Micro-arc oxidation treatment method for zirconium and zirconium alloy surfaces
1. A micro-arc oxidation treatment method for zirconium and zirconium alloy surfaces is characterized by comprising the following steps:
polishing and grinding zirconium and zirconium alloy to obtain a spare material;
using the spare material as an anode, and performing micro-arc oxidation in electrolyte to obtain a micro-arc oxidation coating, wherein the concentration of NaOH in the electrolyte is 1-5 g/L, and Na is contained in the electrolyte2SiO3The concentration of (A) is 5-15 g/L, Na3PO4The concentration of (b) is 15-25 g/L.
2. The micro-arc oxidation treatment method according to claim 1, wherein the micro-arc oxidation voltage is 200-400V, the frequency is 300-400 Hz, the duty ratio is 20-40%, and the time is 5-25 min.
3. The micro-arc oxidation treatment method according to claim 1 or 2, wherein the micro-arc oxidation voltage is 380V, the frequency is 380Hz, the duty ratio is 20%, and the time is 6-10 min.
4. The micro-arc oxidation treatment method according to claim 3, wherein the concentration of NaOH in the electrolyte is 1g/L, Na2SiO3Has a concentration of 6g/L, Na3PO4The concentration of (2) was 17 g/L.
5. The micro-arc oxidation treatment method according to claim 1 or 2, wherein the micro-arc oxidation voltage is 330V, the frequency is 350Hz, the duty ratio is 30%, and the time is 12-16 min.
6. The micro-arc oxidation treatment method according to claim 5, wherein the concentration of NaOH in the electrolyte is 3g/L, Na2SiO3Has a concentration of 10g/L, Na3PO4The concentration of (2) is 20 g/L.
7. The micro-arc oxidation treatment method according to claim 1 or 2, wherein the micro-arc oxidation voltage is 280V, the frequency is 320Hz, the duty cycle is 40%, and the time is 20-24 min.
8. The micro-arc oxidation treatment method according to claim 7, wherein the concentration of NaOH in the electrolyte is 5g/L, Na2SiO3Has a concentration of 14g/L, Na3PO4The concentration of (2) was 23 g/L.
9. The micro arc oxidation treatment method according to claim 1, wherein the polishing and grinding is grinding using sandpaper of 400 mesh, 800 mesh, 1500 mesh, and 2000 mesh in this order.
10. The method for micro-arc oxidation treatment according to claim 1, wherein the micro-arc oxidation uses stainless steel as a cathode.
Background
The zirconium alloy has moderate mechanical property, a lower atomic thermal neutron absorption cross section and good compatibility with nuclear fuel, is mostly used as a core structure material of a water-cooled nuclear reactor, and is corroded by high-temperature and high-pressure circulating cooling water (such as 360 ℃/18.6MPa in a boron lithium water chemical environment) on the outer side of a cladding in the operation process of the reactor, and under the corrosion of the high-temperature and high-pressure circulating cooling water, the zirconium alloy is easy to generate local corrosion, furuncle-shaped corrosion and hydrogen embrittlement. The furuncle-shaped corrosion is generally grey white, the depth can reach dozens of microns, and corrosion products are accumulated to form a thick white oxide film, so that the effective wall thickness of a jacket material can be reduced, the jacket is broken, and the radioactive pollution of circulating cooling water is caused. In addition, damage caused by fretting between the can and the grid can also cause radioactive contamination of the circulating cooling water. Zirconium alloys have poor corrosion resistance at room temperature, greatly limiting their applications.
Disclosure of Invention
In view of the above, the present invention provides a method for micro-arc oxidation treatment of zirconium and zirconium alloy surfaces. The micro-arc oxidation treatment method provided by the invention can improve the corrosion resistance of zirconium and zirconium alloy.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a micro-arc oxidation treatment method for zirconium and zirconium alloy surfaces, which comprises the following steps:
polishing and grinding zirconium and zirconium alloy to obtain a spare material;
using the spare material as an anode, and performing micro-arc oxidation in electrolyte to obtain a micro-arc oxidation coating, wherein the concentration of NaOH in the electrolyte is 1-5 g/L, and Na is contained in the electrolyte2SiO3The concentration of (A) is 5-15 g/L, Na3PO4The concentration of (b) is 15-25 g/L.
Preferably, the voltage of the micro-arc oxidation is 200-400V, the frequency is 300-400 Hz, the duty ratio is 20-40%, and the time is 5-25 min.
Preferably, the voltage of the micro-arc oxidation is 380V, the frequency is 380Hz, the duty ratio is 20%, and the time is 6-10 min.
Preferably, the concentration of NaOH in the electrolyte is 1g/L, Na2SiO3Has a concentration of 6g/L, Na3PO4The concentration of (2) was 17 g/L.
Preferably, the voltage of the micro-arc oxidation is 330V, the frequency is 350Hz, the duty ratio is 30%, and the time is 12-16 min.
Preferably, the concentration of NaOH in the electrolyte is 3g/L, Na2SiO3Has a concentration of 10g/L, Na3PO4The concentration of (2) is 20 g/L.
Preferably, the voltage of the micro-arc oxidation is 280V, the frequency is 320Hz, the duty ratio is 40%, and the time is 20-24 min.
Preferably, the concentration of NaOH in the electrolyte is 5g/L, Na2SiO3Has a concentration of 14g/L, Na3PO4The concentration of (2) was 23 g/L.
Preferably, the polishing and grinding is grinding by using sand paper of 400 meshes, 800 meshes, 1500 meshes and 2000 meshes in sequence.
Preferably, the micro-arc oxidation takes stainless steel as a cathode.
The invention provides a micro-arc oxidation treatment method for zirconium and zirconium alloy surfaces, which comprises the following steps: polishing and grinding zirconium and zirconium alloy to obtain a spare material; using the spare material as an anode, and performing micro-arc oxidation in electrolyte to obtain a micro-arc oxidation coating, wherein the concentration of NaOH in the electrolyte is 1-5 g/L, and Na is contained in the electrolyte2SiO3The concentration of (A) is 5-15 g/L, Na3PO4The concentration of (b) is 15-25 g/L.
Compared with the prior art, the invention has the following beneficial effects:
according to the micro-arc oxidation treatment method for the surfaces of zirconium and zirconium alloy, provided by the invention, zirconium and zirconium alloy are introduced into a high-voltage discharge area from a Faraday area of common anodic oxidation, the defect of hard anodic oxidation is overcome, the comprehensive performance of a micro-arc oxidation coating is improved, the micro-arc oxidation coating is firmly combined with a matrix, and the micro-arc oxidation coating is compact in structure, high in toughness, good in wear resistance, corrosion resistance, high-temperature impact resistance, electric insulation and other characteristics.
Detailed Description
The invention provides a micro-arc oxidation treatment method for zirconium and zirconium alloy surfaces, which comprises the following steps:
polishing and grinding zirconium and zirconium alloy to obtain a spare material;
using the spare material as an anode, and performing micro-arc oxidation in electrolyte to obtain a micro-arc oxidation coating, wherein the concentration of NaOH in the electrolyte is 1-5 g/L, and Na is contained in the electrolyte2SiO3The concentration of (A) is 5-15 g/L, Na3PO4The concentration of (b) is 15-25 g/L.
In the invention, the voltage of the micro-arc oxidation is preferably 200-400V, the frequency is preferably 300-400 Hz, the duty ratio is preferably 20-40%, and the time is preferably 5-25 min.
In a specific embodiment of the invention, the voltage of the micro-arc oxidation is 380V, the frequency is 380Hz, the duty ratio is 20%, the time is 6-10 min, the concentration of NaOH in the electrolyte is 1g/L, and Na is contained in the electrolyte2SiO3Has a concentration of 6g/L, Na3PO4The concentration of (2) was 17 g/L.
In a specific embodiment of the invention, the voltage of the micro-arc oxidation is 330V, the frequency is 350Hz, the duty ratio is 30%, the time is 12-16 min, the concentration of NaOH in the electrolyte is 3g/L, and Na is contained in the electrolyte2SiO3Has a concentration of 10g/L, Na3PO4The concentration of (2) is 20 g/L.
In a specific embodiment of the invention, the voltage of the micro-arc oxidation is 280V, the frequency is 320Hz, the duty ratio is 40%, the time is 20-24 min, and the concentration of NaOH in the electrolyte is preferably 5g/L and Na2SiO3Has a concentration of 14g/L, Na3PO4Is preferably 23g/L
In the present invention, the polishing and grinding is preferably performed by using sandpaper of 400 mesh, 800 mesh, 1500 mesh and 2000 mesh in this order.
In the present invention, the micro-arc oxidation is preferably performed using stainless steel as a cathode.
After the polishing and grinding are finished, the polishing and grinding product is preferably cleaned and then blown dry by cold air for standby.
In order to further illustrate the present invention, the following describes the method for micro-arc oxidation treatment of zirconium and zirconium alloy surfaces in detail with reference to examples, but they should not be construed as limiting the scope of the present invention.
The first embodiment is as follows:
a zirconium micro-arc oxidation treatment method comprises the following steps:
a. polishing zirconium by using 400-mesh, 800-mesh, 1500-mesh and 2000-mesh sand paper in sequence, cleaning, and blowing cold air for later use;
b. preparing an electrolyte, wherein the electrolyte comprises the following components in percentage by weight: NaOH 1g/L, Na2SiO3 6g/L，Na3PO4 17g/L；
c. And (c) putting the zirconium and zirconium alloy treated in the step (a) as an anode into the electrolyte in the step (b), introducing anode current to the zirconium and zirconium alloy sample by taking stainless steel as a cathode under the conditions of 380V voltage, 380Hz frequency and 20% duty ratio, treating for 10min, and forming stable micro-arcs on the surface of the sample to prepare the micro-arc oxidation coating.
The thickness of the formed micro-arc oxidation coating is 7 μm.
Example two:
a zirconium micro-arc oxidation treatment method comprises the following steps:
a. polishing zirconium by using 400-mesh, 800-mesh, 1500-mesh and 2000-mesh sand paper in sequence, cleaning, and blowing cold air for later use;
b. preparing an electrolyte, wherein the electrolyte comprises the following components in percentage by weight: NaOH 3g/L, Na2SiO3 10g/L，Na3PO420g/L；
c. And (c) putting the zirconium and zirconium alloy treated in the step (a) as an anode into the electrolyte in the step (b), introducing anode current to the zirconium and zirconium alloy sample by taking stainless steel as a cathode under the conditions of 330V voltage, 350Hz frequency and 30% duty ratio, treating for 16min, and forming stable micro-arcs on the surface of the sample to prepare the micro-arc oxidation coating.
The thickness of the formed micro-arc oxidation coating is 9 μm.
Example three:
a zirconium micro-arc oxidation treatment method comprises the following steps:
a. polishing zirconium by using 400-mesh, 800-mesh, 1500-mesh and 2000-mesh sand paper in sequence, cleaning, and blowing cold air for later use;
b. preparing an electrolyte, wherein the electrolyte comprises the following components in percentage by weight: NaOH 5g/L, Na2SiO3 14g/L，Na3PO423g/L；
c. And (c) putting the zirconium and zirconium alloy treated in the step (a) as an anode into the electrolyte in the step (b), introducing anode current to the zirconium and zirconium alloy sample by taking stainless steel as a cathode under the conditions of voltage 280V, frequency 320Hz and duty ratio 40%, treating for 24min, and forming stable micro-arcs on the surface of the sample to prepare the micro-arc oxidation coating.
The thickness of the formed micro-arc oxidation coating is 12 μm.
The performance of the coatings formed in examples one to three was tested and the results are shown in table 1. As shown in Table 1, according to the micro-arc oxidation treatment method for the surfaces of zirconium and zirconium alloys, provided by the invention, zirconium and zirconium alloys are introduced into a high-voltage discharge area from a Faraday area of common anodic oxidation, the defect of hard anodic oxidation is overcome, the comprehensive performance of a micro-arc oxidation coating is improved, the micro-arc oxidation coating is firmly combined with a substrate, and the micro-arc oxidation coating has the characteristics of compact structure, high toughness, good wear resistance, corrosion resistance, high-temperature impact resistance, electric insulation and the like.
Table 1 results of performance testing of coatings formed by examples one-three
Numbering
Film thickness μm
Microhardness HV
Example one
7
301.3
Example two
9
340.1
EXAMPLE III
12
394.5
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention.
