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Tough silicon carbide composite material containing fibrous boride
Matsuhashi, T., Suzuki, K., Saito, K., Ogawa, H., Aga, M., Yamamiya, T., Sugimoto, K. and Tsuruta, Y. (Toho Rayon Co, Ltd and Taisei Corporation, both of Tokyo, Japan) US Pat 5 030 282 (9 July 1991) This composite is composed of unidirectional continuous carbon fibres and a cured cement composition. The raw material for the composite contains 5-30 volume% carbon fibres. The cement composition contains 30 weight% of particles which are 0.014).I times smaller than the average diameter of the fibres; the rest of the cement particles are 0.1 1 times the average diameter of the fibres in size. Tungsten carbide-containing hard alloy that may be processed by melting Scruggs, D.M. and Croopnick, G.A. (Amorphous Metals Technologies, Inc, Irvine, CA, USA) US Pat 5 030 519 (9 July 1992) The composite has 15-60 weight% tungsten carbide dispersed in a matrix containing 15-45 weight% Cr, 0-3 weight%, Si, 2-6 weight% B, 3-11 weight% Ti with the balance being Fe. Stabilised glass reinforced polyacetal compositions Wagman, M.E. (E.I. Du Pont de Nemours and Company, Wilmington, DE, USA) US Pat 5 030 668 (9 July 1991) A composite consists of 0.02-1.0 weight% of at least one epoxy-containing compound, 5 50 weight% glass fibres coated with at least one polyurethane and 49-94.98 weight% of at least one polyacetal polymer. Glass fibre reinforced polyolefin resin composition Nomura, M., Mizuno, H. and Wada, K. (Idemitsu Petrochemical Company Limited, Tokyo, Japan) US Pat 5 030 682 (9 July 1991) A composite contains 100 parts by weight of 15-80 weight% polypropylene-1 with a density of 0.814).91 g cm -3, 2 0 ~ 0 weight% polypropylene-1 with a density of at least 0.9 g cm 3 and 5-50 weight% glass fibre with 0-5 parts by weight of polyolefin modified with an unsaturated carboxylic acid or its derivative and 0.01-3 parts by weight of a crystal nucleating agent. Carbon fibre reinforced cement concrete composites improved by using chemical agents (Chung, D.D.L. of Pittsburgh, PA, USA) US Pat 5 032 181 (16 July 1991) A concrete with high tensile and flexural strength, low electrical resistivity and good electromagnetic shielding properties is described. The concrete comprises Portland cement, 0.1-4 weight% of carbon fibres, 0.020.1 weight% polyethanolamine and either 0.1-1 weight% of metal sulfate and metal aluminium sulfate admixture or 0.1-! weight% of metal nitrate and 0.1 3 weight% of metal chloride. Thermoplastic web and process for manufacture same Isayev, A.I. and Subramanian, P.R. (The University of Akron, Akron, OH, USA) US Pat 5 032 433 (16 July 1991) An open web of interconnected fibres comprises a thermoplastic-based polymer matrix reinforced with microscopic fibres of a liquid crystal polymer, wherein the microscopic fibres were formed in situ. Reinforced polymers Hanley, S.J. (Shell Oil Company, Houston, TX, USA) US Pat 5 034 431 (23 July 1991)
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A composition comprises a linearly alternating polymer of carbon monoxide and at least one ethylenically unsaturated hydrocarbon and 1-45 weight% of glass fibre coated with a sizing agent. The sizing agent contains an aminosilane and polymeric film former with polyurethane and epoxy functional groups. Composite dental cement composition containing titanium Cohen, B.I., Deutsch, A.S. and Sharma, B.D. (Essential Dental Systems, Inc, South Hackensack, N J, USA) US Pat 5 034 433 (23 July 1991) The dental cement contains 10-50 weight% polymer matrix, 35-80 weight% filler and 2-5 weight% titanium powder. At least 2 weight% of the total composition is silanated titanium powder. Thermoplastic moulding materials based on polyamides and polyester elastomers Betz, W., Plachetta, C., Koch, E.M. Blinne, G. and Pipper, G. (BASF Aktiengesellschaft, Ludwigshafen, Germany) US Pat 5 034 450 (23 July 1991) A moulding material comprises 50-99 weight% thermoplastic polyamide with a melting point > 200°C, 1 5 weight% of a segmented copoly(ether-ester) containing long chain segments derived from poly(alkylene) ether glycols and short chain segments derived from diols and 0-50 weight% fibrous or particulate material or a mixture of stabilizers, anti-oxidants, lubricants, mould release agents or colourants.
PROCESSES Bridge joint construction Benneyworth, D.F. and Baker, R.J. (Koch Materials Company, Wichita, KS, USA) US Pat 5 024 554 (18 June 1991) The expansion gap between structural members is overlaid with a channel lined with an elastomeric material. A base layer of aggregate and elastomeric binder is applied and then one or more succeeding layers of aggregate and elastomeric binder are applied with the thickness of each layer being about the same as the maximum size of the aggregate. Finally, a top layer which contains substantially smaller aggregates is applied. Method and apparatus for composite pole repair Owen, R.A and Hannay, R.C. (Team, Inc, Alvin, TX, USA) US Pat 5 027 575 (2 July 1991) A method of in situ repair is described in which the area round the pole is excavated to a predetermined depth; the surface of the pole is cleaned and treated in this region. Fibre mats saturated with liquid composite are used to form a cylindrical encasement of desired thickness. The mats are saturated by placing them in a liquid-filled tray and rolling them with a paint roller to remove entrapped air. Melt process for the production of metalmatrix composite materials with enhanced particle/matrix wetting Lloyd, D.J., McLeod, A.D. and Morris, P.L. (Alcan International Ltd, Montreal, Canada) US Pat 5 028 392 (2 July 1991) A molten aluminium alloy that contains at least some magnesium and less than 35 volume% insoluble particles is placed in a closed reactor; a vacuum is applied; the inter-
COMPOSITES. NUMBER 7 . 1993
ior is then pressurized with nitrogen gas; the alloy and particles are mixed; and then the reactor is evacuated in a stepwise manner. Method and titanium aluminide matrix composite Eylon, D.E., Revelos, W.C. and Smith, P.R. (Secretary of the Air Force, Washington, DC, USA) US Pat 5 030 277 (9 July 1991) Filaments of silicon carbide, silicon-carbidecoated boron, boron-carbide-coated boron, titanium-carbide-coated silicon carbide or silicon-coated silicon carbide are coated with a beta-stabilized Ti3A1 powder containing an excess, sacrifical quanitity of beta-stabilizer. The coated filaments are formed into a preform with a beta-stablized Ti3A1 powder conmining no excess stabilizer and the composite is consolidated by the application of heat and pressure to the preform. Process for producing ceramic composites Ogata, T., Mori, T. and Kuwajima, H. (Toray Industries, Inc, Tokyo, Japan) US Pat 5 030 597 (9 July 1991) A powder of at least one of ZrB2, HfB2, ZrC, HfC, ZrN and HfN is mixed with a powder of at least one of TiC, TiN and TiO2. The mixture is sintered in a non-oxidizing atmosphere to form a composite containing at least one of Ti2, TiC or TiN and at least one ofZrC, ZrN, Zr02, HfC, HfN and Hf02. System for nondestructively determining composite material parameters Kline, R.A. (Board of Regents of the OU, Norman, OK, USA) US Pat 5 031 457 (16 July 1991) Two independent acoustic waves are propagated t h r o u g h a composite with known density, component elastic moduli and lay-up sequence; their velocities are determined and, along with the thickness of the material, used to calculate the fibre volume fraction and resin porosity of the composite. High impact resistant ceramic composite Derkacy, J.A. (Aluminium Company of America, Pittsburgh, PA, USA) US Pat 5 032 550 (16 July 1991) A mixture of 60-75 volume% ,8-SIC, 25-40 volume% TiB2 and 0.5-3 weight% A1203 is hot pressed (at a temperature less than that required for t-SiC to convert to ~-SiC) to form a fl-SiC/TiB2 composite with high impact resistance. Tough silicon carbide composite material containing fibrous boride Tani, T. and Wada, S. (Kabushiki Kaisha Toyota Chuo Kenkyusho, Aichi, Japan) US Pat 5 034 355 (23 July 1991) A composite is formed of silicon carbide and a boride of formula MxBy (x and y are both' integers) wherein at least 10% of the boride is the form of fbres with an aspect ratio greater than 3. The composite is produced by first preparing a mixture of silicon carbide, a nonboride compound containing at least one ele-I ment of groups IVa to Via (of which at least 10% is in the form of fibres with an aspect ratio of 3 or above) and a boron-containingI compound which does not contain any ele-! ments of groups IVa to Via but which con-, tains more boron that required stoichiometri-i cally to form a boride with the IVa to Via element present. This mixture is then sintered! in a vacuum or non-oxidizing atmosphere t~ produce the composite.
596
A composition comprises a linearly alternating polymer of carbon monoxide and at least one ethylenically unsaturated hydrocarbon and 1-45 weight% of glass fibre coated with a sizing agent. The sizing agent contains an aminosilane and polymeric film former with polyurethane and epoxy functional groups. Composite dental cement composition containing titanium Cohen, B.I., Deutsch, A.S. and Sharma, B.D. (Essential Dental Systems, Inc, South Hackensack, N J, USA) US Pat 5 034 433 (23 July 1991) The dental cement contains 10-50 weight% polymer matrix, 35-80 weight% filler and 2-5 weight% titanium powder. At least 2 weight% of the total composition is silanated titanium powder. Thermoplastic moulding materials based on polyamides and polyester elastomers Betz, W., Plachetta, C., Koch, E.M. Blinne, G. and Pipper, G. (BASF Aktiengesellschaft, Ludwigshafen, Germany) US Pat 5 034 450 (23 July 1991) A moulding material comprises 50-99 weight% thermoplastic polyamide with a melting point > 200°C, 1 5 weight% of a segmented copoly(ether-ester) containing long chain segments derived from poly(alkylene) ether glycols and short chain segments derived from diols and 0-50 weight% fibrous or particulate material or a mixture of stabilizers, anti-oxidants, lubricants, mould release agents or colourants.
PROCESSES Bridge joint construction Benneyworth, D.F. and Baker, R.J. (Koch Materials Company, Wichita, KS, USA) US Pat 5 024 554 (18 June 1991) The expansion gap between structural members is overlaid with a channel lined with an elastomeric material. A base layer of aggregate and elastomeric binder is applied and then one or more succeeding layers of aggregate and elastomeric binder are applied with the thickness of each layer being about the same as the maximum size of the aggregate. Finally, a top layer which contains substantially smaller aggregates is applied. Method and apparatus for composite pole repair Owen, R.A and Hannay, R.C. (Team, Inc, Alvin, TX, USA) US Pat 5 027 575 (2 July 1991) A method of in situ repair is described in which the area round the pole is excavated to a predetermined depth; the surface of the pole is cleaned and treated in this region. Fibre mats saturated with liquid composite are used to form a cylindrical encasement of desired thickness. The mats are saturated by placing them in a liquid-filled tray and rolling them with a paint roller to remove entrapped air. Melt process for the production of metalmatrix composite materials with enhanced particle/matrix wetting Lloyd, D.J., McLeod, A.D. and Morris, P.L. (Alcan International Ltd, Montreal, Canada) US Pat 5 028 392 (2 July 1991) A molten aluminium alloy that contains at least some magnesium and less than 35 volume% insoluble particles is placed in a closed reactor; a vacuum is applied; the inter-
COMPOSITES. NUMBER 7 . 1993
ior is then pressurized with nitrogen gas; the alloy and particles are mixed; and then the reactor is evacuated in a stepwise manner. Method and titanium aluminide matrix composite Eylon, D.E., Revelos, W.C. and Smith, P.R. (Secretary of the Air Force, Washington, DC, USA) US Pat 5 030 277 (9 July 1991) Filaments of silicon carbide, silicon-carbidecoated boron, boron-carbide-coated boron, titanium-carbide-coated silicon carbide or silicon-coated silicon carbide are coated with a beta-stabilized Ti3A1 powder containing an excess, sacrifical quanitity of beta-stabilizer. The coated filaments are formed into a preform with a beta-stablized Ti3A1 powder conmining no excess stabilizer and the composite is consolidated by the application of heat and pressure to the preform. Process for producing ceramic composites Ogata, T., Mori, T. and Kuwajima, H. (Toray Industries, Inc, Tokyo, Japan) US Pat 5 030 597 (9 July 1991) A powder of at least one of ZrB2, HfB2, ZrC, HfC, ZrN and HfN is mixed with a powder of at least one of TiC, TiN and TiO2. The mixture is sintered in a non-oxidizing atmosphere to form a composite containing at least one of Ti2, TiC or TiN and at least one ofZrC, ZrN, Zr02, HfC, HfN and Hf02. System for nondestructively determining composite material parameters Kline, R.A. (Board of Regents of the OU, Norman, OK, USA) US Pat 5 031 457 (16 July 1991) Two independent acoustic waves are propagated t h r o u g h a composite with known density, component elastic moduli and lay-up sequence; their velocities are determined and, along with the thickness of the material, used to calculate the fibre volume fraction and resin porosity of the composite. High impact resistant ceramic composite Derkacy, J.A. (Aluminium Company of America, Pittsburgh, PA, USA) US Pat 5 032 550 (16 July 1991) A mixture of 60-75 volume% ,8-SIC, 25-40 volume% TiB2 and 0.5-3 weight% A1203 is hot pressed (at a temperature less than that required for t-SiC to convert to ~-SiC) to form a fl-SiC/TiB2 composite with high impact resistance. Tough silicon carbide composite material containing fibrous boride Tani, T. and Wada, S. (Kabushiki Kaisha Toyota Chuo Kenkyusho, Aichi, Japan) US Pat 5 034 355 (23 July 1991) A composite is formed of silicon carbide and a boride of formula MxBy (x and y are both' integers) wherein at least 10% of the boride is the form of fbres with an aspect ratio greater than 3. The composite is produced by first preparing a mixture of silicon carbide, a nonboride compound containing at least one ele-I ment of groups IVa to Via (of which at least 10% is in the form of fibres with an aspect ratio of 3 or above) and a boron-containingI compound which does not contain any ele-! ments of groups IVa to Via but which con-, tains more boron that required stoichiometri-i cally to form a boride with the IVa to Via element present. This mixture is then sintered! in a vacuum or non-oxidizing atmosphere t~ produce the composite.