Title of Invention | "SINTERED CERAMIC, SLIDE PART THEREFROM, AND PROCESS FOR PRODUCING SINTERED CERAMIC" |
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Abstract | CERAMIC SINTERED BODY AND PROCESS OF PRODUCTION THEREOF H ABSTRACT It is an object of the invention to provide a ceramic sintered body that has a dense structure and minimal cracking and that exhibits excellent sliding properties even in a non-lubricated state, as well as a process for its production and sliding parts that employ the same. According to a preferred mode, the sintered body of the invention comprises silicon carbide as the parent material and further contains a solid lubricant A with a mean particle size of no greater than 5 i^m and a solid lubricant B with a mean particle size of 10-70 (xm. o n S ' S L , J Mixing M Spray drying _ Screening _ Molding! Firing _ Lapping H8-10 ~i bo»mi".5ii n^^°°'^'^°°Q^p'^n^^°^'^'"^^'^n^Q^p^n^^'^^p''^^^n'^^^ |
Full Text | DESCRIPTION CERAMIC SINTERED BODY AND PROCESS OF PRODUCTION THEREOF W Technical Field 5 [0001] The present invention relates to a ceramic sintered body, and to a process for production of such body. The present invention also relates to sliding parts employing such a ceramic sintered body. Background Art IP [0002] Most sintered silicon carbides are extremely hard and exhibit 10 good lubricity when used with water lubrication, while their wear resistance and chemical resistance are also excellent. They are therefore widely used in sliding parts such as mechanical seals, bearings and the like. For mechanical seal applications, in particular, they may be used even in situations with a high PV value, which 15 represents the product of the contact pressure and rotation rate on the sliding surface, and therefore sintered silicon carbides (silicon carbide ceramics) are considered to be highly useful materials. Moreover, it is jp^ well knovm that sintered silicon carbides can be used with even higher PV values if pores are introduced therein. 20 [0003] Conventional sintered silicon carbides have exhibited satisfactory properties against sliding friction when liquid films are formed on the sliding surfaces (this will hereinafter be referred to as "lubricated state"). However in the complete absence of liquid films on sliding surfaces or with inadequate formation of liquid films, (this 25 will hereinafter be referred to as "non-lubricated state"), they create solid friction and have therefore tended to cause seizing of sliding 7 We claim: ^ P 1. A ceramic sintered body comprising silicon carbide as the parent material, a solid lubricant A with a mean particle size of no greater than 5 ^im and a solid lubricant B with a mean particle size of 10-70 ^m, containing the solid lubricant A at 3-10 parts by weight and the solid lubricant B at 2-8 parts by weight with respect to 100 parts by weight of the silicon carbide, the total content of the solid lubricant A and the solid lubricant B in the ceramic sintered body being 5-15 parts by weight with respect to 100 parts by weight of the silicon carbide. 2. A ceramic sintered body as claimed in claim 1, wherein solid lubricant A and solid lubricant B are composed of graphite. 3. A ceramic sintered body as claimed in any one of claims 1 or 2, wherein solid lubricant A is composed of graphite obtained by firing carbon black and graphite obtained by firing a thermosetting resin. 4. A ceramic sintered body as claimed in any one of the claims 1 to 3, wherein solid lubricant B is composed of artificial graphite. 5. A ceramic sintered body as claimed in any one of the claims 1 to 4, wherein the relative density is 92% or greater. 6. A ceramic sintered body as claimed in any one of the claims 1 to 5, which is sintered without pressure. 7. A ceramic sintered body as claimed in any one of the claims 1 to 6, wherein the silicon carbide is aSiC. j 8. A sliding part employing a ceramic sintered body as claimed in any one of the claims 1 to7. 9. A process for the production of a ceramic sintered body, as claimed in any one of the claims 1 to 7, production process comprising a step of firing a mixture containing 41 silicon carbide powder, a thermosetting resin and carbon black with a mean particle ^ ^ size of no greater than 150 nm, as well as artificial graphite with a mean particle size of 10-70 nm. 10. A process as claimed in claim 9, wherein the mixture containing 2-8 parts by weight of the carbon black with a mean particle size of no greater than 150 imi, 2-8 parts by weight of the artificial graphite with a mean particle size of 10-70 |xm and 1-3 parts by weight of a the thermosetting resin in terms of carbon, with respect to 100 parts by j weight of the silicon carbide powder. 11. A process as claimed in claim 9 or 10, wherein the thermosetting resin contains a phenol resin and/or furan resin. Dated this lO"' day of July, 2008. Hitachi ChemicahCompany, Ltd. (Dev Robinson) of Amarchand & Mangaldas & SureshA. Shroff&Co. Attorneys for the Applicant 42 |
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6074-delnp-2008-Abstract-(01-08-2013).pdf
6074-delnp-2008-Claims-(01-08-2013).pdf
6074-delnp-2008-Correspondence-Others-(01-08-2013).pdf
6074-delnp-2008-Correspondence-Others-(14-02-2013).pdf
6074-delnp-2008-correspondence-others.pdf
6074-delnp-2008-Description (Complete)-(01-08-2013).pdf
6074-delnp-2008-description (complete).pdf
6074-delnp-2008-Form-13 (21-07-2008).pdf
6074-delnp-2008-Form-2-(01-08-2013).pdf
6074-delnp-2008-Form-3-(14-02-2013).pdf
6074-delnp-2008-Petition-137-(01-08-2013).pdf
Patent Number | 258634 | ||||||||||||
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Indian Patent Application Number | 6074/DELNP/2008 | ||||||||||||
PG Journal Number | 05/2014 | ||||||||||||
Publication Date | 31-Jan-2014 | ||||||||||||
Grant Date | 27-Jan-2014 | ||||||||||||
Date of Filing | 10-Jul-2008 | ||||||||||||
Name of Patentee | HITACHI CHEMICAL COMPANY, LTD | ||||||||||||
Applicant Address | 1-1, NISHI-SHINJUKU 2-CHOME, SHINJUKU-KU TOKYO 163-0449 JAPAN | ||||||||||||
Inventors:
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PCT International Classification Number | C04B 35/565 | ||||||||||||
PCT International Application Number | PCT/JP2007/053305 | ||||||||||||
PCT International Filing date | 2007-02-22 | ||||||||||||
PCT Conventions:
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