Test on the importance of pretreatment for aluminum surfaces, previous to powder coating |
A correct pretreatment of aluminum is mostly important for a good resistance and a good adhesion of the powder coat layer.
For this reason, the DecoralLab has carried out a study to determine and evaluate its role, showing the defects that can be observed where no pretreatment (or uncorrect pretreatment) has been made.
The following aluminum samples have been prepared:
- No pretreatment;
- Chrome pretreatment;
- Chrome-free pretreatment.
Each kind of pretreatment then has been tested for what regards:
- Resistance to corrosion – salt-spray; (Picture 1)
- Adhesion of the powder-coat layer - cross-cut test, followed by impact test. (Picture 2)
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Picture 1: corrosion test.
Left to right: non-pretreated sample; chrome pretreated sample; chrome-free pretreated sample
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Picture 2: adhesion test.
Left to right: non-pretreated sample; chrome pretreated sample; chrome-free pretreated sample
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The results have proved how pretreated aluminum surfaces perfectly pass the tests carried out, while non-pretreated ones show serious signs of corrosion and loss of adhesion of the powder coat layer in both the tests made.
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DOWNLOAD: "Test on the importance of pretreatment for aluminum surfaces, previous to powder coating - ENG"
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