Chemical conversion coatings--Rinsed and non-rinsed chromate conversion coatings on aluminium and aluminium alloys
Some standard content:
GB/T17460—1998
This standard is equivalent to 1S010546, 1993% chemical conversion film on aluminum and aluminum alloy with rinsed and unrinsed chromate conversion film. Compared with 1S)10546, there are the following changes:
1. "Model" is written in accordance with the provisions of the national standard. 2. Some entries are added in the "Definition" section to make the content in the standard accurate and easy to understand. 3. "Substrate material" is added to "Surface preparation" because the substrate material has a small impact on the film layer but has a great impact on the product appearance.
4. "Electrical insulation performance" in "Film requirements" is cancelled. Because this part does not contain specific technical indicators, this part and other related contents are written into "Characteristics of chromate film". , and the "Film Layer Requirements" in the "Film Layer Requirements" is listed as the 9th. Appendix A and Appendix B of this standard are suggested appendices. This standard was proposed by the State Bureau of Machinery Industry. This standard is organized by the National Technical Committee for Standardization of Metal and Non-metallic Coverings. The responsible drafting unit of this standard is Wuhan Institute of Material Protection. The participating drafting units of this standard are Guangdong Xingfa Aluminum Profile Group Co., Ltd. and Dazhi Youbao Metal Company Color-coated Aluminum Profiles. The main drafters of the final standard are Chen Su, Chen Hongzai, Miao Xinchu, Liu Shiming, Yang Jiwen, Shen Wenying, and Chao Yongyang. GB/T17460—1998
ISO (International Organization for Standardization) is a worldwide union of national standards bodies (IS) member bodies. The work of formulating international standards is generally carried out through IS technical committees. If the member bodies are interested in the topics determined by a technical committee, they can join the committee. ISO is a governmental and non-governmental international organization affiliated with ISO! , and also participate in the work of: other departments of electrotechnical standardization work closely with the International Electrotechnical Commission (IEC)
The international standard draft adopted by the technical committee is first sent to the member bodies for voting. At least 75% of the voting member bodies must approve it before it is published as an international standard.
International Standard IS010546 [S0/TC:07 Metals and Other Components Technical Committee S8 Chemical Conversion Coatings Subcommittee Prepared Annex A and Annex 13 of this International Standard Appendix 1 Scope
National Standard of the People's Republic of China
Chemical Conversion Coatings- Rinsed and Non-rinsed Chromate Conversion Coatings on Aluminium and Aluminium Alloys
Chemical Conversion Coatings- Rinsed and Non-rinsed Chromate Conversion Coatings on Aluminium Into Aluminium Alloys
Chemical Conversion Coatings- Rinsed and Non-rinsed Chromate Conversion Coatings on Aluminium Into Aluminium Alloys This standard specifies the characteristics, customary methods, technical requirements, sampling, classification and film setting of rinsed and unrinsed chromate conversion molds on lead and aluminum alloys. This standard is applicable to the surface chemical conversion treatment of extruded aluminum products, aluminum castings and aluminum coils (strips, wires), etc. 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid: All standards are subject to revision. Parties using this standard should explore the feasibility of using the latest versions of the following standards: G/T 2423.3-1993 Basic environmental test procedures for electrical products Test Ca: Steady-state damp heat or test method (eqv ILC 68-2-3:1969)
(.B/3138-1995 Terminology for processes related to metal plating and chemical treatment (ner IS0 2079:81.nen 150) 2080:81) G13/r 9286--1988
Scratch test for paint and varnish film (eVIS02409:1972) GB/T9792-1988 Conversion die for metal material 1 Unit area 1 Film layer after reduction of fixed weight (eyy 1S0 3892:1980)
GB/10125-1997 Artificial atmosphere corrosion test Salt spray test (V1S09227:1990) GBT 12609-1590 Electrodeposited metal coating and inspection procedures for finishing (eqV1S04519: 1980) 3 Definitions
In addition to the terms and definitions used in GB/T3138, this standard also uses the following definitions: 3.1 Chromate conversion coating
The process of placing the workpiece in a solution containing chromium to form a very thin passive chromium-containing protective film on the surface 3.2 Chromate conversion coating Chromite conversion coating The passive chromium-containing protective film generated by the workpiece after the chromate conversion treatment is referred to as chromate film. In this standard, unless otherwise specified, chromate film should be the sum of phosphate-free chromate film and chromate phosphate film. 3.3 Rinse chromate coating Rinse chromate coating before drying in water. This type of film is generally used for extruded lead products, cast aluminum and coiled strips, shallow materials). 3.4 Non-rinsed chromate coating Chromate coating is a chromate coating that is directly dried without water rinsing. This special type of film is usually used for aluminum sheet coils that need to be immediately washed or attached with other coatings. It is also called coil film. Approved by the State Administration of Quality and Technical Supervision on August 12, 1998 and implemented on July 1, 1999
4 Characteristics of chromate film
GB/T 17460—1998
Chromate film has an anti-corrosion effect on the base material and can also be used as the base layer of other coatings. The green chromate phosphate film can be stored for a long time. After 1 to 2 months at room temperature, the best corrosion resistance can be obtained. The contact resistance of chromate conversion film is lower than that of cathode conversion film. It increases with the increase of film mass per unit area. For colorless, light yellow or light green chromate cushion layer, the film thickness is small, the contact resistance value is low, and the contact resistance value increases very little with the increase of film mass per unit area. For dark brown, dark yellow or dark green film, the film thickness is large, the contact resistance value is large, and the contact resistance value increases greatly with the increase of film mass per unit area.
5 Chromate film formation method
5.1 Surface preparation
5-71 Base material
There should be no visible defects such as bubbles, holes, grooves, non-metallic impurities, small pits, and pores on the base material. Otherwise it will damage the appearance and performance of the chromate film.
5.1.2 Surface requirements and pretreatment
The surface of the workpiece to be treated should be clean, basically free of oxidation scars and any other contaminants such as metal chips, grinding dust, oil, grease, lubricants, and acrylic. Therefore, the workpiece must be cleaned and acid-etched if necessary before chromate conversion treatment. The bottom surface should be completely free of all unreacted reactive materials before rinsing and chromate conversion treatment. 5.2 Chromate conversion treatment
The required sequence of chromate conversion treatment depends on the surface state of the workpiece to be treated, the type of aluminum alloy used, and the external requirements of the workpiece. Appendix B (Recommended) Figure BI shows a selection of recommended treatment procedures. 5.3 Chromate conversion treatment instructions
Non-aluminum metal materials shall not be treated in a chromate conversion treatment solution to avoid the original loss of aluminum alloy materials. Chromate conversion treatment is usually achieved by such techniques as stirring (without stirring), spraying, rolling or deep wiping. These techniques must be used in accordance with the operating procedures of the chromate conversion treatment process used. Chromate conversion treatment is usually a temporary, but the cost and quality of the conversion film are not guaranteed! The trivalent chromium salt and other components can have various effects on the appearance and hardness of the film. Therefore, the composition of the chromate conversion treatment solution is also affected by the pH value of the solution, temperature, treatment time, solution agitation, and the characteristics and surface condition of the alloy being treated.
The chromate conversion film must be rinsed continuously. If the acid conversion film is used as a subsequent layer, rinse in water with a conductivity of less than 100μs/cm. If the chromate conversion film is rinsed with hot water, the rinsing time must be as short as possible to prevent hexavalent decomposition. The drying temperature (measured product) should not exceed 65°C for acid films (without phosphate) and 8°C for chromate films to avoid excessive dehydration. The drying of chromate films without rinsing should be carried out according to the manufacturer's regulations. If the chromate conversion film is a pre-coating layer, the drying before coating should be carried out in two steps without skipping the pre-coating and the second drying at 0°C in order to obtain the best adhesion. 6 Technical requirements for film layers
6.1. Description
The chromate conversion film hardens with the gradual dehydration and aging. Therefore, do not touch or touch it within 24 hours after treatment. Be careful. All tests (including corrosion test) should be carried out after 21 hours. 6.2 Properties
GB/T 17460—1998
The base layer should adhere and not powder. There is no effective method to measure the adhesion of chromate conversion film on lead. Therefore, the adhesion of the chromate film can be estimated by measuring the adhesion of the second layer of organic film coated on the chromate film. According to regulations, the chromate conversion film should pass the organic film adhesion test specified in GB/T 9286. 6.3 Corrosion resistance If the neutral salt spray test specified in GB/10123 is carried out, after three separate test pieces (see Section 1) are exposed for the time listed in Table 1, the total number of isolated points or pits visible to the naked eye shall not exceed 8, and the diameter of each point or pit shall not exceed 1 mm. The number of isolated points or pits on the surface of each single specimen shall not exceed 10, and the diameter of the points or pits shall not be greater than 1 hour. Points within 10 mm from the edge of the test bar are not counted. The test force method specified in CB/T2423.3 can also be used. Table 1: For corrosion-resistant parts, categories are... Silver alloys that cannot be heat treated, alloys that can be heat treated, and nominal silicon-containing alloys, nominal calcium-containing alloys. 1) The categories are consistent with traditional practices and do not reflect the level of resistance. The extended exposure time is shown for chromium-coated surfaces without additional films. This test does not provide performance data for surfaces covered with organic films. 2) The exposure time reflects the relative resistance of various types of alloys, but there is no direct relationship between the time of exposure in the neutral salt drop test and the performance in use.
6.4 Unit volume film mass
The unit area film mass of the conversion film surface shall be in accordance with the values listed in Table 2 and measured by the method specified in GB/T972. A larger film mass is not necessarily better, which is especially the case when it is used as a base layer. 7 Sampling and test pieces
Unless otherwise specified, the batch sampling method of GB/T126G9 shall be used for sampling. The test pieces shall have the same alloy composition and surface state as the one they represent. The size shall be 1m×1m. 8 Classification
The finishing film is divided into 6 categories. The most important characteristics are shown in Table 2. Using chromate conversion treatment (without phosphate), various types of films (13 categories) for different purposes can be obtained. For example, the films can be roughly divided into three regions in terms of film thickness: brown films with the best corrosion resistance, yellow medium-order films suitable for use as organic film base layers, or colorless films with the best electrical conductivity. Yellow film color ranges from yellow to rainbow yellow: using chromate-phosphate conversion treatment. The color of the obtained film layer (4~~6 types) ranges from green to rainbow green. It is difficult to ensure that the color of the obtained phosphate conversion film is consistent with the expectation. The dyeing method can be used to solve this problem. However, only the chromate film with a film layer greater than 1/m can be dyed. Dyeing has little effect on the corrosion resistance of the obtained layer. The color and uniformity of the film layer vary with the type of alloy and the surface condition of the workpiece. There are differences in color on the surface and color depth between regions. Normal category
Light green
GB/T 17460--1998
Table 2 Classification of chromate film
Film quality per unit area
0. 2~-1. 3
0. 05 ~-3. 2
0. 05 ~-0. 2
Corrosion protection
Best corrosion resistance, generally used as the final finishing Medium resistance, used as a paint primer and for bonding with rubber, weak insulation performance Medium corrosion resistance Used as a primer and for bonding with rubber Note: The category can be determined according to tradition and has nothing to do with the degree of corrosion resistance. The quality of the film layer shall be tested in accordance with the provisions of B/S52. 9 Film identification
The presence of chromium in the conversion film can be determined by observation and the test described in Appendix A (indicative appendix). 9.1 Chromate film (excluding phosphates 1-3) is identified by the test method described in A2 and A3. If the film layer contains phosphate and chromium but does not contain phosphate, the film layer can be identified as a chromate film (excluding phosphate).
9.2 Chromate-phosphate film (4-6)
It is identified by the test method described in A2 and A3. If the film layer contains phosphate and chromium but does not contain zinc, the film layer can be identified as a chromate-phosphate film. In this test, whether the film layer contains zinc is determined to distinguish the chromate-phosphate film from the anodic ammonium film and the zinc-based phosphate film.
A1 Reagent
GB/T 17460—1998
Appendix A
(Appendix to benzene extraction)
Qualitative test of film layer composition
During the test, analytical reagents and distilled water or deionized water are allowed to be used. A1.15% (mass ratio) sodium hydroxide (NaOH) solution. A1.220% (mass ratio) hydrogen peroxide (H2O2) solution. A1.330% (mass ratio) hydrogen peroxide (H2O2) solution. A1.410% (mass ratio) acetic acid (CHCOOH) solution. A1.5 10% (mass ratio) lead nitrate [Ph(NO.>, two solutions. A1.6 65 (mass ratio> concentrated nitric acid (HNO.) solution (p: 1.4g/cm2)). A1.7 38% (mass ratio) nitric acid (HN.) solution can be prepared by mixing 1 liter of concentrated nitric acid A1.6) with a small amount of vanadate in a volume ratio of 1:7. A1.B Lead acid forging reagent
88.5g ammonium vanadate [(NH4)Mo.024H0], add 34ml of ammonia solution containing 25% (m/m) NH4 and 240g nitrate money A1.9). Mix and dissolve in water, shake with a spoon. Dilute to 1L, A1.9 ammonium nitrate (NIINO.),
A1.1025 (mass ratio) hydrochloric acid (HC) solution A1.TT 5% (mass ratio) potassium vanadate LK, Fe(CN) solution. 41.12 25% (mass ratio) sulfuric acid (SO4) solution A1.13 0.5% (mass ratio) phenolic acid (C11.02) solution. The solvent is ethanol A2 Determination of chromium
Add 5 ml of hydrogen peroxide solution (A1.3) to 50 ml of sodium hydroxide solution (A1.1). Treat a sample with a surface area of about 300 cm2. Pour the solution at 50-60 °C over the sample without repeating until the film is completely removed. Pour the resulting solution into a bowl and boil until the peroxide is completely decomposed (about 5-6 min), cool it, and precipitate it with lead nitrate solution (A1.5). If there is a yellow precipitate, it means that hexavalent chromium is present. The minimum amount of total chromium that can be measured by this method is about 100 g per square meter of surface area. A3 Determination of phosphate
In order to determine whether there is phosphate in the chromate film, the surface area of the sample to be tested is about 100 cm2. Treat the sample with 100 ml of sodium hydroxide solution (A1.1) at 80-90°C until the film is completely dissolved, or at least until the film is clearly visible on the surface. Filter the resulting solution, take 25 ml of the filtrate and hydrate it with nitric acid solution.3. The test method specified in Table 1 is for corrosion resistant parts. Category ... Silver alloys that cannot be heat treated. Alloys that can be heat treated. Cast alloys with nominal silicon content. Nominal calcium alloys with nominal calcium content. 1) The category is consistent with the traditional practice and does not reflect the level of resistance. The extended exposure time is shown for chromium-coated surfaces without additional films. This test does not provide performance data for surfaces covered with organic films. 2) The exposure time reflects the relative resistance of various types of alloys, but there is no direct relationship between the performance in use and the time lost in the neutral salt drop test.
6.4 Unit volume film mass
The unit area film mass of the conversion film surface shall be in accordance with the values listed in Table 2 and measured by the method specified in GB/T972. A larger film mass is not necessarily better, which is especially the case when it is used as a base layer. 7 Sampling and test pieces
Unless otherwise specified, the batch sampling method of GB/T126G9 shall be used for sampling. The test pieces shall have the same alloy composition and surface state as the one they represent. The size shall be 1m×1m. 8 Classification
The finishing film is divided into 6 categories. The most important characteristics are shown in Table 2. Using chromate conversion treatment (without phosphate), various types of films (13 categories) for different purposes can be obtained. For example, the films can be roughly divided into three regions in terms of film thickness: brown films with the best corrosion resistance, yellow medium-order films suitable for use as organic film base layers, or colorless films with the best electrical conductivity. Yellow film color ranges from yellow to rainbow yellow: using chromate-phosphate conversion treatment. The color of the obtained film layer (4~~6 types) ranges from green to rainbow green. It is difficult to ensure that the color of the obtained phosphate conversion film is consistent with the expectation. The dyeing method can be used to solve this problem. However, only the chromate film with a film layer greater than 1/m can be dyed. Dyeing has little effect on the corrosion resistance of the obtained layer. The color and uniformity of the film layer vary with the type of alloy and the surface condition of the workpiece. There are differences in color on the surface and color depth between regions. Normal category
Light green
GB/T 17460--1998
Table 2 Classification of chromate film
Film quality per unit area
0. 2~-1. 3
0. 05 ~-3. 2
0. 05 ~-0. 2
Corrosion protection
Best corrosion resistance, generally used as the final finishing Medium resistance, used as a paint primer and for bonding with rubber, weak insulation performance Medium corrosion resistance Used as a primer and for bonding with rubber Note: The category can be determined according to tradition and has nothing to do with the degree of corrosion resistance. The quality of the film layer shall be tested in accordance with the provisions of B/S52. 9 Film identification
The presence of chromium in the conversion film can be determined by observation and the test described in Appendix A (indicative appendix). 9.1 Chromate film (excluding phosphates 1-3) is identified by the test method described in A2 and A3. If the film layer contains phosphate and chromium but does not contain phosphate, the film layer can be identified as a chromate film (excluding phosphate).
9.2 Chromate-phosphate film (4-6)
It is identified by the test method described in A2 and A3. If the film layer contains phosphate and chromium but does not contain zinc, the film layer can be identified as a chromate-phosphate film. In this test, whether the film layer contains zinc is determined to distinguish the chromate-phosphate film from the anodic ammonium film and the zinc-based phosphate film.
A1 Reagent
GB/T 17460—1998
Appendix A
(Appendix to benzene extraction)
Qualitative test of film layer composition
During the test, analytical reagents and distilled water or deionized water are allowed to be used. A1.15% (mass ratio) sodium hydroxide (NaOH) solution. A1.220% (mass ratio) hydrogen peroxide (H2O2) solution. A1.330% (mass ratio) hydrogen peroxide (H2O2) solution. A1.410% (mass ratio) acetic acid (CHCOOH) solution. A1.5 10% (mass ratio) lead nitrate [Ph(NO.>, two solutions. A1.6 65 (mass ratio> concentrated nitric acid (HNO.) solution (p: 1.4g/cm2)). A1.7 38% (mass ratio) nitric acid (HN.) solution can be prepared by mixing 1 liter of concentrated nitric acid A1.6) with a small amount of vanadate in a volume ratio of 1:7. A1.B Lead acid forging reagent
88.5g ammonium vanadate [(NH4)Mo.024H0], add 34ml of ammonia solution containing 25% (m/m) NH4 and 240g nitrate money A1.9). Mix and dissolve in water, shake with a spoon. Dilute to 1L, A1.9 ammonium nitrate (NIINO.),
A1.1025 (mass ratio) hydrochloric acid (HC) solution A1.TT 5% (mass ratio) potassium vanadate LK, Fe(CN) solution. 41.12 25% (mass ratio) sulfuric acid (SO4) solution A1.13 0.5% (mass ratio) phenolic acid (C11.02) solution. The solvent is ethanol A2 Determination of chromium
Add 5 ml of hydrogen peroxide solution (A1.3) to 50 ml of sodium hydroxide solution (A1.1). Treat a sample with a surface area of about 300 cm2. Pour the solution at 50-60 °C over the sample without repeating until the film is completely removed. Pour the resulting solution into a bowl and boil until the peroxide is completely decomposed (about 5-6 min), cool it, and precipitate it with lead nitrate solution (A1.5). If there is a yellow precipitate, it means that hexavalent chromium is present. The minimum amount of total chromium that can be measured by this method is about 100 g per square meter of surface area. A3 Determination of phosphate
In order to determine whether there is phosphate in the chromate film, the surface area of the sample to be tested is about 100 cm2. Treat the sample with 100 ml of sodium hydroxide solution (A1.1) at 80-90°C until the film is completely dissolved, or at least until the film is clearly visible on the surface. Filter the resulting solution, take 25 ml of the filtrate and hydrate it with nitric acid solution.3. The test method specified in Table 1 is for corrosion resistant parts. Category ... Silver alloys that cannot be heat treated. Alloys that can be heat treated. Cast alloys with nominal silicon content. Nominal calcium alloys with nominal calcium content. 1) The category is consistent with the traditional practice and does not reflect the level of resistance. The extended exposure time is shown for chromium-coated surfaces without additional films. This test does not provide performance data for surfaces covered with organic films. 2) The exposure time reflects the relative resistance of various types of alloys, but there is no direct relationship between the performance in use and the time lost in the neutral salt drop test.
6.4 Unit volume film mass
The unit area film mass of the conversion film surface shall be in accordance with the values listed in Table 2 and measured by the method specified in GB/T972. A larger film mass is not necessarily better, which is especially the case when it is used as a base layer. 7 Sampling and test pieces
Unless otherwise specified, the batch sampling method of GB/T126G9 shall be used for sampling. The test pieces shall have the same alloy composition and surface state as the one they represent. The size shall be 1m×1m. 8 Classification
The finishing film is divided into 6 categories. The most important characteristics are shown in Table 2. Using chromate conversion treatment (without phosphate), various types of films (13 categories) for different purposes can be obtained. For example, the films can be roughly divided into three regions in terms of film thickness: brown films with the best corrosion resistance, yellow medium-order films suitable for use as organic film base layers, or colorless films with the best electrical conductivity. Yellow film color ranges from yellow to rainbow yellow: using chromate-phosphate conversion treatment. The color of the obtained film layer (4~~6 types) ranges from green to rainbow green. It is difficult to ensure that the color of the obtained phosphate conversion film is consistent with the expectation. The dyeing method can be used to solve this problem. However, only the chromate film with a film layer greater than 1/m can be dyed. Dyeing has little effect on the corrosion resistance of the obtained layer. The color and uniformity of the film layer vary with the type of alloy and the surface condition of the workpiece. There are differences in color on the surface and color depth between regions. Normal category
Light green
GB/T 17460--1998
Table 2 Classification of chromate film
Film quality per unit area
0. 2~-1. 3
0. 05 ~-3. 2
0. 05 ~-0. 2
Corrosion protection
Best corrosion resistance, generally used as the final finishing Medium resistance, used as a paint primer and for bonding with rubber, weak insulation performance Medium corrosion resistance Used as a primer and for bonding with rubber Note: The category can be determined according to tradition and has nothing to do with the degree of corrosion resistance. The quality of the film layer shall be tested in accordance with the provisions of B/S52. 9 Film identification
The presence of chromium in the conversion film can be determined by observation and the test described in Appendix A (indicative appendix). 9.1 Chromate film (excluding phosphates 1-3) is identified by the test method described in A2 and A3. If the film layer contains phosphate and chromium but does not contain phosphate, the film layer can be identified as a chromate film (excluding phosphate).
9.2 Chromate-phosphate film (4-6)
It is identified by the test method described in A2 and A3. If the film layer contains phosphate and chromium but does not contain zinc, the film layer can be identified as a chromate-phosphate film. In this test, whether the film layer contains zinc is determined to distinguish the chromate-phosphate film from the anodic ammonium film and the zinc-based phosphate film.
A1 Reagent
GB/T 17460—1998
Appendix A
(Appendix to benzene extraction)
Qualitative test of film layer composition
During the test, analytical reagents and distilled water or deionized water are allowed to be used. A1.15% (mass ratio) sodium hydroxide (NaOH) solution. A1.220% (mass ratio) hydrogen peroxide (H2O2) solution. A1.330% (mass ratio) hydrogen peroxide (H2O2) solution. A1.410% (mass ratio) acetic acid (CHCOOH) solution. A1.5 10% (mass ratio) lead nitrate [Ph(NO.>, two solutions. A1.6 65 (mass ratio> concentrated nitric acid (HNO.) solution (p: 1.4g/cm2)). A1.7 38% (mass ratio) nitric acid (HN.) solution can be prepared by mixing 1 liter of concentrated nitric acid A1.6) with a small amount of vanadate in a volume ratio of 1:7. A1.B Lead acid forging reagent
88.5g ammonium vanadate [(NH4)Mo.024H0], add 34ml of ammonia solution containing 25% (m/m) NH4 and 240g nitrate money A1.9). Mix and dissolve in water, shake with a spoon. Dilute to 1L, A1.9 ammonium nitrate (NIINO.),
A1.1025 (mass ratio) hydrochloric acid (HC) solution A1.TT 5% (mass ratio) potassium vanadate LK, Fe(CN) solution. 41.12 25% (mass ratio) sulfuric acid (SO4) solution A1.13 0.5% (mass ratio) phenolic acid (C11.02) solution. The solvent is ethanol A2 Determination of chromium
Add 5 ml of hydrogen peroxide solution (A1.3) to 50 ml of sodium hydroxide solution (A1.1). Treat a sample with a surface area of about 300 cm2. Pour the solution at 50-60 °C over the sample without repeating until the film is completely removed. Pour the resulting solution into a bowl and boil until the peroxide is completely decomposed (about 5-6 min), cool it, and precipitate it with lead nitrate solution (A1.5). If there is a yellow precipitate, it means that hexavalent chromium is present. The minimum amount of total chromium that can be measured by this method is about 100 g per square meter of surface area. A3 Determination of phosphate
In order to determine whether there is phosphate in the chromate film, the surface area of the sample to be tested is about 100 cm2. Treat the sample with 100 ml of sodium hydroxide solution (A1.1) at 80-90°C until the film is completely dissolved, or at least until the film is clearly visible on the surface. Filter the resulting solution, take 25 ml of the filtrate and hydrate it with nitric acid solution.To distinguish the chromic acid trace-phosphate film from the anodic ammonium film and the zinc phosphate film. bzxZ.net
A1 Reagent
GB/T 17460—1998
Appendix A
(Appendix to the extraction of benzene)
Qualitative test of film layer composition
During the test, analytical reagents and distilled water or deionized water are allowed to be used. A1.15% (mass ratio) sodium hydroxide (NaOH) solution. A1.220% (mass ratio) hydrogen peroxide (H2O2) solution. A1.330% (mass ratio) hydrogen peroxide (H2O2) solution. A1.410% (mass ratio) acetic acid (CHCOOH) solution. A1.5 10% (mass ratio) lead nitrate [Ph(NO.>, two solutions. A1.6 65 (mass ratio> concentrated nitric acid (HNO.) solution (p: 1.4g/cm2)). A1.7 38% (mass ratio) nitric acid (HN.) solution can be prepared by mixing 1 liter of concentrated nitric acid A1.6) with a small amount of vanadate in a volume ratio of 1:7. A1.B Lead acid forging reagent
88.5g ammonium vanadate [(NH4)Mo.024H0], add 34ml of ammonia solution containing 25% (m/m) NH4 and 240g nitrate money A1.9). Mix and dissolve in water, shake with a spoon. Dilute to 1L, A1.9 ammonium nitrate (NIINO.),
A1.1025 (mass ratio) hydrochloric acid (HC) solution A1.TT 5% (mass ratio) potassium vanadate LK, Fe(CN) solution. 41.12 25% (mass ratio) sulfuric acid (SO4) solution A1.13 0.5% (mass ratio) phenolic acid (C11.02) solution. The solvent is ethanol A2 Determination of chromium
Add 5 ml of hydrogen peroxide solution (A1.3) to 50 ml of sodium hydroxide solution (A1.1). Treat a sample with a surface area of about 300 cm2. Pour the solution at 50-60 °C over the sample without repeating until the film is completely removed. Pour the resulting solution into a bowl and boil until the peroxide is completely decomposed (about 5-6 min), cool it, and precipitate it with lead nitrate solution (A1.5). If there is a yellow precipitate, it means that hexavalent chromium is present. The minimum amount of total chromium that can be measured by this method is about 100 g per square meter of surface area. A3 Determination of phosphate
In order to determine whether there is phosphate in the chromate film, the surface area of the sample to be tested is about 100 cm2. Treat the sample with 100 ml of sodium hydroxide solution (A1.1) at 80-90°C until the film is completely dissolved, or at least until the film is clearly visible on the surface. Filter the resulting solution, take 25 ml of the filtrate and hydrate it with nitric acid solution.To distinguish the chromic acid trace-phosphate film from the anodic ammonium film and the zinc phosphate film.
A1 Reagent
GB/T 17460—1998
Appendix A
(Appendix to the extraction of benzene)
Qualitative test of film layer composition
During the test, analytical reagents and distilled water or deionized water are allowed to be used. A1.15% (mass ratio) sodium hydroxide (NaOH) solution. A1.220% (mass ratio) hydrogen peroxide (H2O2) solution. A1.330% (mass ratio) hydrogen peroxide (H2O2) solution. A1.410% (mass ratio) acetic acid (CHCOOH) solution. A1.5 10% (mass ratio) lead nitrate [Ph(NO.>, two solutions. A1.6 65 (mass ratio> concentrated nitric acid (HNO.) solution (p: 1.4g/cm2)). A1.7 38% (mass ratio) nitric acid (HN.) solution can be prepared by mixing 1 liter of concentrated nitric acid A1.6) with a small amount of vanadate in a volume ratio of 1:7. A1.B Lead acid forging reagent
88.5g ammonium vanadate [(NH4)Mo.024H0], add 34ml of ammonia solution containing 25% (m/m) NH4 and 240g nitrate money A1.9). Mix and dissolve in water, shake with a spoon. Dilute to 1L, A1.9 ammonium nitrate (NIINO.),
A1.1025 (mass ratio) hydrochloric acid (HC) solution A1.TT 5% (mass ratio) potassium vanadate LK, Fe(CN) solution. 41.12 25% (mass ratio) sulfuric acid (SO4) solution A1.13 0.5% (mass ratio) phenolic acid (C11.02) solution. The solvent is ethanol A2 Determination of chromium
Add 5 ml of hydrogen peroxide solution (A1.3) to 50 ml of sodium hydroxide solution (A1.1). Treat a sample with a surface area of about 300 cm2. Pour the solution at 50-60 °C over the sample without repeating until the film is completely removed. Pour the resulting solution into a bowl and boil until the peroxide is completely decomposed (about 5-6 min), cool it, and precipitate it with lead nitrate solution (A1.5). If there is a yellow precipitate, it means that hexavalent chromium is present. The minimum amount of total chromium that can be measured by this method is about 100 g per square meter of surface area. A3 Determination of phosphate
In order to determine whether there is phosphate in the chromate film, the surface area of the sample to be tested is about 100 cm2. Treat the sample with 100 ml of sodium hydroxide solution (A1.1) at 80-90°C until the film is completely dissolved, or at least until the film is clearly visible on the surface. Filter the resulting solution, take 25 ml of the filtrate and hydrate it with nitric acid solution., making it weakly acidic.
GB/T 17460 - 1998
After adding 5 ml of potassium ferrous sulfate solution (A).11), if a greenish-white precipitate appears, it indicates the presence of zinc. The minimum amount of zinc that can be measured by this method is about 20 mZ zinc per square meter of surface. Appendix B
(Tyr's Appendix)
Selection of treatment procedures
Acid water slush
Anti-agent
Alkaline hydrogel
Cold water rafting
(Descaling, extinction, acid and drag ratio)
【Fu or】
Cold water washing
Nitric acid addition
Cold water washing
Chromium whipping conversion Treatment
.F&:'C:)
Cold water rinse
Hot water rinse
Transparent-yellow--red color
(less than 5)
There is water solution
Second drying
(169--110-)
Be careful when bleaching to avoid chemical condensation and full price. H1 Aluminum-chromic acid conversion treatment process
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