公开(公告)号：EP0853683A1

公开(公告)日：1998-07-22

申请号：EP96937648.0

申请日：1996-10-02

Applicant: THE DOW CHEMICAL COMPANY

Inventor： DUNMEAD, Stephen, D. ,  ROMANOWSKY, Michael, J.

IPC: C22C29 ,  B22F3 ,  C22C1

CPC classification number: C22C1/058 ,  B22F2999/00 ,  C22C29/00 ,  B22F3/14

Abstract: Ceramic-ceramic and ceramic-metal composite materials are disclosed which contain at least two ceramic phases and at least one metallic phase. At least one of these ceramic phases is a metal boride or mixture of metal borides and another of the ceramic phases is a metallic nitride, metallic carbide, or a mixture of metallic nitride and a metallic carbide. These composite materials may be made by a combustion synthesis process which includes the step of igniting a mixture of at least one element selected from titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, aluminum and silicon, or a combination of two or more thereof, at least one boron compound selected from boron nitride, boron carbide, or a combination thereof and an ignition temperature reducing amount of a metal selected from iron, cobalt, nickel, copper, aluminum, silicon, palladium, platinum, silver, gold, ruthenium, rhodium, osmium, and iridium, or a mixture of two or more thereof, provided that at least one of the aforementioned elements is different from at least one of the aforementioned metals. This process permits a high degree of control over the microstructure of the product and relatively low pressures are required to obtain high composite material density. A densified product having high density and a finely grained microstructure may be obtained by applying mechanical pressure during combustion synthesis. The composites have improved hardness, toughness, strength, resistance to wear, and resistance to catastrophic failure.

公开(公告)号：EP0698002A1

公开(公告)日：1996-02-28

申请号：EP94923870.0

申请日：1994-04-26

Applicant: THE DOW CHEMICAL COMPANY

Inventor： DUBENSKY, Ellen, M. ,  DUNMEAD, Stephen, D. ,  NILSSON, Robert, T.

IPC: C04B35

CPC classification number: C04B35/6455 ,  C04B35/5607 ,  C04B35/5611 ,  C04B35/5622 ,  C04B35/5626 ,  C04B35/58007 ,  C04B35/645

Abstract: Densified refractory carbide and solid solution carbide materials that have an average grain size of less than 1.1 νm, a density of at least 98 % of theoretical may be prepared by any conventional densification procedure. Pressure densified tungsten carbide ceramic materials exhibit a simultaneous increase in Vickers hardness and a toughness (KIC) with decreasing average grain size.

公开(公告)号：EP0613449B1

公开(公告)日：1995-12-13

申请号：EP92922209.9

申请日：1992-10-26

Applicant: THE DOW CHEMICAL COMPANY

Inventor： DUNMEAD, Stephen, D. ,  MOORE, William, G. ,  GRINDAHL, Eric, J.

IPC: C01B31/34

CPC classification number: B82Y30/00 ,  C01B32/949 ,  C01P2004/62 ,  C01P2004/64 ,  C01P2006/12 ,  C01P2006/80

Abstract: A method for forming monotungsten carbide, comprising heating a solid, non-elemental tungsten-containing material in a flowing atmosphere containing molecular hydrogen and molecular methane for a time sufficient to convert substantially all of the tungsten-containing material to monotungsten carbide, The heating brings the temperature of the tungsten-containing material to a first elevated temperature of from about 520 to about 550 DEG C. and, subsequently, at a rate of from about 3 to about 10 DEG C. per minute, the heating brings the temperature from the first elevated temperature to a second elevated temperature of about 800 to about 900 DEG C. Thereafter the temperature is held at the second elevated temperature for at least about 15 minutes. At least about 50 weight percent of the monotungsten carbide formed is formed while holding the temperature at the second elevated temperature.

公开(公告)号：EP0745145B1

公开(公告)日：1997-11-05

申请号：EP95910222.9

申请日：1995-02-10

Applicant: THE DOW CHEMICAL COMPANY

Inventor： DUNMEAD, Stephen, D. ,  MOSSNER, David, D.

IPC: C22C29/08 ,  C01B31/34 ,  C01B31/30 ,  C22C29/10

CPC classification number: C01B32/949 ,  C01B32/90 ,  C01B32/907 ,  C01P2004/62 ,  C01P2006/80

Abstract: A method of making metallic carbide powders includes heating a non-static solid reactant mixture of a metal oxide and a source of carbon to a first elevated temperature which is sufficient to cause at least partial carburization of the mixture. The heating is performed in a non-reducing atmosphere having a total pressure of at least one atmosphere for a sufficient time to form a partially-carburized mixture. The source of carbon is employed at a level which is less than the stoichiometric amount needed to produce the metallic carbide. The method may further include admixing a sufficient level of a source of carbon to the partially-carburized mixture to form an adjusted mixture having a total carbon content of the stoichiometric amount needed to make the metallic carbide and carburizing the adjusted mixture in a hydrogen-containing atmosphere at a second elevated temperature which is sufficient to cause the adjusted mixture to form the metallic carbide having a particle size of less than 0.2 micrometers in diameter.

公开(公告)号：EP0698002B1

公开(公告)日：1997-11-05

申请号：EP94923870.3

申请日：1994-04-26

Applicant: THE DOW CHEMICAL COMPANY

Inventor： DUBENSKY, Ellen, M. ,  DUNMEAD, Stephen, D. ,  NILSSON, Robert, T.

IPC: C04B35/56

CPC classification number: C04B35/6455 ,  C04B35/5607 ,  C04B35/5611 ,  C04B35/5622 ,  C04B35/5626 ,  C04B35/58007 ,  C04B35/645

Abstract: Densified refractory carbide and solid solution carbide materials that have an average grain size of less than 1.1 νm, a density of at least 98 % of theoretical may be prepared by any conventional densification procedure. Pressure densified tungsten carbide ceramic materials exhibit a simultaneous increase in Vickers hardness and a toughness (KIC) with decreasing average grain size.

公开(公告)号：EP0755367A1

公开(公告)日：1997-01-29

申请号：EP95916972.0

申请日：1995-04-14

Applicant: THE DOW CHEMICAL COMPANY

Inventor： DUNMEAD, Stephen, D. ,  WEIMER, Alan, W. ,  CARROLL, Daniel, F. ,  EISMAN, Glenn, A. ,  COCHRAN, Gene, A. ,  SUSNITZKY, David, W. ,  BEAMAN, Donald, R. ,  NILSEN, Kevin, J.

IPC: C04B35 ,  C01B21

CPC classification number: B82Y30/00 ,  C01B21/0685 ,  C01P2004/62 ,  C01P2004/64 ,  C01P2006/10 ,  C01P2006/12 ,  C04B35/584 ,  C04B35/593

Abstract: Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.

公开(公告)号：EP0713477B1

公开(公告)日：1997-08-13

申请号：EP94918140.8

申请日：1994-05-26

Applicant: THE DOW CHEMICAL COMPANY

Inventor： DUNMEAD, Stephen, D. ,  MOORE, William, G. ,  WEIMER, Alan, W. ,  EISMAN, Glenn, A. ,  HENLEY, John, P.

IPC: C01B31/30 ,  C01B31/34

CPC classification number: C04B35/5622 ,  B82Y30/00 ,  C01B32/914 ,  C01B32/921 ,  C01B32/949 ,  C04B35/5607 ,  C04B35/5611 ,  C04B35/5626 ,  C04B35/62615 ,  C04B35/6265 ,  C04B35/62675 ,  C04B35/6268 ,  C04B2235/3232 ,  C04B2235/3244 ,  C04B2235/3251 ,  C04B2235/3256 ,  C04B2235/3258 ,  C04B2235/3839 ,  C04B2235/3843 ,  C04B2235/3847 ,  C04B2235/424 ,  C04B2235/5445 ,  C04B2235/5454 ,  C04B2235/761

Abstract: A method for making submicrometer metallic carbides and submicrometer solid solution metallic carbides from a source of at least one metallic oxide and carbon involves the rapid heating of a reactive particulate mixture of the source(s) and carbon in order to achieve a resulting particulate size of less than 1 micrometer. The rapid heating may produce either a finished product or a precursor. If a precursor is produced, it may be admixed with additional carbon and subjected to a second rapid heating step to prepare a finished product. Submicrometer sized metallic carbides and solid solution metallic carbides were suitable for use in commercial ceramic applications. The smaller sized particles produce a product having superior toughness and hardness.

公开(公告)号：EP0713477A1

公开(公告)日：1996-05-29

申请号：EP94918140.0

申请日：1994-05-26

Applicant: THE DOW CHEMICAL COMPANY

Inventor： DUNMEAD, Stephen, D. ,  MOORE, William, G. ,  WEIMER, Alan, W. ,  EISMAN, Glenn, A. ,  HENLEY, John, P.

IPC: C01B31 ,  C04B35 ,  C22C1

CPC classification number: C04B35/5622 ,  B82Y30/00 ,  C01B32/914 ,  C01B32/921 ,  C01B32/949 ,  C04B35/5607 ,  C04B35/5611 ,  C04B35/5626 ,  C04B35/62615 ,  C04B35/6265 ,  C04B35/62675 ,  C04B35/6268 ,  C04B2235/3232 ,  C04B2235/3244 ,  C04B2235/3251 ,  C04B2235/3256 ,  C04B2235/3258 ,  C04B2235/3839 ,  C04B2235/3843 ,  C04B2235/3847 ,  C04B2235/424 ,  C04B2235/5445 ,  C04B2235/5454 ,  C04B2235/761

Abstract: A method for making submicrometer metallic carbides and submicrometer solid solution metallic carbides from a source of at least one metallic oxide and carbon involves the rapid heating of a reactive particulate mixture of the source(s) and carbon in order to achieve a resulting particulate size of less than 1 micrometer. The rapid heating may produce either a finished product or a precursor. If a precursor is produced, it may be admixed with additional carbon and subjected to a second rapid heating step to prepare a finished product. Submicrometer sized metallic carbides and solid solution metallic carbides were suitable for use in commercial ceramic applications. The smaller sized particles produce a product having superior toughness and hardness.

公开(公告)号：EP0691943A1

公开(公告)日：1996-01-17

申请号：EP94908643.0

申请日：1994-01-27

Applicant: THE DOW CHEMICAL COMPANY

Inventor： DUNMEAD, Stephen, D. ,  MOORE, William, G. ,  HOWARD, Kevin, E. ,  MORSE, Kevin, C.

IPC: C04B41 ,  C01B21 ,  C04B35

CPC classification number: C04B41/009 ,  C01B21/0602 ,  C01B21/072 ,  C01B21/0722 ,  C01P2002/50 ,  C01P2004/10 ,  C01P2004/20 ,  C01P2004/54 ,  C01P2004/61 ,  C01P2004/62 ,  C01P2006/10 ,  C01P2006/12 ,  C01P2006/80 ,  C04B35/651 ,  C04B35/806 ,  C04B41/5089 ,  C04B41/85 ,  Y10T428/12042 ,  C04B41/0072 ,  C04B41/4535 ,  C04B35/58 ,  C04B38/00

Abstract: Aluminum nitride powder, aluminum nitride platelets, powdered solid solutions of aluminum nitride and at least one other ceramic material such as silicon carbide, and composites of aluminum nitride and transition metal borides or carbides are prepared by combustion synthesis at low gaseous nitrogen pressures. Porous bodies of aluminum nitride or composites of aluminum nitride and transition metal borides or carbides are also prepared by combustion synthesis at these pressures. The porous bodies are suitable for infiltration, either as formed or after being coated with at least one layer of a silicate material, by polymers or metals.