A method of inhibiting a-element whisker growth in a max phase friction material

Abstract

The application discloses a method for inhibiting A element whisker growth in MAX phase friction material, comprising the following steps: step one, mixing M, A, C and M' elements, sintering under argon protection without pressure to obtain a MAX phase solid solution with M site solid solution elements, wherein M element is a transition metal element, A element is a main group element, and M' element is V, Cr or Nb; the molar ratio of (M+M'), A and C is 2:(1-1.2):1; step two, acid washing the MAX phase solid solution with M site solid solution elements, stirring reaction, vacuum filtration and vacuum drying. The application can fundamentally inhibit A element whisker growth, has simple preparation process, low cost, can be applied to high temperature and high humidity environment, has good corrosion resistance; the solid solution strengthening of the MAX solid solution hinders the decomposition of the MAX phase, cuts off the material source required for the surface A whisker growth, can effectively inhibit the whisker growth, and resist damage such as polishing, polishing, scratching and ball milling.

Description

TECHNICAL FIELD

[0001] The present application relates to a whisker growth inhibition method, in particular to a method for inhibiting A element whisker growth in MAX phase friction materials. BACKGROUND

[0002] MAX phase is a ternary layered carbide or nitride ceramic material, and its chemical formula is M n+1 AX n wherein M is a transition metal element, A is a main group element, and X is carbon or nitrogen. MAX phase has excellent properties of both metal and ceramic, such as good electrical and thermal conductivity, and thermal shock resistance, which makes it have great application prospects in many fields, such as friction materials, electrical contact materials, and radiation resistant materials. However, in recent years, it has been found that many MAX phases have A-site metal whisker growth phenomenon. For example, Cr2GaC, Ti2SnC, Ti2InC, and other MAX phases with low melting point metals at A-site, after slight grinding, polishing, scratching, ball milling, and other damage, a large number of metal whiskers grow. Metal whisker growth can cause short circuit, steam arc, and debris pollution, which seriously threatens the service reliability of MAX phase materials.

[0003] Currently, the main method to inhibit metal whisker growth of materials is to coat a protective coating on the surface of the material. However, the coating may wear out during use, reducing the protective effect. Moreover, the stability of the coating may be affected in high-temperature or chemical corrosion environments. The preparation and maintenance of the coating can be relatively complex, and may affect other properties of the material.

[0004] In the prior art, there are few methods that can fundamentally inhibit the whisker growth of MAX phase materials. A method for inhibiting metal whisker growth in MAX phase is disclosed in Chinese Patent No. 202210047770.6, which uses alloying method to capture active A atoms separated from MAX phase by solid solution of metal phase, cutting off the atomic source of whisker growth and inhibiting A element whisker growth. However, due to the introduction of metal phase, the dual-phase structure cannot be applied to corrosive marine environments, and the corrosion resistance needs to be further improved. A method for inhibiting A element whisker growth in MAX phase is disclosed in Chinese Patent No. 202210047770.6, which uses oxidation film forming element A' to perform solid solution treatment on A site in MAX phase. However, this method cannot inhibit the decomposition of MAX phase under external force, and cannot fundamentally reduce the A element generated by MAX decomposition. SUMMARY

[0005] The purpose of the present application is to overcome the deficiencies in the prior art, and to provide a method for inhibiting A element whisker growth in MAX phase friction materials, which is simple and convenient, low in cost, and cuts off the source of A whisker growth on the surface.

[0006] Technical solution: The method for inhibiting the whisker growth of element A in the MAX phase friction material comprises the following steps:

[0007] Step one, mix M, A, C, M' elements, sinter under argon protection without pressure, get MAX phase solid solution with M site solid solution elements, M element is transition metal element, A element is main group element, M' element is V, Cr or Nb; the molar ratio of (M+M'), A, C is 2:(1-1.2):1;

[0008] Step two, the MAX phase solid solution with M site solid solution elements is pickled, stirred, vacuum filtered and vacuum dried.

[0009] Further, in step one, the M element is any one of Ti, Zr, Lu, Hf, Sc, Mo, Ta, Cr, Nb. The A element is any one of Sn, In, Ga, Zn, Cd, Pb.

[0010] Further, in step one, the MAX phase is any one of Ti2SnC, Zr2SnC, Sc2SnC, Lu2SnC, Hf2SnC, Hf2SnN, Ti3SnC2, Ti2InC, Ti2InN, Zr2InC, Zr2InN, Hf2InC, Hf2InN, Sc2InC, Ti3InC2, Zr3InC2, Hf3InC2, Ti2GaC, Ti2GaN, Mo2GaC, Ta2GaC, Sc2GaC, Ti3GaC2, Ti2ZnC, Ti2ZnN, Ti3ZnC2, Ti2CdC, Hf2PbC, Ti2PbC, Zr2PbC.

[0011] Further, in step one, the concentration of M' element in the M site of the MAX phase is 20.0-99.9at%. The temperature of pressureless sintering is 1300-1350℃, and the time is 2-3h.

[0012] Further, in step two, the pickling uses hydrochloric acid with a concentration of 1-2mol / L. The stirring speed is 450-550r / min. The reaction temperature is 40-50℃, and the reaction time is 5-12h. The vacuum drying temperature is 60-70℃, and the time is 8-12h.

[0013] Further, the MAX phase solid solution obtained in step two has higher oxidation resistance and decomposition resistance during mechanical damage treatment. The mechanical damage method is any one of polishing, polishing, scratching and ball milling. After the MAX phase solid solution is damaged, the suitable culture conditions for inhibiting whisker growth are: the temperature is lower than the melting point of the A whisker element, preferably room temperature, and the humidity is 0-100%.

[0014] Preparation principle: the prepared MAX phase solid solution is stacked in a sandwich structure by M6X octahedral layers containing M site solid solution atoms and A atom layers, has the same crystal structure as the MAX phase material, and it is feasible for elements such as Nb, Cr and V to enter the M layer. After the M' atoms are solid-solved into the MAX phase, solid solution strengthening is generated, the decomposition of the MAX phase is hindered, the source of material required for the growth of A whiskers on the surface is fundamentally reduced, the growth of whiskers can be effectively inhibited, and the MAX phase can also improve the oxidation resistance of the MAX phase, resist the decomposition of the MAX phase accelerated by oxidation, and resist damage such as polishing, polishing, scratching and ball milling to a certain extent.

[0015] Beneficial effects: compared with the prior art, the present application has the following remarkable features:

[0016] 1. A element whisker growth can be fundamentally inhibited, the preparation process is simple, the cost is relatively low, it can be applied to high temperature and high humidity environment, and has good corrosion resistance;

[0017] 2. The solid solution strengthening of the MAX solid solution hinders the decomposition of the MAX phase, cuts off the source of material required for the growth of A whiskers on the surface, and can effectively inhibit the growth of whiskers;

[0018] 3. After the M' element is solid-solved into the MAX phase, it also plays a role in improving the oxidation resistance of the MAX phase, resisting the decomposition of the MAX phase accelerated by oxidation, and resisting damage such as polishing, polishing, scratching and ball milling to a certain extent;

[0019] 4. The present application is suitable for all MAX phases, and after ball milling treatment, the MAX phase containing M' solid solution atoms appears whisker inhibition effect after long-term culture at room temperature. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the whisker growth situation diagram of example 1 of the present application after 6 months of culture at room temperature;

[0021] Figure 2 is the whisker growth situation diagram of example 2 of the present application after 6 months of culture at room temperature;

[0022] Figure 3 is the whisker growth situation diagram of example 3 of the present application after 6 months of culture at room temperature;

[0023] Figure 4 is the whisker growth situation diagram of comparative example 1 after 2 days of culture at room temperature;

[0024] Figure 5 is the whisker growth situation diagram of comparative example 2 after 2 days of culture at room temperature;

[0025] Figure 6is the content of element A generated by mechanochemical decomposition of Comparative Example 1, Example 1 and Example 2 measured by ICP;

[0026] Figure 7 is the TEM image and element distribution map of the particles after ball milling in Example 1, Example 2 and Comparative Example 1;

[0027] Figure 8 is the temperature-variable and isothermal oxidation weight gain curve of the MAX phase in Example 1, Example 2 and Comparative Example 1 at 600℃ in air atmosphere, a is the temperature-variable oxidation weight gain from room temperature to 600℃, and b is the isothermal oxidation weight gain at 600℃ for one hour. DETAILED DESCRIPTION

[0028] In each of the following examples, the particle size of the graphite powder is 30 microns.

[0029] Example 1

[0030] A method for inhibiting the growth of A element whiskers in a MAX phase friction material, comprising the following steps:

[0031] S1, commercially available Ti powder, Sn powder, V powder, graphite powder are mixed uniformly according to the molar ratio of 1:1.1:1:1, and then sintered at 1300℃ for 2h by pressureless sintering method, the protective gas is argon, to obtain a MAX phase solid solution with M site solid solution elements (Ti 0.5 V 0.5 )2SnC; the MAX phase is Ti2SnC; the concentration of V powder in the M site of the MAX phase is 50at%;

[0032] S2, first, the MAX phase solid solution with M site solid solution elements is acid washed to remove impurities, 5g (Ti 0.5 V 0.5 )2SnC is added to 100ml of 1mol / L hydrochloric acid, and the reaction is accelerated by magnetic stirring, the stirring speed is 500r / min, the reaction temperature is 40℃, and the reaction time is 12h; after the impurities are removed, the liquid phase is removed by vacuum filtration, and the obtained (Ti 0.5 V 0.5 )2SnC solid phase powder is placed in a vacuum drying oven for drying, the drying temperature is 60℃, and the drying time is 12h.

[0033] S3, whisker inhibition test:

[0034] S3.1, 5g of dried (Ti 0.5 V 0.5)2SnC powder and 50 g stainless steel grinding balls were added into a stainless steel ball mill jar, and placed in a planetary ball mill for ball milling at a speed of 650 r / min for 8 h to obtain the ball-milled powder;

[0035] S3.2, 1 g of the ball-milled powder was cold-pressed at 800 MPa to obtain a flake sample;

[0036] S3.3, the flake sample was cultured at room temperature and 80% humidity for 6 months, and then the whisker growth on the surface of the sample was observed.

[0037] As shown in Figure 1 , it can be seen that the sample obtained in Example 1 has no whisker growth after the MAX phase is damaged by ball milling.

[0038] Example 2

[0039] A method for inhibiting the growth of A element whiskers in a MAX phase friction material, comprising the following steps:

[0040] S1, commercially available Ti powder, Sn powder, Nb powder and graphite powder were mixed uniformly according to a molar ratio of 1:1.1:1:1, and then sintered at 1300°C for 2 h by pressureless sintering, with argon as the protective gas, to obtain a MAX phase solid solution (Ti 0.5 Nb 0.5 )2SnC; the MAX phase is Ti2SnC; the concentration of Nb powder in the M site of the MAX phase is 50 at%;

[0041] S2, first, the MAX phase solid solution with M site solid solution elements was acid washed to remove impurities, 5 g of (Ti 0.5 Nb 0.5 )2SnC was added to 100 ml of 1 mol / L hydrochloric acid, and the reaction was accelerated by magnetic stirring at a speed of 500 r / min, and the reaction temperature was 40°C, and the reaction time was 5 h; after the impurities were removed, the liquid phase was removed by vacuum filtration, and the obtained (Ti 0.5 Nb 0.5 )2SnC solid phase powder was placed in a vacuum drying oven for drying, and the drying temperature was 60°C, and the drying time was 12 h.

[0042] S3, whisker inhibition test:

[0043] S3.1, 5 g of the dried (Ti 0.5 Nb 0.5 )2SnC powder and 50 g of stainless steel grinding balls were added into a stainless steel ball mill jar, and placed in a planetary ball mill for ball milling at a speed of 650 r / min for 8 h to obtain the ball-milled powder;

[0044] S3.2, take out the powder after ball milling, take 1 g of powder and cold-press at 800 MPa to obtain a flake sample;

[0045] S3.3, place the flake sample in a room temperature environment with a humidity of 80% for 6 months, and then observe the whisker growth on the surface of the sample.

[0046] As shown in Figure 2 , it can be seen that the sample obtained in Example 2 has no whisker growth after the MAX phase is damaged by ball milling.

[0047] Example 3

[0048] A method for inhibiting the growth of A element whiskers in a MAX phase friction material, comprising the following steps:

[0049] S1, mix commercial Ti powder, In powder, V powder and graphite powder uniformly according to a molar ratio of 1:1.1:1:1, and then sinter at 1350°C for 2 h by pressureless sintering, with argon as the protective gas, to obtain a MAX phase solid solution (Ti 0.5 V 0.5 )2InC; the MAX phase is Ti2InC; the concentration of V powder in the M site of the MAX phase is 50 at%;

[0050] S2, first, acid wash the MAX phase solid solution with M site solid solution elements to remove impurities, add 5 g of (Ti 0.5 V 0.5 )2InC to 100 ml of 1 mol / L hydrochloric acid, accelerate the reaction by magnetic stirring, the stirring speed is 500 r / min, the reaction temperature is 50°C, and the reaction time is 5 h; after the impurities are removed, remove the liquid phase by vacuum filtration, and put the obtained (Ti 0.5 V 0.5 )2InC solid phase powder into a vacuum drying oven, dry at a temperature of 60°C for 8 h.

[0051] S3, whisker inhibition test:

[0052] S3.1, take 5 g of dried (Ti 0.5 V 0.5 )2InC powder and 50 g of stainless steel grinding balls and put them into a stainless steel ball mill tank, and place them in a planetary ball mill for ball milling, the ball milling speed is 650 r / min, the ball milling time is 8 h, and the powder after ball milling is obtained;

[0053] S3.2, take out the powder after ball milling, take 1 g of powder and cold-press at 800 MPa to obtain a flake sample;

[0054] S3.3, after the thin slice sample is placed in a room temperature environment with humidity of 80% for 6 months, the whisker growth on the surface of the sample is observed.

[0055] As shown in Figure 3 , it can be seen that the sample obtained in Example 3 has no whisker growth after the surface of the MAX phase is damaged by ball milling.

[0056] Comparative Example 1

[0057] A preparation method of a MAX phase Ti2SnC material without M-site solid solution elements, comprising the following steps: first, acid pickling of the MAX phase to remove impurities, 10g Ti2SnC is added to 200ml of 1mol / L hydrochloric acid, and the reaction is accelerated by magnetic stirring, the magnetic stirring speed is 500r / min, the reaction temperature is 40℃, and the reaction time is 5h; after the impurities removal is completed, the liquid phase is removed by vacuum filtration, and the obtained Ti2SnC solid phase powder is placed in a blast drying oven for drying, the drying temperature is 80℃, and the drying time is 8h.

[0058] Whisker inhibition test:

[0059] (1) 5g of the dried Ti2SnC powder and 50g of stainless steel balls are added to a stainless steel ball mill jar, and the ball milling is carried out in a planetary ball mill, the ball milling speed is 650r / min, the ball milling time is 8h, and the ball-milled powder is obtained;

[0060] (2) the ball-milled powder is taken out, and 1g of the powder is cold-pressed at 800MPa to obtain a thin slice sample;

[0061] (3) after the thin slice sample is placed in a room temperature environment for 2 days, the humidity is 80%, and the whisker growth on the surface of the sample is observed.

[0062] As shown in Figure 4 , it can be seen that the sample surface has very obvious whisker growth.

[0063] Comparative Example 2

[0064] A preparation method of a MAX phase Ti2InC material without M-site solid solution elements, comprising the following steps: first, acid pickling of the MAX phase to remove impurities, 10g Ti2InC is added to 200ml of 1mol / L hydrochloric acid, and the reaction is accelerated by magnetic stirring, the magnetic stirring speed is 500r / min, the reaction temperature is 40℃, and the reaction time is 5h; after the impurities removal is completed, the liquid phase is removed by vacuum filtration, and the obtained Ti2InC solid phase powder is placed in a blast drying oven for drying, the drying temperature is 80℃, and the drying time is 8h.

[0065] Whisker inhibition test:

[0066] (1) Take 5 g of Ti2InC powder dried and 50 g of stainless steel grinding balls into a stainless steel ball mill jar, and place it in a planetary ball mill for ball milling, the ball milling speed is 650 r / min, the ball milling time is 8 h, and the ball-milled powder is obtained;

[0067] (2) Take out the ball-milled powder, and take 1 g of the powder to cold-press a flake sample under 800 MPa;

[0068] (3) Place the flake sample in a room temperature environment for 2 days, and then observe the whisker growth on the surface of the sample.

[0069] As shown in Figure 5 , it can be seen that there is obvious whisker growth on the surface of the sample.

[0070] By using the same treatment method, the sample surface of Comparative Example 1 appears obvious whisker growth after being cultured at room temperature for 2 days, while the samples of Example 1 and Example 2 do not appear whisker growth even after being cultured at room temperature for 6 months, which indicates that the V and Nb elements solid-solved into the Ti layer of Ti2SnC can play a whisker inhibition role. By comparing Example 3 and Comparative Example 2, it can be seen that the M-site solid-solution method is also applicable to Ti2InC MAX phase.

[0071] Figure 6 The A element content generated by the decomposition of Comparative Example 1, Example 1 and Example 2 after ball milling treatment is measured by ICP, and it can be seen that under the same damage treatment conditions, the M-site solid-solution treatment can significantly inhibit the decomposition of the MAX phase.

[0072] Figure 7 The element distribution diagram of Comparative Example 1, Example 1 and Example 2 after ball milling treatment is shown in

[0073] To evaluate the oxidation resistance of the MAX phase with M-site solid-solution elements obtained by the method of the present application, 1 g of the dried powder of Example 1-2 and Comparative Example 1 is taken and cold-pressed into a flake sample under 800 MPa, and then the flake sample is tested for oxidation weight gain in air, and the results are shown in Figure 8 Figure 8 ​It can be seen that the weight gain of the MAX phase material in the air atmosphere is due to the oxidation of M elements and A elements to form metal oxides. Whether it is from room temperature to 600℃, or at 600℃ for one hour, the weight gain of Comparative Example 1 is the largest, while the oxidation weight gain of the MAX phase with M-site solid solution is significantly reduced, indicating that the M-site solid solution can enhance the oxidation resistance of the MAX phase. After M-site solid solution treatment, the oxidation resistance of the MAX phase will be improved to some extent, thereby also helping to resist mechanical damage such as ball milling and reducing the degree of damage to the MAX phase grains, and the surface is not easy to grow whiskers.

[0074] Example 4

[0075] A method for inhibiting the growth of A element whiskers in a MAX phase friction material, comprising the following steps:

[0076] S1, mix commercial Zr powder, In powder, Nb powder and graphite powder according to the molar ratio of 1.6:1.1:0.4:1, then sinter at 1320℃ for 3h by pressureless sintering method, the protective gas is argon, to obtain a MAX phase solid solution with M-site solid solution elements (Zr 0.8 Nb 0.2 )2TlC; the MAX phase is Zr2InC; the concentration of Nb powder in the M site of the MAX phase is 20at%;

[0077] S2, first, the MAX phase solid solution with M-site solid solution elements is acid washed to remove impurities, 5g (Zr 0.8 Nb 0.2 )2InC is added to 100ml of 2mol / L hydrochloric acid, and the reaction is accelerated by magnetic stirring at a speed of 450r / min, and the reaction temperature is 45℃, and the reaction time is 10h; after the impurities are removed, the liquid phase is removed by vacuum filtration, and the obtained (Zr 0.8 Nb 0.2 )2InC solid phase powder is placed in a vacuum drying oven for drying, the drying temperature is 65℃, and the drying time is 10h.

[0078] S3, whisker inhibition test:

[0079] S3.1, 5g of dried (Zr 0.8 Nb 0.2 )2InC powder and 50g of stainless steel balls are added to a stainless steel ball mill jar and placed in a planetary ball mill for ball milling at a speed of 650r / min for 8h to obtain a ball-milled powder;

[0080] S3.2, the ball-milled powder is taken out, and 1g of the powder is cold-pressed at 800MPa to obtain a thin sheet sample;

[0081] S3.3, after the thin sample is placed in a room temperature environment with humidity of 10% for 6 months, the whisker growth on the surface of the sample is observed. It can be seen that there is no whisker growth on the surface of the sample.

[0082] Example 5

[0083] A method for inhibiting the whisker growth of an A element in a MAX phase friction material, comprising the following steps:

[0084] S1, commercially available Ti powder, Ga powder, Cr powder and graphite powder are uniformly mixed according to a molar ratio of 1.4:1.1:0.6:1, and then a pressureless sintering method is used to sinter at 1330°C for 2.5h, with argon as the protective gas, to obtain a MAX phase solid solution (Ti 0.7 Cr 0.3 )2GaC; the MAX phase is Ti2GaC; the concentration of Cr powder in the M position of the MAX phase is 30at%;

[0085] S2, first, the MAX phase solid solution with M site solid solution elements is subjected to acid pickling to remove impurities. 5g (Ti 0.7 Cr 0.3 )2GaC is added to 100ml of 1.5mol / L hydrochloric acid, and magnetic stirring is used to accelerate the reaction. The stirring speed is 550r / min, the reaction temperature is 45°C, and the reaction time is 8h. After the impurities are removed, the liquid phase is removed by vacuum filtration, and the obtained (Ti 0.7 Cr 0.3 )2GaC solid phase powder is placed in a vacuum drying oven for drying. The drying temperature is 70°C, and the drying time is 9h.

[0086] S3, whisker inhibition test:

[0087] S3.1, 5g of the dried (Ti 0.7 Cr 0.3 )2GaC powder and 50g of stainless steel grinding balls are added to a stainless steel ball mill jar, and then placed in a planetary ball mill for ball milling. The ball milling speed is 650r / min, and the ball milling time is 8h, to obtain the ball milled powder;

[0088] S3.2, the ball milled powder is taken out, and 1g of the powder is cold pressed at 800MPa to obtain a thin sample;

[0089] S3.3, after the thin sample is placed in a room temperature environment with humidity of 10% for 6 months, the whisker growth on the surface of the sample is observed. It can be seen that there is no whisker growth on the surface of the sample.

[0090] Example 6

[0091] The remaining steps of the embodiment are the same as those of Example 1, except that in S1, the raw materials are Zr powder, Sn powder, V powder and graphite powder, which are mixed uniformly in a molar ratio of 1.2:1:0.8:1, and the MAX phase solid solution (Zr 0.6 V 0.4 )2SnC; the MAX phase is Zr2SnC, and the concentration of V powder in the M site of the MAX phase is 40 at%.

[0092] Example 7

[0093] The remaining steps of the embodiment are the same as those of Example 1, except that in S1, the raw materials are Lu powder, Sn powder, Nb powder and graphite powder, which are mixed uniformly in a molar ratio of 1.2:1:0.8:1, and the MAX phase solid solution (Lu 0.5 Nb 0.5 )2SnC; the MAX phase is Lu2SnC.

[0094] Example 8

[0095] The remaining steps of the embodiment are the same as those of Example 1, except that in S1, the raw materials are Hf powder, Sn powder, V powder and graphite powder, which are mixed uniformly in a molar ratio of 0.8:1:1.2:1, and the MAX phase solid solution (Hf 0.4 V 0.6 )2SnC; the MAX phase is Hf2SnC, and the concentration of V powder in the M site of the MAX phase is 60 at%.

[0096] Example 9

[0097] The remaining steps of the embodiment are the same as those of Example 1, except that in S1, the raw materials are TiN powder, In powder and VN powder, which are mixed uniformly in a molar ratio of 0.6:1:1.4:1, and the MAX phase solid solution (Ti 0.3 V 0.7 )2InN; the MAX phase is Ti2InN, and the concentration of V powder in the M site of the MAX phase is 70 at%.

[0098] Example 10

[0099] The remaining steps of the embodiment are the same as those of Example 1, except that in S1, the raw materials are TiN powder, In powder and NbN powder, and the MAX phase solid solution (Ti 0.5 Nb 0.5 )2InN; the MAX phase is Ti2InN.

[0100] Example 11

[0101] The remaining steps of this embodiment are the same as those of Example 1, except that in S1, the raw materials are Zr powder, In powder, V powder and graphite powder, which are mixed uniformly in a molar ratio of 0.4:1:1.6:1, and the MAX phase solid solution (Zr 0.2 V 0.8 )2InC, the MAX phase being Zr2InC, and the concentration of V powder in the M site of the MAX phase being 80 at%.

[0102] Example 12

[0103] The remaining steps of this embodiment are the same as those of Example 1, except that in S1, the raw materials are Sc powder, Ga powder, V powder and graphite powder, which are mixed uniformly in a molar ratio of 0.2:1.2:1.8:1, and the MAX phase solid solution (Sc 0.1 V 0.9 )2GaC, the MAX phase being Sc2GaC, and the concentration of V powder in the M site of the MAX phase being 90 at%.

[0104] Example 13

[0105] The remaining steps of this embodiment are the same as those of Example 1, except that in S1, the raw materials are Mo powder, Ga powder, V powder and graphite powder, and the MAX phase solid solution (Mo 0.5 V 0.5 )2GaC, the MAX phase being Mo2GaC.

[0106] Example 14

[0107] The remaining steps of this embodiment are the same as those of Example 1, except that in S1, the raw materials are Ta powder, Ga powder, Nb powder and graphite powder, and the MAX phase solid solution (Ta 0.5 Nb 0.5 )2GaC, the MAX phase being Ta2GaC.

[0108] Example 15

[0109] The remaining steps of this embodiment are the same as those of Example 1, except that in S1, the raw materials are Ti powder, Cd powder, Nb powder and graphite powder, and the MAX phase solid solution (Ti 0.5 Nb 0.5 )2CdC, the MAX phase being Ti2CdC.

[0110] Example 16

[0111] The remaining steps of this embodiment are the same as those of Example 1, except that in S1, the raw materials are Hf powder, Pb powder, V powder and graphite powder, and the MAX phase solid solution (Hf 0.5V 0.5 )2PbC; MAX phase is Hf2PbC.

Claims

1. A method of inhibiting A element whisker growth in a MAX phase friction material, characterized by, The method comprises the following steps: Step one, mixing M, A, C, M' elements, sintering under argon protection to obtain a MAX phase solid solution with M site solid solution elements, M element is any one of Ti, Zr, Lu, Hf, Sc, Mo, Ta, A element is any one of Sn, In, Ga, Pb, M' element is V, Cr or Nb, the molar ratio of (M+M'), A, C is 2:(1-1.2):1; Step two, acid washing the MAX phase solid solution with M site solid solution elements, stirring reaction, vacuum filtration, vacuum drying; In the step one, the concentration of M' element in the M site of the MAX phase is 20.0-99.9 at%; In the step one, the temperature of pressureless sintering is 1300-1350℃, and the time is 2-3 h.

2. The method of claim 1, wherein the MAX phase friction material is characterized by: In the step one, the MAX phase is any one of Ti2SnC, Zr2SnC, Sc2SnC, Lu2SnC, Hf2SnC, Ti3SnC2, Ti2InC, Zr2InC, Hf2InC, Sc2InC, Ti3InC2, Zr3InC2, Hf3InC2, Ti2GaC, Mo2GaC, Ta2GaC, Sc2GaC, Ti3GaC2, Hf2PbC, Ti2PbC, Zr2PbC.

3. The method of claim 1, wherein the MAX phase friction material is characterized by: In the step two, the acid pickling uses hydrochloric acid with a concentration of 1-2 mol / L.

4. The method of claim 1, wherein the MAX phase friction material is characterized by: In the step two, the stirring speed is 450-550 r / min.

5. The method of claim 1, wherein the MAX phase friction material is characterized by: In the step two, the reaction temperature is 40-50℃, and the reaction time is 5-12 h.

6. The method of claim 1, wherein the MAX phase friction material is characterized by: In the step two, the temperature of vacuum drying is 60-70℃, and the time is 8-12 h.

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