Wear Resistant Coating for Phonograph Records and Other Recording Media
Original Publication Date: 1978-Feb-01
Included in the Prior Art Database: 2005-Feb-20
Phonograph records are formed by pressing a disc of a thermoplastic material such as polyvinyl chloride. These plastic materials have the necessary properties for faithfully reproducing the recording grooves, but they are relatively soft and susceptible to stylus wear and scratching. This coating is hard and wear resistant, and is adapted for phonograph records. It can be applied after the record is pressed. The record is placed in close proximity to a metal electrode, and is overcoated with a thin film of a diamond-like amorphous carbon by impressing an RF potential on the electrode in propane gas. The RF excites a glow discharge in the propane, and a hard, wear-resistant coating of amorphous carbon forms on the record.