Method for rapidly testing growth tendency of metal whiskers and in-situ growth of metal whiskers

Abstract

According to the method for rapidly testing the growth tendency of the metal whiskers and growing the metal whiskers in situ, the MAX phase serves as an A metal atom source, the growth tendency of the metal whiskers is rapidly tested, and a new technology for preparing the metal whiskers in a large scale is developed by means of the phenomenon. According to the method, an MAX phase and an alloy matrix form metallurgical bonding through hot pressing, active A atoms are provided for growth of the metal whiskers, and therefore reliable and rapid detection of the growth tendency of the metal whiskers on the to-be-detected alloy is achieved. The innovation and significance of the invention are as follows: (1) A-site atoms provided by the MAX phase are utilized to test the accommodation limit of different alloy components and organization structures to active A atoms, a new rapid and reliable metal whisker growth tendency evaluation technology is developed, and the method has important significance in evaluation of Sn whisker growth problems in electronic connection; and (2) a new technology for in-situ and rapid growth of the metal whiskers in the metal matrix is developed, and a new technical approach is provided for preparation of micro-nano devices such as MEMS (micro-electromechanical systems) and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials, and particularly relates to a new reliable and rapid testing method for the growth tendency of metal whiskers and a new technology for preparing metal whiskers. Background Art

[0002] As a potential hazard, Sn whiskers have been widely studied. They pose a serious threat to the safety and reliability of electronic devices through failure modes such as short circuits, system contamination, and metal vapor arcs. So far, there has been a research history of more than seventy years. On the official website of the National Aeronautics and Space Administration (NASA), there are detailed records of device short circuits and failures caused by the spontaneous growth of tin whiskers over the past seventy years. Many major accidents have highlighted the severity and complexity of the whisker problem. However, with the development of electronic devices towards miniaturization and high density, the problem of tin whiskers has become increasingly severe and has become an important factor restricting the improvement of device reliability. Based on this, the attention of the country and the industry to the testing of tin whiskers has increased significantly. On December 1, 2023, the country officially issued a notice on the formulation of the tin whisker test standard for electronic components.

[0003] Currently, representative methods for evaluating the growth tendency of Sn whiskers only consider environmental parameters such as temperature, humidity, and pressure to test the growth tendency of Sn whiskers. However, these methods cannot overcome the problems of poor repeatability and long cycle of test results. NASA clearly stated the remarks that "there is no correct theory and test method to predict the growth trend of whiskers". The main reason for the difficulty in evaluating the growth tendency of whiskers is the large randomness of whisker growth (the growth position is random, and the incubation period ranges from a few minutes to several years). The root cause is the unclear generation mechanism and random quantity of active Sn atoms in the Sn alloy. Although vibration, temperature change, etc. may cause stress, intergranular friction, and induce active Sn atoms, these mechanisms are unclear, difficult to control, and difficult to quantify. Therefore, by controlling and quantifying the active Sn atoms in the matrix, it is possible to accurately and reliably evaluate the tolerance limit of the matrix to active Sn atoms, and then evaluate the growth tendency of whiskers. In fact, in addition to the common Sn metal whiskers causing these problems, the growth of metal whiskers such as Cd, Zn, and In will also pose hazards to the electronic system. Therefore, in order to ensure the safety and service life of electronic products, there is an urgent need to find a stable, reliable, and quantitative method for testing the growth tendency of whiskers.

[0004] On the other hand, metal whiskers have excellent mechanical properties due to their extremely few crystal defects and exhibit extremely high strength. At the same time, in terms of electrical and thermal conductivity, the electron and phonon scattering effects are extremely significant, and affected by plasma phenomena, they show unique characteristics in surface light propagation and emission, making them have broad application prospects in the fields of optical circuits and high-performance nano-devices. However, existing metal whisker growth technologies (such as vapor-liquid-solid method, template method, chemical polyol synthesis method) are limited by factors such as chemical reduction process and vapor pressure control, and it is difficult to achieve large-scale preparation. Therefore, there is an urgent need to develop a rapid and large-scale metal whisker preparation method to promote the further development of micro-nano devices. Summary of the Invention

[0005] Technical Problem: The purpose of the present invention is to provide a method for rapidly testing the growth tendency of metal whiskers and in-situ growing metal whiskers. Based on the active A-site metal atoms generated by the layered crystal MAX phase, on the one hand, a reliable method for rapidly testing the growth tendency of metal whiskers is provided to evaluate the growth risk of metal whiskers in coatings and solders; on the other hand, a new method for rapidly preparing metal whiskers of various components is provided to promote the development of micro-nano device preparation.

[0006] Technical Solution: A method for rapidly testing the growth tendency of metal whiskers according to the present invention includes the following steps:

[0007] Step 1. Using the MAX phase as the source of A metal atoms, mixing it with the alloy to be tested in a set ratio to form a uniform sample;

[0008] Step 2. Hot-pressing the uniformly mixed sample in Step 1 into a formed body;

[0009] Step 3. Heat-treating the formed sample in Step 2 to thermally diffuse out the active A atoms;

[0010] Step 4. Placing the sample containing active A atoms in Step 3 under set conditions for cultivation to grow A-site metal whiskers;

[0011] Step 5. Evaluating the growth tendency of A metal whiskers on the surface of the substrate according to the number of implanted active A atoms, cultivation conditions, and whisker growth conditions of the sample after cultivation in Step 4.

[0012] Wherein,

[0013] The MAX phase described in Step 1 is M n+1 AX nThe MAX phase is a type of ternary layered compound, where M is a pre-transition group metal element such as Sc, Ti, V, Cr, Zr, Nb, Mo, Hf, or Ta, A is a main group element such as Al, Si, Ga, Ge, In, Sn, or Pb, X is C or N, and n = 1, 2, 3, or 4; the set ratio is that MAX and the alloy are weighed according to a molar ratio of 0.01 - 0.99 and then mixed, and they are mixed by a powder mixer for 1 - 24 h. The alloy to be measured includes Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Pd, Ag, In, Sn, Hf, Ta, W, Pt, Au, Pb, Bi, and alloys including SnBi, SnPb, SnZn, SnAg, SnAl, SnCu, SnCd, SnGa, SnNi, SnCo, SnIn, SnRE, SnMg, SnAgCu, SnPbAg, CuMnSn, SnSbCu, SnAgCuBi, SnSbCuPb.

[0014] For the hot pressing and forming described in step 2, the temperature is 20 - 1000 °C, the pressure is 20 - 800 MPa, and the time is 1 - 60 min; the conditions for the heat treatment described in step 3 are heating to 100 - 1200 °C in an argon or nitrogen atmosphere and holding for 0 - 24 h.

[0015] The cultivation under the set conditions described in step 4 means cultivating for 1 - 3 days at 25 - 120 °C and 0% - 100% relative humidity. After cultivation, metal whiskers can grow on the sample surface.

[0016] The number of active A atoms described in step 5 is tested by weight loss during pickling with hydrochloric acid, sulfuric acid, or nitric acid with a concentration of 0.1 - 6 mol / L; for the growth situation of the whiskers, the growth situation of the whiskers is comprehensively determined by counting the number, density, and length of whiskers grown in the range of 10 - 1000 μm. 2 The growth situation of the whiskers is comprehensively determined by counting the number, density, and length of whiskers grown in the range of 10 - 1000 μm.

[0017] A method for in-situ growth of metal whiskers in the present invention implants the MAX phase into the alloy matrix according to a set ratio, uses the thermal diffusion of A-layer atoms in the MAX phase to generate a large number of active A atoms, and after cultivation in a constant temperature and humidity environment, metal whiskers grow in-situ on the sample surface.

[0018] The MAX described is M n+1 AX nThe MAX phase is a type of ternary layered compound, where M is a pre-transition group metal element such as Sc, Ti, V, Cr, Zr, Nb, Mo, Hf, or Ta, A is a main group element such as Al, Si, Ga, Ge, In, Sn, or Pb, X is C or N, and n = 1, 2, 3, or 4; the alloy matrix includes Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Pd, Ag, In, Sn, Hf, Ta, W, Pt, Au, Pb, Bi, and alloys including SnBi, SnPb, SnZn, SnAg, SnAl, SnCu, SnCd, SnGa, SnNi, SnCo, SnIn, SnRE, SnMg, SnAgCu, SnPbAg, CuMnSn, SnSbCu, SnAgCuBi, SnSbCuPb.

[0019] The implantation of the MAX phase into the alloy matrix in a set ratio means weighing and mixing the MAX phase and the alloy in a molar ratio of 0.01 - 0.99 for 1 - 24 h, and then maintaining for 1 - 60 min at 20 - 1000 °C and 20 - 800 MPa, followed by pressing into shape to achieve tight bonding.

[0020] The generation of a large number of active A atoms by thermal diffusion means heating the formed sample to 100 - 1200 °C and holding for 0 - 24 h in an argon or nitrogen atmosphere to generate a large number of active A atoms using the MAX phase.

[0021] The constant temperature and humidity environment means culturing for 1 - 3 days under conditions of 25 - 120 °C and 0% - 100% relative humidity, and a large number of A-site metal whiskers grow in-situ on the sample surface; different components of A-site metal whiskers are grown by implanting different types of MAX phases.

[0022] Technical principle: The essence of whisker growth is the process of diffusion, aggregation, nucleation, and growth of active A atoms. During the heat treatment process of the MAX phase, A-site atoms will thermally diffuse out of the MAX phase lattice to form active A atoms. By changing the composition of the MAX phase, the composition of the whiskers can be controlled, and the temperature and time of thermal diffusion can be regulated to quantify the active A atoms.

[0023] Beneficial effects: Compared with the prior art, the present invention has achieved the following remarkable effects:

[0024] The present invention efficiently generates a large number of active A atoms by thermal diffusion and implants them into the alloy matrix, avoiding the randomness of whisker growth;

[0025] The present invention evaluates the tolerance limit of active A atoms in the alloy material by controlling the implantation amount of active A atoms;

[0026] The present invention is applicable to evaluating all materials that can implant active A atoms and achieve metallurgical bonding in the prior art;

[0027] By controlling the type of MAX phase implantation, the present invention can grow a large number of different components of metal whiskers in situ quickly.

[0028] The present invention is environmentally friendly and efficient, and the diversity of whisker components is easy to control. Description of the Drawings

[0029] Figure 1 It is a diagram of the whisker growth situation after the sample of Example 1 of the present invention is cultured in a constant temperature and humidity box at 60 °C and 80% relative humidity for 30 days.

[0030] Figure 2 It is a diagram of the whisker growth situation after the sample of Example 2 of the present invention is cultured in a constant temperature and humidity box at 60 °C and 80% relative humidity for 1 day.

[0031] Figure 3 It is a diagram of the whisker growth situation after the sample of Example 3 of the present invention is cultured in a constant temperature and humidity box at 60 °C and 80% relative humidity for 1 day.

[0032] Figure 4 It is a diagram of the whisker growth situation after the sample of Example 4 of the present invention is cultured in a constant temperature and humidity box at 60 °C and 80% relative humidity for 1 day.

[0033] Figure 5 It is a diagram of the whisker growth situation after the sample of Example 5 of the present invention is cultured in a constant temperature and humidity box at 60 °C and 80% relative humidity for 1 day.

[0034] Figure 6 It is a diagram of the whisker growth situation after the sample of Example 7 of the present invention is cultured in a constant temperature and humidity box at 25 °C and 50% relative humidity for 1 day.

[0035] Figure 7 It is a diagram of the whisker growth situation after the sample of Example 8 of the present invention is cultured in a constant temperature and humidity box at 25 °C and 50% relative humidity for 1 day.

[0036] Figure 8 It is a diagram of the whisker growth situation after the sample of Example 9 of the present invention is cultured in a constant temperature and humidity box at 25 °C and 50% relative humidity for 1 day. Detailed Embodiments

[0037] The present invention provides a method for quickly testing the growth tendency of metal whiskers, which includes the following steps:

[0038] Step 1. Using the MAX phase as the A metal atom source, mixing it with the alloy to be tested in a set ratio to form a uniform sample.

[0039] Step 2. Hot-pressing the uniformly mixed sample in Step 1 into a mold.

[0040] Step 3. Heat-treat the sample formed in Step 2 to thermally diffuse the active A atoms;

[0041] Step 4. Place the sample containing the active A atoms in Step 3 under set conditions for cultivation to grow A-site metal whiskers;

[0042] Step 5. Evaluate the growth tendency of A-metal whiskers on the matrix surface of the sample after cultivation in Step 4 according to the number of implanted active A atoms, cultivation conditions, and whisker growth conditions.

[0043] Among them, the MAX phase is M n+1 AX n phase is a class of ternary layered compounds, M is a pre-transition group metal element Sc, Ti, V, Cr, Zr, Nb, Mo, Hf or Ta, A is a main group element Al, Si, Ga, Ge, In, Sn or Pb, X is C, N, n = 1, 2, 3 or 4; the set ratio is that MAX and the alloy are weighed and mixed according to a molar ratio of 0.01 - 0.99, and mixed by a powder mixer for 1 - 24 h. The alloy to be measured includes Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Pd, Ag, In, Sn, Hf, Ta, W, Pt, Au, Pb, Bi, and alloys, including SnBi, SnPb, SnZn, SnAg, SnAl, SnCu, SnCd, SnGa, SnNi, SnCo, SnIn, SnRE, SnMg, SnAgCu, SnPbAg, CuMnSn, SnSbCu, SnAgCuBi, SnSbCuPb.

[0044] Example 1

[0045] In this example, Ti2SnC is implanted into the SnBi matrix according to a molar ratio of 0.05, and metallurgical bonding is achieved by hot pressing. After heat treatment for a period of time, active Sn atoms are produced and grow into whiskers. Then, a stereomicroscope and an optical microscope are used to observe the whisker growth state. The specific steps are as follows:

[0046] (1) Uniformly mix Ti2SnC and SnBi powder in a three-dimensional powder mixer according to a molar ratio of 0.05:1 for 2 h;

[0047] (2) Keep the pressure of the mixed powder at 120 °C and 600 MPa for 5 min to make a disk sample with a diameter of 15 mm;

[0048] (3) Heat the prepared disk sample to 230 °C and keep it warm for 12 h in an argon environment to thermally diffuse active Sn atoms from Ti2SnC;

[0049] (4) Place the heat-treated sample in a thermo-hygrostat at 25 °C and 80% relative humidity and continuously incubate for 30 days;

[0050] (5) Place the incubated sample under a stereomicroscope and an optical microscope to observe the whisker growth state.

[0051] Example 2

[0052] In this example, Ti2SnC is implanted into the SnBi matrix at a molar ratio of 0.10, and metallurgical bonding is achieved by hot pressing. After heat treatment for a period of time, active Sn atoms are produced and grow into whiskers. Then, a stereomicroscope and an optical microscope are used to observe the whisker growth state. The specific steps are as follows:

[0053] (1) Uniformly mix Ti2SnC and SnBi powder in a three-dimensional powder mixer at a molar ratio of 0.10:1 for 4 h;

[0054] (2) Keep the pressure of the mixed powder at 130 °C and 500 MPa for 5 min to make a disk sample with a diameter of 15 mm;

[0055] (3) Heat the prepared disk sample to 230 °C and keep it warm for 12 h in an argon atmosphere to allow Ti2SnC to thermally diffuse active Sn atoms;

[0056] (4) Place the heat-treated sample in a thermo-hygrostat at 25 °C and 80% relative humidity and continuously incubate for 1 day; (5) Place the incubated sample under a stereomicroscope and an optical microscope to observe the whisker growth state.

[0057] Example 3

[0058] In this example, by implanting Ti2SnC into the SnBi matrix at a molar ratio of 0.20, metallurgical bonding is achieved by hot pressing. After heat treatment for a period of time, active Sn atoms are produced and grow into whiskers. Then, a stereomicroscope and an optical microscope are used to observe the whisker growth state. The specific steps are as follows:

[0059] (1) Uniformly mix Ti2SnC and SnBi powder in a three-dimensional powder mixer at a molar ratio of 0.20:1 for 8 h;

[0060] (2) Keep the pressure of the mixed powder at 120 °C and 600 MPa for 5 min to make a disk sample with a diameter of 15 mm;

[0061] (3) Heat the prepared disk sample to 230 °C and keep it warm for 12 h in an argon atmosphere to allow Ti2SnC to thermally diffuse active Sn atoms;

[0062] (4) Place the heat-treated sample in a constant temperature and humidity chamber at 25 °C and 80% relative humidity for continuous incubation for 1 day; (5) Place the incubated sample under a stereomicroscope and an optical microscope to observe the whisker growth state.

[0063] Example 4

[0064] In this example, Ti2SnC was implanted into the SnPb matrix at a molar ratio of 0.10, and metallurgical bonding was achieved by hot pressing. After a period of heat treatment, active Sn atoms were produced and grew into whiskers. Then, a stereomicroscope and an optical microscope were used to observe the whisker growth state. The specific steps are as follows:

[0065] (1) Uniformly mix Ti2SnC and SnPb powder in a three-dimensional powder mixer at a molar ratio of 0.10:1 for 6 h;

[0066] (2) Keep the mixed powder under pressure at 150 °C and 500 MPa for 5 min to make a disk sample with a diameter of 15 mm;

[0067] (3) Heat the prepared disk sample to 230 °C and hold for 12 h in a nitrogen environment to allow Ti2SnC to thermally diffuse out active Sn atoms;

[0068] (4) Place the heat-treated sample in a constant temperature and humidity chamber at 25 °C and 80% relative humidity for continuous incubation for 1 day; (5) Place the incubated sample under a stereomicroscope and an optical microscope to observe the whisker growth state.

[0069] Example 5

[0070] In this example, Ti2SnC was implanted into the SnAgCu matrix at a molar ratio of 0.10, and metallurgical bonding was achieved by hot pressing. After a period of heat treatment, active Sn atoms were produced and grew into whiskers. Then, a stereomicroscope and an optical microscope were used to observe the whisker growth state. The specific steps are as follows

[0071] (1) Uniformly mix Ti2SnC and SnAgCu powder in a three-dimensional powder mixer at a molar ratio of 0.10:1 for 8 h;

[0072] (2) Keep the mixed powder under pressure at 180 °C and 500 MPa for 5 min to make a disk sample with a diameter of 15 mm;

[0073] (3) Heat the prepared disk sample to 230 °C and hold for 12 h in a nitrogen environment to allow Ti2SnC to thermally diffuse out active Sn atoms;

[0074] (4) Place the heat-treated sample in a constant temperature and humidity chamber at 25 °C and 80% relative humidity for continuous incubation for 3 days; (5) Place the incubated sample under a stereomicroscope and an optical microscope to observe the whisker growth state.

[0075] Example 6

[0076] In this example, Ti3ZnC2 was implanted into the Cu matrix at a molar ratio of 0.20, and metallurgical bonding was achieved by hot pressing. After heat treatment for a period of time, active Zn atoms were produced and grew into whiskers. Then, a stereomicroscope and an optical microscope were used to observe the growth state of the whiskers. The specific steps were as follows:

[0077] (1) Ti3ZnC2 and Cu powder were uniformly mixed in a three-dimensional powder mixer for 8 h at a molar ratio of 0.20:1;

[0078] (2) The mixed powder was kept under pressure for 2 min at 400 °C and 300 MPa to form a disk sample with a diameter of 15 mm;

[0079] (3) The prepared disk sample was heated to 900 °C and held for 4 h in an argon atmosphere to allow Ti3ZnC2 to thermally diffuse active Zn atoms;

[0080] (4) The heat-treated sample was placed in a constant temperature and humidity chamber at 25 °C and 50% relative humidity and continuously cultured for 1 day; (5) The cultured sample was placed under a stereomicroscope and an optical microscope to observe the growth state of the whiskers.

[0081] Example 7

[0082] In this example, Ti2CdC was implanted into the Ag matrix at a molar ratio of 0.10, and metallurgical bonding was achieved by hot pressing. After heat treatment for a period of time, active Cd atoms were produced and grew into whiskers. Then, a stereomicroscope and an optical microscope were used to observe the growth state of the whiskers. The specific steps were as follows:

[0083] (1) Ti2CdC and Ag powder were uniformly mixed in a three-dimensional powder mixer for 10 h at a molar ratio of 0.10:1;

[0084] (2) The mixed powder was kept under pressure for 15 min at 400 °C and 200 MPa to form a disk sample with a diameter of 15 mm;

[0085] (3) The prepared disk sample was heat-treated at 900 °C for 4 h in an argon atmosphere using a tube furnace to allow Ti2CdC to thermally diffuse active Cd atoms;

[0086] (4) The heat-treated sample was placed in a constant temperature and humidity chamber at 25 °C and 50% relative humidity and continuously cultured for 1 day; (5) The cultured sample was placed under a stereomicroscope and an optical microscope to observe the growth state of the whiskers.

[0087] Example 8

[0088] In this embodiment, Ti2InC is implanted into an Al matrix at a molar ratio of 0.10, and metallurgical bonding is achieved by hot pressing. After a period of heat treatment, active Sn atoms are generated and grow into whiskers. Then, a stereo microscope and an optical microscope are used to observe the growth state of the whiskers. The specific steps are as follows:

[0089] (1) Ti2InC and Al powder were uniformly mixed in a three-dimensional powder mixer at a molar ratio of 0.30:1 for 8 h;

[0090] (2) The mixed powder was pressurized at 400°C and 200 MPa for 5 min to form a disc sample with a diameter of 15 mm;

[0091] (3) The prepared disk sample was heat treated at 650°C for 12 h in a tube furnace under a nitrogen environment to allow the Ti2InC to thermally diffuse active In atoms;

[0092] (4) placing the heat-treated sample in a constant temperature and humidity chamber at 25° C. and 50% relative humidity for continuous cultivation for 3 days; (5) placing the cultivated sample under a stereo microscope and an optical microscope to observe the growth state of the whiskers.

[0093] Figure 1 , Figure 2 , Figure 3 The whisker growth diagrams of Example 1, Example 2, and Example 3 after culturing for 30 days, 1 day, and 1 day at 60°C and 80% relative humidity are shown respectively. It can be seen that at the same heat treatment temperature, the amount of active Sn atoms generated by thermal diffusion increases with the increase in the amount of Ti2SnC implanted, which is manifested in the increase in the density and number of whiskers on a macro scale. It can be seen that the thermal drive of Ti2SnC to generate active Sn atoms and implant them into metals or alloys can achieve the purpose of accelerating whisker growth and can be used to evaluate the tendency of whisker growth. Moreover, at a molar ratio of SnBi:Ti2SnC=1:0.05, no whiskers grow, and when the molar ratio is 1:0.1, trace whisker growth occurs. It can be evaluated that the tolerance limit of SnBi for active Sn atoms is located at a molar ratio of SnBi:Ti2SnC=1:0.05-1:0.10, which quantifies the tendency of Sn whisker growth in the SnBi system.

[0094] Figure 2 , Figure 4 , Figure 5They are respectively the diagrams of whisker growth after Example 2, Example 4, and Example 5 were cultured at 60 °C and 80% relative humidity for 1 day. It can be seen that on the basis of implanting the same content of Ti2SnC (through pickling weight loss test, the number of active Sn atoms generated is about 35% of the Sn content in the Ti2SnC matrix), the density, quantity, and length of whisker growth are different. This is because different Sn-based alloy solders have different tolerance limits for active Sn atoms and different abilities to prevent active Sn atoms from escaping to the surface to grow whiskers. It can be seen that the whisker inhibition abilities of different alloys are as follows: SnPb > SnBi > SnAgCu.

[0095] Figure 2 , Figure 6 , Figure 7 , Figure 8 They are respectively the diagrams of whisker growth after Example 2, Example 6, Example 7, and Example 8 were cultured at 25 °C and 50% relative humidity for 3 days. Different types of MAX phases (Ti2SnC, Ti3ZnC2, Ti2CdC, Ti2InC) were implanted into different alloy matrices, and metallurgical bonding was achieved through forming at suitable temperature and pressure. Then, active Sn, Zn, Cd, and In atoms were released through the thermal diffusion process and grew into metal whiskers, thereby enabling the preparation of metal whiskers with various compositions. By selecting more appropriate heat treatment temperature and time, large-scale preparation of metal whiskers can be realized. Further, by adjusting the implantation amount of MAX phases (such as Ti2SnC, Ti3ZnC2, Ti2CdC, Ti2InC, etc.), whisker growth phenomena similar to those in Example 1, Example 2, and Example 3 can be obtained, and then the tolerance limit of different alloy matrices for active A atoms can be evaluated, and the risk of whisker growth can be measured.

[0096] This method generates active A atoms through the thermal diffusion method of MAX phase A-site atoms, quantitatively provides the active A atoms required for whisker growth for the matrix to be evaluated, accelerates the whisker growth on the surface of the alloy matrix to be evaluated, and whisker growth appears within three days to complete the evaluation of the whisker growth tendency. At the same time, observe the whisker growth situation on the Sn-based alloy solder under the condition of the same content of active Sn atoms (Example 2, Example 4, Example 5), and compare it with the mature SnPb solder in the industry. By comparing whether whiskers grow and the growth state, the whisker growth tendency in the material can be evaluated.

[0097] Therefore, through the method of the present invention, the tin whisker growth tendency can be effectively, reliably, and quickly evaluated, and a large number of metal whiskers with various compositions can be rapidly prepared in situ.

Claims

1. A method for rapidly testing the growth tendency of metal whiskers, characterized in that, It includes the following steps: Step 1. Using the MAX phase as the source of A metal atoms, mix it with the alloy to be measured in a set proportion to form a uniform sample; Step 2. Hot-press the uniformly mixed sample in Step 1 into a shape; Step 3. Heat-treat the shaped sample in Step 2 to thermally diffuse active A atoms; Step 4. Place the sample containing active A atoms in Step 3 under set conditions for cultivation to grow A-site metal whiskers; Step 5. Evaluate the growth tendency of A-metal whiskers on the matrix surface of the sample after cultivation in Step 4 according to the number of implanted active A atoms, cultivation conditions, and whisker growth conditions.

2. The method for quickly testing the growth tendency of metal whiskers according to claim 1, wherein The MAX phase described in step 1 is M n+1 AX n The phase is a kind of ternary layered compound. M is a pre-transition group metal element Sc, Ti, V, Cr, Zr, Nb, Mo, Hf or Ta. A is a main group element Al, Si, Ga, Ge, In, Sn or Pb. X is C or N, and n = 1, 2, 3 or 4. The set ratio is that MAX and the alloy are weighed and mixed according to a molar ratio of 0.01 - 0.99, and then mixed by a powder mixer for 1 - 24 h. The alloy to be measured includes Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Pd, Ag, In, Sn, Hf, Ta, W, Pt, Au, Pb, Bi, and alloys, including SnBi, SnPb, SnZn, SnAg, SnAl, SnCu, SnCd, SnGa, SnNi, SnCo, SnIn, SnRE, SnMg, SnAgCu, SnPbAg, CuMnSn, SnSbCu, SnAgCuBi, SnSbCuPb.

3. The method for quickly testing the growth tendency of metal whiskers according to claim 1, characterized in that, For the hot-pressing in Step 2, the temperature is 20 - 1000 °C, the pressure is 20 - 800 MPa, and the time is 1 - 60 min; the conditions for the heat treatment in Step 3 are heating to 100 - 1200 °C in an argon or nitrogen atmosphere and holding for 0 - 24 h.

4. The method for quickly testing the growth tendency of metal whiskers according to claim 1, characterized in that, The cultivation under the set conditions in Step 4 means cultivating for 1 - 3 days at 25 - 120 °C and 0% - 100% relative humidity, and A-site metal whiskers can grow after cultivation.

5. The method for rapidly testing the growth tendency of metal whiskers according to claim 1, characterized in that The number of active A atoms described in Step 5 is tested by weight loss during pickling with hydrochloric acid, sulfuric acid, or nitric acid at a concentration of 0.1 - 6 mol / L; the whisker growth condition is comprehensively determined by counting the number, density, and length of whiskers grown within the 2 range of 10 - 1000 μm.

6. A method for in-situ growth of metal whiskers, characterized in that, The MAX phase is implanted into the alloy matrix in a set proportion, and a large number of active A atoms are generated by the thermal diffusion of the A-layer atoms of the MAX phase. After cultivation in a constant temperature and humidity environment, metal whiskers grow in-situ on the sample surface.

7. A method for in-situ growth of metal whiskers according to claim 6, characterized in that, The MAX is M n+ 1AX n The MAX is a kind of ternary layered compound. M is a pre-transition group metal element Sc, Ti, V, Cr, Zr, Nb, Mo, Hf or Ta. A is a main group element Al, Si, Ga, Ge, In, Sn or Pb. X is C or N, and n = 1, 2, 3 or 4. The alloy matrix includes Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Pd, Ag, In, Sn, Hf, Ta, W, Pt, Au, Pb, Bi, and alloys including SnBi, SnPb, SnZn, SnAg, SnAl, SnCu, SnCd, SnGa, SnNi, SnCo, SnIn, SnRE, SnMg, SnAgCu, SnPbAg, CuMnSn, SnSbCu, SnAgCuBi, SnSbCuPb.

8. A method for in-situ growing metal whiskers according to claim 6, characterized in that, The implanting the MAX phase into the alloy matrix in a set proportion means weighing and mixing the MAX phase and the alloy in a molar ratio of 0.01 - 0.99 for 1 - 24 h, and then keeping it at 20 - 1000 °C and 20 - 800 MPa for 1 - 60 min and then pressing it into shape to achieve tight bonding.

9. The method for in-situ growing metal whiskers according to claim 6, wherein The thermal diffusion to generate a large number of active A atoms means heating the shaped sample to 100 - 1200 °C and holding for 0 - 24 h in an argon or nitrogen atmosphere, and using the MAX phase to generate a large number of active A atoms.

10. A method for in-situ growing metal whiskers according to claim 6, characterized in that, The constant temperature and humidity environment means that after cultivating for 1 - 3 days at 25 - 120 °C and 0% - 100% relative humidity, a large number of A-site metal whiskers grow in-situ on the sample surface; different components of A-site metal whiskers can be grown by implanting different types of MAX phases.

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