GB/T 8015.1-1987 Test method for thickness of anodic oxide film on aluminium and aluminium alloys - Gravimetric method GB/T8015.1-1987 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test methods for thickness of anodicOxidation coatings on aluminium andaluminium alloys--Gravimetric methodUDC 669.715:620.197.2: 531.717.1GB 8015.1--87IS O 2106-1982This standard specifies the measurement of the thickness of anodic oxide coatings on aluminium and lithium alloy products by the gravimetric method. This standard is applicable to most aluminium products except those with a copper content greater than 6%. This standard is equivalent to ISO2106-1982 "Aluminium and aluminium alloy anodic oxidation-Determination of mass per unit area (surface density) of anodic oxide coatings-Gravimetric method".
1 Principle of the method
The area and mass of the anodic oxide film sample are first calculated, and then placed in a mixed solution of phosphoric acid and chromium trioxide of known concentration that has no obvious diffuse etching effect on the substrate. This solution can dissolve the oxide film. After the oxide film is dissolved, the mass of the sample is weighed and its weight loss is calculated. This weight loss is the mass per unit area of ​​the oxide film surface density, usually expressed in milligrams per unit square decimeter. If the precise thickness of the film and the mass per unit area of ​​the oxide film are known, the approximate density of the oxide film can be calculated. On the contrary, if the formation conditions of the oxide film and its density are known, the average mass of the film can be calculated by measuring the surface density (mass per unit area), and the thickness of the oxide film can also be estimated. This method is a destructive testing method. 2 Apparatus
2.1 Laboratory balance; accuracy is 0.1 mg. 2.2 Beaker. wwW.bzxz.Net
2.3 Heater.
3 Solution
Phosphoric acid - 35ml, (p1.7/ml).
Crystalline chromium trioxide - 20g.
Add distilled water (or deionized water) to liters. 4 Test steps
4.1 Pretreatment
The area of ​​the surface to be tested is about 0.08~1dm2, and the mass of the sample should not exceed 100g. If the surface is dirty or contaminated by grease and other substances, it must be cleaned with a suitable organic solvent (such as gasoline, alcohol, trichloroethylene). Sometimes it is possible to calculate the weight of a certain surface on the sample. In this way, the oxide film on the other side can be removed by mechanical methods or by immersing one side in a chemical reagent.
In addition, a protective agent can be applied to the other side of the sample to prevent the test solution from corroding it. China National Nonferrous Metals Industry Corporation approved on April 22, 1987, implemented on May 1, 1988
4.2 Operation
GB8015.1—87
First calculate the area of ​​the anodized sample, weigh its mass (accurate to 0.1 mg), and then soak the sample in a 100℃ phosphoric acid-chromic acid solution for 10 minutes. Take out the sample, wash it with distilled water, dry it, and weigh it again. Repeat the soaking and weighing in this way until there is no more weight loss.
Note: The newly prepared reagent can generally dissolve the oxide film completely within 10 minutes. As the solution is kept for a longer time, the film removal ability decreases. Before the oxide film becomes difficult to dissolve, 1L of solution can dissolve about 12g of oxide film. 5 Calculation and Expression
5.1 Surface Density
The surface density (the mass per unit area of ​​the oxide film) can be calculated according to formula (1): PAE
Where: PA surface density (mass per unit area of ​​the oxide film), mg/dm2; mi--the mass of the sample before the oxide film is dissolved, gmz--the mass of the sample after the oxide film is dissolved, gA-area, refers to the area covered with the oxide film, dm2. 5.2 Film Thickness Estimation
The average film thickness can be calculated according to formula (2):
Where: 8-
-Average film thickness, μm;
p--density, g/cm3.
: The thickness of the oxide film depends on the alloy composition, the anodizing process and the sealing process. Under normal process conditions, the density of the oxide film is between 2.3 and 3 g/cmJ.
The oxide film generated by aluminum and aluminum alloys without copper in a sulfuric acid solution at 20°C under direct current is estimated to have a density of 2.6 g/cm2 after sealing, and a density of about 2.4 g/cm2 for unsealed oxide films. Since the density is an approximate value, this method is only An approximate thickness value can be obtained. When the film thickness is equal to or less than 10um, the estimated oxide film thickness is relatively accurate. 6
Test report
The test report should include the following contents:
This standard number,
The test method used;
The results and the expression method used;
Abnormal phenomena during the test.
Additional remarks:
This standard was drafted by Northeast Light Alloy T Factory. The main drafters of this standard are Gao Kangzhi and Wang Ziyi. 364
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