Virginia Tech Intellectual Properties Inc

Center for Innovative Technology

Virginia Polytechnic Institute and State University

Other

American Research Corporation of Virginia

Virginia Polytechnic and State University

Vpi&su

The Center of Innovative Technology

Virginia Polytechnic Institute

Jesse J Brown

Nancy R Brown

Deidre A Hirschfeld

Tingkai Li

Tawei Sun

Howard P Groger

Jin-Min Kim

Robert E Swanson

Usha Varshney

Yaping Yang

Sandra Gonzalez

Sandra Gonzales

Dean-Mo Liu

K H Lee

Steven Van Aken

Min Kang

Mg.sub.x Al.sub.2-2x Ti.sub.1+x O.sub.5 (x.ltoreq.0.2) protective coatings have been developed for both dense and porous substrates, such as SiC and Si.sub.3 N.sub.4, using a chemical solution processing method involving the hydrolysis and condensation of magnesium, aluminum and titanium precursors. The solution viscosities, pH values, H.sub.2 O/alkoxide molar ratios, and dip coating withdrawal rates which are optimum for crack-free Mg.sub.x Al.sub.2-2x Ti.sub.1+x O.sub.5 (x.ltoreq.0.2) are 1.0 to 6.2 cP, pH 1-4.5, molar ratio 1.5-10, and withdrawal rate of 2.2-8.0 cm/min, respectively. Conversion of the amorphous coating to crystalline Mg.sub.x Al.sub.2-2x Ti.sub.1+x O.sub.5 (x.ltoreq.0.2) is achieved by a succession of calcination below 450.degree. C. and a final heat treatment above 1000.degree. C. for ten hours with controlled heating and cooling rates.

Magnesium doped .beta.-aluminum titanate thin film coating

Alumino-silicate glass-ceramic coated carbon-carbon composite and graphitic substrates having resistance to oxidation and thermal cycling. The coatings are fabricated from plasma-sprayed powders of beta-spodumene, cordierite, beta-eucryptite or beta-quartz and are rapidly recrystallized by laser processing.

Laser densification of glass ceramic coatings on carbon-carbon composite

.beta.-Al.sub.2 TiO.sub.5 protective coatings have been developed for both dense and porous ceramics such as SiC and Si.sub.3 N.sub.4 using a chemical solution processing method involving the hydrolysis and condensation of aluminum tri-sec butoxide and titanium butoxide. The solution viscosities, pH values, H.sub.2 O/alkoxide molar ratios, and dip coating withdrawal rates required for crack-free .beta.-Al.sub.2 TiO.sub.5 are 1.0 to 6.2 cP, pH 1-4.5, molar ratio 1.5-10, and withdrawal rate of 2.2-8.0 cm/min, respectively. Conversion of the amorphous coating to crystalline .beta.-Al.sub.2 TiO.sub.5 is achieved by a succession of calcination below 450.degree. C. and a final heat-treatment at 1300.degree. C. for ten hours with controlled heating and cooling rates.

Sol-gel .beta.-aluminum titanate thin film coating

A scrubber for industrial exhaust systems advantageously employs liquid gallium to adsorb vapor phase mercury as well as sub-micron sized particulates such as other trace metal constituents from a hot gas exhaust stream in an industrial exhaust system. The temperature of the liquid gallium is elevated for optimum adsorption efficiency, and subsequently lowered to separate the adsorbed mercury and other species.

Heavy metal/particulate trap for hot gas clean-up

Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure are created using sol-gel processes. The processes have particular application in creating calcium magnesium zirconium phosphate, CMZP, coatings and foams.

Alkali corrosion resistant coatings and ceramic foams having superfine

A high temperature ceramic filter is produced from a composition containing refractory cement, aggregate, pore forming additives, and sintering agents. The pore forming additives are synthetic or organic powders or fibers which sublimate, melt, or otherwise disintegrate to produce In situ pores in the cement during the refractory treatment of a cast filter. The filters produced are permeable to high temperature gases commonly found in a coal furnace and can be used to collect particulate matter present in those gases.

Compositions for forming high temperature ceramic particulate filters

A heat processing procedure is used to create reinforcing whiskers of TiO.sub.2 in glass-ceramic materials in the LAS and MAS family. The heat processing procedure has particular application in creating TiO.sub.2 in-situ in a modified .beta.-eucryptite system.

Method of making in-situ whisker reinforced glass ceramic

Compositions having the general formula (Ca.sub.x Mg.sub.1-x)Zr.sub.4 (PO.sub.4).sub.6 where x is between 0.5 and 0.99 are produced by solid state and sol-gel processes. In a preferred embodiment, when x is between 0.5 and 0.8, the MgCZP materials have near-zero coefficients of thermal expansion. The MgCZPs of the present invention also show unusually low thermal conductivities, and are stable at high temperatures. Macrostructures formed from MgCZP are useful in a wide variety of high-temperature applications. In a preferred process, calcium, magnesium, and zirconium nitrate solutions have their pH adjusted to between 7 and 9 either before or after the addition of ammonium dihydrogen phosphate. After dehydration to a gel, and calcination at temperatures in excess of 850.degree. C. for approximately 16 hours, single phase crystalline MgCZP powders with particle sizes ranging from approximately 20 nm to 50 nm result. The MgCZP powders are then sintered at temperatures ranging from 1200.degree. C. to 1350.degree. C. to form solid macrostructures with near-zero bulk coefficients of thermal expansion and low thermal conductivities. Porous macrostructures of the MgCZP powders of the present invention are also formed by combination with a polymeric powder and a binding agent, and sintering at high temperatures. The porosity of the resulting macrostructures can be adjusted by varying the particle size of the polymeric powder used.

Ceramic materials with low thermal conductivity and low coefficients of

A high temperature ceramic filter is produced from a composition containing efractory cement, aggregate, pore forming additives, and sintering agents. The pore forming additives are synthetic or organic powders or fibers which sublimate, melt, or otherwise disintegrate to produce in situ pores in the cement during the refractory treatment of a cast filter. The filters produced are permeable to high temperature gases commonly found in a coal furnace and can be used to collect particulate matter present in those gases.

Growing community of inventors

Christiansburg, VA, United States of America

Jesse J Brown