The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 07, 2004
Filed:
Nov. 12, 2002
Robert T. Foister, Rochester Hills, MI (US);
Vardarajan R. Iyengar, Macomb, MI (US);
Sally M. Yurgelevic, Eastpointe, MI (US);
Delphi Technologies, Inc., Troy, MI (US);
Abstract
An MR fluid formulation comprising water-atomized iron powder dispersed in a liquid vehicle, wherein the atomized iron powder contributes to a higher magnetic effect, a lower viscosity and suitability for high temperature applications. The magnetizable particles are prepared by controlled water atomization and comprise iron having a passivating oxide surface layer. The passivating oxide surface layer advantageously comprises iron oxide and at least one alloying metal oxide, such as manganese oxide. Advantageously, the particles have a grain size of at least 4 &mgr;m and a mean diameter in the range of about 8-25 &mgr;m. The liquid vehicle advantageously comprises a mixture of at least two liquid components of different surface functionality and an organoclay stabilization mixture in which at least one organoclay is selected for each liquid vehicle component. Exemplary MR fluid formulations of the present invention utilize a high-viscosity, low volatility base fluid, water-atomized iron powder, multi-component organoclays and multi-component additives to achieve the desired viscosity and durability of a fully formulated MR fluid which will satisfy the requirements of second and third generation MR fluids.