CN-116511738-B - Metal laser drilling and inner wall efficient electrolysis post-treatment processing method and device with thermal barrier coating

CN116511738BCN 116511738 BCN116511738 BCN 116511738BCN-116511738-B

Abstract

The invention discloses a device and a method for metal laser drilling with a thermal barrier coating and high-efficiency electrolytic aftertreatment processing of an inner wall, and belongs to the field of special processing. The invention realizes high-efficiency drilling by laser, simultaneously fills the micropores with electrolyte by capillary force while drilling the micropores, overflows from the upper surface part, introduces a deep cooling environment above to realize instant freezing of the electrolyte containing the carbon nano tubes in the micropores, perfectly adheres the shape of a conductive icicle to the inner wall of the hole, then takes a mesh electrode on a thermal barrier coating as a cathode and a metal workpiece with the thermal barrier coating as an anode, gradually melts the icicle by generated current and starts electrolysis on the inner wall, and further carries out electrolytic treatment on the inner wall by introducing a low-pressure environment below to start the electrolyte to flow in the hole and take away processing products. The method ensures that the heat damage position of the inner wall of the hole is isolated by oxygen to the greatest extent and is subjected to accurate electrolytic treatment, and simultaneously, the melted electrolyte can carry out secondary electrolytic treatment on the heat damage position and take away products, so that the wall of the high-quality air film hole can be obtained.

Inventors

ZHU HAO
Mao Dongchen
LU JINZHONG
ZHANG CHAOYANG
ZHANG WENJIA
LIU YANG
XU KUN
WU YUCHENG
WEI WENQIAN

Assignees

江苏大学

Dates

Publication Date: 20260512
Application Date: 20230517

Claims (8)

1. A laser drilling and efficient electrolytic post-treatment processing method for metal with thermal barrier coating and inner wall is characterized by comprising the steps of carrying out laser drilling on a metal workpiece with thermal barrier coating, filling electrolyte into micropores, freezing the electrolyte in the micropores to form micro ice columns, carrying out electrochemical processing on the inner wall of the micropores by taking the metal workpiece with thermal barrier coating as an anode and a netlike electrode as a cathode so as to eliminate or reduce thermal damage of the inner wall caused by the laser processing of the micropores, introducing a low-pressure environment below the metal workpiece with thermal barrier coating, after the micro ice columns are completely melted, enabling the electrolyte to flow through the micropores from top to bottom under the action of an upper-lower pressure difference, carrying out further electrolytic treatment on the inner wall of the holes, taking away processed products, and stirring the electrolyte by a stirring device to provide the low-pressure environment.
2. The method for processing the metal workpiece with the thermal barrier coating through the laser drilling and the high-efficiency electrolysis aftertreatment of the inner wall is characterized in that the metal workpiece with the thermal barrier coating is subjected to micro-hole drilling through laser, electrolyte is contacted with the lower side of the metal workpiece with the thermal barrier coating, the electrolyte fills the micro-holes under the action of the change factors of capillary force and optical breakdown pressure while the laser drilling is conducted, overflows on the upper surface of the metal workpiece with the thermal barrier coating, liquid drop bulges are formed near the inlets of the micro-holes, a cryogenic environment is introduced above the metal workpiece with the thermal barrier coating, the electrolyte in the micro-holes is frozen instantaneously, an electrolyte ice column is formed in the micro-holes after the laser drilling is completed, the shape of the ice column is attached to the inner wall of the micro-holes, and micro-bulges are formed at the inlets of the micro-holes.
3. The method for processing the metal with the thermal barrier coating through laser drilling and high-efficiency electrolysis aftertreatment of the inner wall according to claim 2 is characterized in that the electrolyte contains carbon nanotubes, and the frozen carbon nanotubes can form a conductive network to endow the icicle with conductivity.
4. The method for processing the metal with the thermal barrier coating through the laser drilling and the high-efficiency electrolysis aftertreatment of the inner wall is characterized in that a reticular electrode is adopted as a cathode, the reticular electrode is attached to the upper surface of the metal workpiece with the thermal barrier coating and is connected with each micro ice column through a microprotrusion at a micropore inlet, the metal workpiece with the thermal barrier coating is adopted as an anode, an external direct current pulse power supply is connected, current is generated, heat is generated at the interface of the ice column and the micropore inner wall, the ice column is gradually melted, and meanwhile, the inner wall of the hole starts to electrolyze.
5. The method for processing the metal with the thermal barrier coating through laser drilling and high-efficiency electrolysis aftertreatment of the inner wall according to claim 1 is characterized in that the metal workpiece with the thermal barrier coating is a DD6 nickel-based single crystal superalloy blade.
6. The processing device of the high-efficiency electrolytic post-treatment processing method for the metal with the thermal barrier coating, which is disclosed in any one of claims 1 to 5, is characterized by comprising an optical path system, an electrolytic processing system, a cooling system and a stirring system, wherein the optical path system comprises a laser, an optical fiber and a focusing lens, the laser is connected with the optical fiber, the laser irradiates the metal workpiece with the thermal barrier coating through the focusing lens, the upper end of the metal workpiece with the thermal barrier coating is placed in the cooling system, the electrolytic processing system comprises a direct current pulse power supply, a voltmeter, an ammeter and a reticular electrode, the positive electrode of the direct current pulse power supply is connected with the metal workpiece with the thermal barrier coating, the negative electrode of the direct current pulse power supply is connected with the reticular electrode, the electrolytic reaction is observed and regulated through the voltmeter and the ammeter, the cooling system comprises a pressure supply device, a cylindrical cryogenic sealing device, a vaporization spray head and a liquid nitrogen storage tank, liquid in the liquid nitrogen storage tank is pressurized through the pressure supply device, conveyed to a circulation hole of the cylindrical cryogenic sealing device through a pipeline, finally sprayed to the upper side of the metal workpiece with the thermal barrier coating through the vaporization spray head, a cryogenic environment is formed, the stirring system comprises an anchor stirring device, the stirring device is arranged in the middle of the blade type, and the stirring device is positioned in the middle of the processing device, when the metal workpiece is rotated under a high-speed condition, and a high-speed thermal barrier coating is formed, and a high-speed rotary condition when the stirring condition is formed.
7. The processing device according to claim 6, wherein the electrolyte is sodium nitrate or sodium chloride, and the mass fraction thereof is 10% -30%.
8. The processing apparatus of claim 6, wherein the laser is a nanosecond or picosecond laser.

Description

Metal laser drilling and inner wall efficient electrolysis post-treatment processing method and device with thermal barrier coating Technical Field The invention relates to the technical field of special processing, in particular to a device and a method for metal laser drilling with a thermal barrier coating and high-efficiency electrolytic aftertreatment processing of an inner wall. Background Improving the high temperature resistance of turbine blades is a key to improving the aeroengine technology, and the current mainstream methods are a gas film cooling technology and a thermal barrier coating technology. The thermal barrier coating has low thermal conductivity, can reduce the temperature of the blade substrate, plays a role in thermal protection, and simultaneously forms a layer of cooling air film with low temperature on the surface of the blade by spraying cold air into high-temperature air flow, so that the temperature of the surface of the blade is reduced. The blade air film hole has the characteristics of small aperture, large quantity, high depth-diameter ratio, complex space angle and extremely high quality requirement, and is mainly processed by adopting modes such as electric spark, long pulse laser, electrohydraulic beam current and the like at present. The electric machining process can not realize secondary machining due to the non-conductive thermal barrier coating, the defects of coating surface falling, cracks, coating edge breakage and the like caused by the traditional long-pulse laser, the electro-hydraulic beam machining efficiency is low, hole type control is difficult, electrolyte is corrosive, special holes are difficult to machine, and the electro-hydraulic beam-electrochemical and laser-electric spark combined machining modes can realize secondary machining, but the uniformity of the holes is limited to a certain extent. The Chinese patent publication No. CN112171184A discloses a composite processing method of a blade air film hole, which comprises the steps of firstly drilling a required air film hole on a thermal barrier coating alloy substrate by utilizing laser, then taking a drill bit rotating at a high speed as a cathode, taking a blade as an anode, moving the drill bit up and down, carrying out online electrolysis post-treatment on a part of the air film hole of a metal substrate, eliminating the defects of residual stress, a heat affected zone and the like in the drilling process, and simultaneously suspending micro abrasive particles in electrolyte, and carrying out micro impact scratching on the hole wall under the drive of the drill bit rotating at a high speed to generate a grinding-like polishing effect. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a device and a method for processing metal with a thermal barrier coating by laser drilling and high-efficiency electrolytic aftertreatment of an inner wall, thereby solving the difficult problems of difficult processing of the metal with the thermal barrier coating and great thermal damage. The present invention achieves the above technical object by the following means. A laser drilling and high-efficiency electrolytic post-treatment processing method for metal with thermal barrier coating comprises the steps of carrying out laser drilling on a metal workpiece with thermal barrier coating, filling electrolyte into micropores, freezing the electrolyte in the micropores to form micro ice columns, and carrying out electrochemical processing on the inner wall of the micropores by taking the metal workpiece with thermal barrier coating as an anode and taking a netlike electrode as a cathode so as to eliminate or reduce the heat damage of the inner wall caused by laser processing of the micropores. According to the scheme, micropores are formed in the metal workpiece with the thermal barrier coating through laser, the lower side of the metal workpiece with the thermal barrier coating is contacted with electrolyte, the electrolyte fills the micropores under the action of the change factors of capillary force and optical breakdown pressure while laser drilling is completed, the electrolyte overflows from the upper surface of the metal workpiece with the thermal barrier coating to form liquid drop bulges near the inlets of the micropores, a cryogenic environment is introduced above the metal workpiece with the thermal barrier coating, instant freezing of the electrolyte in the micropores is realized, an electrolyte ice column is formed in the drilled micropores after laser drilling is completed, the shape of the ice column is attached to the inner wall of the micropores, and the microprotrusions are formed at the inlets of the micropores. In the scheme, the electrolyte contains the carbon nano tube, and the carbon nano tube can form a conductive network after freezing so as to endow the ice column with conductivity. In the scheme, a reticular electrode is adopted as a cathode