| CPC C22C 38/22 (2013.01) [C23C 8/18 (2013.01); F04C 18/344 (2013.01); F04C 2220/12 (2013.01); F05C 2201/0409 (2013.01); F05C 2201/0436 (2013.01); F05C 2201/0439 (2013.01)] | 5 Claims |

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1. A cam ring and plate module for vehicle vacuum pumps, comprising:
a cam ring comprising an accommodation space configured to receive a rotor and a plurality of vanes, and a diaphragm configured to surround the accommodation space;
an upper plate positioned at one side of the cam ring and configured to seal the accommodation space; and
a lower plate positioned at an opposite side of the cam ring and configured to seal the accommodation space;
wherein the cam ring, the upper plate, and the lower plate each comprise an iron-based base material comprising molybdenum; and
wherein the cam ring, the upper plate, and the lower plate each comprise an oxide layer comprising magnetite (Fe3O4) formed on surfaces thereof.
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