A phase change self-lubricating copper alloy, a preparation method and application thereof

Abstract

The present application belongs to the technical field of self-lubricating alloy, and particularly relates to a phase change self-lubricating copper alloy and a preparation method and application thereof. The present application provides a phase change self-lubricating copper alloy, which comprises the following chemical components in mass percentage: Cu 60.0% to 83.0%, Ni 2.0% to 25.0%, Sn 1.0% to 9.0%, Mn 1.0% to 5.0%, W 0.5% to 1.5%, Ta 0.5% to 1.5%, Pb 2.0% to 4.0%, MoO3 2.0% to 4.0%, CaF2 2.0% to 5.0%, and graphite 1.0% to 4.5%. The phase change self-lubricating copper alloy has high hardness, high strength, low friction coefficient and good wear resistance. The phase change self-lubricating copper alloy can be used to prepare gas turbine compressor guide vane bushings and other parts which require sufficient strength, toughness, wear resistance and high-temperature resistance, and has considerable market application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of self-lubricating alloys, and particularly relates to a phase-change self-lubricating copper alloy and a preparation method and application thereof. BACKGROUND

[0002] The failure of the gas turbine compressor guide vane bushing is a serious problem that may be encountered during the operation of the gas turbine. As a key component of the gas turbine compressor, the failure of the bushing will directly affect the performance and overall operation stability of the gas turbine. The material used to prepare the bushing needs to have sufficient strength, toughness and high-temperature resistance. If the material used to prepare the bushing cannot withstand the high-temperature working environment or has insufficient wear resistance, it may lead to the failure of the bushing during operation, thereby affecting the normal operation of the gas turbine. At the same time, since the friction between the bushing and the guide vane shaft is in a dry friction state, the material used to manufacture the bushing needs to have good self-lubricating performance and wear resistance.

[0003] Self-lubricating copper alloy is a material that can be used in dry friction conditions. This type of material is generally manufactured by powder metallurgy. Due to its good self-lubricating performance, products or components made of this material can still maintain a low friction coefficient and stable friction performance without external lubricants. The gas turbine compressor guide vane bushing needs to withstand large loads, high temperatures and mechanical vibrations during operation, so the material used to prepare the bushing not only needs to have good self-lubricating performance, but also needs to have the same high hardness and high strength as cast copper alloys. The existing disclosed self-lubricating alloy materials mostly use non-metallic phase materials, and the volume fraction of non-metallic phase is too large, which will result in a hardness and strength much lower than that of cast copper alloys. Moreover, the hardness, strength, friction coefficient, wear rate and processing performance of the existing disclosed self-lubricating alloy materials cannot meet the technical requirements of the gas turbine compressor guide vane bushing. The bushing prepared by using the existing self-lubricating alloy material is prone to jamming during the operation of the gas turbine, which seriously affects the normal operation of the gas turbine. SUMMARY

[0004] Therefore, the present application aims to provide a phase-change self-lubricating copper alloy and a preparation method and application thereof. The phase-change self-lubricating copper alloy provided by the present application has high hardness and high strength, low friction coefficient and good wear resistance.

[0005] The application provides a phase change self-lubricating copper alloy, which comprises the following chemical components in percentage by mass: Cu 60.0%-83.0%, Ni 2.0%-25.0%, Sn 1.0%-9.0%, Mn 1.0%-5.0%, W 0.5%-1.5%, Ta 0.5%-1.5%, Pb 2.0%-4.0%, MoO3 2.0%-4.0%, CaF2 2.0%-5.0%, and graphite 1.0%-4.5%.

[0006] The application further provides a preparation method of the phase change self-lubricating copper alloy.

[0007] CuNiSnMn alloy powder, W powder and Ta powder are ball milled to obtain premixed gold powder;

[0008] The premixed gold powder is mixed with composite spheroidization powder, and then is pressed to obtain a blank;

[0009] The blank is sintered in a reducing atmosphere to obtain an alloy preform;

[0010] The alloy preform is subjected to phase change treatment in a reducing atmosphere to obtain the phase change self-lubricating copper alloy;

[0011] The composite spheroidization powder comprises PbO, MoO3, CaF2 and graphite.

[0012] Preferably, the CuNiSnMn alloy powder is atomized powder with a particle size of 10-76 mu m;

[0013] The W powder and the Ta powder are both spherical powder; the particle size of the W powder is 1-5 mu m; and the particle size of the Ta powder is 1-5 mu m.

[0014] Preferably, the particle size of the composite spheroidization powder is 60-120 mu m.

[0015] Preferably, the preparation method of the composite spheroidization powder comprises:

[0016] PbO powder, MoO3 powder, CaF2 powder and graphite powder are spheroidized to obtain the composite spheroidization powder;

[0017] The particle size of the PbO powder is 1-5 mu m; the particle size of the MoO3 powder is 1-10 mu m; the particle size of the CaF2 powder is 10-22 mu m; and the particle size of the graphite powder is 10-20 mu m.

[0018] Preferably, the ball milling time is 4-8 h.

[0019] Preferably, the pressure of the pressing is 280-320 MPa.

[0020] Preferably, the sintering and phase transformation treatment are carried out in the same reducing atmosphere; the reducing atmosphere is pure hydrogen or ammonia decomposition gas.

[0021] The sintering temperature is 950-960 DEG C, and the holding time is 2-6h.

[0022] The phase transformation treatment temperature is (520±10) DEG C, and the holding time is 3-5h.

[0023] The application also provides application of the phase transformation self-lubricating copper alloy or the phase transformation self-lubricating copper alloy prepared by the preparation method in a gas turbine compressor guide vane bushing.

[0024] Preferably, the guide vane bushing comprises the phase transformation self-lubricating copper alloy and FM-3600 polytetrafluoroethylene dry film lubricant; the phase transformation self-lubricating copper alloy is the phase transformation self-lubricating copper alloy or the phase transformation self-lubricating copper alloy prepared by the preparation method.

[0025] The application provides a phase transformation self-lubricating copper alloy, which comprises the following chemical components in mass percentage: Cu 60.0%-83.0%, Ni 2.0%-25.0%, Sn 1.0%-9.0%, Mn 1.0%-5.0%, W 0.5%-1.5%, Ta 0.5%-1.5%, Pb 2.0%-4.0%, MoO3 2.0%-4.0%, CaF2 2.0%-5.0% and graphite 1.0%-4.5%.

[0026] The material design principle of the phase transformation self-lubricating copper alloy is that: the phase transformation strengthening and toughening of the CuNiSnMn alloy, the wear-resistant phase of the high-melting-point metals W and Ta, the composite spheroidization of PbO, MoO3, CaF2 and graphite are combined, so that the material has high hardness, high strength, low friction coefficient and good wear resistance.

[0027] The results of the embodiment show that: the Brinell hardness of the phase transformation self-lubricating copper alloy is 220-320 HB, the yield strength is 350-450 MPa, the friction coefficient is 0.10-0.18, and the wear rate is (1.5*10 -5 -8.0*10 -5 )mm 3 / (Nm).

[0028] The application further provides a preparation method of the phase-change self-lubricating copper alloy, and the preparation method comprises the following steps: ball milling the CuNiSnMn alloy powder, the W powder and the Ta powder to obtain premixed metal powder; mixing the premixed metal powder with composite spheroidized powder, and pressing to obtain a blank; sintering the blank in a reducing atmosphere to obtain an alloy preform; and performing phase change treatment on the alloy preform in the reducing atmosphere to obtain the phase-change self-lubricating copper alloy; and the composite spheroidized powder comprises PbO, MoO3, CaF2 and graphite.

[0029] The phase change of the CuNiSnMn alloy greatly improves the hardness and strength of the powder metallurgy copper alloy; after the spherical W and Ta are added as hard phase, the two kinds of factors improve the hardness and wear resistance of the phase-change self-lubricating alloy; and the spheroidization of the PbO, MoO3, CaF2 and graphite solid lubricants reduces the crack source in the material and improves the toughness of the material. The phase-change self-lubricating copper alloy has high hardness and high strength, and has excellent self-lubricating performance and good wear resistance.

[0030] Specifically, the spherical micro-morphology of the composite spheroidized powder can reduce the stress concentration at the interface between the metal phase and the non-metal phase, reduce the crack source in the raw material, and further improve the internal toughness of the phase-change self-lubricating copper alloy material; and the spherical composite spheroidized powder is denser when smelting with the CuNiSnMn alloy powder, the W powder and the Ta powder, thereby further improving the density, hardness and strength of the phase-change self-lubricating copper alloy. The preparation method provided by the application sintering the blank in a reducing atmosphere, so that the PbO is reduced to metal Pb at the sintering temperature, and the reduced metal Pb is in a liquid state, so that the spheroidized solid lubricant composite spheroidized powder is denser under the action of the liquid metal Pb, thereby further improving the density, hardness and strength of the phase-change self-lubricating alloy. The soft metal Pb and Sn and the non-metallic phases MoO3, CaF2 and graphite can form a stable lubricating film on the friction surface during friction, so that the prepared phase-change self-lubricating copper alloy has high hardness, high strength, low friction coefficient and good wear resistance. The preparation method provided by the application is simple, does not need to add various additives, has low cost, is easy to industrialize, and has considerable market application prospect.

[0031] The application further provides an application of the phase-change self-lubricating copper alloy in a gas turbine compressor guide vane bushing.

[0032] The guide vane bushing provided by the present invention comprises a phase change self-lubricating copper alloy and FM-3600 polytetrafluoroethylene dry film lubricant; the phase change self-lubricating copper alloy is the phase change self-lubricating copper alloy described in the above technical solution.

[0033] The main manufacturing steps of the gas turbine compressor guide vane bushing provided by this invention include machining a phase change self-lubricating copper alloy and coating the friction surface of the guide vane bushing with FM-3600 polytetrafluoroethylene dry film lubricant. The dry film lubricant is mainly composed of polytetrafluoroethylene and has a thickness of 10-20 μm. The phase change self-lubricating copper alloy guide vane bushing is characterized by high bonding strength between the phase change self-lubricating copper alloy and the dry film lubricant. Dry film lubricant is a general technology for self-lubricating bushing parts; it is used only as a general technology in this invention and is not included within the scope of the claims of this invention.

[0034] The gas turbine compressor guide vane bushing prepared using the phase change self-lubricating copper alloy provided by this invention is suitable for harsh service conditions. The bushing has a low coefficient of friction, good wear resistance, and its service life can match that of the entire gas turbine equipment. Attached Figure Description

[0035] Brinell hardness / HB A schematic diagram of the gas turbine compressor guide vane bushing structure prepared in Example 1;

[0036] Yield strength / MPa This is a schematic diagram of the gas turbine compressor guide vane bushing structure prepared in Example 2. Detailed Implementation

[0037] This invention provides a phase change self-lubricating copper alloy, comprising the following chemical composition by weight percentage:

[0038] Cu 60.0%–83.0%, Ni 2.0%–25.0%, Sn 1.0%–9.0%, Mn 1.0%–5.0%, W 0.5%–1.5%, Ta 0.5%–1.5%, Pb 2.0%–4.0%, MoO3 2.0%–4.0%, CaF2 2.0%–5.0%, Graphite 1.0%–4.5%.

[0039] The phase transformation self-lubricating alloy provided by the present invention comprises a chemical composition of Cu, the mass percentage of which is 60.0% to 83.0%, preferably 73.0% to 80.0%. In the present invention, the Cu exists in solid solution form and acts as the alloy matrix, serving as the matrix for the phase transformation toughening component.

[0040] The phase change self-lubricating alloy provided by the application comprises a chemical component Ni, and the mass percentage of Ni is 2.0% to 25.0%, preferably 8.0% to 15.0%. In the application, Ni is a key component for phase change toughening, which can strengthen the copper alloy matrix and improve the hardness and strength of the phase change self-lubricating copper alloy.

[0041] The phase change self-lubricating alloy provided by the application comprises a chemical component Sn, and the mass percentage of Sn is 1.0% to 9.0%, preferably 4.0% to 9.0%. In the application, Sn is a key component for phase change toughening, which can strengthen the copper alloy matrix and improve the hardness and strength of the phase change self-lubricating copper alloy.

[0042] The phase change self-lubricating alloy provided by the application comprises a chemical component Mn, and the mass percentage of Mn is 1.0% to 5.0%, preferably 2.0% to 4.0%. In the application, Mn is a key component for phase change toughening, which can strengthen the copper alloy matrix and improve the hardness and strength of the phase change self-lubricating copper alloy.

[0043] The phase change self-lubricating alloy provided by the application comprises a chemical component W, and the mass percentage of W is 0.5% to 1.5%, preferably 1.0% to 1.5%. In the application, W is a high-melting-point wear-resistant metal, which is dispersedly distributed in the phase change self-lubricating copper alloy as a hard phase, becomes a micro support point of the friction surface of the phase change self-lubricating copper alloy, and thus improves the hardness and wear resistance of the phase change self-lubricating copper alloy.

[0044] The phase change self-lubricating alloy provided by the application comprises a chemical component Ta, and the mass percentage of Ta is 0.5% to 1.5%, preferably 1.0% to 1.5%. In the application, Ta is a high-melting-point wear-resistant metal, which is dispersedly distributed in the phase change self-lubricating copper alloy as a hard phase, becomes a micro support point of the friction surface of the phase change self-lubricating copper alloy, and thus improves the hardness and wear resistance of the phase change self-lubricating copper alloy.

[0045] The phase change self-lubricating alloy provided by the application comprises a chemical component Pb, and the mass percentage of Pb is 2.0% to 4.0%, preferably 1.5% to 4.0%. In the application, Pb exists in the form of elemental metal phase, and Pb can reduce the friction coefficient of the phase change self-lubricating copper alloy.

[0046] The phase change self-lubricating alloy provided by the application comprises a chemical component MoO3, and the mass percentage of MoO3 is 2.0% to 4.0%, preferably 2.0% to 3.0%. In the application, MoO3 can reduce the friction coefficient of the phase change self-lubricating copper alloy, acts as an oxide solid lubricant, can be transferred on the friction surface during the friction process, prevents the adhesion of the friction surface, and makes the prepared phase change self-lubricating copper alloy have a low friction coefficient and good wear resistance.

[0047] The phase change self-lubricating alloy provided by the application comprises a chemical component CaF2, the mass percentage of which is 2.0% to 5.0%, preferably 2.0% to 4.0%. In the application, CaF2 can reduce the friction coefficient of the phase change self-lubricating copper alloy, as a fluoride solid lubricant, can be transferred on the friction surface in the friction process, prevents the adhesion of the friction surface, and makes the prepared phase change self-lubricating copper alloy have low friction coefficient and good wear resistance.

[0048] The phase change self-lubricating alloy provided by the application comprises a chemical component graphite, the mass percentage of which is 1.0% to 4.5%, preferably 1.5% to 3.5%. In the application, graphite can reduce the friction coefficient of the phase change self-lubricating copper alloy, as the main component of the solid lubricant in the application, can form a stable lubricating film on the friction surface in the friction process, and makes the prepared phase change self-lubricating copper alloy have low friction coefficient and good wear resistance.

[0049] The application further provides a preparation method of the phase change self-lubricating copper alloy.

[0050] The CuNiSnMn alloy powder, the W powder and the Ta powder are ball milled to obtain a premixed gold powder.

[0051] The premixed gold powder is mixed with a composite spheroidization powder, and is pressed to obtain a blank.

[0052] The blank is sintered in a reducing atmosphere to obtain an alloy pre-product.

[0053] The alloy pre-product is subjected to phase change treatment in a reducing atmosphere to obtain the phase change self-lubricating copper alloy.

[0054] The composite spheroidization powder comprises PbO, MoO3, CaF2 and graphite.

[0055] In the application, the raw materials used in the application are preferably commercially available products, unless otherwise specified.

[0056] The CuNiSnMn alloy powder, the W powder and the Ta powder are ball milled to obtain a premixed gold powder.

[0057] In the application, the CuNiSnMn alloy powder is preferably an atomized powder, and the particle size is preferably 10 to 76 μm.

[0058] In the application, the W powder and the Ta powder are preferably spherical powders. In the application, the particle size of the W powder is preferably 1 to 5 μm, and more preferably 1 to 3 μm. In the application, the particle size of the Ta powder is preferably 1 to 5 μm, and more preferably 1 to 3 μm.

[0059] In the present application, the ball milling is preferably performed in a ball mill. In the present application, the ball milling time is preferably 4-8 hours. The present application ball-mills CuNiSnMn alloy powder, W powder and Ta powder, which can mix the components uniformly, is beneficial to sintering and can prevent component segregation.

[0060] After obtaining the premixed gold powder, the present application mixes the premixed gold powder with composite spheroidization powder, and performs pressing to obtain a blank.

[0061] In the present application, the composite spheroidization powder comprises PbO, MoO3, CaF2 and graphite. In the present application, the particle size of the composite spheroidization powder is preferably 60-120 μm, and more preferably 90-120 μm.

[0062] In the present application, the preparation method of the composite spheroidization powder preferably comprises: spheroidizing PbO powder, MoO3 powder, CaF2 powder and graphite powder to obtain the composite spheroidization powder. In the present application, the particle size of the PbO powder is preferably 1-5 μm. In the present application, the particle size of the MoO3 powder is preferably 1-10 μm. In the present application, the particle size of the CaF2 powder is preferably 10-22 μm. In the present application, the particle size of the graphite powder is preferably 10-20 μm. In the present application, the spheroidization mode preferably comprises centrifugal spray granulation. The present application does not make specific limitation to the centrifugal spray granulation, which can be operated according to the conventional operation in the art. The present application spheroidizes solid lubricant PbO powder, MoO3 powder, CaF2 powder and graphite powder, which reduces the crack source in the phase-change self-lubricating copper alloy and improves the toughness of the phase-change self-lubricating copper alloy. Spheroidization is to reduce the stress concentration at the interface between the metal phase and the non-metal phase, thereby improving the toughness. In the present application, MoO3, CaF2 and graphite can reduce the friction coefficient of the phase-change self-lubricating copper alloy; and the spherical micro-morphology of the composite spheroidization powder can reduce the stress concentration at the interface between the metal phase and the non-metal phase, thereby improving the internal toughness of the phase-change self-lubricating copper alloy material.

[0063] In the present application, the pressing is preferably performed in a mold. In the present application, the pressure of the pressing is preferably 280-320 MPa, and more preferably 300-320 MPa.

[0064] After obtaining the blank, the present application sintering the blank in a reducing atmosphere to obtain an alloy preform.

[0065] In the present application, the reducing atmosphere is preferably pure hydrogen or ammonia decomposition gas. In the present application, the sintering is preferably performed in a hydrogen furnace. In the present application, the sintering temperature is preferably 950-960℃, and the holding time is preferably 2-6h. In the present application, the heating rate to the sintering temperature is preferably 1-5℃ / min. The present application sintering the blank in a reducing atmosphere, and in the sintering process, PbO is reduced to metallic Pb, and the hardness and strength of the prepared phase change self-lubricating alloy are higher; at the sintering temperature, the reduced metallic Pb is in a liquid state, so that the solid lubricant composite spheroidized powder which has been spheroidized is more compact under the action of the liquid metallic Pb, further improving the compactness, hardness and strength of the phase change self-lubricating alloy.

[0066] After obtaining the alloy preform, the present application performs phase change treatment on the alloy preform in a reducing atmosphere to obtain the phase change self-lubricating copper alloy.

[0067] In the present application, the reducing atmosphere is preferably pure hydrogen or ammonia decomposition gas. In the present application, the phase change treatment is preferably performed in a hydrogen furnace. In the present application, the phase change treatment temperature is preferably (520±10)℃, and the holding time is preferably 3-5h.

[0068] The present application performs phase change treatment on the prepared alloy preform in a reducing atmosphere, and the components in the alloy preform undergo phase change reaction at a specific temperature, Cu, Ni, Sn and Mn form strong and tough structures in the alloy, improving the hardness and strength of the phase change self-lubricating copper alloy; W and Ta form hard phases and are dispersedly distributed in the phase change self-lubricating copper alloy to become micro support points on the friction surface of the phase change self-lubricating copper alloy, thereby improving the hardness and wear resistance of the phase change self-lubricating copper alloy; soft metals Pb and Sn and non-metallic phases MoO3, CaF2 and graphite make the prepared phase change self-lubricating copper alloy have low friction coefficient and good wear resistance.

[0069] The present application also provides the application of the phase change self-lubricating copper alloy or the phase change self-lubricating copper alloy prepared by the preparation method in a gas turbine compressor guide vane bushing.

[0070] In the present application, the guide vane bushing preferably comprises the phase change self-lubricating copper alloy and FM-3600 polytetrafluoroethylene dry film lubricant. In the present application, when the guide vane bushing is a half-and-half bushing, a positioning pin is preferably included, and the material of the positioning pin is preferably 304 stainless steel.

[0071] In the present application, the bushing is mechanically processed from the phase change self-lubricating copper alloy described in the above technical solution. The present application does not limit the specific operation mode of the mechanical processing, which can be performed according to the conventional operation in the field.

[0072] In the present application, the dry film lubricant is preferably coated on the surface of the phase change self-lubricating copper alloy. In the present application, the coating thickness of the dry film lubricant is preferably 10-20 μm. In the present application, the phase change self-lubricating copper alloy has a high bonding strength with the dry film lubricant.

[0073] The technical solutions of the present application are further illustrated by specific embodiments below, and those skilled in the art should understand that the embodiments are only used to understand the present application and should not be regarded as specific limitations on the present application.

[0074] Example 1

[0075] The raw materials used in the preparation of the phase change self-lubricating copper alloy in this example are: CuNiSnMn alloy powder, which is atomized powder, with a particle size of 44-76 μm; W powder and Ta powder, which are spherical powders, with a particle size of 1-3 μm; PbO powder, MoO3 powder, CaF2 powder and graphite powder, with particle sizes of 1-5 μm, 1-10 μm, 10-22 μm and 10-20 μm, respectively.

[0076] The preparation method and main parameters for preparing the phase change self-lubricating copper alloy in this example are as follows:

[0077] (1) The PbO powder, MoO3 powder, CaF2 powder and graphite powder are spheroidized by centrifugal spray granulation in a mass ratio of 4:4:2:3 to obtain composite spheroidized powder in the form of spherical powder, and the particle size of the composite spheroidized powder is 90-120 μm;

[0078] (2) The CuNiSnMn alloy powder, W powder and Ta powder are ball milled in a mass ratio of 12:13 to obtain pre-mixed gold powder;

[0079] (3) The obtained pre-mixed gold powder is mixed with the composite spheroidized powder, and is pressed in a steel mold, with a pressing pressure of 300 MPa, to obtain a blank;

[0080] (4) The obtained blank is sintered in a reducing atmosphere of ammonia decomposition gas, with a sintering temperature of 960 °C and a holding time of 6 h, to obtain an alloy preform;

[0081] (5) The obtained alloy preform is subjected to phase change treatment in a reducing atmosphere of ammonia decomposition gas, with a phase change temperature of 520±10 °C and a holding time of 4 h, to obtain a phase change self-lubricating alloy.

[0082] The chemical composition of the phase change self-lubricating copper alloy obtained in this example is: Cu 74.5%, Ni 3.0%, Sn 5.0%, Mn 2.0%, W 1.2%, Ta 1.3%, Pb 4.0%, MoO3 4.0%, CaF2 2.0%, and graphite 3.0%.

[0083] The Brinell hardness of the prepared phase change self-lubricating copper alloy was tested according to GB / T 231.1-2018 "Metallic Materials Brinell Hardness Test"; the yield strength was tested according to GB / T 7314-2017 "Metallic Materials Compression Test at Room Temperature"; the friction coefficient and wear rate were tested according to GB / T 12444-2006 "Metallic Materials Wear Test Method Ring Block Sliding Wear Test". The test results are shown in Table 1.

[0084] Table 1 Test results of the phase change self-lubricating copper alloy prepared in Example 1

[0085] Coefficient of friction Test item Test result 268 Brinell hardness / HB 420 Yield strength / MPa 0.12 Wear rate / x 10 -5 mm 3 (Nm) 2.2

[0086] Example 2

[0087] The raw materials used for preparing the phase change self-lubricating copper alloy in this example were as follows: CuNiSnMn alloy powder was atomized powder with a particle size of 44-76 μm; W powder and Ta powder were spherical powders with a particle size of 1-3 μm; the particle sizes of PbO powder, MoO3 powder, CaF2 powder and graphite powder were 1-5 μm, 1-10 μm, 10-22 μm and 10-20 μm, respectively.

[0088] The preparation method and main parameters for preparing the phase change self-lubricating copper alloy in this example were as follows:

[0089] (1) The PbO powder, MoO3 powder, CaF2 powder and graphite powder were spheroidized and powdered by centrifugal spray granulation in a mass ratio of 1:1:2:1 to obtain composite spheroidized powder as spherical powder with a particle size of 90-120 μm;

[0090] (2) The CuNiSnMn alloy powder, W powder and Ta powder were ball milled in a mass ratio of 85:1:1 to obtain a pre-mixed gold powder;

[0091] (3) The obtained pre-mixed gold powder was mixed with the composite spheroidized powder, and was pressed in a steel mold at a pressure of 320 MPa to obtain a blank;

[0092] (4) The obtained blank was sintered in a reducing atmosphere of ammonia decomposition gas at a sintering temperature of 960℃ for 4h to obtain an alloy preform;

[0093] (5) The obtained alloy preform was subjected to phase change treatment in a reducing atmosphere of ammonia decomposition gas at a phase change temperature of 520±10℃ for 4h to obtain a phase change self-lubricating alloy.

[0094] The chemical composition of the phase change self-lubricating copper alloy obtained in the embodiment is: Cu accounts for 63.0%, Ni accounts for 15.0%, Sn accounts for 7.0%, Mn accounts for 3.0%, W accounts for 1.0%, Ta accounts for 1.0%, Pb accounts for 2.0%, MoO3 accounts for 2.0%, CaF2 accounts for 4.0%, and graphite accounts for 2.0%.

[0095] The Brinell hardness of the phase change self-lubricating copper alloy prepared is tested according to GB / T 231.1-2018 “Metallic Materials Brinell Hardness Test”; the yield strength is tested according to GB / T 7314-2017 “Metallic Materials Room Temperature Compression Test”; the friction coefficient and the wear rate are tested according to GB / T 12444-2006 “Metallic Materials Wear Test Method Ring-Block Sliding Wear Test”. The test results are shown in Table 2.

[0096] Table 2 Test results of the phase change self-lubricating copper alloy prepared in Example 2

[0097] Coefficient of friction Test item Test result 320 Brinell hardness / HB 450 Yield strength / MPa 0.15 Wear rate / x 10 -5 mm 3 (Nm) 1.5

[0098] Comparative Example 1

[0099] The difference from Example 1 is that the composite spheroidizing powder is not added.

[0100] The chemical composition of the phase change self-lubricating copper alloy obtained in the embodiment is: Cu accounts for 87.5%, Ni accounts for 3.0%, Sn accounts for 5.0%, Mn accounts for 2.0%, W accounts for 1.2%, and Ta accounts for 1.3%;

[0101] The test results are shown in Table 3.

[0102] Table 3 Test results of the phase change self-lubricating copper alloy prepared in Comparative Example 1

[0103] Coefficient of friction Test item Test result 288 Brinell hardness / HB 560 Yield strength / MPa 0.38 Wear rate / x 10 -5 mm 3 (Nm) 85

[0104] Comparative Example 2

[0105] The difference from Example 2 is that the W powder is not added.

[0106] The chemical composition of the phase change self-lubricating copper alloy obtained in the embodiment is: Cu accounts for 64.0%, Ni accounts for 15.0%, Sn accounts for 7.0%, Mn accounts for 3.0%, Ta accounts for 1.0%, Pb accounts for 2.0%, MoO3 accounts for 2.0%, CaF2 accounts for 4.0%, and graphite accounts for 2.0%;

[0107] The test results are shown in Table 4.

[0108] Table 4 Test results of the phase change self-lubricating copper alloy prepared in Comparative Example 2

[0109] Coefficient of friction Figure 1 Figure 1 295 Figure 2 435 Figure 2 0.13 Wear rate / x 10 -5 mm 3 (Nm) 8.6

[0110] Comparative Example 3

[0111] The difference from Example 1 is that Ta powder is not added.

[0112] The chemical composition of the phase change self-lubricating copper alloy obtained in this example is: Cu 75.8%, Ni 3.0%, Sn 5.0%, Mn 2.0%, W 1.2%, Pb 4.0%, MoO3 4.0%, CaF2 2.0%, graphite 3.0%;

[0113] The test results are shown in Table 5.

[0114] Table 5 Test results of the phase change self-lubricating copper alloy prepared in Comparative Example 3

[0115]

[0116]

[0117] Application Example 1

[0118] A bushing is prepared using the phase change self-lubricating copper alloy prepared in Example 1, and the bushing is a gas turbine guide vane outer end bushing characterized by a single-side flange type. The phase change self-lubricating copper alloy is located at the inner ring friction surface and the flange end surface, and both are coated with FM-3600 polytetrafluoroethylene dry film lubricant, and the thickness of the FM-3600 polytetrafluoroethylene dry film lubricant is 15 μm. The structure is shown in ​ .

[0119] ​ M: 1 is the phase change self-lubricating copper alloy prepared in Example 1; 2 is the FM-3600 polytetrafluoroethylene dry film lubricant coating.

[0120] Application effect: The phase change self-lubricating copper alloy provided in the application is applied to the 700 MW heavy gas turbine (H level) compressor bushing, realizing the self-lubrication and maintenance-free function of the gas turbine compressor bushing, and replacing the imported products.

[0121] Application Example 2

[0122] A bushing is prepared using the phase change self-lubricating copper alloy prepared in Example 2, and the bushing is a gas turbine compressor guide vane bushing characterized by a double-side flange type. The bushing is a half-type bushing, and the left and right halves are fixed by stainless steel pins. The phase change self-lubricating copper alloy is located at the inner ring friction surface and the flange end surface at two places, and both are coated with FM-3600 polytetrafluoroethylene dry film lubricant, and the thickness of the FM-3600 polytetrafluoroethylene dry film lubricant is 15 μm. The structure is shown in ​ .

[0123] ​ Medium: 3 is a split bushing (left); 4 is an FM-3600 polytetrafluoroethylene dry film lubricant coating; 5 is a split bushing (right); 6 is a pin.

[0124] Application effect: the self-lubricating copper alloy bushing provided by the application is applied to a 700MW heavy gas turbine (H level) compressor bushing, realizes self-lubrication and maintenance-free function of the gas turbine compressor bushing, and replaces imported products.

[0125] The above only describes the preferred embodiments of the present application, and does not limit the present application in any form. It should be noted that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A phase change self-lubricating copper alloy characterized by comprising, in mass %, The chemical components include the following mass percentages: Cu 60.0%-83.0%, Ni 2.0%-25.0%, Sn 1.0%-9.0%, Mn 1.0%-5.0%, W 0.5%-1.5%, Ta 0.5%-1.5%, Pb 2.0%-4.0%, MoO3 2.0%-4.0%, CaF2 2.0%-5.0%, and graphite 1.0%-4.5%.

2. The method for preparing the phase transformation self-lubricating copper alloy according to claim 1, characterized in that, The method comprises the following steps: CuNiSnMn alloy powder, W powder and Ta powder are ball milled to obtain premixed gold powder; The premixed gold powder is mixed with composite spheroidization powder, and then pressed to obtain a blank; The blank is sintered in a reducing atmosphere to obtain an alloy preform; The alloy preform is subjected to phase transformation treatment in a reducing atmosphere to obtain the phase change self-lubricating copper alloy; the phase transformation treatment is performed at a temperature of (520 ± 10) ℃ for 3-5 h; The composite spheroidization powder comprises PbO, MoO3, CaF2 and graphite.

3. The preparation method according to claim 2, characterized in that, The CuNiSnMn alloy powder is atomized powder with a particle size of 10-76 μm; The W powder and the Ta powder are both spherical powder; the particle size of the W powder is 1-5 μm; and the particle size of the Ta powder is 1-5 μm.

4. The production method according to claim 2, characterized by, The particle size of the composite spheroidization powder is 60-120 μm.

5. The production method according to claim 2 or 4, characterized by, The preparation method of the composite spheroidization powder comprises: PbO powder, MoO3 powder, CaF2 powder and graphite powder are spheroidized to obtain the composite spheroidization powder; The particle size of the PbO powder is 1-5 μm; the particle size of the MoO3 powder is 1-10 μm; the particle size of the CaF2 powder is 10-22 μm; and the particle size of the graphite powder is 10-20 μm.

6. The preparation method according to claim 2, characterized in that, The ball milling time is 4-8 h.

7. The preparation method according to claim 2, characterized in that, The pressure of the pressing is 280-320 MPa.

8. The preparation method according to claim 2, characterized in that, The sintering and the phase transformation treatment are performed in the same reducing atmosphere; the reducing atmosphere is pure hydrogen or ammonia decomposition gas; The sintering is performed at a temperature of 950-960 ℃ for 2-6 h.

9. The phase change self-lubricating copper alloy of claim 1 or the phase change self-lubricating copper alloy prepared by the preparation method of any one of claims 2-8 is applied to a guide vane bushing of a gas turbine compressor.

10. Use according to claim 9, characterized in that, The guide vane bushing comprises the phase change self-lubricating copper alloy and FM-3600 polytetrafluoroethylene dry film lubricant.

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