Surface Finishing Tutorial

#098 Alumite Classification according to JIS Standards: Anodic Oxide Films on AL and AL Alloys - 2

Category : Anodizing

October14, 2011

(4) Alkali corrosion resistance

Table 4 shows the allowable alkali corrosion ranges specified for the respective types of alumite film subjected to either the alkaline dropping corrosion resistance test or the electromotive force measurement test. (See the next section for the procedural details of the alkaline dropping corrosion resistance test and the electromotive force measurement test.)

[Table 4] Alkali corrosion resistance ranges (seconds)

Type	Alkali dropping	Electromotive force measurement
AA3	N/A
AA6	30 or more	90 or more
AA10	50 or more	150 or more
AA15	75 or more	225 or more
AA20	N/A/td>	300 or more
AA25	N/A	375 or more

(5) CASS corrosion resistance

Table 5 shows the CASS corrosion resistance ranges specified for the respective types of alumite films as subjected to the CASS corrosion test.

[Table 5] CASS corrosion resistance ranges

Type	Test duration (h)	Rating number
AA3	N/A
AA6	8	9 or more
AA10	16
AA15	32
AA20	56
AA25	72

(6) Wear resistance

Table 6 shows the wear and abrasion resistance ranges for the respective types of alumite films as subjected to the sand-falling abrasion resistance test, the abrasive jet test, or the reciprocating wear test. (See

[Table 6] Wear resistance

Type	Sand-falling abrasion resistance test (s)	Abrasive jet test (s)	Reciprocating wear test (DS/μm)
AA3	N/A
AA6	150 or more	N/A	Number of times of reciprocating motion required to wear 1 μm of alumite film
AA10	500 or more	24 or more
AA15	750 or more	36 or more
AA20	1,000 or more	48 or more
AA25	1,250 or more	60 or more

(7) Stain resistance

Table 7 shows the stain resistance range specified for all types of alumite films as subjected to the chromic-phosphoric solution immersion test, the dye spot test, or the admittance test:

[Table 7] Stain resistance

Type	Chromic-phosphoric solution immersion test (g/dm²)	Dye spot test (degree of staining (grade))	Admittance test (μS*) (Microsemens per film thickness of 20 μm)
AA3 to AA25	0.03 or less	0 to 2	20 or less

(8) Designation convention for alumite films

The designation of an alumite consists of a prefix for type, followed by letters for corrosion resistance, wear resistance, and stain resistance in this order:

Alkaline dropping corrosion resistance test = KS; electromotive force measurement test = KG; CASS corrosion test = L; sand-falling abrasion resistance test = WF; abrasive jet test = WJ; dye spot test = SD; chromic-phosphoric solution immersion test = SP

Example 1: AA15/L-WJ: 15 μm-thick film, having passed the CASS corrosion test and the abrasive jet test
Example 2: AA6/KS-WF: 6 μm-thick film, having passed the alkaline dropping corrosion resistance test and the sand-falling abrasion resistance test

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