Alloy Powder Coating and Outgassing

Although we strive to provide the best possible results, several critical factors must be considered before proceeding with Alloy Powder Coating and Outgassing. This process requires curing at a temperature of at least 180 degrees Celsius, which can lead to chemical reactions in certain metals and castings. For instance, porous materials such as aluminum alloys, magnesium, and some cast irons may release gas or air trapped within microbubbles during oven curing. This phenomenon can create small bubbles beneath the cured powder coating, which may be mistaken for poor preparation or contamination.

These bubbles are a result of outgassing, which occurs when the trapped gas expands and escapes through tiny holes or microcracks in the coating. While this issue can sometimes be mitigated by reworking the parts or using an anti-gassing product, these methods do not always yield successful results. In the case of low-quality castings, the only effective solution is to use wet paints and appropriate fillers, as other measures cannot prevent outgassing.

Additionally, corrosion may pose a problem with certain alloys . Despite thorough preparation and media blasting to remove rust, micro-holes can persist, leading to outgassing. While fillers are generally not used for powder coating due to the risk of burning or expanding, high-temperature fillers may be applied in specific instances of corrosion.

Ultimately, outgassing occurs when entrapped gases are released during the curing process, resulting in pinholes in the coating. This can allow moisture or corrosive substances to penetrate the coating, potentially leading to its failure. Substrate materials, surface contaminants, and the powder itself can all contribute to outgassing. Castings and zinc-coated substrates are particularly prone to this issue, especially when heavy coatings are applied in a single layer. Certain types of coatings are also more susceptible to causing outgassing. Unfortunately, if outgassing occurs, we are unable to provide any guarantees.