TW201908531A - Cathodic electrolytic passivating treatment method for chromium-rich iron-based stainless steel elements forming a passivation film that is dense with corrosion resistant characteristic - Google Patents

Abstract

The present invention discloses a cathodic electrolytic passivating treatment method for chromium-rich iron-based stainless steel elements, which comprises utilizing an electrochemical electrolysis process on a surface of an iron-based stainless steel element containing 10% wt or more of chromium, using a product made of chromium-rich iron-based stainless raw material or chromium-rich iron-based stainless steel element as cathode, placing it in a trivalent chromium electrolytic solution, forming a passivation film by electrolysis on the surface under a working condition, wherein the passivation film is dense with corrosion resistant characteristic.

Description

 Chromium-based iron-based stainless steel element cathode electrolytic passivation treatment method    [Chinese]  

The invention discloses a method for electrochemically electrolyzing a surface of an iron-based stainless steel component rich in chromium or using a chromium-rich iron-based stainless steel component on the surface of an iron-based stainless steel component containing 10% by weight or more of chromium. The component is a cathode, which is placed in a trivalent chromium electrolyte. Under a working condition, a passivation film is formed on the surface thereof, and the passivation film is dense and has corrosion resistance.

The invention relates to a method for cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element, in particular to electrolytically form a highly corrosion-resistant passivation film on the surface thereof by cathodic electrolysis.

Chromium-rich iron-based stainless steel is a general term for iron alloys containing 10%-30% by weight of chromium, or industrially often referred to as stainless steel. Stainless steel is not as susceptible to corrosion and rust as ordinary steel. The main reason is that chromium in steel More than 12% chromium, on the surface, easy to form a complete and dense anti-oxidation and heat-resistant chromium oxide protective film with oxygen, so it can effectively insulate corrosion inward, and even have the ability to repair the chromium oxide protective film by itself, thus achieving Corrosion resistant function. When the chromium content is less than 10% by weight, only the oxide film can be formed on the surface instead of being oxidized. This steel is often called weathering steel.

Stainless steel is divided into five categories: fat iron, Worth iron, Ma Tian iron, precipitation hardened and duplex stainless steel. The Osbane iron type stainless steel is formed by adding chromium (content of about 16 to 25 wt%) and nickel (content of about 7 to 20 wt%) to the base material of iron. Austin's iron-type stainless steel has the best resistance to corrosion. This steel is commonly used in the 300 series in the world, accounting for 70% of the total use of stainless steel. The main elements of the ferrite-type stainless steel are iron and chromium, and the chromium content is about 12 to 30% by weight. It is often referred to as 400 series stainless steel in the world. Since the alloying element is less nickel, it is a cheaper stainless steel, and the corrosion resistance is also inferior to that of the Osbane iron type stainless steel, wherein the representative steel type is 430 stainless steel, and the chromium content is about 17% by weight. The granulated stainless steel has a chromium content of about 12 to 17% by weight, a carbon content of about 0.15 to 1.2% by weight, a 400 series and a 500 series stainless steel, a basic type of 410, and a chromium content of about 13% by weight. Ma Tian loose iron stainless steel has the advantages of high hardness, high strength and low price, but its ductility and corrosion resistance are poor. As for the precipitation hardening type stainless steel, based on 17-7 Aosta iron type stainless steel, a small amount of aluminum and copper alloy elements are added, which has excellent strength, corrosion resistance and machinability, and is suitable for high-precision components for use in aerospace industry and the like. Internationally, it is called 600 series stainless steel. The purpose of the duplex stainless steel is to overcome the shortcomings of the Worthfield iron-type stainless steel which is prone to stress corrosion in a chlorine-containing environment. This steel grade adjusted the chromium content to 24% by weight; the nickel content was adjusted to 7 wt% or more.

Stainless Passivation Treatment is a thin and transparent oxide layer on the surface of stainless steel. In particular, chromium oxide is the main oxide composition, which can corrode the environment and increase the corrosion resistance. The passivation process should conform to QQ. -P-35C, ASTM A967-99, ASTM A380-99 and other specifications.

In the QQ-P-35C specification, for most of the stainless steel (such as 300 series) and other Type VI passivation treatment methods, Type VI uses about 30% nitric acid under the catalysis of temperature for passivation treatment. For Type S140 series stainless steel or S303, S430, S347, S416, etc. using Type II passivation treatment, Type II uses 20% nitric acid and 2% sodium dichromate (potassium) at temperature. The passivation treatment method is carried out under the catalysis. Further, it is also possible to passivate citric acid to S303, 304, 321, 420, 430, and 440C. In practice, Type VI treatment causes rapid changes in nitric acid concentration due to reaction area and temperature. Passivation treatment is difficult to control, and it is often difficult to pass salt spray test and red blood salt test. Citric acid passivation can only be used with only a few stainless steel materials. limits. In the better production efficiency, controllability and quality of stainless steel passivation treatment, it is better to use chromic acid and sodium dichromate (potassium) (as described in Type II above), but chromic acid and sodium dichromate (potassium) The problem of hexavalent chromium (Cr ⁶⁺ ), hexavalent chromium is very toxic (about 100 times more than trivalent chromium), is a very serious carcinogen, produced by hexavalent chromium plating The wastewater and products can not be naturally degraded and eliminated in nature. When the concentration of chromium in the air is 0.15~0.3mg/m3, it will cause perforation of the diaphragm in the nose. When the concentration of chromium in drinking water is above 0.1mg/l, it will It causes vomiting, invades the intestines and kidneys, and accumulates in living organisms, and has a long incubation period. Governments around the world have enacted relevant laws and regulations on the surface treatment of hexavalent chromium, gradually restricting the use of hexavalent chromium and reducing its emissions. In many products, there is no requirement for hexavalent chromium (Cr ⁶⁺ ) to comply with RoHS regulations.

A metallic ceramic is a ceramic-like structure of a non-metallic element impregnated with a metal element, which has both metallic and ceramic properties, for example, some co-construction. The material has the hardness of ordinary ceramics and very good corrosion resistance, or both metallic luster and electrical conductivity, or the color of black oxide ceramics; Taiwan patents TW M498114, TW M501441, TW I456093, TW M487936 and Chinese patent CN201310239181.9 et al. disclose the use of electroplating method (commonly known as wet method) to form a metal oxide ceramic layer on a substrate. For example, a plating layer coated with a chrome-cobalt-cobalt composite coating layer has good corrosion resistance, but chrome oxide cobalt The coating of the composite coating is thick and soft, and it is dark black, which changes the appearance and is not easy to replace with existing mechanical products.

In view of the techniques disclosed in the foregoing prior art, there is a difficulty in implementing the passivation treatment for stainless steel, which is substantially difficult to implement. If the plating layer using the chrome-cobalt-cobalt composite coating is limited, the plating layer is thick and soft, and is deep. Black Ze has changed its appearance. Based on the future trend of the advancement of the machinery industry, it is necessary to develop newer technologies and propose effective and specific improvement plans. The invention is based on the aforementioned motive, and develops a cathode electrolytic passivation treatment method with high compactness and good corrosion resistance by using electrochemical technology, and is applied to a chromium-rich iron-based stainless steel component to improve the existing production bottleneck of the mechanical industry. To improve quality and productivity is an urgent need.

In view of the above problems of the prior art, the main object of the present invention is to provide a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element which is made of a component substrate and A layer of chromium oxide ceramic passivation layer is electroplated on the component substrate by electroplating. The material of the element substrate is selected from the alloy of any combination of iron, nickel, chromium, molybdenum, copper and aluminum, and the chromium content is 10% by weight or more. The chromium oxide ceramic passivation layer is formed on the element substrate by electroplating, consisting of chromium element, oxygen element, hydrogen element and phosphorus element, and is an amorphous phase structure; the composition includes at least the following: chromium (Cr And chromium oxide; wherein, the chromium oxide is chromium oxide (Cr ₂ O ₃ ), chromium trioxide (Cr ₃ O ₄ ) or the like.

The chrome oxide ceramic passivation layer is adhered to the surface of the element substrate by electroplating to form an amorphous phase chromia structure; the chrome oxide ceramic passivation layer is a wet electrochemical plating method, and a metal layer is plated on the component substrate. Metallic ceramic.

The chromium oxide ceramic passivation layer has a thickness of 0.1 to 0.5 μm, and may have a thickness of 0.5 to 1.0 μm or less for different applications; the chromium oxide ceramic passivation layer on the plating is white to grayish black, and the gray scale value thereof is (gray value scale) (L%) is between 50 and 87; where the grayscale value is the degree of black measurement, using 100 gray scales, the grayscale brightness from grayscale value 0 (black) to grayscale The value is 99 (white). The thickness of the chrome oxide ceramic passivation layer refers to the average thickness of the plating layer, and does not refer to the thickness of the specific measurement point, which is the same as the following, and will not be described again.

The chromium oxide ceramic passivation layer is composed of an amorphous phase structure composed of chromium element, oxygen element, hydrogen element and phosphorus element, and contains a high content ratio of chromium oxide (Cr ₂ O ₃ ) and chromium trioxide (Cr). ₃ O ₄ ), the chrome oxide ceramic passivation layer is ceramized, the plating layer is light gray tone, and its gray value scale (L%) is between 50 and 87.

Another main object of the present invention is to provide a method for electrochemically preparing a chromium-rich iron-based stainless steel component of a chromium oxide ceramic passivation layer, which solves the problem that the chromium-rich iron-based stainless steel component of the prior art is not weather resistant or It is difficult to passivate and other issues. The method comprises the following steps: S1: providing a chromium-rich iron-based stainless steel component, the substrate of the chromium-rich iron-based stainless steel component is an element substrate, and the material of the component substrate is selected from the group consisting of iron, nickel, chromium, An alloy of any combination of molybdenum, copper, and aluminum, and having a chromium content of 10% by weight or more; in practical applications, the element substrate is a chromium-rich iron-based stainless steel element to be plated or a part thereof; S2: Configuring a chromium oxide ceramic passivation plating solution comprising: a trivalent chromium salt, a complex agent, and a pH conditioning agent to form a trivalent chromium An aqueous solution of a plating solution; a trivalent chromium salt system provides sequestration of a trivalent chromium (Cr ⁺³ ) ion with a chelating agent, and the pH adjusting agent functions to stabilize the electrochemical characteristics of the chromium oxide ceramic passivation plating solution, and to generate an electrochemical The efficiency of electro-ion plating can be maintained during the reaction; wherein the trivalent chromium main salt can be selected from a trivalent chromium main salt of sulfuric acid, a trivalent chromium main salt of chloric acid, or a combination thereof; wherein the sulfuric acid is trivalent chromium The main salt system contains trivalent chromium (Cr ⁺³ ) and sulfur a compound formed by an acid group (SO4 ^-2 ) such as chromium sulfate (Cr ₂ (SO 4 ) ₃ ), ammonium chromium sulfate (NH ₄ Cr(SO ₄ ) ₂ .12H ₂ O), potassium chromium sulfate (CrK(SO ₄ ) ₂ ) .12H ₂ O); the chloric acid-based trivalent chromium main salt is a compound formed by trivalent chromium (Cr ⁺³ ) and one of chloride ion (Cl ⁻ ) and perchloric acid ion (ClO 4 ⁻ ) or a combination thereof. Such as chromium chloride (CrCl ₃ .6H ₂ O), chromium perchlorate (Cr (ClO ₄ ) ₃ ); the chelating agent comprises formic acid, formate, acetic acid, acetate, or a combination thereof, such as One or a combination of formic acid (HCOOH), ammonium formate (HCOONH ₄ ), sodium formate (HCOONa), acetic acid (CH3COOH), ammonium acetate (CH3COONH ₄ ), sodium acetate (CH3COONa), potassium acetate (CH3COOK), or a combination thereof; The invention comprises a combination of a borate and an ammonium salt, wherein the borate is selected from the group consisting of boric acid, sodium tetraborate (Na ₂ B ₄ O ₇ .10H ₂ O), sodium perborate (NaBO ₃ . _n H ₂ O) or a combination thereof; wherein the ammonium salt is selected from the group consisting of ammonium nitrate (NH ₄ NO ₃ ), ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), ammonium chloride (NH ₄ Cl), ammonium hydrogen sulfate (NH ₄ HSO ₄ ) Or a combination thereof; the conditioning agent comprises an amine or a guanamine, wherein the amine or guanamine is selected from ethylene diamine (C) ₂ H ₄ (NH ₂ ) ₂ ), dimethylamine ((CH ₃ ) ₂ NH), propylamine (C ₃ H ₉ N), acetamide (CH ₃ CONH ₂ ), acrylamide (CH ₂ =CHCONH ₂ And one or a combination of benzamidine (C ₆ H ₅ CONH ₂ ).

In order to electroplat the electroplated layer having the required function, the trivalent chromium main salt, the chelating agent and the pH adjuster should have a proper formulation ratio. Preferably, the trivalent chromium main salt in the chromium oxide ceramic passivation plating solution is used. The trivalent chromium (Cr ⁺³ ) molar concentration is 0.5 to 1.5 M, the molar concentration of the carbon element of the chelating agent is 0.5 to 0.8, and the molar concentration of boron and ammonium of the pH adjusting agent is 1.7. 4.5 to 1; S3: electroplating, the element substrate is placed as a cathode, and immersed in a chromium oxide ceramic passivation plating solution; electroplating is performed under a plating temperature condition and a current density condition for performing the electroplating And simultaneously stirring the chromium oxide ceramic passivation plating solution; after a predetermined time, forming the chromium oxide ceramic passivation layer on the surface of the conductive layer of the element substrate; the current density condition ranges from 30 A/dm ² to 60 A/ Between dm ² ; wherein the plating temperature condition is an operation set temperature of 45 ° C or less, and preferably the plating temperature condition is within ± 3 ° C of the set temperature.

S4: placing the plated chromium-rich iron-based stainless steel component in an atmosphere oven, which is vacuum, filled with dry air or filled with nitrogen gas, preferably to fill a nitrogen-rich gas, In order to facilitate the discharge of water. The atmosphere oven is baked at a dehydration temperature condition of 165 ° C or less to form a chromium oxide ceramic passivation layer on the element substrate; the formed chromium oxide ceramic passivation layer is amorphous The phase chromia structure is attached to all or a part of the surface of the element substrate, and the amorphous phase chromia structure comprises at least a chromium element, an oxygen element, a hydrogen element and a phosphorus element; the composition comprises at least the following: chromium (Cr), Chromium oxide; among them, chromium oxide is chromium oxide (Cr ₂ O ₃ ), chromium trioxide (Cr ₃ O ₄ ) or the like. .

Herein, the various chemicals listed in the above-mentioned trivalent chromium main salt, chelating agent, and pH adjuster are not limited, and are the same trivalent chromium salt, formate, acetate, borate, ammonium salt, It is within the scope of the invention for the amine or guanamine, other chemicals of the metal salt to be able to achieve the same function if properly combined.

In view of the above, a chromium-rich iron-based stainless steel element cathode electrolytic passivation treatment according to the present invention may have one or more of the following advantages:

(1) The cathode electrolytic electrolytic passivation treatment of the chromium-rich iron-based stainless steel element of the present invention can electrochemically form a dense chromium oxide by using a chromium-rich iron-based stainless steel element, which can replace the chemical immersion method of the prior art. Passivation treatment, etc.

(2) Chromium-rich iron-based stainless steel element cathode electrolytic passivation treatment can form a high oxygen content chromium oxide ceramic passivation layer on the surface of any stainless steel substrate component, and an oxide-ceramic amorphous structure ( Ceramic properties), and by the oxidization of the amorphous structure of the amorphous structure and corrosion resistance, the chromium-rich iron-based stainless steel component can increase the service life and meet the demand of corrosion-resistant mechanical components.

(3) The cathode electrolytic electrolytic passivation treatment of the chromium-rich iron-based stainless steel element of the invention adopts trivalent chromium plating, the plating solution and the waste water are trivalent chromium and do not contain hexavalent chromium, and the trivalent chromium is far less toxic than the six price. Chromium can reduce the burden on the environment, is a clean product and meets RoHS and REACH requirements.

For a better understanding of the features and technical aspects of the present invention, reference should be made to the accompanying drawings.

1‧‧‧Component substrate

2‧‧‧Surgical knives

21‧‧‧Mechanical components

22‧‧‧Water tap

3‧‧‧Chromium oxide ceramic passivation layer

1 is a schematic view showing a first group of embodiments of a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element of the present invention; and FIG. 2 is a second group of a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 3 is a schematic view showing a third embodiment of the cathodic electrolytic passivation treatment of the chromium-rich iron-based stainless steel element of the present invention.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the appended claims.

The cathodic electrolytic passivation treatment of the chromium-rich iron-based stainless steel element of the present invention is made by electrochemical plating, and is described as follows: S1: providing a chromium-rich iron-based stainless steel component, the chromium-rich iron-based stainless steel component The substrate is made of stainless steel and has a chromium content of 10% by weight or more; S2: a chromium oxide ceramic passivation plating solution comprising: a trivalent chromium salt, a chelating agent ( The complex agent and the pH conditioning agent are formulated into an aqueous solution of a trivalent chromium plating solution; for the non-limiting formulation and operating conditions, the formulation of the chromium oxide ceramic passivation plating solution of the present invention is as shown in Table 1.

The above concentration is expressed by M (mole/l) as the molar amount of the pure substance per liter of the chromium oxide ceramic passivation plating solution, which does not contain the mass of the impurity; the following are the same.

Wherein, the trivalent chromium main salt may be selected from a sulfuric acid trivalent chromium main salt, a chloric acid trivalent chromium main salt or a combination thereof; wherein the sulfuric acid trivalent chromium main salt system comprises trivalent chromium (Cr ⁺³⁾ ) a compound formed with sulfate (SO ₄ ^-2 ), such as chromium sulfate (Cr ₂ (SO ₄ ) ₃ ), ammonium ammonium sulfate (NH ₄ Cr(SO ₄ ) ₂ ‧12H ₂ O), potassium chromium sulfate (CrK) (SO ₄ ) ₂ ‧12H ₂ O); the chloric acid-based trivalent chromium main salt is one of trivalent chromium (Cr ⁺³ ) and chloride ion (Cl ⁻ ) and perchlorate ion (ClO 4 ⁻ ) or a compound formed by the combination, such as chromium chloride (CrCl ₃ .6H ₂ O), chromium perchlorate (Cr(ClO ₄ ) ₃ )

In order to electroplat the electroplated layer having the required function, the trivalent chromium main salt, the chelating agent and the pH adjuster should have a proper formulation ratio. Preferably, the trivalent chromium main salt in the chromium oxide ceramic passivation plating solution is used. The trivalent chromium (Cr ⁺³ ) molar concentration is 0.5 to 1.5 M, the molar concentration of the carbon element of the chelating agent is 0.5 to 0.8, and the molar concentration of boron and ammonium of the pH adjusting agent is 1.7. 4.5 to 1; S3: electroplating, the element substrate is placed as a cathode, and immersed in a chromium oxide ceramic passivation plating solution; electroplating is performed under a plating temperature condition and a current density condition, and the plating temperature condition is The operation set temperature is 45 ° C or less, and preferably the plating temperature condition is within ± 3 ° C of the set temperature.

S4: placing the plated chromium-rich iron-based stainless steel component in an atmosphere oven, which is vacuum, filled with dry air or filled with nitrogen gas, preferably to fill a nitrogen-rich gas, In order to facilitate the discharge of water. The atmosphere oven is baked at a dehydration temperature condition of 165 ° C or less to form a chromium oxide ceramic passivation layer on the element substrate.

The element substrate 1 used in the following examples of the present invention is a stainless steel having a chromium content of 10% by weight or more, which is one of the modes adopted in the examples, but is not limited thereto.

The chromium oxide ceramic passivation plating solution for forming the chromium oxide ceramic passivation layer 3 of the present invention comprises: an aqueous solution formed by a trivalent chromium main salt, a chelating agent, a pH adjuster and a tempering agent; For the chelation of the plating solution, the chelating agent of the present invention may be selected from formic acid (HCOOH), acetic acid (CH3COOH) or a salt thereof, such as formic acid (HCOOH), ammonium formate (HCOONH ₄ ), sodium formate (HCOONa), acetic acid (CH3COOH). One or a combination of ammonium acetate (CH3COONH ₄ ), sodium acetate (CH3COONa), potassium acetate (CH3COOK), or a combination thereof, increases the oxygen content of the chromium oxide ceramic passivation layer 3 when the relative concentration of the chelating agent is increased.

The pH adjuster of the chromium oxide ceramic passivation plating solution is used for adjusting the plating solution. Generally, a salt having a low degree of dissociation can be used, and the function of a buffer agent is also used. The commonly used additive is inorganic. Acid salts, ammonium salts, boric acid or salts thereof, such as borate selected from boric acid (H ₃ BO ₃ ), sodium tetraborate (Na ₂ B ₄ O ₇ .10H ₂ O), sodium perborate (NaBO ₃ .nH ₂ O) one or a combination thereof; wherein the ammonium salt is selected from ammonium nitrate (NH ₄ NO ₃ ), ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), ammonium chloride (NH ₄ Cl) And one or a combination of ammonium hydrogen sulfate (NH ₄ HSO ₄ ), when the relative concentration of the pH adjuster is increased, the corrosion resistance of the chromium oxide ceramic passivation layer 3 can be improved.

The following examples are various examples of the cathodic electrolytic passivation treatment of the chromium-rich iron-based stainless steel element of the present invention, but the actual aspect is not limited thereto.

<First Group of Embodiments>

1 is a schematic view of a first set of embodiments of the present invention. The component substrate 1 of the scalpel 2 is various stainless steels. The degreasing solution, the pickling solution and the chromium oxide ceramic passivation plating solution of the electroplating process are prepared; the purpose of the degreasing solution is to remove the grease on the surface of the component substrate 1, and an organic solvent, a neutral degreasing agent, an alkaline degreasing agent or an acid may be used. a degreasing agent; the purpose of the pickling solution is to remove the oxide on the surface of the element substrate 1 and activate the surface of the element substrate 1, and dilute sulfuric acid, dilute hydrochloric acid, dilute nitric acid, dilute phosphoric acid or a mixed acid solution thereof may be used; This shows that for different surface conditions of the component substrate 1, degreasing and pickling are not necessary processing procedures.

Next, a chromium oxide ceramic passivation layer 3 is formed on all or a part of the surface of the element substrate 1 by electroplating to form a chromium-rich iron-based stainless steel element 2. Since the chromium oxide ceramic passivation plating solution is used, a chromium oxide-based chromium oxide ceramic passivation layer 3 can be formed under appropriate operating conditions; for electroless plating of the chromium oxide ceramic passivation layer 3 before electroplating Then, a portion of the non-electroplated chrome oxide ceramic passivation layer 3 may be shielded first by using a tool such as anti-painting, anti-plating, and anti-plating. In this embodiment, after analysis, the formed chromium oxide ceramic passivation layer 3 is formed by electroplating to form an amorphous phase chromia structure, which is attached to the surface of the element substrate 1, and the chromium oxide ceramic passivation layer 3 is mainly composed of It consists of chromium, oxygen, and phosphorus to form an amorphous phase chromia structure. As shown in Fig. 2, it is a schematic diagram of the cathodic electrolytic passivation treatment 1 of the chromium-rich iron-based stainless steel element of the present embodiment. In the chromium oxide ceramic passivation plating solution of the present embodiment, the formulation of Table 1 is used, but not This is limited.

<Second Group of Embodiments>

Please refer to FIG. 2, which is a schematic view of a second set of embodiments of the present invention. The component substrate 1 of the aerospace mechanical component 21 is various stainless steels. The chromium oxide ceramic passivation plating solution in the examples of the present embodiment uses the formulation of Table 1, and will not be repeatedly listed here.

The chromium-rich iron-based stainless steel element 1 of the chrome oxide ceramic passivation layer 3 of the present embodiment is attached to the element substrate 1 by electroplating to form a chromium oxide ceramic passivation layer 3, and is made into aerospace mechanical component. 21, the formed chromium oxide ceramic passivation layer 3 is formed by electroplating to form an amorphous phase chromia structure, attached to the surface of the element substrate 1, and the chromium oxide ceramic passivation layer 3 consists mainly of chromium, oxygen, and phosphorus. Elements such as elements.

<Third Group Embodiment>

As shown in Fig. 3, it is a schematic diagram of the cathodic electrolytic passivation treatment 1 of the chromium-rich iron-based stainless steel element of the present embodiment, which is based on the bathroom faucet 22, and the chromium oxide ceramic passivation plating system in the present embodiment. Use the formula of Table 1 and it will not be repeated here.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

Claims (7)

A method for manufacturing a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel component for coating a chromium oxide ceramic passivation layer on a component substrate of a chromium-rich iron-based stainless steel component, comprising the steps of: providing a a chromium-rich iron-based stainless steel component, the substrate of the chromium-rich iron-based stainless steel component is an element substrate, and the material of the component substrate is selected from any combination of iron, nickel, chromium, molybdenum, copper, and aluminum. Alloy having a chromium content of 10% by weight or more; using the chromium-rich iron-based stainless steel element as a cathode and immersing in a chromium oxide ceramic passivation plating solution; electroplating at a plating temperature condition and a current density Electroplating is performed to form a chromium oxide ceramic passivation layer on the element substrate; wherein the chromium oxide ceramic passivation plating solution comprises at least: a trivalent chromium main salt, a chelating agent and a pH adjusting agent. An aqueous solution; wherein the trivalent chromium main salt is one of or a combination of a monosulfate trivalent chromium main salt or a monochloro acid trivalent chromium main salt; wherein the sulfuric acid trivalent chromium main salt system comprises trivalent chromium (Cr ⁺³⁾ and sulfur (SO ₄ ^-2) compound formed roots, the trivalent chromium-based acid salt-based master comprising trivalent chromium (Cr ⁺³⁾ and chloride ions (Cl ^-), perchlorate ion (ClO ₄ ^-) of both a compound formed by one or a combination thereof; wherein the pH adjuster comprises a combination of a borate and an ammonium salt; wherein the trivalent chromium (Cr ⁺³ ) of the trivalent chromium main salt in the chromium oxide ceramic passivation plating solution The concentration of the ear is 0.5 to 1.5 M, the molar concentration of the carbon element of the chelating agent is 0.5 to 0.8, and the molar concentration of boron and ammonium of the pH adjusting agent is 1.7 to 4.5 to 1; wherein the plating temperature is The condition is 45 ° C or less, and the current density condition is 30 to 60 A/dm ² ; the chromium oxide ceramic passivation layer is composed of chromium element, oxygen element, hydrogen element and phosphorus element, and is an amorphous phase chromium oxide structure adhesion. All or part of the surface of the component substrate.  The method for manufacturing a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element according to claim 1 is further placed in an atmosphere oven after electroplating to be baked at a dehydration temperature condition; wherein the atmosphere The oven is vacuum, filled with dry air or filled with nitrogen; wherein the dehydration temperature condition is 165 ° C or less.   The method for manufacturing a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element according to claim 1, wherein the chromium oxide ceramic passivation layer component comprises at least the following: chromium (Cr), chromium oxide; wherein, oxidation Chromium is chromium oxide (Cr ₂ O ₃ ) or chromium trioxide (Cr ₃ O ₄ ).  The method for producing a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element according to claim 1, wherein the chelating agent comprises one of formic acid, formate, acetic acid, acetate, or a combination thereof.   The method for producing a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element according to claim 1, wherein the borate is selected from the group consisting of boric acid (HBO ₃ ) and sodium tetraborate (Na ₂ B ₄ O _{7 )} . 10H ₂ O), sodium perborate (NaBO ₃ .nH ₂ O) or a combination thereof; wherein the ammonium salt is selected from ammonium nitrate (NH ₄ NO ₃ ), ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), One or a combination of ammonium chloride (NH ₄ Cl), ammonium hydrogen sulfate (NH ₄ HSO ₄ ).  The method for producing a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element according to claim 1, wherein the chromium oxide ceramic passivation layer has a thickness of 0.1 to 1.0 μm.    The method for producing a cathodic electrolytic passivation treatment of a chromium-rich iron-based stainless steel element according to claim 1, wherein the chromium oxide ceramic passivation layer has a gray value scale (L%) of 50 to Between 87.