Abstract: The present invention relates to a magnetorheological fluid composition and a process for preparing the same, which has excellent magnetorheological properties. The fluid composition exhibits change in rheological characteristics in the presence of an external magnetic field. Further, the magnetorheological characteristics of the fluid composition can be optimised for the improved magnetic sensitivity to external magnetic field and negligible magnetic retentivity after removal of the external magnetic field. The sensitivity of the fluid to external magnetic field can be varied by varying the pure iron content of the magnetic sensitive particles composition while, the magnetic retentivity of the fluid (after removal of external magnetic field) can be varied by varying the ferrite alloy content of the same. The fluid composition utilises a magnetic sensitive particles stabiliser or surfactant, which is synthesised from the carrier fluid used in the fluid composition.
Type:
Grant
Filed:
October 3, 2001
Date of Patent:
April 5, 2005
Assignee:
The Adviser Defence Research and Development Organisation, Ministry of Defence, Government of India
Inventors:
Reji John, Narayana Das Janardhanan Pillai
Abstract: The present invention relates to a magneto sensitive fluid composition and a process of its preparation. The electrical conductivity of the composition varies reversibly in the presence of an external magnetic field. The composition, which is practically an insulator, starts behaving as a conductor in the presence of a magnetic field. The fluid is basically a magnetrheological composition in which the magnetic sensitive particles are admixed with conductive additives in the form of conductive metallic or non-metallic powder. The change in electrical conductivity of the composition is in addition to the change in rheological characteristics of the composition in the presence of an external magnetic field.
Type:
Grant
Filed:
June 6, 2002
Date of Patent:
June 1, 2004
Assignee:
The Adviser-Defence Research & Development Organisation
Ministry of Defence, Government of India
Inventors:
Reji John, Narayana Das Janardhan Pillai