Steam nozzles for PVD

Abstract

The present invention provides a vapor jet coater for continuously depositing a metal coating, and a method for depositing such a coating. [Solution] The steam jet coater 1 comprises a distribution chamber 2 configured to be connectable to an evaporator tube, and a steam outlet orifice 3 connected to the distribution chamber, which is capable of injecting metal alloy steam along the main injection plan and main injection direction, and the steam outlet orifice having i. a converging section and ii. a diverging section in a continuous manner.

Description

[Technical Field]

[0001] This invention relates to a vapor jet coater and vacuum deposition equipment for continuously depositing a metal coating. The invention also relates to a method for depositing such a coating.

[0002] The present invention is intended, but not limited to, the deposition of a zinc or zinc-magnesium coating onto a running steel strip. Such a coated steel strip can then be cut and shaped, for example by stamping, bending, or forming, and subsequently painted to form parts. [Background technology]

[0003] Several coating methods exist, including hot-dip galvanizing and electrocoating. However, these conventional methods do not provide satisfactory coatings for steel grades containing high levels of easily oxidizable elements such as Si, Mn, Al, P, Cr, or B. As a result, new methods such as vacuum deposition techniques like JVD (jet deposition) have been developed.

[0004] In JVD, a supersonic-propelled metallic vapor spray comes into contact with the substrate. International Publication No. 97 / 47782 and International Publication No. 2009 / 047333 describe such processes.

[0005] International Publication No. 2015 / 015237 discloses a process aimed at improving the transient protection against corrosion of steel coated by JVD (jet deposition). This process involves a ratio of 2 × 10⁻¹⁰ of the pressure in the deposition chamber to the pressure in the zinc injection chamber. -3 From 5.5 x 10 -2 This is done by coating a steel substrate in a vacuum deposition facility.

[0006] WO 2019 / 239314 discloses vapor jet coating that prevents particulate defects. As shown in FIG. 1, this vapor jet coater 101 is formed from a distribution chamber 102 and a vapor outlet orifice 103 provided with a converging portion 104.

[0007] Nevertheless, it has been observed that prior art apparatuses result in a void concentration of about 2%. This limits the mechanical resistance of the coating and causes adhesion problems of the coating that limit the thickness of the coating. PRIOR ART DOCUMENT PATENT DOCUMENT

[0008] Patent Document 1 WO 97 / 47782 Patent Document 2 WO 2009 / 047333 Patent Document 3 WO 2015 / 015237 Patent Document 4 WO 2019 / 239314 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0009] An object of the present invention is to improve the drawbacks of prior art apparatuses and processes. MEANS FOR SOLVING THE PROBLEM

[0010] Other features and advantages will become apparent from the following detailed description of the present invention.

[0011] To explain the present invention, various embodiments are described with particular reference to the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] [Figure 1]It is a diagram of an embodiment of a conventional vapor jet coater. [Figure 2] It is a diagram of an embodiment of a vapor jet coater according to the present invention. [Figure 3] It is a diagram of a first embodiment of a vapor outlet orifice according to the present invention. [Figure 4] It is a diagram of a second embodiment of a vapor outlet orifice according to the present invention. [Figure 5] It is a diagram of an embodiment of a vacuum deposition apparatus according to the present invention. [Figure 6] It is a diagram of an SEM image of a coating formed by a conventional vapor jet coater. [Figure 7] It is a diagram of an SEM image of a coating formed by a vapor jet coater according to the present invention.

Mode for Carrying Out the Invention

[0013] The present invention relates to a vapor jet coater 1 for depositing a coating formed of a metal or a metal alloy on a traveling substrate (S) as shown in FIG. 2 and FIG. 3, wherein the vapor jet coater a distribution chamber 2 configured to be connectable to an evaporation tube; a vapor outlet orifice 3 connected to said distribution chamber 2 and capable of injecting metal alloy vapor along a main injection plane (P) and a main injection direction (D), i. a converging portion 4 comprising a wall defining two converging surfaces (5, 6), one on each side of said injection plane (P), said two surfaces (5, 6) having a distance C on the inlet side ENTRY and are spaced apart from a distance C on the outlet side EXIT , wherein the ratio C EE (C ENTRY / C EXIT ) is 1.2 to 10,; ii. a diverging portion 7 comprising a wall defining two diverging surfaces (8, 9), one on each side of said injection plane (P), said two surfaces (8, 9) having a distance D on the inlet side ENTRY and a distance D on the outlet side EXITspaced apart from, ratio D EE (D ENTRY / D EXIT ) is 0.1 to 0.8, a diverging portion 7, and a steam outlet orifice 3 continuously provided with, and continuously provided.

[0014] Hereinafter, the main injection direction (D) is expressed with respect to the movement of the injected metal alloy vapor.

[0015] Preferably, the substrate is a strip material.

[0016] Preferably, the traveling substrate is a metal substrate. Even more preferably, the traveling substrate is a steel substrate.

[0017] Preferably, the traveling substrate has a composition containing, in weight percent, 0.15<Si<0.4, 0.5<Mn<2.5, 0.1<C<0.4, P≦0.03, S≦0.02, 0.01<Al≦0.1, Cu≦0.2, Ti+Nb≦0.20, Cr+Mo≦1, with the balance being Fe and unavoidable impurities.

[0018] Preferably, the traveling substrate has a composition containing, in weight percent, 0.15<Si<0.6, 0.17<Mn<2.3, 0.1<C<0.4, P≦0.05, S≦0.01, 0.015<Al≦1.0, Cu≦0.2, B≦0.005, Ti+Nb≦0.15, Cr+Mo≦1.4, with the balance being Fe and unavoidable impurities.

[0019] The vapor jet coater 1 is an acoustic wave vapor jet coater, that is, a coater capable of generating a sonic vapor jet. This type of coater is also generally called a JVD (Jet Vapor Deposition) apparatus.

[0020] The function of the distribution chamber 2 is to uniformly distribute the metal vapor along the vapor outlet orifice and therefore along the width of the substrate. As shown in Figures 2 and 5, the distribution chamber 2 is configured to be connectable to the evaporator tube 10, which means that the metal vapor can flow from the evaporator tube 10 to the distribution chamber 2.

[0021] Preferably, the distribution chamber 2 includes a reheating means 11, such as a heating cartridge. Such a reheating means allows the metal vapor coming from the evaporator tube to be reheated after its expansion as it enters the vapor outlet orifice 3, thereby preventing condensation at the vapor outlet orifice.

[0022] Preferably, the reheating means extends along the length of the distribution chamber, and more preferably along the entire length. The number and position of the reheating means can be adjusted to optimize the reheating of the steam.

[0023] The steam outlet orifice 3 is connected to the distribution chamber 2, which means that metallic steam can flow from the distribution chamber 2 to the steam outlet orifice 3. This connection is preferably made through an opening cut into the wall of the distribution chamber.

[0024] The vapor outlet orifice 3 and the divergent geometric shape are configured to prevent any flow disturbance in the divergent section.

[0025] As shown in Figure 2, the steam outlet orifice includes a converging section 4 and a diverging section 7.

[0026] The convergence section 4 has two surfaces (5, 6) on each side of the injection plan (P) that converge toward each other.

[0027] The two surfaces define the inlet and outlet sides. Through the inlet side, the metal vapor enters the convergence section from the repair chamber 2. Through the outlet side, the metal vapor exits the convergence section.

[0028] In a plan perpendicular to the main injection plan, the convergence plane is at a distance C on the outlet side. EXIT Distance C on the entrance side ENTRY They are separated by only that much. Furthermore, the ratio

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[0029] "Converging toward each other" means that the inlet width of the steam outlet orifice is smaller than the outlet width. This does not restrict the shape of the sides.

[0030] Such a convergence section allows the jet, or metallic vapor jet, to be accelerated to supersonic speed at the exit of the convergence section.

[0031] The diverging section 7 has two surfaces (8, 9), one on each side of the injection plan (P), and the two surfaces (8, 9) diverge from each other.

[0032] The two surfaces define the inlet and outlet sides. Metal vapor enters the venting section through the inlet side. Metal vapor exits the venting section through the outlet side.

[0033] In a plan perpendicular to the main injection plan, the diverging surface is at a distance D on the inlet side. ENTRY Distance D from the exit side EXIT They are separated from each other. Furthermore,

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[0034] "Converging toward each other" means that the inlet width of the steam outlet orifice is greater than the outlet width. This does not restrict the shape of the sides.

[0035] As long as the jet velocity is supersonic at the inlet of this section, such a divergence allows the jet, i.e., the metallic vapor jet, to accelerate and its pressure to decrease.

[0036] The inventors have found that having such a converging section followed by such a diverging section makes it possible to reduce jet expansion (in the case of the same vapor flow) when it enters the vacuum chamber due to a decrease in jet pressure.

[0037] Reducing jet expansion allows for a decrease in coating porosity at both the steel coating interface and the coating surface.

[0038] Preferably, in the convergence portion, the ratio C EE The range is 3 to 5.

[0039] Preferably, in the convergence section, the two surfaces are essentially symmetrical with respect to the main injection plan (P). Such an arrangement improves the uniformity of the coating.

[0040] Preferably, in the convergence portion, the cross-section along the plan perpendicular to its length is trapezoidal. More preferably, in the convergence portion, the cross-section along the plan perpendicular to its length is isosceles trapezoidal.

[0041] Preferably, in the convergence portion, the base angle of the isosceles trapezoid has a value greater than 60°.

[0042] Preferably, the length L of the convergence portion. CONV The length is 80mm to 250mm. The length is aligned with the main thrust direction D.

[0043] Preferably, distance C ENTRY The distance C is 30mm to 180mm. More preferably, the distance C ENTRY The range is 50mm to 150mm.

[0044] Preferably, distance C EXIT The distance C is 30mm to 75mm. More preferably, the distance C EXIT The range is 35mm to 55mm.

[0045] Preferably, the angle between the main injection plan (P) and one of the two walls defining the convergence planes (5, 6) is 5° to 45°, preferably 15° to 35°.

[0046] Preferably, the beginning of the entrance to the convergence section 4 has a radius of curvature ρ according to the following conditions. ENTRY It exhibits, that is, 0.5 × C ENTRY <ρ ENTRY <2×C ENTRY That is the case.

[0047] Preferably, the divergence portion, the ratio D EE The range is 0.3 to 0.6.

[0048] Preferably, in the divergence section, the two surfaces are symmetrical with respect to the main injection plan (P).

[0049] Preferably, in the diverging portion, the cross-section along the plan perpendicular to its length is trapezoidal. More preferably, in the diverging portion, the cross-section along the plan perpendicular to its length is isosceles trapezoidal.

[0050] Preferably, in the diverging portion, the base angle of the isosceles trapezoid has a value greater than 60°.

[0051] Preferably, the length of the emission section is 30 mm to 280 mm. The length is aligned with the main injection direction D.

[0052] Preferably, distance D ENTRY The distance is 20mm to 60mm. More preferably, the distance D ENTRY The range is 30mm to 50mm.

[0053] Preferably, distance D EXIT The range is 50mm to 210mm. More preferably, the distance D EXIT The range is 60mm to 200mm.

[0054] Preferably, the converging portion and the diverging portion are continuous. More preferably, the curvature at the junction between the converging portion and the diverging portion is less than 40°, preferably less than 30°.

[0055] Preferably, a neutral section having a wall with two faces, one on each side of the injection plan (P), is positioned between the converging and diverging sections, and the two spaces are spaced apart from a distance that is essentially constant along the main injection direction D. More preferably, the curvature between the converging and neutral sections is less than 40°, preferably less than 30°. Even more preferably, the curvature between the diverging and neutral sections is less than 40°, preferably less than 30°.

[0056] Preferably, as shown in Figure 4, the steam outlet orifice 3 has an end with two parallel surfaces (80, 90) on each side of the injection plan (P), and the distance between the two surfaces is D EXIT They are spaced apart. More preferably, the end portion has a length of 5% to 15% of the length of the diverging portion (7).

[0057] This end is located downstream of the convergence point when tracing the path of the metal vapor.

[0058] As shown in Figure 5, the present invention also relates to a vacuum deposition apparatus 12 for continuously depositing a coating formed from a metal or metal alloy onto a moving substrate (S), the apparatus comprising a deposition chamber 13 suitable for passing the substrate (S) along a given path, An evaporation crucible 14 suitable for supplying metal or metal alloy vapor, Evaporator tube 10 and The aforementioned at least one steam jet coater 1, It is equipped with a continuous array of features.

[0059] This apparatus includes means 15 for passing substrates through a deposition chamber. The substrates can be actuated by any suitable means depending on the properties and shape of the substrates. Rotating support rollers capable of supporting steel strips can be used in particular.

[0060] The deposition chamber is preferably 10 -8 ~10 -3 Preferably, it is a sealable box maintained under bar pressure. Preferably, the deposition chamber has an inlet lock and an outlet lock (not shown) between them, between which a substrate S, such as a steel strip, can travel along a given path in the direction of travel.

[0061] A steam jet coater is suitable for spraying metal alloy vapor coming from an evaporation crucible 14 onto a moving substrate S.

[0062] The evaporation crucible 14 mainly consists of a pot and a cover. The evaporation crucible is provided with heating means that enable the formation of metal vapor and supply to the steam jet coater. The evaporation crucible is also provided with an induction heater, which has the advantage of making stirring and homogenization of the metal alloy bath easier.

[0063] The evaporator tube 10 is connected to the evaporation crucible 14 on one end and to the steam jet coater 1 on the other end. Preferably, a valve located between the evaporator and the ejector controls the flow of metallic vapor.

[0064] These different parts may be made of, for example, graphite.

[0065] The present invention also relates to a method for continuously depositing a coating formed from at least one metal in a vacuum deposition facility onto a moving substrate (S), wherein the method is performed under pressure P VACUUM In the vacuum chamber having the above, metal vapor passes through at least one vapor outlet orifice to pressure P EJECTED The process includes the step of spraying toward the side surface of the moving substrate, thereby forming at least one layer of metal, (P EJECTED / P VACUUM The value is 2 to 15, and the ejected steam has a supersonic velocity on the inlet side of the diverter 7.

[0066] P VACUUM This is the pressure in the chamber as measured by the pressure sensor.

[0067] Pressure P in the distribution chamber REP The zinc mass flow rate D is calculated using the following equation (1). ZINC , zinc temperature T inside the distribution chamber ZINC , and section A of the ejector throat THROAT It can be derived from this.

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[0068] Next, the pressure P of the jet ejected by the steam outlet orifice EJECTED This can be calculated using the following formula (2).

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[0069] The moving substrate is preferably a metal strip, and more preferably a steel strip. The width of the moving substrate is preferably 200 to 2200 mm.

[0070] The moving substrate preferably has a travel speed of 10 to 800 m / min.

[0071] The aforementioned at least one metal layer is preferably formed by the condensation of the injected vapor.

[0072] Preferably, the coating thickness is 0.1 to 20 μm. If it is less than 0.1 μm, the corrosion protection of the coating is insufficient.

[0073] The coating preferably contains zinc as the main element. The coating may also contain the following additional elements, namely chromium, nickel, titanium, manganese, magnesium, silicon, and aluminum, which may be considered individually or in combination.

[0074] Preferably, P EJECTED / P VACUUM The ratio is between 2 and 10. Such a ratio further reduces jet expansion within the vacuum chamber.

[0075] Preferably, the P VACCUM is 1.10 -4 mbar~3.10 -1 It's mbar.

[0076] Preferably, the steam jet coater is located at a distance of 20 mm to 80 mm from the moving substrate.

[0077] Preferably, the metal vapor stream injected by the steam jet coater is 3 to 300 g.s -1 That is the case.

[0078] The present invention also relates to a steel sheet having a metal coating that is manufactured as described above and may be unavoidable during manufacturing, wherein the metal coating has a porosity of less than 1%.

[0079] The steel sheet is preferably hot-rolled and then cold-rolled so that it can be used in the manufacture of automotive body parts. The present invention is not necessarily limited to this field, and applications can be found for any steel part, regardless of its end use.

[0080] The substrate steel can be, for example, a specific grade of VHS steel (generally with very high strength of 450-900 MPa) or UHR (generally with ultra-high strength exceeding 900 MPa), and is highly susceptible to oxidation, namely, the following elements: Steel free of interstitial elements (IF - extremely low carbon), which may contain up to 0.1% (by weight) of Ti. Duplex steels such as DP 500 DP steel can contain up to 1200 (by weight) 3% Mn in combination with up to 1% (by weight) Si, Cr and / or Al. For example, TRIP steel (plastic transformation induced) such as TRIP steel 780 containing approximately 1.6% (by weight) Mn and 1.5% Si, TRIP steel or phosphorus-containing two-phase steel, TWIP steel (TWining-induced plasticity) - steel with a high Mn content (generally 17 to 25% by weight), Fe-Al, for example, low-density steel that may contain up to 10% (by weight) Al, Stainless steel with a high chromium content (generally 13-35% by weight) is produced by combining it with other alloying elements (Si, Mn, Al, etc.). That is the case.

[0081] Vacancy density is estimated by comparing the contrast of SEM images. Approximately 10 images were used to evaluate vacancies. Vacancy density estimation is performed using a square cross-section with sides equal in size to the coating thickness. Darker pixels correspond to vacancies.

[0082] Preferably, the metal coating comprises at least one layer of pure zinc. The steel sheet may optionally be coated with one or more layers in addition to the zinc layer in a manner suitable for the desired properties of the final product. The zinc layer is preferably the top layer of the coating.

[0083] Preferably, the layer of paint produced by electrophoresis is located on top of the metal coating.

[0084] Experimental results To demonstrate the effect of the patented steam jet coater on the density of the coating, comparative tests were conducted on steel strips that had been zinc-coated by a jet deposition process in the same vacuum deposition facility.

[0085] As shown in Figure 5, the vacuum deposition apparatus comprises a deposition chamber suitable for continuously passing a substrate along a given path, an evaporation crucible suitable for zinc vapor, an evaporation tube, and a vapor jet coater.

[0086] To compare the results, two samples, A and B, were fabricated. Both coatings were made from martensitic steel (MS1500 from ArcelorMittal) with the same composition.

[0087] In both JVD processes, the pressure P in the vacuum chamber VACUUM is 1.2 × 10 -4 The crowbar is used, the distance between the steam jet coater and the substrate is 50 mm, and the steam flow is approximately 108 g.s. -1 That is the case.

[0088] The substrate of Sample A is coated with a vapor jet coater as described in International Publication No. 2019 / 129314, and the vapor jet coater comprises only a convergence section as shown in Figure 1. The key features of the vapor jet coater are summarized in Table 1.

[0089] The substrate of Sample B is coated with a vapor jet coating as claimed and shown in Figure 4, and comprises a convergence section, a diverging section, and then an edge. Key features of the vapor jet coater are summarized in Table 1.

[0090] SEM images were taken for each sample, and the density of the zinc coating was estimated using 10 SEM images.

[0091] The pore density is significantly reduced when the patented vapor jet coating is used. Furthermore, the zinc coating is more uniform.

[0092] This improvement in coating is visually evident when comparing the SEM images of the zinc coatings of sample A (Figure 6) and B (Figure 7).

[0093] Experimental results clearly demonstrate that the present invention improves coatings by reducing vacancy concentration.

[0094] [Table 1]

Claims

1. A steam jet coater 1 for depositing a coating made of metal or a metal alloy onto a moving substrate (S), wherein the steam jet coater is A distribution chamber 2 configured to be connectable to an evaporator tube, A vapor outlet orifice 3 connected to the distribution chamber 2, which can inject metal alloy vapor along the main injection plan (P) and main injection direction (D), iii. A convergence section 4 having walls that define two convergence surfaces (5, 6), one on each side of the injection plan (P), wherein the two surfaces (5, 6) are separated by a distance C on the inlet side. ＥＮＴＲＹ From, and the distance C on the exit side. ＥＸＩＴ Separated from, ratio C ＥＥ (C ＥＮＴＲＹ / C ＥＸＩＴ ) is 1.2 to 10, the convergence section 4 and iv. a diverging portion 7 comprising walls defining two converging surfaces (8, 9), one on each side of said injection plan (P), wherein said two surfaces (8, 9) are spaced apart by a distance D on the inlet side ＥＮＴＲＹ and by a distance D on the outlet side ＥＸＩＴ , and the ratio D ＥＥ (D ＥＮＴＲＹ / D ＥＸＩＴ ) is 0.1 to 0.8, and the diverging portion 7; A steam outlet orifice (3) is provided with a continuous series of these, A steam jet coater 1 is equipped with a continuous stream of these.

2. In the convergence section, the ratio C ＥＥ The steam jet coater according to claim 1, wherein the coefficient is 3 to 5.

3. The steam jet coater according to claim 1 or 2, wherein the cross-section of the convergence portion, along a plan perpendicular to its length, is trapezoidal.

4. In the divergence section, the ratio D ＥＥ A steam jet coater according to any one of claims 1 to 3, wherein the coefficient of the heat is 0.25 to 0.

35.

5. The steam jet coater according to any one of claims 1 to 4, wherein the cross-section of the diverging section, along a plan perpendicular to its length, is trapezoidal.

6. The steam outlet orifice 3 has an end with two parallel surfaces (80, 90) on each side of the injection plan (P), and the distance between the two surfaces is D ＥＸＩＴ A coated vapor jet according to any one of claims 1 to 5, which is separated from the

7. A vacuum deposition apparatus for continuously depositing a coating made of metal or a metal alloy onto a moving substrate (S), wherein the apparatus comprises: An evaporator crucible suitable for supplying metal or metal alloy vapor, Evaporator tube and A deposition chamber suitable for passing a substrate along a given path, A steam jet coater according to any one of claims 1 to 6, A vacuum deposition system equipped with a continuous array of these features.

8. A method for continuously depositing a coating formed from at least one metal in a vacuum deposition apparatus according to claim 7 onto a moving substrate (S), wherein the method is performed at a pressure P ＶＡＣＵＵＭ In the vacuum chamber having the above, metal vapor passes through at least one vapor outlet orifice to pressure P ＥＪＥＣＴＥＤ (P ＥＪＥＣＴＥＤ / P ＶＡＣＵＵＭ The method wherein the values ​​are 2 to 15, and the injected steam has a supersonic velocity on the inlet side of the emission section 7.

9. The method according to claim 8, wherein the steam jet coater is located at a distance of 20 mm to 80 mm from the moving substrate.

10. (P ＥＪＥＣＴＥＤ / P ＶＡＣＵＵＭ The method according to any one of claims 8 or 9, wherein ) is 2 to 10.

11. The aforementioned P ＶＡＣＵＵＭ is 1.10 －４ mbar ~ 3.10 －１ The method according to any one of claims 8 to 10, wherein the value is mbar.

12. The metal vapor stream injected by the aforementioned steam jet coater is 3 to 300 g. －１ The method according to any one of claims 8 to 11.

13. A manufactured steel sheet according to any one of claims 8 to 12, comprising a metal coating, containing trace amounts of impurities that are sometimes unavoidable during manufacturing, and the metal coating having a pore concentration of less than 1%.

14. The steel plate according to claim 13, wherein a layer of paint produced by electrophoresis is located on top of the metal coating.

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