Patent ID: 8277617

Claim:
A method of depositing coatings onto the interior surface of a hollow substrate comprising: providing a vacuum chamber; providing a hollow substrate having opposing interior surfaces and a longitudinal axis (Y) wherein a cross-sectional distance between said hollow substrate opposing surfaces varies between at least two locations along said hollow substrate longitudinal axis; providing a target comprising Cu—Cr alloys, wherein Cr particles are provided in a Cu matrix and Cr is present in the range of 5 to 25 weight percent, having opposing external surfaces and a longitudinal axis wherein a cross-sectional distance between said target opposing surfaces varies between at least two locations along said target longitudinal axis and wherein said exterior surface of said target conforms to at least a portion of said interior surface of said hollow substrate, and wherein said interior surface of said substrate and said exterior surface of said target are separated by a distance (X) wherein said distance (X) varies no more than +/−15% along the entirety of said target longitudinal axis; providing a magnetic assembly including magnets mounted on a magnet support within said target including a secondary power source comprising a coil wrapped around said magnetic assembly; feeding an inert gas into said vacuum chamber; biasing said magnets and said secondary power source and forming a plasma from at least a portion of said inert gas; forming a coating on said interior surface of said hollow substrate, wherein said coating has a thickness and said thickness does not vary by more than +/−20% along the entirety of said hollow substrate interior surface and said coating includes Cr particles in the range of 0.1 to 10 nm in size and said coating includes Cr present in the range of 5 to 25 weight percent; and wherein said hollow substrate, along said longitudinal axis (Y), has openings on each end of said hollow substrate, one of said openings with a cross sectional dimension (CD 1 ), an interior cross-sectional dimension (CD 2 ), and the other of said openings having a cross-sectional dimension (CD 3 ) wherein (CD 1 ) is less than (CD 3 ).