Erosion-resistant and wide-range corrosion-resistant nickel-copper-molybdenum alloy and preparation method thereof

Abstract

The invention discloses a nickel-copper-molybdenum alloy with scouring resistance and wide-range corrosion resistance and a preparation method, and belongs to the field of nickel-based wear-resistant and corrosion-resistant alloys. The alloy comprises the following components in percentage by mass: 57.9 to 67.9 percent of Ni, 20 to 30 percent of Cu, 10 percent of Mo, 1 to 3 percent of W and 0.3 percent of Y2O3. The preparation method of the nickel alloy material comprises the steps that Ni powder, Cu powder, NiMo powder, W powder and Y2O3 powder are weighed according to the proportion and mixed to be uniform; blank pre-pressing treatment is conducted on the evenly-mixed metal powder, the metal powder is die-cast into a block, and a pressed blank is formed; the pressing blank is sintered, and a nickel alloy crude product is obtained after sintering is finished; the copper content of the nickel alloy material crude product is detected, the copper loss degree is judged, copper powder is supplemented, and the smelting step is repeated till the percentage content of the copper element in the nickel alloy material crude product reaches the standard; repeating the smelting step for more than three times until the pressed blank is completely and uniformly smelted and the content of each component reaches the standard, and sequentially carrying out ordered annealing and rolling for more than three times to prepare the nickel alloy material; the prepared nickel alloy material has wide-range corrosion resistance and processability, and can be applied to the field of marine chemical industry.

Description

Technical Field

[0001] This invention relates to a nickel-copper-molybdenum alloy with erosion resistance and wide-range corrosion resistance, and its preparation method, belonging to the field of nickel-based wear-resistant and corrosion-resistant alloys. Background Technology

[0002] Nickel-based metals and their alloys are widely used in harsh environments such as aviation, marine, chemical, and energy sectors due to their excellent corrosion resistance, high-temperature mechanical properties, and good processing characteristics. Among them, Monel alloys (Ni-Cu system), as classic corrosion-resistant nickel-based materials, exhibit outstanding performance in reducing media, seawater, and alkaline environments. To further expand their application in more complex corrosive environments such as those containing halides and hot concentrated acids, traditional casting processes struggle to suppress component segregation and volatilization under high copper content, leading to unstable thermodynamic conditions required for ordering. While conventional heat treatment can induce short-range ordering, it cannot ensure the uniformity and stability of long-range ordered structures on a macroscopic scale. Furthermore, the synergistic mechanism between added strengthening phases and the ordered matrix has not been effectively controlled, often resulting in uneven microstructure and weak interfacial bonding, limiting the further development of high-performance nickel alloys. Therefore, this invention actively guides the formation and stabilization of ordered solid solutions during dynamic processes and achieves microscopic coupling between these solutions and the multi-component strengthening phases W and Y₂O₃, thereby obtaining nickel alloy materials with both excellent corrosion resistance and good processing formability on a macroscopic scale. Summary of the Invention

[0003] One of the objectives of this invention is to provide a nickel-copper-molybdenum alloy that is resistant to erosion and has a wide range of corrosion resistance. The nickel alloy material comprises, by mass percentage: 57.9-67.9% Ni, 20-30% Cu, 10% Mo, 1-3% W, and 0.3% Y2O3.

[0004] Another object of the present invention is to provide a method for preparing the aforementioned erosion-resistant and wide-range corrosion-resistant nickel-copper-molybdenum alloy, specifically comprising the following steps: (1) Weigh out Ni, Cu, NiMo, W and Y2O3 powders by mass percentage and mix them evenly; (2) The uniformly mixed metal powder is molded into a block shape to obtain a pressed blank; (3) The pressed blank is sintered in an atmosphere sintering furnace, and the crude product of nickel alloy material is obtained after the sintering is completed; (4) The Cu content of the crude nickel alloy material obtained after smelting is tested, and Cu powder is added. Step (3) is repeated until the content of each component in the crude nickel alloy material meets the standard. (5) The crude product after smelting is subjected to ordered annealing to obtain a crude nickel-based alloy product; (6) The crude product is cold rolled, and steps (5) and (6) are repeated at least three times to obtain the final ordered face-centered cubic nickel-based alloy.

[0005] Preferably, the specific method of smelting according to the present invention is as follows: evacuating the smelting apparatus to a vacuum level of ≤9×10⁻⁶. -4 Pa, high-purity argon gas is introduced into the device until the internal pressure is -0.05 MPa; the pressed blank is then melted.

[0006] Preferably, in step (3) of the present invention, the smelting process adopts a step-by-step heating method: from room temperature to 500°C: slow heating at 5°C / min; from 500°C to 900°C: medium heating at 10°C / min; from 900°C to 1250°C: rapid heating at 15°C / min; heat preservation: heat preservation at 1250°C for 2 hours, followed by water quenching.

[0007] Preferably, in step (5) of the present invention, the ordered annealing temperature is 650°C, the holding time is 6-8 hours, and then the furnace is slowly cooled.

[0008] Preferably, the cold rolling conditions of the present invention are: a pass reduction rate of 8%-25%, a cumulative reduction rate of 40%-60%, and a rolling speed of 20-60 m / min.

[0009] This invention improves alloying by adding molybdenum, forming a Ni-Cu-Mo alloy. Under specific composition and heat treatment conditions, this alloy can form a long-range ordered solid solution. This ordered structure can effectively hinder dislocation movement and optimize surface passivation behavior, thus theoretically providing a microstructural basis for simultaneously improving the strength, plasticity and corrosion resistance of the alloy.

[0010] The beneficial effects of this invention are: (1) A face-centered cubic (FCC) matrix is ​​constructed with 57.9-67.9% Ni, whose inherent d-electron orbital characteristics provide an electron supply basis for the formation of the surface passivation film; the addition of 20-30% Cu forms a continuous solid solution with Ni, giving it good antioxidant properties; the addition of 10% Mo forms a solid solution with Nickel, giving it resistance to non-oxidizing acids, and thermodynamically promotes the formation of MoO2 at the passivation film / substrate interface, effectively inhibiting the destruction of the passivation film in a high-temperature acidic environment; the introduction of 1-3% W forms a (Mo,W)O2 solid solution oxide with Mo, which, in the presence of Cl, - In the medium, W 6 + ions can preferentially react with Cl. - Formation [WOCI5] - Soluble complexes; the reaction occurs on the outer layer of the passivation film, avoiding Cl... - Penetration to the film / substrate interface induces pitting corrosion; the addition of Y2O3 increases the yield of Y³ +During the growth of the oxide film, ions segregate at the grain boundaries, inhibiting oxygen vacancy diffusion through the space charge effect, thus making the passivation film growth rate more uniform. Secondly, the Y2O3 particle / matrix interface acts as a hydrogen trap, reducing the hydrogen permeation rate in the scouring environment. Finally, during thermal cycling, Y2O3 increases the recrystallization temperature by about 150°C through the pinning effect, maintaining the stability of the fine-grained structure under scouring conditions.

[0011] (2) Vacuum melting avoids the decomposition of Y2O3 dispersed phase and the generation of endogenous oxides such as NiO and MoO during the melting process, ensuring that a pure metal melt is obtained.

[0012] (3) From room temperature to 500℃: slowly increase the temperature by 5℃ / min. During this stage, the gas and moisture adsorbed on the surface of the metal powder are allowed to slowly escape, while the surface of Y2O3 particles relaxes and reconstructs, exposing a more stable crystal plane; from 500℃ to 900℃: increase the temperature at a medium speed of 10℃ / min to promote the uniform diffusion of Mo into the Ni-Cu matrix; from 900℃ to 1250℃: increase the temperature rapidly by 15℃ / min to force the alloy to directly form a uniformly composed supersaturated solid solution, creating conditions for the subsequent single-mode ordered transformation; heat preservation: heat preservation at 1250℃ for 2 hours, followed by water quenching to avoid the precipitation of harmful equilibrium phases during the cooling process.

[0013] (4) When the ordering annealing temperature is 650℃, the ordering driving force reaches the maximum, and the holding time is 6-8h to obtain a uniformly mixed L12 ordered solid solution of NiCuMo. Attached Figure Description

[0014] Figure 1 This is a surface morphology diagram of nickel powder; Figure 2 This is a surface morphology diagram of copper powder; Figure 3 The phase diagram for the NiCuMo ternary alloy; Figure 4 The electrochemical polarization curves for Example 1 are shown below. Figure 5 The electrochemical polarization curves for Example 2 are shown below. Figure 6 The electrochemical polarization curves for Example 3 are shown below. Figure 7 The electrochemical polarization curves for Example 4 are shown below. Figure 8 The electrochemical polarization curves for Example 5 are shown below. Figure 9 The electrochemical polarization curves for Example 6 are shown below. Figure 10 The electrochemical polarization curves are for Comparative Example 1. Figure 11The electrochemical polarization curves are for Comparative Example 2; Figure 12 The electrochemical polarization curves are for Comparative Example 3; Figure 13 The electrochemical polarization curves are for Comparative Example 4; Figure 14 The image shows the electrochemical polarization curves for Comparative Example 5. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, but the scope of protection of the present invention is not limited to the content described.

[0016] Example 1 This embodiment prepares nickel-based alloy materials according to the following method: (1) Weigh the following raw materials by mass percentage: 27.9% Ni, 20% Cu, 50% Ni80Mo20, 1~3% W, and 0.3% Y2O3 and mix them evenly.

[0017] (2) The uniformly mixed powder is molded into a block shape to obtain a pressed blank; (3) The pressed blank is sintered in an atmosphere sintering furnace, and the crude product of nickel alloy material is obtained after the sintering is completed; (4) The Cu content of the crude nickel alloy material obtained after smelting is tested, and Cu powder is added. Step (3) is repeated until the Ni content, Cu content and Mo content in the crude nickel alloy material reach 30%, 20% and 10% respectively. (5) The crude product after smelting is subjected to ordered annealing to obtain the final nickel-based alloy product.

[0018] (6) Cold roll the crude product to eliminate defects; repeat steps (5) and (6) at least three times to obtain the final ordered face-centered cubic nickel-based alloy.

[0019] Electrochemical experiments were conducted on the nickel-based material prepared in Example 1, specifically including the following steps: (1) Cut the smelted sample into pieces of 10mm×10mm×5mm.

[0020] (2) Connect the sample with an electric wire, leaving only a 10mm×10mm working surface exposed. Use 3.5% NaCl solution as the electrolyte and a platinum electrode as the counter electrode. Set the corrosion voltage to -1~1V and use an electrochemical workstation for electrochemical detection.

[0021] (3) Fit the anodic polarization curve and the cathode curve to obtain the corrosion voltage and corrosion current of the alloy.

[0022] Tests showed that the nickel-based alloy prepared in this embodiment had smooth anodic and cathodic polarization curves, with a passivation range parallel to the x-axis. The corrosion voltage was -0.61V and the corrosion current was 4.74E-5, obtained by Tafel extrapolation. The low corrosion current indicates a low corrosion rate and good corrosion resistance. The surface was relatively intact after polarization, with no obvious cracks.

[0023] Example 2 This embodiment uses the same method as Example 1 to prepare nickel-based alloy materials, the difference being: as shown in Table 1, the Ni content in this embodiment is 25.9% and the Cu content is 22%.

[0024] Tests showed that the nickel-based alloy prepared in this embodiment had smooth anodic and cathodic polarization curves, with a passivation range parallel to the x-axis. The corrosion voltage was -0.51V and the corrosion current was 5.40E-5, obtained by Tafel extrapolation. The low corrosion current indicates a low corrosion rate and good corrosion resistance. The surface was relatively intact after polarization, with no obvious cracks.

[0025] Example 3 This embodiment uses the same method as Example 1 to prepare nickel-based alloy materials, the difference being: as shown in Table 1, the Ni content in this embodiment is 23.9% and the Cu content is 24%.

[0026] Tests showed that the nickel-based alloy prepared in this embodiment had smooth anodic and cathodic polarization curves, with a passivation range parallel to the x-axis. The corrosion voltage was -0.38V and the corrosion current was 5.2E-5, obtained by Tafel extrapolation. The low corrosion current indicates a low corrosion rate and good corrosion resistance. The surface was relatively intact after polarization, with no obvious cracks.

[0027] Example 4 This embodiment uses the same method as Example 1 to prepare nickel-based alloy materials, the difference being: as shown in Table 1, the Ni content in this embodiment is 21.9% and the Cu content is 26%.

[0028] Tests showed that the nickel-based alloy prepared in this embodiment had smooth anodic and cathodic polarization curves, with a passivation range parallel to the x-axis. The corrosion voltage was -0.29V and the corrosion current was 4.69E-5, obtained by Tafel extrapolation. The low corrosion current indicates a low corrosion rate and good corrosion resistance. The surface was relatively intact after polarization, with no obvious cracks.

[0029] Example 5 This embodiment uses the same method as Example 1 to prepare nickel-based alloy materials, the difference being: as shown in Table 1, the Ni content in this embodiment is 19.9% ​​and the Cu content is 28%.

[0030] Tests showed that the nickel-based alloy prepared in this embodiment had smooth anodic and cathodic polarization curves, with a passivation range parallel to the x-axis. The corrosion voltage was 0.51V and the corrosion current was 3.47E-5, obtained by Tafel extrapolation. The low corrosion current indicates a low corrosion rate and good corrosion resistance. The surface was relatively intact after polarization, with no obvious cracks.

[0031] Example 6 This embodiment uses the same method as Example 1 to prepare nickel-based alloy materials, the difference being: as shown in Table 1, the Ni content in this embodiment is 17.9% and the Cu content is 30%.

[0032] Tests showed that the nickel-based alloy prepared in this embodiment had smooth anodic and cathodic polarization curves, with a passivation range parallel to the x-axis. The corrosion voltage was -0.63V and the corrosion current was 5.46E-5, obtained by Tafel extrapolation. The low corrosion current indicates a low corrosion rate and good corrosion resistance. The surface was relatively intact after polarization, with no obvious cracks.

[0033] Comparative Example 1 The preparation method of Comparative Example 1 is the same as that of Example 1, except that the Ni content is 99.9%, as shown in Table 1.

[0034] Electrochemical analysis was performed on pure nickel prepared by powder metallurgy, using the same testing methods as in Example 1; the electrochemical results after polarization are as follows. Figure 10 As shown, the corrosion voltage obtained by Tafel extrapolation is -1.3V and the corrosion current is 4.92E-4. The corrosion voltage is low, indicating a strong tendency to corrode. The corrosion current is large, indicating a fast corrosion rate. This shows that the pure nickel alloy has a large corrosion area and poor corrosion resistance.

[0035] Comparative Example 2 The preparation method of Comparative Example 2 is the same as that of Example 1, except that the content of Ni80Mo20 is 98%, as shown in Table 3.

[0036] Electrochemical analysis was performed on Ni80Mo20 prepared by powder metallurgy, using the same testing methods as in Example 1. The electrochemical results after polarization are as follows: Figure 11 As shown, the corrosion voltage obtained by Tafel extrapolation is -1.18V and the corrosion current is 5.03E-4. The corrosion voltage is low, indicating a serious tendency to corrode. The corrosion current is large, indicating a fast corrosion rate. This indicates that many cracks are generated after polarization, suggesting poor corrosion resistance.

[0037] Comparative Example 3 The preparation method of Comparative Example 3 is the same as that of Example 1, except that, as shown in Table 1, the content of Ni is 47.9% and the content of Ni80Mo20 is 50%.

[0038] The alloys prepared in the comparative example were subjected to electrochemical testing and analysis, using the same testing methods as in Example 1; the electrochemical results after polarization are as follows: Figure 12 As shown, the corrosion voltage obtained by Tafel extrapolation is -1.21V and the corrosion current is 5.11E-4. The corrosion voltage is low, indicating a strong tendency to corrode. The corrosion current is large, indicating a fast corrosion rate. After polarization, the surface of Comparative Example 3 has many cracks and poor corrosion resistance.

[0039] Comparative Example 4 The preparation method of Comparative Example 4 is the same as that of Example 1, except that, as shown in Table 1, the content of Cu is 47.9% and the content of Ni80Mo20 is 50%.

[0040] Electrochemical tests were performed on Comparative Example 4, using the same methods as in Example 1; the electrochemical results after polarization are as follows: Figure 13 As shown, the corrosion voltage obtained by Tafel extrapolation is -1.25V and the corrosion current is 5.03E-4. The corrosion voltage is low, indicating a strong tendency to corrode. The corrosion current is large, indicating a fast corrosion rate. After polarization, Comparative Example 3 shows that the surface produces more cracks and has poor corrosion resistance.

[0041] Comparative Example 5 The preparation method of Comparative Example 5 is the same as that of Example 1, except that, as shown in Table 1, the content of Ni is 49% and the content of Cu is 50%.

[0042] Electrochemical tests were performed on Example 5, using the same methods as in Example 1; the electrochemical results after polarization are as follows: Figure 14 As shown, the corrosion voltage obtained by Tafel extrapolation is -1.0V and the corrosion current is 5.31E-4. The corrosion voltage is low, indicating a strong tendency to corrode. The corrosion current is large, indicating a fast corrosion rate. After polarization, the surface of Comparative Example 3 has many cracks and poor corrosion resistance.

[0043] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A nickel-copper-molybdenum alloy with erosion resistance and wide-range corrosion resistance, characterized in that: The nickel alloy material comprises, by mass percentage: 57.9-67.9% Ni, 20-30% Cu, 10% Mo, 1-3% W, and 0.3% Y2O3.

2. The method for preparing the erosion-resistant and wide-range corrosion-resistant nickel-copper-molybdenum alloy according to claim 1, characterized in that, Specifically, the following steps are included: (1) Weigh out Ni, Cu, NiMo alloy, W, and Y2O3 powders by mass percentage and mix them evenly; (2) The uniformly mixed metal powder is molded into a block shape to obtain a pressed blank; (3) The pressed blank is sintered in an atmosphere sintering furnace, and the crude product of nickel alloy material is obtained after the sintering is completed; (4) The Cu content of the crude nickel alloy material obtained after smelting is tested, and Cu powder is added. Step (3) is repeated until the content of each component in the crude nickel alloy material meets the standard. (5) The crude product after smelting is subjected to ordered annealing to obtain a crude nickel-based alloy product; (6) The crude product is cold rolled, and steps (5) and (6) are repeated at least three times to obtain the final ordered face-centered cubic nickel-based alloy.

3. The method for preparing the erosion-resistant and wide-range corrosion-resistant nickel-copper-molybdenum alloy according to claim 2, characterized in that, The specific method of smelting is as follows: the smelting apparatus is evacuated to a vacuum level of ≤9×10. -4 Pa, high-purity argon gas is introduced into the device until the internal pressure is -0.05 MPa; the pressed blank is then melted.

4. The method for preparing the erosion-resistant and wide-range corrosion-resistant nickel-copper-molybdenum alloy according to claim 2, characterized in that, In step (3), the smelting process adopts a step-by-step heating method: from room temperature to 500℃: slow heating at 5℃ / min; from 500℃ to 900℃: medium heating at 10℃ / min; from 900℃ to 1250℃: rapid heating at 15℃ / min. Heat preservation: Hold at 1250℃ for 2 hours, then water quench.

5. The method for preparing the erosion-resistant and wide-range corrosion-resistant nickel-copper-molybdenum alloy according to claim 2, characterized in that, In step (5), the ordered annealing temperature is 650℃, the holding time is 6-8h, and then it is slowly cooled in the furnace.

6. The method for preparing the erosion-resistant and wide-range corrosion-resistant nickel-copper-molybdenum alloy according to claim 2, characterized in that, The conditions for cold rolling are: a reduction rate of 8%-25% per pass, a cumulative reduction rate of 40%-60%, and a rolling speed of 20-60 m / min.

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