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:
Apr. 18, 2000
Filed:
Jul. 27, 1998
Richard Lawrence Allor, Livonia, MI (US);
Gary Mark Crosbie, Dearborn, MI (US);
Douglas George Mcwatt, Livonia, MI (US);
Arup Kumar Gangopadhyay, Novi, MI (US);
Ford Global Technologies, Inc., Dearborn, MI (US);
Abstract
Method of surface finishing covalent-ionic ceramics comprising: (a) repeatedly rubbing a finishing medium against an exposed surface of the ceramic, the medium being constituted of an ionic bonded oxide having grains harder than the grains of the covalent-ionic bonded ceramic; (b) interrupting the rubbing at frequent intervals to dress the medium by a single point diamond tool; and (c) continuing the repeated rubbing and dressing interruptions of steps (a) and (b) until a surface roughness of about 0.04 micrometer Ra has been achieved on the ceramic and the exposed surface of the ceramic retains an ionic residue of the finishing medium. Also, a method of effecting reduced friction between lubricated rubbing surfaces, comprising: (a) forming one of the rubbing surfaces of silicon nitride based ceramics having a polished surface roughness about 0.04 micrometer Ra with an ionic residue thereon resulting from finishing with an ionic-bonded oxide having grains harder than the grains of the silicon nitride ceramic; and (b) operating the silicon nitride rubbing surface against the other rubbing surface while lubricating the interface between such rubbing surfaces with oil in a mixed hydrodynamic regime, whereby the ionic residue is effective to react with additives in said lubricant oil to form a transfer film on said silicon nitride ceramic that reduces contact friction.