Before PVD, there was anodization and powder coating.
The process of physical vapor deposition (PVD) has been utilized for decades. Prior to its mainstream application, it was used in the military to decrease the high levels of friction wear on metallic parts.
Physical vapor deposition is efficient and the finish will not wear off. Essentially, the process of PVD thermal evaporation bonds layer of metal compounds to the designated metal. Nowadays, you’ll frequently see this process used in the coating of watch bands.
Before this process was heavily relied on, powder coating and anodization were two preferred methods. Mind you, this wasn’t too long ago, roughly around the 80’s and early 90’s. Now, the idea of powder coating was revolutionary for that time, but there were several issues that came with it. First of all, the process of powder coating requires a paint to be “baked” onto the metal using an industrial oven. As you might expect, the powder would come out much thicker than the PVD coating nowadays. Additionally, it also chips off over time, leaving splotches of bare metal around the area.
Another type of coating process that was commonly used was the application of black oxide. Formerly used by gunsmiths, black oxide is similar to anodization in that it gives a dark finish to the coated metal. The inexpensiveness of this method made it a popular choice. The downside to seeing this process through is that it doesn’t penetrate into the metal deep enough, creating durability and volume issues.