Talk:Phosphate conversion coating: Difference between revisions
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How to varify the quality of the phosphating. Is there any specific tests are available? |
How to varify the quality of the phosphating. Is there any specific tests are available? |
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Revision as of 05:39, 19 October 2010
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How to varify the quality of the phosphating. Is there any specific tests are available?
Dubious
I tagged the sentence about how zinc phosphate is used to prevent rusting, because that makes no sense. Zinc can't rust. It can corrode, and I have a feeling that's what is meant, but I want to confirm. --Wizard191 (talk) 00:24, 29 August 2008 (UTC)
- I believe it should be interpreted as "the zinc phosphate prevents rusting of the steel (the substrate which is treated by zinc phosphating)". Finn Toten (talk) 10:59, 5 December 2008 (UTC)
- Yes. Yaf (talk) 16:01, 5 December 2008 (UTC)
- I am by no means an expert in this field, but the way I understand phosphate conversion coatings is that the material is put in a vat of acid and that converts the surface of the item into a phosphate coating. As such, I understand zinc phosphate as having zinc as the starting material, which can't rust. Wizard191 (talk) 14:22, 5 December 2008 (UTC)
- No. A Zinc phosphate coating is what protects an underlying steel surface. The starting material is steel. Ph is carefully controlled, as well as temperature, for the particular bath that is a combination of zinc phosphate, an assortment of other compounds in small quantities, and an acid solution. Once the temperature of the bath is brought up to the proper range, the steel item to be given rust protection is placed in the vat of heated liquid. Lots of bubbles and outgassing results from the phosphatizing process of the steel (should only be done with lots of ventilation or outdoors). Once the bubbles stop, the process is over, and the steel item is removed and washed down. Once cool, oil is added, to fill the pores in the phosphate coating on the surface, thereby increasing the resistance to rusting, for items that are not going to be painted. Alternatively, paint can also be applied over the phosphate coating to fill the pores, in which case, no oil is used. Yaf (talk) 16:01, 5 December 2008 (UTC)
- But then how is it a "conversion coating"? I thought it converted the surface of the material, not coating it with a substance. Wizard191 (talk) 16:31, 5 December 2008 (UTC)
- No. A Zinc phosphate coating is what protects an underlying steel surface. The starting material is steel. Ph is carefully controlled, as well as temperature, for the particular bath that is a combination of zinc phosphate, an assortment of other compounds in small quantities, and an acid solution. Once the temperature of the bath is brought up to the proper range, the steel item to be given rust protection is placed in the vat of heated liquid. Lots of bubbles and outgassing results from the phosphatizing process of the steel (should only be done with lots of ventilation or outdoors). Once the bubbles stop, the process is over, and the steel item is removed and washed down. Once cool, oil is added, to fill the pores in the phosphate coating on the surface, thereby increasing the resistance to rusting, for items that are not going to be painted. Alternatively, paint can also be applied over the phosphate coating to fill the pores, in which case, no oil is used. Yaf (talk) 16:01, 5 December 2008 (UTC)