Showing papers on "Boron oxide published in 2001"

Unique morphologies of boron nitride nanotubes

Abstract: Unusual morphological features of boron nitride nanotubes produced via metal–oxide-promoted high-temperature syntheses from carbon nanotubes, boron oxide, and nitrogen were observed using high-resolution transmission electron microscopy. The tubes normally displayed open ends and preferentially two or four tubular layers as revealed by statistical analysis of 600 nanotubes. In addition, the total amount of tubes with even number of shells (61% occurrence) markedly prevailed over that with odd number of shells (39%). All three characteristics are exceptional for BN compared to other layered materials which may be assembled in tubules.

A novel boron nitride supported Pt catalyst for VOC incineration

Abstract: Low-crystalline hexagonal boron nitride (h-BN) and γ-alumina supported Pt catalysts were employed to investigate the catalytic destruction of volatile organic compounds (VOC). The 0.3 wt.% Pt catalysts were prepared via incipient wetness method using H2PtCl6 as precursor. The oxidation of volatile gasoline was performed in a concentration of 2500 ppmv with volume hour space velocity (VHSV) near 20 000 h−1 from 100 to 500°C. Instead of deactivation, the activity of Pt/h-BN increased significantly in the second run of the oxidation reaction. The light-off temperature (50% conversion) decreased from 210 to 160–170°C in the second run of oxidation. Furthermore, 95% conversion was achieved at less than 200°C. Meanwhile, the Pt/γ-Al2O3 became deactivated in the second run of oxidation. The activity of Pt/h-BN was maintained for three temperature cycles. Long-term oxidation proved that Pt/h-BN activity did not decline over up to 80 h. The positive binding energy shift from XPS revealed that a few boron oxide impurities contaminated on the h-BN surface, these provided the anchorage for the Pt clusters. Metallic Pt surface was oxidized to PtO during the initial oxidation, thus enhancing the oxidation activity. Based on irreversible H2 chemisorption, the platinum dispersion of Pt/h-BN were near 20% and did not change after oxidation at 500°C. Metal sintering was minimal, owing to the high thermal conductivity of h-BN, which prevented any hot spots of oxidation on Pt sites. In sum, experimental results demonstrated that Pt/h-BN was a promising catalyst for VOC destruction.

Grey glass composition including erbium

Abstract: A grey glass composition employing as its colorant portion at least iron (Fe2O3/FeO) and erbium oxide (e.g., Er2O3), and also preferably selenium and cobalt. An exemplary colorant portion for use in a glass composition (with a soda lime silica or other suitable base glass) includes, by weight percentage : total iron (expressed as Fe2O3) :0.1 to 0.6%; erbium oxide (e.g., Er2O3) : 0.3 to 1.5%; selenium (Se) : 0.0002 to 0.0010%; cobalt oxide (e.g., Co3O4) : 0.0005 to 0.0018%; titanium oxide (e.g., TiO2) : 0.0 to 1.0%; boron oxide (e.g., B2O3) : 0.0 to 2.0%. The resulting glass may exhibit high visible transmittance (Lta), while at the same time low UV and IR transmittance.

Grey glass composition including erbium and holmium

Abstract: A glass composition employing as its colorant portion at least iron (total iron expressed as Fe 2 O 3 ), erbium (e.g., Er 2 O 3 ), and holmium (e.g., Ho 2 O 3 ). The glass may be grey or otherwise colored in different embodiments. In certain example embodiments the colorant portion may include, by weight percentage: Ingredient wt. % total iron: 0.10-0.90% erbium oxide: 0.20-2.50% selenium: 0.0-0.0020% cobalt oxide: 0.0-0.0050% titanium oxide: 0.0-2.0% boron oxide: 0.0-2.0% holmium oxide: 0.10-1.60% thulium oxide: 0.0-2.0% ytterbium oxide: 0.0-3.0% lutetium oxide: 0.0-1.0%.

Polarization interactions and boroxol ring formation in boron oxide: A molecular dynamics study

Abstract: We employ molecular dynamics (MD) simulations to study the structure of vitreous boron oxide. Although six-membered boroxol rings have been observed at fractions over 60% by various experimental techniques, simulation methods have not produced similar results. We adapt the polarization model, which includes many body polarization effects thought to stabilize such structures, for boron–oxygen interactions. This model is then used in MD simulations of boron oxide glass at various temperatures. We find a variation in the fraction of rings depending on the temperature of the system during network formation. The maximum ring fraction (∼33%) occurs when the sample is prepared at low temperatures. At these temperatures, the energy level of boron atoms in rings is 1.6% lower than the energies of boron atoms outside of rings. When higher equilibration temperatures are used, the fraction drops to 11%. Thus, two factors are relevant to boroxol ring formation in simulations of boron oxide, a model which incorporates polarization effects or their equivalent, and the appropriate manipulation of temperature history.

Insulator ceramic composition

Abstract: An insulator ceramic composition making it possible to obtain a sintered material which can be fired at low temperature of 1000° C., can be co-sintered with Ag and Cu, exhibits superior mechanical strength, exhibits high Q value and is appropriate for using high frequencies, is provided. The insulator ceramic composition is composed of (A) an MgO—MgAl 2 O 4 ceramic powder, and (B) a glass powder containing silicon oxide in a proportion of about 13 to 50 weight % in terms of SiO 2 , boron oxide in a proportion of about 3 to 60 weight % in terms of B 2 O 3 , and aluminum oxide in a proportion of 0 to about 20 weight % in terms of Al 2 O 3 .

Article coated with water-repellent film, liquid composition for coating with water-repellent film, and process for producing article coated with water-repellent film

Abstract: There are provided articles coated with high-performance water-repellent films with high hardness that can withstand outdoor use, which are water-repellent film-coated articles that comprise a substrate and a water-repellent film composed mainly of silicon oxide and having a water-repellent group coated on the surface of the substrate, and are characterized by containing at least one type of metal oxide selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide and boron oxide, as well as a process for preparation of such water-repellent film-coated articles at a high rate of productivity and a coating liquid composition for preparation of such water-repellent film-coated articles.

Endoscope optical system including composition having durability to a sterilization treatment

Abstract: A composition has a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light. The composition comprises a group A including 15 to 23 mol % of lanthanum oxide, 3 to 8 mol % of gadolinium oxide, 3 to 8 mol % of tantalum oxide, and 8 mol % or less of yttrium oxide; a group B including 30 to 45 mol % of boron oxide, 20 mol % or less of silicon oxide, and 20 mol % or less of germanium oxide; zero mol % of alkaline metal oxide or alkaline earth metal oxide; and a group D including 0.3 to 15 mol % of niobium oxide and 3 to 15 mol % of zirconium oxide. A mol % ratio A/B between the group A and group B is 80% or more, and a dissolving-out rate of metal ion of the composition is 0.002×10−6 mol/hour or less per square centimeter. In case of applying the composition to an endoscope including an observation system and an illuminating system, an optical element disposed at the outer surface of the observation system and an optical element disposed at the outer surface of the illuminating system are formed of the composition.

Insulative ceramic compact

Abstract: An insulative ceramic compact is composed of a fired mixture of (A) a MgAl 2 O 4 , Mg 3 B 2 O 6 and/or Mg 2 B 2 0 5 ceramic powder, and (3) a glass powder including from about 13 to 50% by weight of silicon oxide in terms of SiO 2 , from 8 to 60% by weight of boron oxide in terms of B 2 O 3 , about 20% by weight or less of aluminum oxide in terms of A1 2 O 3 , and from about 10 to 55% by weight of magnesium oxide in terms of MgO. The insulative ceramic compact can be obtained by firing at low temperatures of about 1000° C. or less, can be obtained by sintering with Ag or Cu, has a low dielectric constant and a high Q value, and is suitable for use in the high-frequency range.

Density as a probe of oxide glass structure

Abstract: In this paper we examine the proposition that density and molar volume can be directly related to short range structure in a host of oxide glasses. In particular, we look at a variety of borates, silicates, germanates, vanadates, and thioborates. Within these families we report results from both binary and ternary systems. We believe it is possible to see evidence in density trends for changes in the short range order as modification of the glass proceeds. For example we see evidence for coordination changes. Also we speculate that it is possible to discern changes in this physical property due to changes at the intermediate or mesounit level; as an example the density of vitreous boron oxide is some 40% lower than its crystal form. This is thought due to the presence of boroxol rings in the glass and absence of such rings in the crystal.

Thermal, acoustic, and nuclear magnetic resonance studies of cesium borate glasses

Abstract: The purpose of this study was to compare the physical properties and structure of cesium borate glasses. Cesium borate glasses can be denoted as RCs 2 O.B 2 O 3 , where R is the molar ratio of cesium oxide to boron oxide. We report a detailed study of the glass transition temperature (T g ) of these cesium borate glasses with 0.0 ≤ R ≤ 0.55. Initially, the T g increased monotonically as R rose. It then leveled out at R = 0.35 and fell at R = 0.425. The T g data obtained using a differential scanning calorimeter (DSC) are in good agreement with Kodama et al.'s T g results from a differential thermal analyzer (DTA) as well as Chryssikos' model of the number of bridging oxygens per boron (Z). We determined the fraction of boron atoms in tetrahedral co-ordination, N 4 , for the same cesium borate glass samples using 11 B NMR. The N 4 fractions followed a curve similar to that of the T g results until R = 0.45, where it continued to rise as the T g fell. Also, the N 4 data have a similar trend but are consistently higher than those calculated from a model which employed Kodama and Kojima's ultrasonic velocity data. Finally, the NMR data do not display a significant lowering of the N 4 fraction in cesium borate when compared to lithium borate glasses.

Boron compound/amine oxide compositions

Abstract: The present invention provides a composition comprising an amine oxide and a boron compound. The boron compound may be boric acid, diboron tetrahydroxide, a borate, a boron oxide, a borane, or any combination of any of the foregoing. Another embodiment of the present invention is a method for preserving and/or waterproofing a wood substrate by contacting the composition with the wood substrate. Yet another embodiment of the present invention is a method for controlling plants, insects, or fungi or regulating the growth of plants comprising applying an insecticidal, herbicidal, fungicidal, or plant growth regulating effective amount of a composition of the present invention to the plants, fungi, insects, the seeds of the plants, or the area on which the plants or fungi grow.

Conductive paste and ceramic electronic device using the same

Abstract: A conductive paste is provided which can ensure plating adhesion and joint strength between an external electrode and a ceramic body, and which can prevent sticking between electronic devices. The conductive paste, which contains substantially no alkaline earth metal and no lead, comprises powdered silver; a powdered glass containing an alkali metal oxide, boron oxide, silicon oxide, zinc oxide, and aluminum oxide; and an organic vehicle; wherein the powdered glass is composed of about 5 to 12 percent by weight of alkali metal oxide as M 2 O, M being at least one element selected from the group consisting of Li, Na, K, Rb, Cs and Fr, about 35 to 45 percent by weight of boron oxide as B 2 O 3 , about 10 to 20 percent by weight of silicon oxide as SiO 2 , about 35 to 45 percent by weight of zinc oxide as ZnO, and about 1 to 5 percent by weight of aluminum oxide as Al 2 O 3 .

Molecular Dynamics Study of the Self-Diffusion of Ions in B2O3 Melt at High Pressure

Abstract: Molecular dynamics (MD) simulations were carried out in order to investigate the structure and transport properties of boron oxide melt, as a function of pressure. The simulations show a rapid initial increase in the diffusion coefficients of boron and oxygen ions to ∼5−7 GPa, followed by a slower increase from 7 to 14 GPa. The increase in ion diffusivities is correlated with an increase in the proportion of BO4 to BO3 units. These results can be used to help rationalize an increase in growth rate of boron suboxide (B6O) crystals, observed from B2O3−B6O melts in the 0−4 GPa pressure range.

Barium lanthanum silicate glass-ceramics

Abstract: This invention relates to glass-ceramic materials in the BaO-La2O3-SiO2 system, which are suitable for processing via a powder route, and which, after heat-treatment have a combination of high thermal expansion and excellent refractoriness. The precursor glass powders of the present invention have compositions on a weight percent basis of 10-55% BaO, 3-50% La2O3, 25-48% SiO2 and optionally up to 30% in total of other compatible metal oxides. The powders are substantially free from alkali metal oxides and from boron oxide such that the refractoriness of the glass-ceramic materials is not compromised. The materials may be advantageously employed at high temperatures in direct combination with other materials of high expansion or may be used to join or hermetically seal components made of other materials having similarly high expansion.

Composite element and method for preparation thereof

Abstract: A composite element which has a substrate (12) and a mixture film (14) formed on the surface thereof, wherein the mixture film (14) is comprised of a mixture of a boron oxide and a photocatalytic titanium oxide, exhibits high light transmissivity and is colorless and transparent. The composite element can be used for suppressing surface reflection or interference color, improving photocatalytic decomposition characteristics, increasing the speed of enhancing hydrophilicity, or the like.

Container for housing electronic component

Abstract: PROBLEM TO BE SOLVED: To make a container smaller and thinner while improving the sealing performance thereof. SOLUTION: The container for housing an electronic component comprises an insulation substrate 1 having a concave portion in the top face, and a lid 2 which is joined to the top face of the insulation substrate 1 via a glass sealing material 6 having a space between itself and the insulation substrate 1 to airtightly house an electronic component 3. The lid 2 is formed of a plate material having a thickness of 0.3 mm or less. The outside dimension of the lid 2 is smaller by 0.1-0.3 mm than that of the insulation substrate 1, with external sides of the lid 2 receding by 0.02-0.28 mm from those of the insulation substrate 1 over the entire circumference of the insulation substrate 1. The glass sealing material 6 is formed of a glass component added with an willemite compound of 20-40 wt.% whose average grain diameter is 2.5-4 μm and the maximum grain diameter is 35 μm or less. The glass component contains bismuth oxide of 65-80 wt.%, sodium oxide of 5-15 wt.%, boron oxide of 2-10 wt.%, barium oxide of 1-5 wt.%, copper oxide of 1-5 wt.%, aluminum oxide of 0.5-2 wt.%, silicon oxide of 0.5-2 wt.%, and zinc oxide of 0.5-2 wt.%. COPYRIGHT: (C)2005,JPO&NCIPI

Carbonaceous cathode with enhanced wettability for aluminum production

Abstract: A method of preparing carbonaceous blocks or bodies for use in a cathode in an electrolytic cell for producing aluminum wherein the cell contains an electrolyte and has molten aluminum contacting the cathode, the cathode having improved wettability with molten aluminum. The method comprises the steps of providing a carbonaceous block and a boron oxide containing melt. The carbonaceous block is immersed in the melt and pressure is applied to the melt to impregnate the melt into pores in the block. Thereafter, the carbonaceous block is withdrawn from the melt, the block having boron oxide containing melt intruded into pores therein, the boron oxide capable of reacting with a source of titanium or zirconium or like metal to form titanium or zirconium diboride during heatup or operation of said cell.

Dielectric ceramic composition and multi layered ceramic substrate

Abstract: A multilayered ceramic substrate is produced by laminating and sintering insulating ceramic layers and one or more dielectric ceramic layers. The insulating ceramic layer is composed of a BaO—Al 2 O 3 -SiO 2 low temperature sintering ceramic material. The dielectric ceramic layer is composed of a dielectric ceramic material containing a dielectric ceramic component represented by BaO—TiO 2 -(Nd 1—m Me m )O {fraction (3/2)} wherein Me is a lanthanoid and 0≦m≦1.0, and a glass component of about 20.0 to 65.0 mole percent of barium oxide, about 5.0 to 50.0 mole percent of silicon oxide and about 10.0 to 50.0 mole percent of boron oxide.

Compositions comprising a boron compound and an amine oxide

Abstract: The present invention provides a composition comprising an amine oxide and a boron compound. The boron compound may be boric acid, diboron tetrahydroxide, a borate, a boron oxide, a borane, or any combination of any of the foregoing. Another embodiment of the present invention is a method for preserving and/or waterproofing a wood substrate by contacting the composition with the wood substrate. Yet another embodiment of the present invention is a method for controlling plants, insects, or fungi or regulating the growth of plants comprising applying an insecticidal, herbicidal, fungicidal, or plant growth regulating effective amount of a composition of the present invention to the plants, fungi, insects, the seeds of the plants, or the area on which the plants or fungi grow.

Zinc oxide based sintered body and its manufacturing method and zinc oxide varistor

Abstract: PROBLEM TO BE SOLVED: To develop a zinc oxide based sintered boy for a zinc oxide varistor, which has a superior non-linear resistance characteristic and high reliability and is stable to heat treatment, where a leak current, in particular, in a low- current region is small. SOLUTION: Mixed powder of bismuth oxide and antimony oxide is heat- treated at 900 deg.C and is then cooled and powdered to make synthetic powder containing bismuth oxide and antimony oxide, and mixed powder containing boron oxide and chromium oxide is heat-treated at 370 deg.C and is then cooled and powdered to make synthesis powder containing boron oxide and chromium oxide. Then the synthetic powder containing bismuth oxide and antimony oxide, the synthesis powder containing boron oxide and chromium oxide, iron group oxide powders at least selected from among cobalt oxide, manganese oxide and nickel oxide, and aluminum compound are added to zinc oxide and mixed, molded, and burned at 950 deg.C to manufacture the zinc oxide based sintered body.

Electrically conductive paste and ceramic electronic component

Abstract: PROBLEM TO BE SOLVED: To provide an electrically conductive paste and ceramic electronic component, in which the strength of connection between an external electrode and a ceramic element assembly and an adhesion of metal plating are secured, and an adhesion among electronic components can be prevented. SOLUTION: In an electrically conductive paste and ceramic electronic component an electrically conductive powder including Ag, glass powder, and an organic vehicle are included, and substantially, the alkaline earth metals and lead are not contained. In the glass powder, alkaline metal oxide, boron oxide, silicon dioxide, zinc oxide, and aluminum oxide are included and when each of them are expressed as M2O (M is at least one of the kinds selected from among Li, Na, K, Rb, Cs, and Fr), B2O3, SiO2, ZnO, and Al2O3, the range with respect to a glass composition of 100 weight % are in the range 5<=M2O<=12, 35<=B2O3<=45, 10<=SiO2<=20, 35<=ZnO<=45, and 1<=Al2O3<=5 (in weight %).

Potassium-zinc-silicate glass sintering at low temperature

Abstract: Potassium-zinc silicate glass contains (in wt.%): 60.0-72.0 silica, 1.0-5.0 lithium oxide, 10.0-23.0 potassium oxide and 8.5-20.0 zinc oxide. Preferred Features: The glass additionally contains (in wt.%): 0-4.0 sodium oxide (Na2O), 0-4.0 magnesium oxide (MgO), 0-3.6 calcium oxide (CaO), 0-3.0 strontium oxide (SrO), 0-8.0 aluminum oxide (Al2O3), 0-3.3 boron oxide (B2O), 0-3.0 lanthanum oxide (La2O3), 0-6.0 zirconia (ZrO2), 0-2.5 titania (TiO2), 0-2.0 cerium oxide (CeO2), 0-5.0 tin oxide (SnO2), 0-1.0 phosphorus oxide (P2O5), 0-1.8 terbium oxide (Tb4O7), and 0-1.1 fluorine (F). The glass does not crystallize during thermal treatment in the region of 600-800 degrees C for 1 minute to 1 hour. The glass has a sintering temperature of less than 800, especially 760 degrees C or less, and has a linear thermal expansion coefficient of less than 12.3 x 10 K measured in the region of 100-400 degrees C. The glass additionally contains an apatite glass ceramic containing (in wt.%): 56.0-65.0 silica (SiO2), 1.8-5.3 lithium oxide (Li2O), 9.0-16.0 zinc oxide (ZnO), 3.5-10.5 calcium oxide (CaO), 2.0-6.0 P2O5 and 0.5-1.0 F.

Glass Formation and Properties of Glasses in the PbO–ZnO–B2O3System

Abstract: Glasses in the PbO–ZnO–B2O3system with a lead oxide content of less than 65 mol % are studied. The glass formation region for these glasses is determined. Their crystallization ability, density, and moisture resistance and the thermal, optical, and electrical properties are investigated. The composition–property curves are constructed. It is found that these dependences exhibit anomalies for glasses along the composition joins with constant boron oxide contents of 40 and 50 mol %. These anomalies can be associated with the change in the role of lead ions in the glass structure.

Laser synthesis of boron nitride powder

Abstract: Fine boron nitride powder has been synthesized from boron oxide by laser-induced reactions. Experiments were performed in a closed vacuum chamber to investigate the synthesis of boron nitride from the reaction system B 2 O 3 CH 4 and NH 3 using a CW 50 Watt CO 2 laser beam. The powders produced under different gas ratios of CH 4 /NH 3 have been characterized by infrared spectroscopy and in an environmental scanning electron microscope. The results show that the powders consist of a mixture of both cubic and hexagonal boron nitride.

Low-temperature burnable ceramic composition and ceramic multilayer substrate

Abstract: PROBLEM TO BE SOLVED: To a low-temperature burnable ceramic composition simultaneously sinterable together with a low-melting metal such as silver, copper, etc., having high strength and electric characteristics in good balance. SOLUTION: This low-temperature burnable ceramic composition is obtained by compounding (A) a ceramic component having crystal phases of MgO and MgAl2O4 with (B) a glass component composed of 13-50 wt.% of silicon oxide, 3-30 wt.% of boron oxide and 40-80 wt.% of an alkaline earth metal oxide.

Composition having improved durability to aterilization treatment and endoscope using the same

Abstract: A composition has a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light. The composition comprises a group A including 15 to 23 mol % of lanthanum oxide, 3 to 8 mol % of gadolinium oxide, 3 to 8 mol % of tantalum oxide, and 8 mol % or less of yttrium oxide; a group B including 30 to 45 mol % of boron oxide, 20 mol % or less of silicon oxide, and 20 mol % or less of germanium oxide; zero mol % of alkaline metal oxide or alkaline earth metal oxide; and a group D including 0.3 to 15 mol % of niobium oxide and 3 to 15 mol % of zirconium oxide. A mol % ratio A/B between the group A and group B is 80% or more, and a dissolving-out rate of metal ion of the composition is 0.002×10 −6 mol/hour or less per square centimeter. In case of applying the composition to an endoscope including an observation system and an illuminating system, an optical element disposed at the outer surface of the observation system and an optical element disposed at the outer surface of the illuminating system are formed of the composition.

Catalyst composition for aromatization of hydrocarbon

Abstract: PROBLEM TO BE SOLVED: To achieve higher selectivity by using a catalyst containing a zeolite comprising one or more elements selected from gallium and a lanthanide, belonging to an MFI, an MEL or an MFI/MEL group, and having a crystal lattice of a silicone oxide and one or more metal oxides selected from an aluminum oxide, a boron oxide and the like. SOLUTION: This catalyst composition comprises a zeolite having one or more elements selected from gallium and a lanthanide, an MFI, an MEL or an MFI/MEL structure, and a crystal lattice comprising a silicone oxide and at least one metal oxide selected from an aluminum oxide, a boron oxide and a gallium oxide. The catalyst composition preferably comprises the zeolite belonging to the MFI group and is characterized by such crystallite that 90% or more thereof has a diameter less than 500 Å and that is capable of forming an aggregate of the particle size less than 1 micron. Further, the catalyst composition may comprise rhenium, which results in providing higher selectivity.