A heat conducting filament, a method of manufacturing a heat conducting filament and an apparatus

Abstract

The present application relates to temperature measurement material preparation technical field, especially to a kind of heat-conducting wire, heat-conducting wire preparation method and equipment.The heat-conducting wire adopts the three-dimensional structure design of core alloy layer combined with gradient protective film: core alloy is tungsten-rhenium matrix doped nano dispersion phase (high stability, high-temperature enhanced type), gradient protective film is 100 to 200nm SiC combination layer and 5 to 10nm functional layer, three-dimensional structure is variable-pitch spiral main body and wave-shaped ceramic support.Preparation method is based on inert atmosphere throughout, including subsection deoxidation, gradient coating, customization annealing, multilayer packaging steps.Equipment integration integrates feeding, heating furnace, inert link components, coating, annealing, packaging and central control system, which can accurately control temperature and monitor.The present application significantly improves the sensitivity, life and batch repeatability of heat-conducting wire, optimizes detection efficiency and reduces manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of temperature measuring material preparation technology, and in particular to a thermal conductive wire, a method for preparing the thermal conductive wire, and equipment. Background Technology

[0002] The thermal conductivity wire is the core thermistor of the thermal conductivity detector (TCD) in a gas chromatograph, and its performance directly determines the detector's sensitivity, repeatability, and lifespan. Current technologies often use pure tungsten wire or traditional tungsten-rhenium alloy wire, which presents the following key drawbacks:

[0003] (1) Material performance bottleneck: Traditional tungsten rhenium wire has poor oxidation resistance and is easily oxidized and corroded in carrier gas containing impurities or water vapor. Its service life is usually less than 1000h. Moreover, it is easy to recrystallize at high temperature, resulting in large fluctuations in resistivity (batch deviation >3%), which in turn leads to unstable detection sensitivity.

[0004] (2) Defects in the preparation process: In the existing process, the “deoxidation-coating-annealing” process of the thermal conductive wire is scattered, and it is easy to come into contact with air during the module transfer process, resulting in secondary oxidation; the annealing cooling curve is single and cannot be adapted to the phase transformation requirements of different alloys, and the residual internal stress leads to poor batch repeatability (RSD>5%).

[0005] (3) Structural design limitations: Traditional thermal conductive wires adopt equal pitch spiral or straight structure, which easily generates eddies when airflow passes through, resulting in uneven heat field distribution, response time of more than 120ms, and measurement error of ±2.1%, which is difficult to meet the requirements of high-precision detection.

[0006] (4) Insufficient equipment and packaging: The existing preparation equipment does not have a dedicated inert atmosphere connection component, and the uniformity of coating depends on manual control; the packaging is mostly a single vacuum bag, which has weak moisture and oxidation prevention capabilities. After 6 months of storage, the resistance change rate is >2%, which affects the product shelf life.

[0007] Therefore, improving the thermal conductivity wire to enhance measurement accuracy is a technical problem that needs to be solved. Summary of the Invention

[0008] The purpose of this invention is to provide a thermal conductive wire, a method for preparing a thermal conductive wire, and an apparatus to solve the problems of low sensitivity and poor repeatability of existing thermal conductive wires, and to efficiently prepare thermal conductive wires with high stability and long lifespan.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] According to one aspect of the present invention, a thermal conductive wire is provided, comprising a core alloy layer and a gradient protective film covering the surface of the core alloy layer, wherein: the core alloy layer is a composite system of a tungsten-rhenium matrix and a nano-dispersed phase, and by weight percentage, the components of the core alloy layer include: W 94.5 to 98.85%, Re 1 to 5%, and nano-dispersed phase 0.15 to 0.6%; the nano-dispersed phase is... and A mixture or HfC;

[0011] The gradient protective film consists of a 100-200 nm SiC bonding layer and a 5-10 nm layer, from the inside out. Functional layer; the main body of the thermal conductive wire is a variable pitch spiral structure, with the pitch increasing from 50μm to 80μm along the airflow direction, the spiral diameter from 0.3 to 0.5mm, and the two ends are provided with wavy alumina ceramic supports with an amplitude of ±15μm and a wavelength of 200μm.

[0012] According to one embodiment of the present invention, when the core alloy layer is of high stability type, the composition by weight percentage is W 96.5% to 98.85%, Re 1% to 3%, 0.1% to 0.3% 0.05% to 0.1%, grain aspect ratio > 5:1, recrystallization temperature ≥ 1600℃, room temperature resistivity 7.2 to 7.5 μΩ·cm, temperature coefficient of resistance to .

[0013] According to one embodiment of the present invention, when the core alloy layer is a high-temperature reinforced type, the composition by weight percentage is W 94.5 to 95%, Re 4.5 to 5%, HfC 0.5%, creep resistance at 1200°C ≥1500h, and room temperature resistivity 7.6 to 7.8μΩ·cm.

[0014] On the other hand, the present invention also provides a method for preparing a thermal conductive wire, which specifically includes the following steps:

[0015] S1, Preparation of prefabricated thermal conductive wire: Select a blank that conforms to the core alloy composition and draw it into a wire with a diameter of 15μm to 50μm and a length of 2cm to 10cm;

[0016] S2, segmented deoxidation: in In a mixed inert atmosphere, 5% of the material is heated according to a stepped heating curve, which is: 200 to 350℃ for 1 to 2 hours, 400 to 600℃ for 1 to 2 hours, and 700 to 900℃ for 1 to 2 hours.

[0017] S3, Gradient protective film preparation: Maintaining an inert atmosphere, the SiC bonding layer is prepared sequentially using CVD process, followed by ALD process to prepare the... Functional layer;

[0018] S4, Customized Annealing: In an inert atmosphere, the cooling curve is selected according to the core alloy type, and the cooling rate is controlled with an accuracy of ±0.5℃ / min;

[0019] S5, multi-layer sealed packaging: sequentially using metal-coated composite film for heat sealing, ceramic box for inert gas filling, and pressure-resistant carton for sealing.

[0020] According to one embodiment of the present invention, in step S3, the conditions of the CVD process are: the precursor is... The volume ratio was 1:4, the temperature was 1100℃, the pressure was 2kPa, and the deposition rate was 30nm / min. The conditions of the ALD process were: trimethylaluminum and water as precursors, temperature 150℃, and pulse cycles 200 to 400 times.

[0021] According to an embodiment of the present invention, in step S4, the cooling curve includes:

[0022] The first cooling curve for high-stability alloys: 600℃ to 300℃ at a cooling rate of 5℃ / min, hold for 1 hour, then cool to 100℃ at a cooling rate of 2℃ / min, hold for 2 hours, and then cool to room temperature; or,

[0023] The second cooling curve for high-temperature reinforced alloys is as follows: cooling from 900℃ to 500℃ at a cooling rate of 8℃ / min, holding for 1.5h, then cooling to 200℃ at a cooling rate of 3℃ / min, holding for 2.5h, and finally cooling to room temperature.

[0024] On the other hand, the present invention also provides a thermal conductive wire preparation device, which prepares thermal conductive wires based on a thermal conductive wire preparation method. The device includes: a feeding device, a heating furnace, a first connecting assembly, a coating device, a second connecting assembly, an annealing device, a discharging device, a packaging device, and a central control system, wherein:

[0025] The feeding device includes an inert atmosphere hopper;

[0026] The heating furnace has a multi-zone independent temperature control structure with a temperature control accuracy of ±1℃.

[0027] Both the first connecting assembly and the second connecting assembly are sealed inert gas transition chambers.

[0028] The coating device integrates a CVD module, an ALD module, and a laser thickness gauge.

[0029] The annealing device has a built-in PLC controller, which controls the execution of the cooling curve.

[0030] The central control system connects all modules and monitors and stores process parameters in real time.

[0031] According to one embodiment of the present invention, the heating furnace has a built-in infrared temperature sensor;

[0032] The CVD module of the coating apparatus includes a precursor preheating system and a gas flow controller;

[0033] The ALD module includes a precursor pulse valve with a response time of <10ms;

[0034] The packaging device integrates a hot press sealing machine, an inert gas filling valve, and a threaded sealing mechanism.

[0035] According to one embodiment of the present invention, the multi-zone independent temperature control structure of the heating furnace includes multiple independent heating zones, each heating zone being equipped with a separate temperature sensor and temperature control module, and the furnace is vented with... In a mixed inert atmosphere The volume ratio is 5% to ensure that the tungsten-rhenium matrix is ​​not over-reduced during the oxide layer removal process.

[0036] According to one embodiment of the present invention, the application of a thermal conductivity wire in a gas chromatograph thermal conductivity detector.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1. Significantly improved performance: The sensitivity of the thermal conductive wire is 40% to 60% higher than that of traditional products, the batch repeatability RSD is <1.5%, and the service life is extended by 3 to 5 times (service life ≥5000h in carrier gas containing 5% water vapor).

[0039] 2. Enhanced process stability: The entire process is conducted in an inert atmosphere to avoid secondary oxidation; a customized annealing curve reduces internal stress; the oxide layer removal rate is ≥99.5%; and the film thickness deviation is <±5%.

[0040] 3. Optimized detection efficiency: The variable pitch spiral structure reduces airflow turbulence, shortens the response time to below 65ms, and reduces the measurement error to ±0.7%;

[0041] 4. Storage and Transportation Guarantee: Multi-layer sealed packaging ensures that the product's resistivity change rate is <0.5% after 12 months of storage at room temperature, and the transportation loss rate is <0.5%.

[0042] 5. High degree of equipment automation: The integrated design reduces human intervention, and the daily output of a single production line is increased to twice that of traditional equipment, while manufacturing costs are reduced by 15% to 20%.

[0043] 6. Using SiC bonding The gradient design, in synergy with the nano-alloy layer, solves the pain points of traditional coatings that are easy to fall off and provide insufficient protection through the gradient coating's "strong bonding + high barrier". Attached Figure Description

[0044] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0045] Figure 1 This is a schematic diagram of the main structure of the thermal conductive wire;

[0046] Figure 2 This is a flowchart of the thermal conductivity wire preparation method;

[0047] Figure 3 This is a schematic diagram of the integrated structure of the thermal conductive wire preparation equipment.

[0048] Explanation of reference numerals in the attached figures

[0049] 301. Feeding device; 302. Heating furnace; 303. First connecting assembly; 304. Second connecting assembly;

[0050] 305. Coating apparatus; 3051. CVD module; 3052. ALD module; 3053. Online monitoring unit;

[0051] 306. Annealing apparatus; 307. Discharge apparatus; 308. Packaging apparatus; 309. Central control system; Detailed Implementation

[0052] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0053] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0054] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c" can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0055] The thermal conductive wire adopts a composite design of "core alloy layer + gradient protective film + three-dimensional optimized structure".

[0056] The core alloy layer is a composite system of "tungsten-rhenium matrix + nano-dispersed phase". It strengthens grain boundaries and inhibits recrystallization through nano-phase, and is divided into two formulations according to performance requirements:

[0057] In highly stable formulations, the components, by weight percentage, include W 96.5% to 98.85%, Re 1% to 3%, 0.1% to 0.3% 0.05% to 0.1%; of which and Uniformly dispersed in the form of 50 to 100 nm nanoparticles, with a grain aspect ratio > 5:1, recrystallization temperature ≥ 1600℃ (600℃ higher than pure tungsten wire), room temperature resistivity stable at 7.2 to 7.5 μΩ·cm, and temperature coefficient of resistance (TCR). to To ensure consistent sensitivity.

[0058] The high-temperature enhanced formulation, by weight percentage, comprises 94.5% to 95% W, 4.5% to 5% Re, and 0.5% HfC. HfC is the chemical formula for hafnium carbide, a binary ceramic material composed of hafnium and carbon, possessing a very high melting point (close to 3900℃), extremely high hardness, and good high-temperature stability. The HfC nanophase forms a continuous network structure along grain boundaries, exhibiting a creep resistance life of ≥1500h at 1200℃ (7 times better than traditional tungsten-rhenium wire), and a room temperature resistivity of 7.6 to 7.8 μΩ·cm, making it suitable for high-temperature detection scenarios (such as gas analysis >800℃).

[0059] A gradient protective film covers the surface of the core alloy layer and consists of a bonding layer and a functional layer from the inside out, solving the problems of easy peeling and weak oxidation resistance of traditional single oxide layers.

[0060] The bonding layer is a 100-200 nm thick SiC layer prepared by chemical vapor deposition (CVD), under the following deposition conditions: =1:4 (volume ratio), temperature 1100℃, pressure 2kPa, crystallinity >90%, and interfacial peel strength with tungsten rhenium matrix >50MPa, ensuring that the coating is not easy to fall off.

[0061] The functional layer is prepared using atomic layer deposition (ALD) with a thickness of 5 to 10 nm. The layer, using trimethylaluminum and water as precursors, was subjected to a temperature of 150°C and 200 to 400 pulse cycles, achieving a density of 99.9% and an oxygen permeability of < It effectively isolates water vapor and oxygen.

[0062] The main structure of the thermal conductor wire adopts a variable pitch spiral structure, with the pitch increasing from 50μm at the inlet end to 80μm at the outlet end, the spiral diameter from 0.3 to 0.5mm, and the number of turns from 5 to 8. This design reduces airflow eddies, improves the uniformity of the thermal field by 30%, and shortens the response time to less than 65ms.

[0063] The thermal conductor wire's support structure uses a corrugated alumina ceramic support with an amplitude of ±15μm, a wavelength of 200μm, and a stress concentration factor of ≤1.4 (33% lower than traditional straight support), improving vibration resistance and reducing the wire breakage rate from 8% to below 1%.

[0064] like Figure 2 As shown, the thermal conductive wire preparation method is based on the combination of full-process inert atmosphere control and precise temperature profile, realizing integrated production of "deoxidation-coating-annealing-packaging" in sequence. The specific steps are as follows:

[0065] S1: Preparation of pre-fabricated thermal conductive wire

[0066] Select billets that conform to the above core alloy formula (such as...) Composite powder sintered billets are processed into fine rods with a diameter of 1 mm to 3 mm by a rotary forging machine, and then drawn in multiple passes by a wire drawing machine (intermediate annealing temperature 800℃ / 10min) to produce wires with a diameter of 15 μm to 50 μm and a length of 2 cm to 10 cm. The wires are placed in an inert atmosphere silo (filled with 99.999% Ar gas) for later use to avoid oxidation during the pretreatment stage.

[0067] S2: Segmented deoxidation treatment

[0068] The pre-fabricated heat-conducting wire is fed into the heating furnace and introduced... Mixed inert atmosphere ( The surface oxide layer was removed using a stepped heating curve with a volume percentage of 5% and an oxygen content of <10ppm. , , ):

[0069] Phase 1: Keep warm at 200 to 350℃ for 1 to 2 hours to soften the surface. ;

[0070] Second stage: Incubate at 400 to 600℃ for 1 to 2 hours to decompose the middle layer. ;

[0071] Third stage: Keep warm at 700 to 900℃ for 1 to 2 hours to achieve complete restoration. Pure tungsten matrix;

[0072] The oxide layer removal rate is ≥99.5%, and there is no excessive reduction of the tungsten-rhenium matrix (Re content loss <0.05%).

[0073] S3: Gradient protective film preparation

[0074] Maintaining an inert atmosphere, the deoxidized thermal conductive wire is transferred to the coating device via the first connecting component (sealed inert transition chamber) to sequentially prepare two protective films:

[0075] SiC bonding layer preparation (CVD process): Precursor is (Volume ratio 1:4), temperature 1100℃, pressure 2kPa, deposition rate 30nm / min, film thickness 100 to 200nm; film thickness deviation <±5% as monitored in real time by laser thickness gauge.

[0076] Functional layer preparation (ALD process): using trimethylaluminum and water as precursors, temperature 150℃, pulse cycling 200 to 400 times (0.025nm deposition per cycle), film thickness 5 to 10nm; precursor pulse valve response time <10ms to ensure coating uniformity.

[0077] S4: Customized Annealing Process

[0078] The coated thermal conductive wire is transferred to the annealing device via the second connecting component (with the same structure as the first connecting component). The following cooling profile is selected based on the core alloy type, and the cooling rate is controlled with an accuracy of ±0.5℃ / min to eliminate internal stress.

[0079] First cooling curve (suitable for high-stability alloys): 600℃ → 300℃ (cooling rate 5℃ / min, holding for 1h) → 100℃ (cooling rate 2℃ / min, holding for 2h) → room temperature;

[0080] Second cooling curve (suitable for high-temperature reinforced alloys): 900℃ → 500℃ (cooling rate 8℃ / min, holding for 1.5h) → 200℃ (cooling rate 3℃ / min, holding for 2.5h) → room temperature.

[0081] S5: Multi-layer sealed packaging

[0082] The system employs an inner, middle, and outer three-layer protective structure to prevent oxidation and moisture absorption during storage and transportation.

[0083] Inner packaging: PET / Al / PE three-layer metal-coated composite film, heat-sealed (temperature 180 to 200℃, pressure 0.3MPa), oxygen permeability < ;

[0084] Intermediate packaging: Ceramic-lined box (with built-in 4A molecular sieve desiccant, moisture absorption rate <0.5g / 24h), filled with 99.999% pure Ar gas, air replacement rate >99.9%;

[0085] Outer packaging: Corrugated cardboard box with a thickness of ≥5mm, sealed with silicone sealing ring thread, and with a drop resistance of ≥1.5m without damage.

[0086] like Figure 3 As shown, the thermal conductive wire preparation equipment is an integrated structure used to implement the above preparation method, ensuring controllable process and stable atmosphere throughout the entire process, specifically including:

[0087] The feeding device 301 includes an inert atmosphere hopper (5 to 10 L capacity, filled with 99.999% Ar gas) and an automatic wire feeding mechanism (wire feeding accuracy ±0.1 mm); a double-layer sealed wire feeding channel is provided between the hopper and the heating furnace (the inner layer is filled with Ar gas at a flow rate of 0.2 to 0.5 L / min; the outer layer is a vacuum isolation layer with a vacuum degree ≤ This prevents the pre-fabricated thermal conductor from coming into contact with air.

[0088] Heating furnace 302 adopts a multi-zone independent temperature control structure (3 independent heating zones). Each heating zone is equipped with a K-type thermocouple (temperature measurement range 0 to 1200℃, accuracy ±0.5℃) and a PID temperature control module, with a temperature control accuracy of ±1℃ and an internal temperature uniformity error of <±2℃. It also features a built-in infrared temperature sensor (detection accuracy ±0.5℃) that provides real-time temperature data feedback to the central control system. The inner wall of the furnace is coated with a 50 to 100 μm thick layer. Ceramic coating prevents the furnace wall from oxidizing and peeling off at high temperatures, thus preventing contamination of the heat-conducting wires.

[0089] Both the first connecting assembly 303 and the second connecting assembly 304 are sealed inert gas transition chambers (volume 1 to 2L), with pneumatic sealing doors at both ends (sealing pressure 0.5MPa). Internally, they are equipped with pressure sensors (range 0 to 0.5MPa, accuracy ±0.01MPa) and a gas replacement system. Each time the chamber doors are opened, a vacuum is first evacuated to... Then, 99.999% Ar gas is added and the process is repeated 3 times to ensure that the oxygen content in the chamber is ≤10ppm. The first connecting component 303 enables seamless connection of the atmosphere between the heating furnace and the coating device, and the second connecting component 304 enables seamless connection between the coating device and the annealing device.

[0090] The coating device 305 integrates a CVD module 3051, an ALD module 3052, and an online monitoring unit 3053.

[0091] CVD Module 3051: Includes a precursor preheating system (temperature control accuracy ±1℃, preheating temperature 80 to 100℃) and a gas flow controller (accuracy ±0.1 sccm), enabling precise control. and The mixing ratio;

[0092] ALD Module 3052: Includes precursor pulse valve (response time < 10ms) and vacuum system (vacuum degree ≤ 1× Pa);

[0093] Online monitoring unit 3053: laser thickness gauge (accuracy ±1nm) and plasma density sensor, which adjust the coating parameters in real time to ensure that the film thickness deviation is <±5%.

[0094] The annealing device 306 includes a heating unit (heating rate of 1 to 10℃ / min), a cooling unit (inert gas cooling, cooling rate of 0.5 to 5℃ / min), and a PLC controller; the PLC can store and execute the above two sets of cooling curves, support the visual editing and parameter locking of temperature-time curves, and avoid human operation deviations.

[0095] Discharge device 307: includes an inert atmosphere transition channel (length 50 to 80 cm, purged with 99.999% Ar gas, airflow rate 0.5 to 1 L / min).

[0096] Packaging device 308: integrates a hot press sealing machine (temperature range 150 to 250℃, pressure 0.2 to 0.5MPa), an Ar gas filling valve (filling pressure 0.15 to 0.2MPa) and a thread sealing mechanism, automatically completing three-layer packaging, with a daily production capacity of ≥5000 pieces per production line (twice that of traditional equipment).

[0097] The central control system 309 uses an industrial touch screen (10.1 inches) to connect various modules and display parameters such as temperature, atmosphere concentration, coating thickness, and wire feeding rate in real time; it supports the storage and retrieval of more than 100 sets of process formulas and can trace historical data by "equipment number-production date-batch number" (storage time ≥ 3 years); it has an abnormal alarm function (such as oxygen content exceeding the standard, temperature deviation exceeding the limit), and the alarm response time is < 1 second.

[0098] Example 1: High-stability thermal conductivity wire ( Preparation of ).

[0099] Preparation of pre-fabricated thermal conductive wire: Select W-3Re alloy billet (Re content 3.00±0.15%, K content 0.006%), draw it into wire with a diameter of 25μm and a length of 5cm, and place it in the Ar gas hopper of the feeding device.

[0100] Segmented deoxidation: The filament is fed into a heating furnace and purged with oxygen. Mixed atmosphere ( (5%), heated according to the following curve: 200℃ for 1.5h → 400℃ for 1.5h → 800℃ for 1.5h, cooled to 300℃, and then transferred to the coating device through the first connecting component.

[0101] Gradient protective film preparation:

[0102] CVD preparation of SiC bonding layer: =1 / 4, temperature 1100℃, pressure 2kPa, deposition 30min, film thickness 150nm;

[0103] ALD preparation Functional layer: Trimethylaluminum / water pulse cycling 300 times, temperature 150℃, film thickness 7nm;

[0104] The laser thickness gauge monitors the film thickness in real time, and the film thickness deviation is controlled within ±3nm.

[0105] Customized annealing: The material is transferred to the annealing device via the second connecting component and cooled using the first cooling curve: 600℃ → 300℃ (5℃ / min, holding for 1h) → 100℃ (2℃ / min, holding for 2h) → room temperature. The resistance value after annealing is 110±0.5Ω.

[0106] Multi-layer sealed packaging: sequentially using PET / Al / PE film for heat sealing (190℃, 0.3MPa), ceramic box for Ar gas filling (99.999% purity), and pressure-resistant carton for sealing.

[0107] Performance testing: Under carrier gas (30 mL / min) and 220℃ conditions, the baseline noise is <0.1 mV; after aging at 300℃ for 1000 h, the resistance change rate is 0.6%; after 12 months of storage at room temperature, the resistance change rate is 0.4%.

[0108] Example 2: Preparation of High-Temperature Enhanced Thermal Conductivity Wire (W-5Re-0.5HfC)

[0109] Preparation of pre-fabricated thermal conductive wire: Select W-5Re alloy billet (Re content 5.0±0.2%), dop with 0.5% HfC nanoparticles (particle size 0.1μm), ball mill for 24h (Ar protection), hot isostatic pressing (2200℃ / 30MPa, 2h), and then draw into wire with a diameter of 30μm and a length of 6cm.

[0110] Segmented deoxidation: The heating furnace atmosphere is... ( (5%), heating curve: 300℃ for 1 hour → 500℃ for 1 hour → 900℃ for 1 hour, then cooled to 400℃ and transferred to the coating device.

[0111] Gradient protective film preparation: SiC layer deposition for 40 min (film thickness 200 nm). Layer cycled 400 times (film thickness 10nm).

[0112] Customized annealing: The second cooling curve is used for cooling: 900℃ → 500℃ (8℃ / min, holding for 1.5h) → 200℃ (3℃ / min, holding for 2.5h) → room temperature.

[0113] Performance testing: Creep resistance at 1200℃ <0.1%; Service life up to 5200h in carrier gas containing 5% water vapor; Temperature coefficient of resistance .

[0114] Example 3: Equipment Operation and Process Traceability

[0115] Using the equipment of this invention, and simultaneously running the process formula of Example 1, the central control system displays in real time:

[0116] Temperatures in each zone of the heating furnace: Zone 1 200±1℃, Zone 2 400±1℃, Zone 3 800±1℃;

[0117] Atmosphere of coating equipment: Content <5ppm, SiC deposition rate 30±1nm / min;

[0118] The annealing apparatus cooling rate is 5 ± 0.2℃ / min (600→300℃ stage).

[0119] All parameters are automatically stored in the database, and the manufacturing process of a single thermal conductive wire can be traced via a QR code.

[0120] The thermal conductive wire, preparation method, and equipment of this invention, through multi-dimensional innovation in materials, structure, process, and equipment, have solved the core pain points of existing thermal conductive wires, such as poor oxidation resistance, short lifespan, poor repeatability, slow response, and dispersed equipment and low precision, compared with the existing technology. This has resulted in significant technological progress and industry value.

[0121] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, disclosure, and other materials. In this specification, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple components. A single processor or other unit can implement several functions listed in the specification. While certain measures are described in different embodiments, this does not mean that these measures cannot be combined to produce good results.

[0122] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications fall within the scope of the invention and its equivalents, the invention is also intended to include such modifications and modifications.

Claims

1. A thermal conductive wire, characterized in that, It includes a core alloy layer and a gradient protective film covering the surface of the core alloy layer, wherein: The core alloy layer is a composite system of tungsten-rhenium matrix and nano-dispersed phase. By weight percentage, the core alloy layer comprises: W 94.5% to 98.85%, Re 1% to 5%, and nano-dispersed phase 0.15% to 0.6%. and A mixture or HfC; The gradient protective film consists of a 100-200 nm SiC bonding layer and a 5-10 nm layer, from the inside out. Functional layer; the main body of the thermal conductive wire is a variable pitch spiral structure, with the pitch increasing from 50μm to 80μm along the airflow direction, the spiral diameter from 0.3 to 0.5mm, and the two ends are provided with wavy alumina ceramic supports with an amplitude of ±15μm and a wavelength of 200μm.

2. The thermal conductive wire according to claim 1, characterized in that, When the core alloy layer is of high stability, its composition by weight percentage is W 96.5% to 98.85%, Re 1% to 3%. 0.1% to 0.3% 0.05% to 0.1%, grain aspect ratio > 5:1, recrystallization temperature ≥ 1600℃, room temperature resistivity 7.2 to 7.5 μΩ·cm, temperature coefficient of resistance to .

3. The thermal conductive wire according to claim 1, characterized in that, When the core alloy layer is a high-temperature reinforced type, its composition by weight percentage is W 94.5 to 95%, Re 4.5 to 5%, HfC 0.5%, creep resistance at 1200℃ ≥1500h, and room temperature resistivity 7.6 to 7.8μΩ·cm.

4. A method for preparing a thermal conductive wire, used to prepare the thermal conductive wire according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1, Preparation of prefabricated thermal conductive wire: Select a blank that conforms to the core alloy composition and draw it into a wire with a diameter of 15 to 50 μm and a length of 2 to 10 cm; S2, segmented deoxidation: in In a mixed inert atmosphere, 5% of the material is heated according to a stepped heating curve, which is: 200 to 350℃ for 1 to 2 hours, 400 to 600℃ for 1 to 2 hours, and 700 to 900℃ for 1 to 2 hours. S3, Gradient protective film preparation: Maintaining an inert atmosphere, the SiC bonding layer is prepared sequentially using CVD process, followed by ALD process to prepare the... Functional layer; S4, Customized Annealing: In an inert atmosphere, the cooling curve is selected according to the core alloy type, and the cooling rate is controlled with an accuracy of ±0.5℃ / min; S5, multi-layer sealed packaging: sequentially using metal-coated composite film for heat sealing, ceramic box for inert gas filling, and pressure-resistant carton for sealing.

5. The method for preparing a thermally conductive wire according to claim 4, characterized in that, In step S3, the conditions for the CVD process are: the precursor is... The volume ratio was 1:4, the temperature was 1100℃, the pressure was 2kPa, and the deposition rate was 30nm / min. The conditions of the ALD process were: trimethylaluminum and water as precursors, temperature 150℃, and pulse cycles 200 to 400 times.

6. The method for preparing a thermally conductive wire according to claim 4, characterized in that, In step S4, the cooling curve includes: The first cooling curve for high-stability alloys: 600℃ to 300℃, cooling rate 5℃ / min, hold for 1 hour, then cool to 100℃, cooling rate 2℃ / min, hold for 2 hours, then cool to room temperature; or, The second cooling curve for high-temperature reinforced alloys is as follows: cooling from 900℃ to 500℃ at a cooling rate of 8℃ / min, holding for 1.5h, then cooling to 200℃ at a cooling rate of 3℃ / min, holding for 2.5h, and finally cooling to room temperature.

7. A thermal conductive wire preparation apparatus, used to implement the thermal conductive wire preparation method according to any one of claims 4 to 6, characterized in that, It includes a feeding device, a heating furnace, a first connecting assembly, a coating device, a second connecting assembly, an annealing device, a discharging device, a packaging device, and a central control system, wherein: The feeding device includes an inert atmosphere hopper; The heating furnace has a multi-zone independent temperature control structure with a temperature control accuracy of ±1℃. Both the first connecting assembly and the second connecting assembly are sealed inert gas transition chambers. The coating device integrates a CVD module, an ALD module, and a laser thickness gauge. The annealing device has a built-in PLC controller, which controls the execution of the cooling curve described in claim 6. The central control system connects all modules and monitors and stores process parameters in real time.

8. The thermal conductivity wire preparation equipment according to claim 7, characterized in that, The heating furnace has a built-in infrared temperature sensor. The CVD module of the coating apparatus includes a precursor preheating system and a gas flow controller; The ALD module includes a precursor pulse valve with a response time of <10ms; The packaging device integrates a hot press sealing machine, an inert gas filling valve, and a threaded sealing mechanism.

9. The thermal conductivity wire preparation equipment according to claim 7, characterized in that, The multi-zone independent temperature control structure of the heating furnace includes multiple independent heating zones, each equipped with a separate temperature sensor and temperature control module, and the furnace is vented with... In a mixed inert atmosphere The volume ratio is 5% to ensure that the tungsten-rhenium matrix is ​​not over-reduced during the oxide layer removal process.

10. The application of the thermal conductivity wire according to any one of claims 1 to 3 in a gas chromatograph thermal conductivity detector.

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