Re: contamination in TBC bond coat

Posted by Gordon England ( on 11:07:42 31/05/06

In Reply to: Re: contamination in TBC bond coat posted by Leon

1. Ventilation air flow can play an important role in coating quality in some circumstances. You will notice this particularly when spraying into internal spaces where good ventilation is difficult to achieve. Over-spray material and dust are not removed, then get entrained back into the spray stream and get included in the coating.
2. For any given powder (as mentioned by Leon powder chemistry, size etc. will produce different effects) the colour of the coating will be effected by the coating temperature during application. Generally, a grey/white colour indicates coating is too cool and a yellow/orange colour too hot. You should not use that as a rule of thumb for coating quality, but noting colour changes can be useful during coating development and monitoring coating quality as this reflects changes in spraying parameters.
Regards Gordon

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