Silicon oxide formation in the disk environment

Among many organic vapor contaminants released from structural components o f hard disk drives, organic siloxanes (released from silicone gaskets, for example) are particularly ominous, as they can be released in a relatively large quantity. It is known that the presence of siloxane contaminants ofte n leads to the formation of silicon oxide at the head-disk interface area. A plausible mechanism for the formation of silicon silicon oxide debris in the disk environment is presented. It is envisaged that volatile siloxane o ligomers such as D4 (octamethyl cyclotetrasiloxane) are released from compo nents containing PDMS (polydimethyl siloxane) and are repolymerized back in to PDMS at the head-disk interface when catalyzed by the acidic component o f a degraded lubricant. The PDMS thus formed, if heated at 300-350 degrees C in a thin-film configuration that would permit facile infusion of oxygen, readily converts to silicon oxide with minimal depolymerization.