There is some process that is applied to the cylinder to minimize the effects of heat. I can't tell you if it's a coating or some other treatment. Titanium has a lower heat threshold and this process retards the effect of high heat to the titanium cylinder to prevent heat related erosion. What I meant in my first post was that the cylinder was not somehow coated with titanium in response to the OP's initial question to clarify that the cylinder is machined form a solid bar of titanium alloy, as opposed to cast or forging.

The erosion, as opposed to corrosion, issue is the effect of high temperatures and titanium's lower resistance to heat than other metals. When that barrier is scrubbed off with an abrasive, it's the resulting heat that will erode the tolerances between the cylinder and the barrel and ultimately destroy the gun.