV or chemical activation etc. (preferably shortly after finishing the coating).

Aligning active or activated bond zones and press them together to make sure the active surface groups of the two DLC layers can unite and form a strong bond.

[0016] DLC bonding according to embodiments of the present invention can provide a pin hole free, highly chemical resistant, mechanically strong and completely biocompatible bond-zone between two substrates. Using this bonding technique to form a (micro)-channel can enable higher flow velocities, a biocompatible flow channel in materials originally not biocompatible, and a reliably strong bond between two substrates for high pressure application. This can be achieved by the material properties of the DLC coating. The DLC coating may lead to a strong decrease of sample dispersion, which can lead to an increase in the level of detection and therefore leads to a better sample resolution. Modification of the DLC layer (by adding -3 -additional atoms during the deposition process) can improve other properties of the layer and thus of the microchannel. This is described e.g. in "Doping and Alloying Effects on DLC Coatings" by J. C. Sanchez-Lopez and A. Fernandez, See httos:filink.sorinaereornichapter/10.1007%2F978-0-387-49891-1 12 Chapter 12 for on overview on doping and alloying effects on DLC coatings.

[0017] According to an exemplary embodiment of the present invention, a method of joining (e.g. in the sense of bonding) a first component with a second component is provided. The first and second components may preferably be so called half elements, for example half shell elements. Such half elements may be used to form a cavity and/or channel e.g. capable for conducting or storing a fluid, when joining such two or more half elements together by a suitable joining technology. The method comprises providing a first side of the first component as well as a second side of the second component with a coating, and pressing together the coating of the first side and the coating of the second side (e.g. by pressing together the coated first side of the first component and the coated second side of the second component) to join the first component with the second component. This allows joining the first and second components by means of the adjoining coatings.

[0018] In one embodiment, the coating is or comprises a layer of diamond-like carbon (DLC). The DLC layer may be a multi-layer being comprised of two or more layers, at least one of which being a DLC layer. DLC has been shown in particular advantageous, e.g. providing high chemical resistance, low friction, high resistant to wear/abrasion, high biocompatibility or bio-inertness, high tensile strength, and/or withstanding high pressures e.g. up to 3000 bar.

[0019] DLC coatings can reduce friction and wear, lower the consumption of lubricants and have a very high micro-hardness, and can thus increase the reliability and service life of key components in mechanical and plant engineering or in motor sports. Due to the mechanical material properties, DLC is highly suited for use in tribological systems and other systems where friction and wear are crucial. Other industrial or life science applications may also require additional properties such as biocompatibility and corrosion suppression, which can also be ensured with DLC.

Thick micro-crystalline diamond-like carbon films are favored for tooling applications, while thinner nano/ultranano-crystalline diamond-like carbon films are well-suited for -4 -mechanical devices ranging from nano-(such as NEMS) to micro-(MEMS and AFM tips) as well as macro-scale devices including mechanically and tribologically relevant surfaces which operate under harsh conditions.

[0020] Diamond-like carbon is typically understood as a mixture of sp2-and sp3-hybridised carbon and is characterized by its amorphous structure. The structure of a-C:H DLC consists mainly of an essentially amorphous network with isolated clusters dominated by sp2 configuration (graphite) with some sp3 configuration (diamond). Additionally, foreign atoms such as hydrogen, Nitrogen, silicon or fluorine can also be incorporated into this carbon lattice. The targeted introduction of further components into the DLC layer system allows the range of properties to be considerably extended.

This includes, for example, the increase of hydrophobicity (reduction of water wettability) or the exact opposite, the increase of wettability with water (hydrophilicity).

[0021] In one embodiment, the coating is or comprises at least one material of the group: 0, Si or N doped DLC, a fluorinated diamond-like carbon (F-DLC, e.g. as disclosed in W00140537, for example in order to tune wetting properties), a suitable ceramic, a carbide, preferably BTiC, Titannitrid (TiN), Ti2AIN, silicon, and similar materials.

[0022] In one embodiment, the coating comprises a dopant. A selection of favorable dopants is given in e.g. US10415904. This allows e.g. to increase adhesion for example to an intermediate layer or base layer, charges for affinity (intended absorption), support bonding, modify chemical resistance, increase/decrease hardness, modify thermal properties, etc. Further, this may allow an exact adjustment of layer properties (e.g. properties of (micro-)channel walls) tailored to the desired application.

[0023] In one embodiment, the coating is of a material suitable for providing a fluidic conduit for transporting a fluid, preferably for providing the fluidic conduit to be biocompatible. Such coating-material may be or comprise one or more of the following: a material having a sufficient layer adhesion e.g. on a substrate, a material being chemically inert, mechanically robust, and/or biocompatible. The material is preferably selected to form dangling bonds e.g. after surface activation and/or during the coating process to enable subsequent bonding. The ability to modify the layer -5 -system by doping to improve hydrophobic effects on the surface for example may be an additional added value.

[0024] In one embodiment, the coating on at least one of the first component and the second component is a multi-layer coating comprising a plurality of layers, preferably comprising at least one of an intermediate layer and an adhesion layer.

This allows coating of certain base materials with any of the aforementioned coating materials like DLC, which do not sufficiently adhere to the base material but to the intermediate layer or adhesion layer while the intermediate layer or adhesion layer have a sufficient adhesion to both the base material and the coating material. Further, this may allow bonding of equal material but also of different substrates for example DLC coated PEEK and DLC coated SST due to flexible DLC layer properties. E.g., a conduit formed by the aforementioned process may be highly pressure stable (>2000 Bar) as it may be fully coated by a mechanically strong DLC coating. To minimize negative effects, like the egg shell effect, layer adhesion and composition of the multi-layer system can be important parameters.

[0025] In one embodiment, after providing the coating and before pressing the first and second sides together, the method further comprises inhibiting passivation of the coated layers at least to a certain extent and for a certain sufficient timespan.

[0026] In one embodiment, after providing the coating and before pressing the first and second sides together, the method comprises activating at least one of the coated layers, preferably by ion bombardment, plasma treatment, corona discharge, ion beam treatment, fast atom bombardment, etching, UV activation, as disclosed e.g. in the publication "Surface Activation", https://www.sciencedirect.comItopicslengineering/surface-activation. or in the document "UV surface pretreatment: cleaning and activation" by Heraeus Noblelight, httos://www heraeus.com/en/ring/the incredible power of light/pre treatment and activation of surfaces.htimi. This may allow the formation of dangling bonds on the surface of the DLC coating, which can be important for the sequential bonding of the activated DLC layers.

[0027] In one embodiment, the method comprises providing a first indentation into the first side of the first component and/or providing a second indentation into the -6 -second side of the second component, or providing the first component having a first indentation in the first side and/or the second component having a second indentation in the second side, and pressing the first side and the second side together, so that a conduit, suitable for fluid transport and/or storage, is at least partly provided by the at least one of the first indentation and the second indentation. This may allow creation of complex (micro-)channel structures that can implement additional functionality to the microchannel like mixing, filtering, dispersion minimization, heat dissipation etc. [0028] In one embodiment, after pressing the first side and the second side together, the first indentation opens into the second indentation.

[0029] In one embodiment, before pressing the first side and the second side together, the method comprises aligning at least one of the first indentation the second indentation, preferably aligning the first indentation with the second indentation.

[0030] In one embodiment, at least one of the first indentation and the second indentation comprises the coating.

[0031] In one embodiment, the first component and the second component are half-shell components being substantially identical at least with respect to the position of the first indentation and the second indentation.

[0032] In one embodiment, the first component and the second component are half-shell components, wherein the first indentation in the first side is positioned mirror-inverted with respect to the second indentation in the second side.

[0033] In one embodiment, the conduit is at least one of: a cavity, preferably a micro-structured cavity, a chamber, a channel, a mixing structure, a filter, and a capillary.

[0034] In one embodiment, the conduit is provided by the first indentation and/or the second indentation, wherein the conduit and/or a flow through direction through the conduit is oriented substantially parallel to the first side and/or the second side.

[0035] In one embodiment, the conduit and/or a flow through direction through the conduit is oriented substantially vertical to the first side and/or the second side, -7 -wherein the conduit is opening into a corresponding conduit into at least one of the first component and the second component.

[0036] In one embodiment, the first component comprises a first conduit opening into the first side, and the second component comprises a second conduit opening into the second side. Preferably, the first conduit is oriented and/or having a flow-through direction being substantially vertical to the first side and/or the first conduit is oriented and/or the second conduit having a flow-through direction being substantially vertical to the second side. The method comprises pressing the first side and the second side together, so that the first conduit opens into the second conduit, and preferably prior to pressing the first side and the second side together, aligning the first conduit with the second conduit.

[0037] An embodiment of the present invention provides a conduit suitable for fluid transport and/or storage. The conduit comprises a first component having a first side with a coating, and a second component having a second side with the coating. The coatings of the first side and the second side are at least partly joined with each other by having been pressed together. The conduit is provided by a first indentation into the first side of the first. Alternatively or in addition, the conduit is provided by a second indentation into the second side of the second component. Alternatively or in addition, the conduit is provided by a first indentation into the first side of the first, and a second indentation into the second side of the second component, wherein the first indentation opens into the second indentation. Alternatively or in addition, the conduit is provided by a first conduit in the first component opening into the first side. Alternatively or in addition, the conduit is provided by a second conduit in the second component opening into the second side. Alternatively or in addition, the conduit is provided by a first conduit in the first component opening into the first side, and a second conduit in the second component opening into the second side, wherein the first conduit opens into the second conduit.

[0038] An embodiment of the present invention provides a separation system for separating compounds of a sample fluid in a mobile phase. The fluid separation 30 system comprises a mobile phase drive, preferably a pumping system, adapted to drive the mobile phase through the fluid separation system, and a separation unit, preferably a chromatographic column, adapted for separating compounds of the -8 -sample fluid in the mobile phase. At least a part of a fluid flow path within the separation system is provided by a conduit according to the aforementioned embodiments.

[0039] Embodiments of the present invention might be embodied based on most conventionally available HPLC systems, such as the Agilent 1220, 1260 and 1290 Infinity LC Series (provided by the applicant Agilent Technologies).

[0040] The separating device preferably comprises a chromatographic column providing the stationary phase. The column might be a glass, metal, ceramic or a composite material tube (e.g. with a diameter from 50 pm to 5 mm and a length of 1 cm to 1 m) or a microfluidic column (as disclosed e.g. in EP 1577012 Al or the Agilent 1200 Series HPLC-Chip/MS System provided by the applicant Agilent Technologies.

[0041] The mobile phase (or eluent) can be either a pure solvent or a mixture of different solvents. It can also contain additives, i.e. be a solution of the said additives in a solvent or a mixture of solvents. It can be chosen e.g. to adjust the retention of the compounds of interest and/or the amount of mobile phase to run the chromatography. The mobile phase can also be chosen so that the different compounds can be separated effectively. The mobile phase might comprise an organic solvent like e.g. methanol or acetonitrile, often diluted with water. For gradient operation water and organic is delivered in separate containers, from which the gradient pump delivers a programmed blend to the system. Other commonly used solvents may be isopropanol, THF, hexane, ethanol and/or any combination thereof or any combination of these with aforementioned solvents.

[0042] The sample fluid might comprise any type of process liquid, natural sample like juice, body fluids like plasma or it may be the result of a reaction like from a fermentation broth.

[0043] The fluid is preferably a liquid but may also be or comprise a gas and/or a supercritical fluid (as e.g. used in supercritical fluid chromatography -SFC -as disclosed e.g. in US 4,982.597 A).

[0044] The pressure in the mobile phase might range from 2-200 MPa (20 to 2000 bar), in particular 10-150 MPa (100 to 1500 bar), and more particular 50-120 MPa -9 - (500 to 1200 bar) [0045] The HPLC system might further comprise a detector for detecting separated compounds of the sample fluid, a fractionating unit for outputting separated compounds of the sample fluid, or any combination thereof. Further details of HPLC system are disclosed with respect to the aforementioned Agilent HPLC series, provided by the applicant Agilent Technologies.

[0046] In the context of this application, the term "fluidic sample" may particularly denote any liquid and/or gaseous medium, optionally including also solid particles, which is to be analyzed. Such a fluidic sample may comprise a plurality of fractions of molecules or particles which shall be separated, for instance biomolecules such as proteins. Since separation of a fluidic sample into fractions involves a certain separation criterion (such as mass, volume, chemical properties, etc.) according to which a separation is carried out, each separated fraction may be further separated by another separation criterion (such as mass, volume, chemical properties, etc.), thereby splitting up or separating a separate fraction into a plurality of sub-fractions.

[0047] In the context of this application, the term "fraction" may particularly denote such a group of molecules or particles of a fluidic sample which have a certain property (such as mass, volume, chemical properties, etc.) in common according to which the separation has been carried out. However, molecules or particles relating to one fraction can still have some degree of heterogeneity, i.e. can be further separated in accordance with another separation criterion.

[0048] In the context of this application, the term "downstream" may particularly denote that a fluidic member located downstream compared to another fluidic member will only be brought in interaction with a fluidic sample or its components after interaction of those with the other fluidic member (hence being arranged upstream). Therefore, the terms "downstream" and "upstream" relate to a general flowing direction of the fluidic sample or its components, but do not necessarily imply a direct uninterrupted fluidic connection from the upstream to the downstream system parts.

[0049] In the context of this application, the term "sample separation apparatus" may particularly denote any apparatus which is capable of separating different -10-fractions of a fluidic sample by applying a certain separation technique. Particularly, two separation units may be provided in such a sample separation apparatus when being configured for a two-dimensional separation. This means that the sample or any of its parts or subset(s) is first separated in accordance with a first separation criterion, and is subsequently separated in accordance with a second separation criterion, which may be the same or different.

[0050] The term "separation unit" may particularly denote a fluidic member through which a fluidic sample is guided and which is configured so that, upon conducting the fluidic sample through the separation unit, the fluidic sample or some of its components will be at least partially separated into different groups of molecules or particles (called fractions or sub-fractions, respectively) according to a certain selection criterion. An example for a separation unit is a liquid chromatography column which is capable of selectively retarding different fractions of the fluidic sample.

[0051] In the context of this application, the terms "fluid drive" or "mobile phase drive" may particularly denote any kind of pump or fluid flow source or supply which is configured for conducting a mobile phase and/or a fluidic sample along a fluidic path. A corresponding fluid supply system may be configured for metering two or more fluids in controlled proportions and for supplying a resultant mixture as a mobile phase. It is possible to provide a plurality of solvent supply lines, each fluidically connected with a respective reservoir containing a respective fluid, a proportioning appliance interposed between the solvent supply lines and the inlet of the fluid drive, the proportioning appliance configured for modulating solvent composition by sequentially coupling selected ones of the solvent supply lines with the inlet of the fluid drive, wherein the fluid drive is configured for taking in fluids from the selected solvent supply lines and for supplying a mixture of the fluids at its outlet. More particularly, one fluid drive can be configured to provide a mobile phase flow which drives or carries the fluidic sample through a respective separation unit, whereas another fluid drive can be configured to provide a further mobile phase flow which drives or carries the fluidic sample or its parts after treatment by respective separation unit, through a further separation unit.

BRIEF DESCRIPTION OF DRAWINGS

[0052] Other objects and many of the attendant advantages of embodiments of the present invention will be readily appreciated and become better understood by reference to the following more detailed description of embodiments in connection with the accompanied drawing(s). Features that are substantially or functionally equal or similar will be referred to by the same reference sign(s). The illustration in the drawing is schematically.

[0053] Figure 1 shows a liquid separation system 10, in accordance with embodiments of the present invention, e.g. used in high performance liquid chromatography (HPLC).

[0054] Figures 2 illustrate in a two-dimensional sectional view a preferred embodiment of a process to provide a fluidic conduit.

[0055] Figure 3 illustrates the process of Figures 2 in a flow chart representation.

[0056] Figures 4-7 illustrate a further embodiments for generating the conduit 290.

[0057] Figure 8 exemplarily illustrates a process for providing a DLC-coating.

[0058] Referring now in greater detail to the drawings, Fig. 1 depicts a general schematic of a liquid separation system 10. A pump 20 receives a mobile phase from a solvent supply 25, typically via a degasser 27, which degases the mobile phase and thus reduces the amount of dissolved gases in it. The pump 20 -as a mobile phase drive -drives the mobile phase through a separating device 30 (such as a chromatographic column) comprising a stationary phase. A sample dispatcher 40 (also referred to as sample introduction apparatus, sample injector, etc.) is provided between the pump 20 and the separating device 30 in order to subject or add (often referred to as sample introduction) portions of one or more sample fluids into the flow of a mobile phase (denoted by reference numeral 200, see also Fig. 2). The stationary phase of the separating device 30 is adapted for separating compounds of the sample fluid, e.g. a liquid. A detector 50 is provided for detecting separated compounds of the sample fluid. A fractionating unit 60 can be provided for outputting separated compounds of sample fluid.

[0059] While the mobile phase can be comprised of one solvent only, it may also be mixed of plurality of solvents. Such mixing might be a low pressure mixing and -12-provided upstream of the pump 20, so that the pump 20 already receives and pumps the mixed solvents as the mobile phase. Alternatively, the pump 20 might be comprised of plural individual pumping units, with plural of the pumping units each receiving and pumping a different solvent or mixture, so that the mixing of the mobile phase (as received by the separating device 30) occurs at high pressure und downstream of the pump 20 (or as part thereof). The composition (mixture) of the mobile phase may be kept constant over time, the so-called isocratic mode, or varied over time, the so-called gradient mode.

[0060] A data processing unit 70, which can be a conventional PC or workstation, might be coupled (as indicated by the dotted arrows) to one or more of the devices in the liquid separation system 10 in order to receive information and/or control operation.

[0061] The liquid separation system 10 comprises different flow paths (not further detailed in Figure 1). For example, a fluid providing flow path is provided between the solvent supply 25 and the pump 20, in order to provide the pump 20 with one or more solvents, typically at or slightly beyond ambient pressure. A high-pressure flow path is provided at least between the pump 20 and an outlet of the separating device 30, wherein the pump 20 pumps the mobile phase, as derived from the one or more solvents provided from the fluid providing flow path, at high pressure, typically in the range of 200-2000 bar. A sampling flow path is provided by and within the sample dispatcher 40 in order to allow injecting the sample fluid into the high-pressure flow path. While most of the sampling flow path is typically subjected to ambient pressure or slightly beyond, at least a part of the sampling flow path can be subjected to pressure in the range of the pressure within the high-pressure flow path, e.g. during injection of the sample fluid. A detection and/or fractionating flow path can be coupled downstream to the separation device 30 in order to detect separated fractions of the sample fluid and/or fractionating such separated fractions. The pressure in the detection and/or fractionating flow path is typically at or slightly beyond ambient pressure.

[0062] Each flow path within the liquid separation system 10 is provided by one or more fluidic conduits (also not further detailed in Figure 1). Each conduit may be provided for example by a cavity, such as a micro-structured cavity, a chamber, a -13-channel, a mixing structure, a filter, a capillary, et cetera, as well known in the art. Each respective conduit is typically selected and designed to accommodate and withstand the respective pressure requirements. Further, each respective conduit may need to be selected to comply with certain requirements, such as biocompatibility, i.e. the (biological) sample fluid shall not be influenced, modified, and/or contaminated by materials of or present in the respective conduit(s). As an example, biocompatibility typically requires that the sample fluid is subjected to no or only a given maximum of metal ions.

[0063] In order to comply with the requirement of biocompatibility, either only certain non-metal materials (such as ceramic or plastic) are used, or metal-containing materials are provided with a coating. Such coating, however, may become difficult to apply for example in small-scale structures, such as microfluidics, and/or in more complex structures, e.g. comprising a plurality of interconnecting conduits.

[0064] Figures 2 illustrate in a two-dimensional sectional view (cut-through representation) a preferred embodiment of a process to provide a fluidic conduit.

Figure 2A shows the first step of providing a first component 200, which may be comprised of a plurality of layered stainless steel (SST) sheets thus providing a bulk material. A first indentation 210 is provided into a first side 220 the first component 200, e.g. by micro-structuring, polishing, edging, or the like. Figure 2B shows the second step of coating the first side 220 of the first component 200 with a coating 230 of a diamond-like carbon (DLC) material. The DLC coating 230 is provided to also and fully cover the first indentation 210.

[0065] Figure 2C illustrates the process of joining the first component 200 (coated on the first side 220 with the DLC coating 230) with a second component 250 being processed e.g. by the same process as shown in Figures 2A and 2B. The first component 200 and the second component 250 represent half-shell components, which can be made substantially identically, and when joined together will provide a full(-shell) element. The first component 200 and the second component 250 are pressed together (indicated by the arrows on either side), so that the coating 230 on the first side 220 is pressed against a coating 260 provided on a second side 270 of the second component 250. The first indentation 210 (into the first side 220 of the first component 200) is aligned with a second indentation 280 into the second side 270 of -14-the second component 250, so that both indentations 210 and 260 together provide a conduit 290.

[0066] Figures 2 show two-dimensional sectional views, so that the first component 200 (together with the first indentation 210 and the first coating 230), the 5 second component 250 (together with the second indentation 280 and the second coating 260), and thus the resulting conduit 290 will further extend into the third dimension perpendicular to the plain of the drawings.

[0067] The process of pressing the coatings 230 and 260 against each other is preferably provided within a short period of time after providing the coatings 230 and 260 and preferably is substantially at the same atmosphere as during coating. In other words, the coatings 230 and 260 are preferably pressed together shortly after the process of coating and before passivation of the coatings 230 and 260 occurs at least to a certain extent. Alternatively, passivation of the coatings 230 and 260 is substantially inhibited, at least to a certain extent.

[0068] An additional step may be provided before pressing the first and second sides 220 and 270 together by activating at least one of the coatings 230 and 260. This may be provided as known in the art, for example by ion bombardment, plasma treatment, corona discharge, ion beam treatment, fast atom bombardment, etching, UV activation.

[0069] The process illustrated with respect to Figures 2 yields in a bulk component 295 having the conduit 290 being coated on side of the first component 200 by the first coating 230 and on side of the second component 250 by the second coating 260. With both coatings 230 and 260 being DLC coatings, the conduit 290 can thus be fully DLC coated, which provides an excellent characteristic in particular for usage in HPLC applications (as explained with respect to Figure 1). Such DLC coated conduit 290 can be employed in any of the flow paths as indicated in Figure 1.

[0070] The various process parameters, e.g. thickness of the coatings 230 and 260, time of coating, temperature and pressure conditions during coating and pressing, applied force for pressing, period of time for pressing, surface activation parameters, et cetera, depend on the respective application, materials, and requirements, and should be selected and adjusted appropriately. Reference is given -15-to similar processes and process requirements, e.g. for providing DLC coatings, as known in the art.

[0071] Instead of or in addition to coating e.g. a multitude of DLC types, other materials such a ceramic, a (preferably) fluorinated diamond-like carbon, carbide, e.g. BTiC, Titannitrid, Ti2AIN, or similar may be applied accordingly. Also, dopants may be used as also known in the art.

[0072] The material of the coatings 230 and 260 is preferably selected for rendering the fluidic conduit 290 suitable for transporting a fluid, preferably for providing the fluidic conduit to be biocompatible, highly pressure stable, and to have low wall friction. DLC has been found as an excellent material for fulfilling such purposes.

[0073] Each of the coatings 230 and 260 can be provided as a multi-layer coating comprising a plurality of layers with each layer having an arbitrary layer thickness, for example comprising an adhesion layer (for achieving a sufficiently good attachment with the respective first side 220 or second side 270) on the respective first side 220 or second side 270, and the coatings 230 and 260 then being coated onto the respective adhesion layers. Other intermediate layers of coatings between adhesion layers and the coatings 230 and 260 may be applied accordingly, as known in the art, in order to achieve the desired properties e.g. for withstanding respective solvents within the conduit 290.

[0074] It is clear that instead of the plurality of layered stainless steel (SST) sheets providing the bulk material, each of the first and second component 200, 250 may also comprised of other materials such as ceramics, polymers, alloys, et cetera. Further, each of the first and second component 200, 250 may be provided as a (singular) bulk component, being comprised of a plurality of sheets, et cetera. Top and bottom substrate can be but do not need to be the same material.

[0075] Figure 3 illustrates the process of Figures 2 in a flow chart representation.

In a step 300, the first component 200 is provided with a first indentation 210. In a step 310, the first side 220 including the first indentation 210 is DLC-coated. In parallel in a step 320, the second component 250 is provided with a second indentation 280, and in a step 330, the second side 270 including the second indentation 280 is also -16-DLC-coated. Both coated component 200 and 250 are then pressed together in a step 340, thus forming the conduit 290 of the bulk component 295 in a step 350. Step 340 may also comprise other steps such as surface activating.

[0076] Figure 4 illustrates another embodiment for generating the conduit 290. In this embodiment, the second component 250 is provided without indentation, so that the resulting conduit 290, when the first component 200 and the second component 250 are pressed together, is provided by the first indentation 210 only.

[0077] While in the embodiment of Figures 2 and 4 the conduit 290 is provided extending substantially perpendicular to the plain of the paper, Figure 5 illustrates another embodiment wherein the conduit 290 extends substantially parallel to the plain of the paper. The first component 200 as well as the second component 250 are provided without indentation but with the respective coatings 230 and 260. The first component 200 comprises a first conduit 500 (indicated by dashed lines in the sectional view representation of Figure 5) extending within the plain of the paper and opening into the first side 220 (bearing the first coating 230). Accordingly, the second component 250 comprises a second conduit 510 (indicated by dashed lines in the sectional view representation of Figure 5) extending within the plain of the paper and opening into the second side 270 (bearing the second coating 260). The first conduit 500 as well as the second conduit 510 may be provided by drilling, micro-machining, etching, 3D-plotting or other (micro-)shaping/machining methods as known in the art.

[0078] In Figure 5, the first coating 230 may also extend (to a certain extent) into the first conduit 500, as indicated by reference numerals 520A and 520B. Such coating extensions 520 may be desired or simply result from the coating process as an unwanted effect. Depending on the specific requirements, an additional step of removing or avoiding such coating extensions 520 e.g. to provide sharp edges as indicated by the coating 260 may be applied, for instance by clogging the conduit of any of the components 200 or 250 or by flushing the conduit 500 with a fluid, preferably an inert gas, while the coating is applied or during short coating break intervals.

[0079] After adequately aligning and pressing the first side 220 bearing the first coating 230 against the second side 270 bearing the second coating 260 and thus -17-joining the first component 200 with the second component 250, the first conduit 500 will open into the second conduit 510 and thus providing the (joined) conduit 290.

[0080] Figure 6 shows a further embodiment similar to the embodiment of Figure 5. For providing a better alignment as well as a better sealing of the first conduit 500 with respect to the second conduit 510, the first component 200 comprises an elevation 600 over the first side 220, and the second component 250 comprises the indentation 280 substantially matching in shape with the elevation 600. The first side 220 including the elevation 600 is coated with the coating 230, while the second side 270 including the indentation 280 is covered with the coating 260. Also similar to Figure 5, the coating 260 will further extend into the second conduit 510, as indicated by reference numerals 610A and 610B. After adequately aligning and pressing the first side 220 bearing the first coating 230 against the second side 270 bearing the second coating 260 and thus joining the first component 200 with the second component 250, the first conduit 500 will open into the second conduit 510 and thus providing the (joined) conduit 290.

[0081] Figure 7 shows another embodiment according to the present invention. In this embodiment, a third component 700 bearing the conduit 290 is inserted between the first and second components 200 and 250. The first side 220 (of the first component 200) is substantially flat and bears the first coating 230. The second side 270 (of the second component 250) is also substantially flat and bears the second coating 260. A side 710 of the third component 700 adjacent to the first side 220 bears a coating 720, and a side 730 adjacent to the second side 270 bears a coating 740. Preferably, the conduit 290 is also coated (preferably on each side), as indicated by reference numeral 750. Such coating 750 of the conduit 290 may be provided with the same coating process as providing the coatings 720 and 740. The first, second and third components 200, 250, 700 will be joined by being pressed together e.g. during their non-saturated phase, as indicated by the two arrows in Figure 7.

[0082] It is clear that the shown embodiments of Figures 2, 4-7 can also be combined, e.g. by pressing the first component 200 as shown in Figure 4 against the second component 250 as shown in Figure 5, thus resulting in the conduit 290 being provided by the second conduit 510 opening into the first indentation 210 and extending substantially perpendicular to the second conduit 510. Further, it is clear -18-that also more than three components can be applied in the same way as aforedescribed.

[0083] Further, it is clear that the aforedescribed process can also be applied solely for joining the first component 200 with the second component 250, however, without providing the conduit 290. While it has been found that the aforedescribed process is in particular useful for generating such conduit 290 having a coating in particular of DLC, the process also works simply for joining respective components together by pressing the respective coatings of the components together.

[0084] Figure 8 exemplarily illustrates a process for providing a DLC-coating. A turnable DLC-coating pol 800 is provided -under vacuum conditions -with a symbolic linear bonding rod 810. A pressing block 820 at one end can move inwardly to press together and align one or more DLC coated parts 830 along the rod 810 towards a non-moving, non-coatable pressing block 840. The same can be achieved also e.g. can with a disc-shaped mounting.

[0085] DLC-Bonding can preferably take place directly in the CVD or PVD coating equipment e.g. by an apparatus that provides a guiding and aligning mechanism for the DLC coated parts in the vacuum, for example as shown in Figure 8. The heat (which diminishes very slowly in the vacuum) from the coating process can be used to facilitate and accelerate the DLC-Bonding process. -19-

Claims (13)

1. CLAIMSA method of joining a first component (200) with a second component (250), comprising: providing a first side (220) of the first component (200) as well as a second side (270) of the second component (250) with a coating (230, 260), and pressing together the coating (230) of the first side (220) and the coating (260) of the second side (270) to join the first component (200) with the second component (250).
2. The method of the preceding claim, wherein: the coating (230, 260) is or comprises a layer, preferably a multi-layer, of diamond-like carbon.
3. 3. The method of any one of the preceding claims, wherein: the coating (230, 260) is or comprises at least one material of the group: a doped diamond-like carbon, fluorinated diamond-like carbon, a ceramic, a carbide, preferably BTiC, Titannitrid, Ti2AIN, silicon, and similar materials.
4. The method of any one of the preceding claims, wherein: the coating (230, 260) comprises a dopant.
5. The method of any one of the preceding claims, wherein: the coating (230, 260) is of a material suitable for providing a fluidic conduit for transporting a fluid, preferably for providing the fluidic conduit to be biocom patible.
6. The method of any one of the preceding claims, wherein: the coating (230, 260) on at least one of the first component (200) and the second component (250) is a multi-layer coating (230, 260) comprising a plurality of layers, preferably comprising at least one of an intermediate layer and an adhesion layer.
7. -20 -The method of any one of the preceding claims, comprising at least one of: after providing the coating (230, 260) and before pressing the first and second sides together, inhibiting passivation of the coated layers at least to a certain extent; after providing the coating (230, 260) and before pressing the first and second sides together, activating at least one of the coated layers, preferably by ion bombardment, plasma treatment, corona discharge, ion beam treatment, fast atom bombardment, etching, UV activation.
8. 8. The method of any one of the preceding claims, comprising: providing a first indentation (210) into the first side (220) of the first component (200) and/or providing a second indentation (280) into the second side (270) of the second component (250), or providing the first component (200) having a first indentation (210) in the first side (220) and/or the second component (250) having a second indentation (280) in the second side (270), and pressing the first side (220) and the second side (270) together, so that a conduit (290), suitable for fluid transport and/or storage, is at least partly provided by the at least one of the first indentation (210) and the second indentation (280).
9. The method of the preceding claim, comprising at least one of: after pressing the first side (220) and the second side (270) together, the first indentation (210) opens into the second indentation (280); before pressing the first side (220) and the second side (270) together: aligning at least one of the first indentation (210) the second indentation (280); at least one of the first indentation (210) and the second indentation (280) comprises the coating (230, 260); the first component (200) and the second component (250) are half-shell components being substantially identical at least with respect to the position of the first indentation (210) and the second indentation (280); -21 -the first component (200) and the second component (250) are half-shell components, wherein the first indentation (210) in the first side (220) is positioned mirror-inverted with respect to the second indentation (280) in the second side (270); the conduit (290) is at least one of: a cavity, preferably a micro-structured cavity, a chamber, a channel, a mixing structure, a filter, and a capillary.
10. 10. The method of any one of the preceding claims 8-9, comprising at least one of: the conduit (290) is provided by the first indentation (210) and/or the second indentation (280), wherein the conduit (290) and/or a flow through direction through the conduit (290) is oriented substantially parallel to the first side (220) and/or the second side (270); the conduit (290) and/or a flow through direction through the conduit (290) is oriented substantially vertical to the first side (220) and/or the second side (270), wherein the conduit (290) is opening into a corresponding conduit (290) into at least one of the first component (200) and the second component (250).
11. 11 The method of any one of the preceding claims, wherein the first component (200) comprises a first conduit (290) opening into the first side (220), and the second component (250) comprises a second conduit (290) opening into the second side (270), the method comprising: pressing the first side (220) and the second side (270) together, so that the first conduit (290) opens into the second conduit (290), and preferably prior to pressing the first side (220) and the second side (270) together, aligning the first conduit (290) with the second conduit (290).
12. 12 A conduit (290) suitable for fluid transport and/or storage, comprising: a first component (200) having a first side (220) with a coating (230, 260), and a second component (250) having a second side (270) with the coating (230, 260), wherein -22 -the coatings (230, 260) of the first side (220) and the second side (270) are at least partly joined with each other by having been pressed together, and the conduit (290) is provided by at least one of: a first indentation (210) into the first side (220) of the first; a second indentation (280) into the second side (270) of the second component (250), a first indentation (210) into the first side (220) of the first, and a second indentation (280) into the second side (270) of the second component (250), wherein the first indentation (210) opens into the second indentation (280), a first conduit (290) in the first component (200) opening into the first side (220), a second conduit (290) in the second component (250) opening into the second side (270), and a first conduit (290) in the first component (200) opening into the first side (220), and a second conduit (290) in the second component (250) opening into the second side (270), wherein the first conduit (290) opens into the second conduit (290).
13. 13 A separation system (10) for separating compounds of a sample fluid in a mobile phase, the fluid separation system (10) comprising.a mobile phase drive (20), preferably a pumping system, adapted to drive the mobile phase through the fluid separation system (10), and a separation unit (30), preferably a chromatographic column, adapted for separating compounds of the sample fluid in the mobile phase, wherein at least a part of a fluid flow path within the separation system (10) is provided by a conduit (290) according to the preceding claim.-23 -