An improved fluid for magnetorheological finishing (MRF) of optical parts is made from carbonyl iron coated with zirconia.
This material is as a long-life polishing agent for use in MRF finishing of optics components. It is also expected to be of use in fluid jet polishing equipment for optical lens fabrication.
The zirconia-coated carbonyl provides the finishing fluid the following advantages: (1) excellent corrosion resistance, (2) tailored abrasiveness by controlling the texture of the zirconia coating, (3) compatibility in magnetic and rheological properties with existing MRF lens finishing equipment. The result is a fluid with long life and stable properties for improved optical finishing.
The fabrication process for coating the carbonyl iron also can be applied to other optical polishing agents, including aluminum oxide, tin oxide and titanium oxide.
The zirconia-coated carbonyl iron is expected to be advantageous in fluid jet finishing because of the mass density of the zirconia-coated iron will be midway between the 5.8 g/cm3 value for zirconia and the 7.8 g/cm3 value for iron.
The coated carbonyl iron may also be valuable in other magnetorheological fluids used for non-abrasive uses outside of optical finishing, such as dampers and brakes in automobiles, but more characterization is required to see if the improvement in corrosion resistance is obtained without significant loss in magnetic properties.
URV Reference Number: 3-11155-09006