Abstract: A method of and an apparatus for vapor-phase synthesizing a hard material use a raw material gas supplied into a reaction tube (6) while irradiating a region of the reaction tube (6) with microwaves (18) of a prescribed frequency for causing a synthesizing reaction to produce the hard material along a prescribed direction, by a plasma generation. In the reaction tube (6), at least two plate electrodes (17a, 17b, 19a, 19b) are oppositely arranged in parallel vertically to electric fields of the microwaves (18), so that the plasma is excited between the plate electrodes (17a, 17b, 19a, 19b) for vapor-phase synthesizing the hard material. The microwaves (18) of high electric power are introduced into the reaction tube (6) through a waveguide (5) without loss, so that strong electric fields can be homogeneously and stably distributed between the opposite plate electrodes.

Abstract: A diamond synthesizing method introduces a mixed gas of hydrocarbon gas and hydrogen gas into a reaction vessel (9) which is maintained under a pressure of 1 to 100 Torr. A dc discharge is caused across a cathode (1) and an anode (2), thereby depositing diamond on a substrate (3) which is placed on the anode (2). A positive column of H.alpha.>CH is produced with a high formation rate of atomic hydrogen for promoting decomposition of the hydrocarbon gas, and the concentration of hydrocarbon is reduced while maintaining the condition. According to this method, it is possible to synthesize high-quality diamond, which hardly any non-diamond carbon components such as amorphous carbon and graphite, at a film forming rate of about 1 .mu.m/h.

Abstract: A diamond synthesizing apparatus has a reaction tube for internally causing a reaction for vapor-phase synthesizing diamond. A plasma generator produces the required microwave plasma in the reaction tube. The reaction tube is coupled with a gas reservoir, which forms a circulation system with the reaction tube. The circulation system is connectable to an exhaust for evacuating its interior. This circulation system further includes a pump for circulating raw material gas, which is a compound containing carbon. A raw material gas supply is also connectable to the circulation system, for intermittently supplying the raw material gas into the circulation system. During the synthesizing operation the circulation system is completely closed. According to this diamond synthesizing apparatus, it is possible to keep pressure fluctuations and composition fluctuations following a reaction and gas addition, to the minimum and to vapor-phase synthesize diamond in very restricted ranges of gas composition and pressure.

Abstract: This invention provides an optical recording material comprising a base and a thin film formed on the base and composed of oxides which are represented by the formula (V.sub.2 O.sub.5).sub.1-x. (M.sub.y O.sub.z).sub.x wherein M.sub.y O.sub.z is at least one of metal oxides, metalloid oxides and non-metal oxides, and 0.ltoreq.x<1 and which have an amorphous or layer structure and a process for preparing an optical recording material, the process comprising the steps of applying to a base a solution, sol solution or gel solution of amorphous oxides represented by the formula (V.sub.2 O.sub.5).sub.1-x.(M.sub.y O.sub.z).sub.x wherein M.sub.y O.sub.z is at least one of metal oxides, metalloid oxides and nonmetal oxides, and 0.ltoreq.x<1, and evaporating off the solvent.

Abstract: This invention provides an amorphous ferromagnetic oxide represented by the formulaA.sub.x.(MmOn).sub.y.(Fe.sub.2 O.sub.3).sub.zwherein A represents at least one of Bi.sub.2 O.sub.3, V.sub.2 O.sub.5, TeO.sub.2 and GeO.sub.2 ; M represents at least one of Mn, Fe, Co, Ni, Cu, Mg, Zn, Cd, Ca, Pb, Ba, Sr and rare earth elements; when M is not a rare earth element, m=1 and n=1; when M is a rare earth element, m=2 and n=3; O<x.ltoreq.80, O<y.ltoreq.60 and 5.ltoreq.z.ltoreq.60 and x+y+z=100, provided that when M is Co, O<x<60, O<y<60 and 40.ltoreq.z.ltoreq.60, and processes for preparing the same.

Abstract: A sintered compact of cubic boron nitride is made by adsorbing and/or diffusing 0.005 to 1.000 percent by weight of water into a boron nitride compact containing alkaline earth metal boron nitride as a catalyst. The so prepared compact is then subjected to a treatment under high pressure at a relatively low temperature to form a dense cubic boron nitride sintered compact of high purity.