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CN-122013290-A - Pulse electrochemical etching method for nickel-based superalloy core plate micro-channel

CN122013290ACN 122013290 ACN122013290 ACN 122013290ACN-122013290-A

Abstract

A pulse electrochemical etching method for a nickel-based superalloy core plate micro-channel belongs to the technical field of metal microstructure manufacturing and surface processing. The invention adopts a corrosion-resistant layer pattern to open windows to limit a forming area, implements pulse electrochemical selective dissolution under the conditions of plate opposition and slit flow liquid supply, enhances the conductivity and wetting bubble removal capability by compounding electrolyte with a sulfuric acid system, and reduces the lateral dissolution tendency by matching with a side corrosion inhibiting additive, and simultaneously combines high-efficiency removal and morphology correction by rough corrosion and finish corrosion sectional excitation of asymmetric bipolar pulses, thereby realizing synchronous promotion of micro-channel processing efficiency, stability and section rectangle degree without changing electrolyte, realizing stable amplification of core plate processes with different sizes by parameterization control of current density and flow of unit area, and effectively solving the problems of large side corrosion tendency, difficult guarantee of section rectangle degree, insufficient dissolution stability, difficult efficiency and morphology balance and the like in the existing processing method.

Inventors

  • JIA ZHIGANG
  • GUO QUANZHONG
  • WANG CHUAN
  • WU LEI
  • WANG YONG

Assignees

  • 中国科学院金属研究所

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. The pulse electrochemical etching method for the nickel-based superalloy core plate micro-channel is characterized by comprising the following steps of: S1, pretreatment, namely pretreating the surface of a nickel-based superalloy core plate, and sequentially carrying out alkaline washing, degreasing, acid washing, ultra-pure water washing and drying; S2, gluing, namely coating anti-corrosion ink on the surface of the core plate, and drying until the core plate is shaped; s3, designing a mask, drawing a mask pattern, and then printing out a film negative to obtain a film mask; S4, exposing, namely placing a film negative on the surface of the core plate resist ink and aligning, and placing the film negative in an ultraviolet exposure machine for exposure; S5, developing, namely placing the exposed core plate in alkaline developer to perform development, so that the resist ink layer of the unexposed area is dissolved, and the resist ink layer of the exposed area is reserved to form a micro-channel pattern windowing area; s6, pulse electrochemical etching, namely, taking a core plate subjected to development windowing treatment as an anode, clamping the core plate and a cathode flat plate with stable performance in acid electrolyte in parallel and oppositely, and applying an asymmetric bipolar pulse power supply under the condition of circulating flow of the acid electrolyte to carry out selective anode dissolution forming on a windowing area, wherein the pulse electrochemical etching process comprises a rough etching section and a fine etching section; s7, demolding, namely immersing the etched core plate in alkaline demolding liquid to remove a corrosion-resistant layer, then carrying out acid washing to neutralize residual alkaline substances, thoroughly cleaning with ultrapure water, and finally drying; And S8, detecting the appearance of the core plate and the size of the micro-channel after film stripping by using a secondary element detector or a contour/microscopic measuring means, and packaging, warehousing or shipping after the detection is qualified.
  2. 2. The pulse electrochemical etching method for the nickel-based superalloy core plate micro-channel is characterized in that in S6, the rough etching section and the finish etching section adopt the same sulfuric acid system to compound conductive acid electrolyte, and the method comprises the following steps of 5.0-30.0 wt% of sulfuric acid, 2.0-12.0 wt% of conductive salt, 0.05-10 g/L of additive and 2-3 g/L of complexing agent; Wherein the conductive salt is sodium sulfate and/or sodium nitrate, the additive is one or more selected from benzotriazole, 2-mercaptobenzimidazole, polyethylene glycol, polyvinylpyrrolidone and sodium dodecyl sulfate, the complexing agent is one or more selected from sodium citrate, sodium tartrate, disodium ethylenediamine tetraacetate and sodium gluconate, and the solvent is ultrapure water.
  3. 3. The pulse electrochemical etching method for the nickel-based superalloy core plate micro-channel is characterized in that the sulfuric acid system is compounded with conductive acid electrolyte, and the conductive acid electrolyte comprises 10.0-25.0 wt% of sulfuric acid and 4.0-8.0 wt% of conductive salt.
  4. 4. The pulse electrochemical etching method for the nickel-based superalloy core plate micro-channel according to claim 2, wherein in S6, the electrode distance between the anode and the cathode is 0.5 mm-1.6 mm, the electrolyte flow rate per unit effective etching area is 0.005L/(min cm 2 )~0.3L/(min·cm 2 ), and the average flow rate in the slit is 0.1 m/S-5 m/S.
  5. 5. The pulsed electrochemical etching method of nickel-base superalloy core fluidic channels of claim 4, wherein the electrolyte flow per effective etching area is 0.01L/(min cm 2 )~0.05L/(min·cm 2 ).
  6. 6. The pulse electrochemical etching method for the nickel-based superalloy core plate micro-channel according to claim 2 or 4, wherein the rough etching section adopts asymmetric bipolar pulse to carry out anodic dissolution, and the asymmetric conditions of strong forward pulse and weak reverse pulse are met, wherein the forward peak voltage U + is 12V-18V, the reverse peak voltage U - is 1.2V-3.0V, and U + >U - , and the pulse frequency is 0.8 KHz-1.0 kHz, 350-600 mu s of forward pulse width t on+ , 40-60 mu s of reverse pulse width t on- and t on+ ＞t on- , and 10A/cm 2 ~25A/cm 2 of average current density j avg of the effective etching area of the rough etching section; The rough etching section obtains 75% -95% of the target etching depth.
  7. 7. The pulse electrochemical etching method for the nickel-based superalloy core plate micro-channel according to claim 2 or 4, wherein the finish etching section is subjected to repair etching by adopting asymmetric bipolar pulse, and the asymmetric conditions of strong forward pulse and weak reverse pulse are met, wherein the forward peak voltage U ' + is 6-9V, the reverse peak voltage U ' - is 0.8-2.0V, and U ' + >U ' - , and the pulse frequency is 10 KHz-18 kHz, a forward pulse width t ' on+ is 10-20 mu s, a reverse pulse width t ' on- is 5-10 mu s, t ' on+ ＞t ' on- , and an average current density j ' avg of the effective etching area of the finish etching section is 3A/cm 2 ~12A/cm 2 .
  8. 8. The pulse electrochemical etching method for the nickel-based superalloy core plate micro-channel according to claim 2 or 4, wherein in S2, a corrosion-resistant ink film forming layer is attached to the core plate, the thickness of the film layer is 40-60 μm, the thickness uniformity is-5%, and the film layer bonding force is more than or equal to 25N/cm.
  9. 9. The pulse electrochemical etching method for the nickel-based superalloy core micro-channel according to claim 2 or 4, wherein in S4, the ultraviolet exposure energy is 100mJ/cm 2 ~200mJ/cm 2 , and the exposure time is 40S-50S.
  10. 10. The pulse electrochemical etching method for the nickel-based superalloy core plate micro-channel according to claim 1, wherein in S5, the developing temperature is 40-45 ℃ and the developing time is 3-10 min.

Description

Pulse electrochemical etching method for nickel-based superalloy core plate micro-channel Technical Field The invention belongs to the technical field of metal microstructure manufacturing and surface processing, relates to a pulse electrochemical etching method for a nickel-based superalloy core plate micro-channel, and particularly relates to a forming method for a nickel-based superalloy micro-channel facing a Printed Circuit Heat Exchanger (PCHE) core plate, in particular to a processing method for forming a windowing pattern through mask exposure and development and combining pulse electrochemical etching. Background The Printed Circuit Heat Exchanger (PCHE) is widely applied to the fields of high-temperature gas cooled reactors, supercritical CO 2 circulation, aerospace, high-end energy equipment and the like due to the advantages of large heat exchange area per unit volume, high temperature and high pressure resistance, compact structure and the like. One of key manufacturing links of PCHE is the processing and forming of core plate micro-channels, the cross section of a common micro-channel tends to be rectangular, the width of a groove is usually in the range of submillimeter to millimeter, the depth can reach about 1mm, and the requirements on the verticality, side erosion and surface morphology of side walls are high. In the prior art, the nickel-based superalloy core plate micro-channel is usually processed by chemical etching or chemical milling. However, chemical etching is generally characterized by isotropic dissolution, obvious lateral dissolution is easy to generate, the rectangular degree of the section of the micro-channel is reduced, the taper of the side wall is increased, the uniformity of the diffusion welding bonding area and the flow inside the heat exchanger is further affected, meanwhile, a passivation film or a corrosion product film is easy to form on the surface of the nickel-based superalloy, the fluctuation of the dissolution rate in the chemical etching process is obvious, and the machining efficiency and the morphology control are difficult to be simultaneously achieved. In addition, simple direct current electrochemical dissolution may also cause processing instability or morphological defects due to bubble coverage, product film accumulation, and local current density non-uniformity. Therefore, there is a need for an electrochemical etching process suitable for a nickel-based superalloy PCHE core plate, which suppresses side etching and improves the cross-sectional rectangularity through electrical parameter control while ensuring higher removal efficiency, and which is simple in process chain and convenient for engineering realization. Disclosure of Invention The invention aims to provide an electrochemical etching method for a nickel-based superalloy core plate micro-channel, which aims to solve the problems that in the existing processing method, side etching tendency is large, cross section rectangle degree is difficult to ensure, dissolution stability is insufficient and efficiency and morphology are difficult to be compatible. In order to solve the technical problems or achieve the purpose of the invention, the technical scheme of the invention comprises the following contents: an electrochemical etching method of a nickel-based superalloy core plate micro-channel comprises the following steps: S1, pretreatment, namely pretreating the surface of a nickel-based superalloy core plate, and sequentially carrying out alkaline washing, degreasing, acid washing, ultra-pure water washing and drying; S2, gluing, namely coating anti-corrosion ink on the surface of the core plate, and drying until the core plate is shaped; s3, designing a mask, drawing a mask pattern, and then printing out a film negative to obtain a film mask; S4, exposing, namely placing a film negative on the surface of the core plate resist ink and aligning, and placing the film negative in an ultraviolet exposure machine for exposure; S5, developing, namely placing the exposed core plate in alkaline developer to perform development, so that the resist ink layer of the unexposed area is dissolved, and the resist ink layer of the exposed area is reserved to form a micro-channel pattern windowing area; S6, pulse electrochemical etching, namely, taking a core plate subjected to development windowing treatment as an anode, clamping the core plate and a cathode flat plate with stable performance in an acid electrolyte in parallel and opposite, applying an asymmetric bipolar pulse power supply under the condition of circulating flow of the acid electrolyte, and performing selective anode dissolution forming on a windowing area, wherein the etching process is divided into a rough etching section and a finish etching section, the rough etching section is used for improving the removal efficiency of a unit area to obtain 75% -95% of a target depth, and the finish etching section is used for inhibiting side etching