Yasushi Kanzaki

Effect of dilution gases in methane on the deposition of diamond-like carbon in a microwave discharge

Abstract Diamond-like carbon was prepared by the decomposition of CH 4 in a microwave discharge. The effect of dilution gases, such as hydrogen, argon and helium, on the deposition was examined on the basis of identification of the deposits and the results of plasma diagnostics. When hydrogen was added diamond-like particles containing large amounts of hydrogen were obtained. Diamond-like films containing graphite and a smaller amount of hydrogen were deposited from the CH 4 -Ar plasma. The deposits from CH 4 and CH 4 -He plasmas consisted only of graphite. The correlation between the deposit and the species present in the plasma is discussed.

Nitriding of titanium in an r.f. discharge II: Effect of the addition of hydrogen to nitrogen on nitriding

Abstract The nitriding of titanium in a nitrogen or a nitrogen-hydrogen plasma prepared using an r.f. discharge was studied. The reaction kinetics obey a general relationship Δ 2 + AΔw = B ( t + τ ) The addition of hydrogen to the nitrogen plasma increased the weight gain. Electron spectroscopy for chemical analysis showed that N 1s based on the N—H bond and Si 2s electrons were present on the surface of the nitrided titanium. The effect of the addition of hydrogen to the nitrogen plasma is discussed in the light of the results of plasma diagnostics, such as emission spectroscopy, mass spectroscopy and the electrical double-probe technique, and the surface analysis.

Nitriding of titanium in microwave discharges

Abstract The nitriding of titanium in nitrogen and nitrogen-hydrogen plasmas prepared using a microwave discharge was studied. Power was supplied from a magnetron to the discharge tube through a rectangular wave guide. The specimens placed in the discharge tube were nitrided in the discharge region and in afterglow region. The nitriding products in the discharge region were similar to those in an r.f. discharge reported previously. In the afterglow region, nitriding proceeded even at 50 °C and it was promoted by increasing the temperature. The effects of active nitrogen in the afterglow region are briefly discussed in the light of the results of plasma diagnostics and surface analysis.

Titanium nitride deposition in an r.f. discharge

Abstract The deposition of titanium nitride (TiN) on a steel substrate from TiCl 4 in an N 2 or an N 2 -H 2 plasma obtained in an r.f. discharge was investigated. It was found that the addition of H 2 to the N 2 plasma promoted the formation of TiN, and that the substrate temperature could be much lower than that used in ordinary chemical vapour deposition processes.

On the yields of glow discharge electrolysis in various atmospheres

Etude de linfluence du milieu gazeux ambiant (Ar, He, N 2 , air ou O 2 ) sur le rendement de loxydation de H 2 SO 4 [H 2 O 2 et H 2 SO 5 ], FeSO 4 [Fe 3+ ], Ce 2 (SO 4 ) 3 [Ce 4+ ] et Tl 2 SO 4 [Tl 3+ ] dans une decharge luminescente

Alkali metal and alkali metal hydroxide intercalates of 2s-tantalum disulfide

Abstract The alkali metal intercalates of the layered compound 2 s -tantalum disulfide were prepared from the respective hexamethylphosphoric triamide solutions of the metals. The c -lattice parameters of the intercalates increased with increase in the crystallographic radii of the metals. All intercalates prepared were superconductors, and the transition temperatures increased as the crystallographic radii of the metals became larger. The intercalates reacted with water to produce hydrogen gas and changed to different intercalates. These had properties similar to those of the corresponding alkali metal hydroxide intercalates prepared from aqueous solutions of the metal hydroxides. The alkali metal hydroxide intercalates, on the other hand, were found to be classified into two groups in terms of the c -lattice parameters; one having c -lattice parameters around 23.8 A and the other 18 A. Lithium and sodium hydroxide intercalates belong to the former type, and potassium, rubidium and cesium hydroxide intercalates, including ammonium hydroxide, to the latter. Dried lithium and sodium hydroxide intercalates were also classified in the latter group. In the former case the disulfide was found to intercalate the cations, conserving the ice-like structure of the surrounding water molecules. In the latter, the cations were intercalated in their naked or primary hydrated states, and the interlayer distances were governed by cointercalated hydroxide ions. The observed superconducting transition temperatures were similar for the intercalates with c -lattice parameters around 18 A irrespective of the particular cation.

Nitriding of titanium with plasma jet under reduced pressure

The nitriding of titanium with argon-nitrogen (3%) and argon-nitrogen (3%)-hydrogen (2%) plasma jets at pressures of 190 torr was studied. The reaction kinetics obeyed mainly a parabolic law. The parabolic kinetic constants were 10−10–10−8 g2 cm−4 s−1, which were 2–3 orders of magnitude larger than those in R.F. discharges. From emission spectroscopy, nitrogen atoms in the excited states were observed. The nitrogen atoms can promote the nitriding reaction. The effect of the addition of hydrogen to nitrogen is also briefly discussed.

Formation of niobium boride from NB2O5 and boron with plasma arc

When a mixture of Nb2O5 and boron is heated to about 3000°C and subsequently annealed at about 2000°C in an argon plasma arc, NbB2 is obtained. The products are found to be superconductors, theTcof which is higher than 4 K. Some properties of the products, such as Vickers hardness and density, are comparable with those of NbB2 prepared from niobium and boron. In the reaction forming NbB2, a white powder is also obtained. The powder is identified as H3BO3 and is formed by the reaction between BO and water in the atmosphere. Therefore, the reaction of NbB2 formation can be written as Nb2O5+9B=2NbB2+5BO.

Heating and quenching of metastable superconducting compounds with a plasma jet

Superconducting compounds, such as cubic α-MoC1−x, cubic β-WC1−x, hexagonal MoB2, and cubic δ-TaN, which are metastable at room temperature, have been formed by heating and quenching of their respective equilibrium phases, such as hexagonal η-MoC1−x, hexagonal WC, rhombohedral Mo2B5, and hexagonal ε-TaN in a plasma jet. From calculations based on a simple model, the quenching rate of particles has been estimated to be 105 deg s−1.

Ion-exchange on synthetic zeolites in non-aqueous ammonia solutions of alkali metal nitrates

Abstract The ion-exchange on synthetic Na zeolites, 4A and 13X, in non-aqueous ammonia solutions of alkali metal nitrates have been investigated. When the ion-exchange was carried out in non-aqueous ammonia solutions of alkali metal nitrates, it was found that ammonia was adsorbed into zeolites as the ion-exchange reaction occurred and a greater amount of alkali metal ions were introduced in zeolites compared with to those exchanged in aqueous solutions. The results showed the formation of a new type of inclusion complex, in which ammoniated alkali metal ions are introduced and nitrate ions are co-included.