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CN-121992357-A - Vacuum coating process for metal substrate and aging-resistant anti-corrosion film

CN121992357ACN 121992357 ACN121992357 ACN 121992357ACN-121992357-A

Abstract

The invention relates to the technical field of metal material surface treatment, and discloses a vacuum coating process of a metal substrate and an aging-resistant anti-corrosion film, which comprises the steps of depositing an anti-corrosion film main layer after a transition layer is deposited, collecting the slope of negative pulse rising edge displacement current in real time, determining a charge adsorption saturation point according to the zero crossing point of a first derivative of the slope, driving to generate a nanosecond controlled overshoot stage to induce atomic transverse migration, switching to a platform stage to maintain deposition and eliminate residual charges in the neutralization stage.

Inventors

  • GAO WENBIN
  • YANG XU

Assignees

  • 苏彩金属(江苏)有限公司

Dates

Publication Date
20260508
Application Date
20251231

Claims (10)

  1. 1. The vacuum coating process of the metal substrate and the ageing-resistant anti-corrosion film is characterized by comprising the following steps of: step S101, depositing a transition layer on the surface of a metal substrate in a vacuum chamber to establish an elastic modulus gradient; Step S102, depositing an anti-corrosion film main layer on the transition layer, and applying a composite pulse bias to the metal substrate through a bias power supply during deposition, wherein the composite pulse bias sequentially comprises a negative pulse section, a dead time section and a positive charge neutralization section in a single period; Step S103, collecting the displacement current flowing through the negative pulse segment rising edge of the metal substrate by using a processor, and calculating the slope k i of the displacement current, wherein k i =di/dt; Step S104, the processor determines that the zero crossing point of the first derivative of the slope k i is the peak time of the displacement current, and drives the bias power supply to generate an overshoot phase with the duration of 50ns to 200ns at the front edge of the negative pulse segment by taking the peak time as the trigger starting point of the overshoot phase; Step S105, bias voltage with peak voltage V p1 is applied to the metal substrate in the overshoot phase, wherein V p1 is set to be 1.5 to 1.8 times of the platform voltage value V p2 of the negative pulse section; And S106, switching to a platform voltage value V p2 after the overshoot stage is finished to maintain vapor atomic deposition, and applying positive voltage in a dead time period after the negative pulse period is turned off so as to lead out residual electron flow in the vacuum chamber and neutralize residual positive charges on the surface of the main layer of the anti-corrosion film.
  2. 2. The vacuum coating process of claim 1, wherein in step S105, the processor determines the set value of the peak voltage V p1 according to the value of the slope k i , the peak voltage V p1 is mapped in positive correlation with the slope k i , the transient amplitude of the slope k i is used to characterize the charge adsorption barrier height of the surface of the main layer of the anti-aging film, and the energy output density of the overshoot stage is adjusted to match the ion momentum entering the surface of the metal substrate with the charge adsorption barrier height.
  3. 3. The vacuum coating process of the metal substrate and the aging-resistant anticorrosive film according to claim 1, wherein the third harmonic component characteristic value phi 3 of the displacement current is extracted in the deposition process of the main layer of the anticorrosive film, and the processor reduces the duty ratio of the composite pulse bias when the time evolution slope of the third harmonic component characteristic value phi 3 exceeds a preset change rate threshold.
  4. 4. The vacuum coating process of claim 1, wherein in step S106, the discharge current decay rate of the forward charge neutralization section is monitored, and when the discharge current decay rate is reduced to a predetermined current change rate threshold, the duration of the forward charge neutralization section is increased and the pulse frequency of the composite pulse bias is synchronously reduced.
  5. 5. The vacuum coating process of the metal substrate and the aging-resistant corrosion-resistant film according to claim 1, wherein the pulse front rising rate of the composite pulse bias voltage is adjusted in the initial 30S to 60S period of depositing the transition layer in the step S101, the pulse front rising rate is set to enable the voltage amplitude to rise from zero to the peak voltage V p1 in 10 -7 S, an anchoring pulse is applied to the metal substrate every five composite pulse bias voltage periods, and the peak voltage of the anchoring pulse is set to be 1.2V p1 .
  6. 6. The process of claim 1, wherein a pulsed process gas is injected into the vacuum chamber 50 μs before the composite pulse bias enters the overshoot phase to form a transient high pressure microenvironment at the edge region of the metal substrate, wherein the process gas stabilizes the momentum injection intensity at the edge region by reducing the ion mean free path in the vacuum chamber, and wherein the injection of the process gas is stopped when the composite pulse bias enters the forward charge neutralization phase.
  7. 7. The vacuum coating process of the metal substrate and the aging-resistant anticorrosive film according to claim 1, wherein the transition layer comprises a gradient functional layer formed by metal elements M and reactive gas elements X, wherein the metal elements M are chromium, titanium or aluminum, the reactive gas elements X are nitrogen or oxygen, the atomic percentage content of the reactive gas elements X is in nonlinear incremental distribution in the thickness direction of the gradient functional layer, and the increasing rate of the reactive gas elements X is smaller in the area close to the metal substrate than in the central area of the gradient functional layer.
  8. 8. The vacuum coating process of a metal substrate and an aging-resistant corrosion-resistant film according to claim 1, wherein a probe pulse with a voltage amplitude of 10% of a plateau voltage value V p2 is applied to the metal substrate at a start point of each period of the composite pulse bias voltage, a feedback current rising rate induced by the probe pulse is calculated, and when the feedback current rising rate exceeds a preset impedance safety threshold, rising edge time of an overshoot stage is widened from 10 -7 s to 10 -6 s, and peak voltage V p1 is synchronously regulated.
  9. 9. The vacuum coating process of the metal substrate and the aging-resistant anticorrosive film according to claim 1, wherein the pulse frequency of the composite pulse bias is set to be 80kHz to 120kHz, the surface temperature of the metal substrate is maintained by utilizing the momentum thermal effect generated by the composite pulse bias in a negative pulse section, and the pulse frequency is set to be matched with the lattice relaxation frequency of the main layer material of the anticorrosive film.
  10. 10. The vacuum coating process of a metal substrate and an aging-resistant anticorrosive film according to claim 1, wherein the deposition is suspended for 30 seconds every 500nm thick film layer is deposited during the deposition of the main anticorrosive film layer, and a forward bias voltage having a magnitude of 10V to 30V is applied to the metal substrate during the suspended deposition.

Description

Vacuum coating process for metal substrate and aging-resistant anti-corrosion film Technical Field The invention belongs to the technical field of surface treatment of metal materials, and particularly relates to a vacuum coating process of a metal substrate and an aging-resistant anti-corrosion film. Background The current vacuum ion plating technology utilizes ions in plasmas to bombard a growth surface to promote film densification, generally applies pulse bias to a metal substrate to strengthen a momentum transfer process in vapor atomic deposition so as to construct a coating with specific protective performance, and aims at the extreme service environments such as offshore high-low temperature alternation, and the like, the improvement of bias amplitude can eliminate internal pores of the film layer to cause the film layer to accumulate residual compressive stress, so that a film forming tissue is in a high-energy compression state, and when periodic shear stress is caused by mismatch of thermal expansion coefficients between a substrate and the film layer, the residual internal stress is superposed with external thermal stress to cause surface layer cracking or interface peeling of the film layer. In the prior art, the integral deposition environment is optimized by improving a vacuum chamber liner structure or a temperature control device, for example, chinese patent publication No. CN114875381A discloses a vacuum coating cavity and vacuum coating equipment, and a separated cooling flow channel is arranged on the periphery of the vacuum cavity to reduce the surface temperature difference caused by uneven distribution of a cooling medium. Therefore, how to realize accurate intervention on the response state of the plasma sheath by remolding the energy input logic of the vacuum pulse bias and realizing self-release growth of stress on the premise of maintaining the high density of the film by utilizing a physical feedback mechanism becomes the technical problem to be solved by the invention. Disclosure of Invention The invention provides a vacuum coating process for a metal substrate and an aging-resistant anti-corrosion film, which comprises the following steps of: step S101, depositing a transition layer on the surface of a metal substrate in a vacuum chamber to establish an elastic modulus gradient; Step S102, depositing an anti-corrosion film main layer on the transition layer, and applying a composite pulse bias to the metal substrate through a bias power supply during deposition, wherein the composite pulse bias sequentially comprises a negative pulse section, a dead time section and a positive charge neutralization section in a single period; Step S103, collecting the displacement current flowing through the negative pulse segment rising edge of the metal substrate by using a processor, and calculating the slope k i of the displacement current, wherein k i =di/dt; Step S104, the processor determines that the zero crossing point of the first derivative of the slope k i is the peak time of the displacement current, and drives the bias power supply to generate an overshoot phase with the duration of 50ns to 200ns at the front edge of the negative pulse segment by taking the peak time as the trigger starting point of the overshoot phase; Step S105, bias voltage with peak voltage V p1 is applied to the metal substrate in the overshoot phase, wherein V p1 is set to be 1.5 to 1.8 times of the platform voltage value V p2 of the negative pulse section; And S106, switching to a platform voltage value V p2 after the overshoot stage is finished to maintain vapor atomic deposition, and applying positive voltage in a dead time period after the negative pulse period is turned off so as to lead out residual electron flow in the vacuum chamber and neutralize residual positive charges on the surface of the main layer of the anti-corrosion film. Preferably, in step S105, the processor determines the set value of the peak voltage V p1 according to the value of the slope k i, the peak voltage V p1 is mapped in positive correlation with the slope k i, the transient amplitude of the slope k i is used to characterize the charge adsorption barrier height of the surface of the main layer of the anti-corrosion film, and the energy output density of the overshoot stage is adjusted to match the ion momentum entering the surface of the metal substrate with the charge adsorption barrier height. Preferably, the third harmonic component characteristic value phi 3 of the displacement current is extracted in the deposition process of the main layer of the anti-corrosion film, and when the time evolution slope of the third harmonic component characteristic value phi 3 exceeds a preset change rate threshold value, the processor reduces the duty ratio of the composite pulse bias voltage so as to maintain the consistency of the crystal texture of the main layer of the anti-corrosion film. Preferably, in step S106, the discharge curr