Abstract: A process for forming a silica film on a substrate, comprising the steps of preparing a liquid composition comprising silicic acid, water, an alkali and an organic solvent, said liquid composition having a volume ratio of water to the organic solvent in a range of 0.2 to 10.0 and a concentration of silicon element in a range of 0.0001 to 5.0 mol/l; contacting a surface of a substrate with the liquid composition; and maintaining the contact between the surface of the substrate with the liquid composition to selectively deposit silica on the surface of the substrate until a silica film is formed on the surface of the substrate.

Abstract: A ceramic guide for a rolling line, used for wire rod transfer in a rolling line, which has a cylindrical contour and a throughhole for wire rod transfer. The throughhole includes a tapered hole and a straight hole of constant diameter, the tapered hole being provided at the wire rod inlet side of the guide. This ceramic guide, when used in a rolling line, is less liable to cause seizure with a wire rod and has higher durability.

Abstract: A ceramic jig for hot rolling is a sintered body consisting essentially of Si.sub.3 N.sub.4, a sintering aid and trace amounts of impurities. In the ceramic jig, crystallization is made among the Si.sub.3 N.sub.4 grains, and a crystalline phase among the grains comprises 80% or more of a J phase, 10% or less of an H phase and 5% or less of a K phase. A reaction of a jig component with iron and water can be inhibited, and the wear of the jig at the time of rolling can be reduced. The seizure of the jig on a steel material does not occur, so that scratches on products can be remarkably reduced.

Abstract: A hydraulic tappet includes a cam sliding portion, a skirt portion and a spring holding portion. The structure has an arrangement that the cam sliding portion is made of ceramic and oil is reserved in the spring holding portion. There is provide a hydraulic tappet capable of efficiently using motive power from a crank shaft, reducing transmission loss and improving the efficiency of the engine.

Abstract: An ultrasonic testing method for detection of flaws in a ball-shaped material to be tested using an ultrasonic probe, wherein a test frequency f (MHz) of the probe and a radius of curvature r (mm) of a tip portion of the probe satisfy the relationship 50 mm.ltoreq.r.sqroot.f.ltoreq.60 mm, and wherein the radius of curvature r (mm) of the tip portion and the diameter D (mm) of an oscillator of the probe satisfy the relationship 0.35 mm.ltoreq.D/r.ltoreq.0.50 mm. The method enables detection of surface and internal flaws in materials, particularly ceramic ball hearings having a diameter ranging from several tens of millimeters down to 10 mm or below.

Abstract: A method for measuring surface roughness of an end face of a honeycomb structure having a plurality of cells by using a stylus having a width corresponding to a width of at least two cells. A honeycomb surface roughness-measuring element, which is adapted for the measurement of a surface roughness of an end face of a honeycomb structure, includes a stylus having a tip, said tip having a widened edge with a width of 2 to 8 mm and a radius of curvature of 1 to 5 .mu.m.

Abstract: An ultrasonic testing method includes the steps of transmitting an ultrasonic wave from a probe to a test article, detecting an internal flaw in the test article by a reflected flaw echo from the internal flaw, and determining the shape of the detected flaw by comparing and analyzing frequency components of the transmitted ultrasonic wave and the reflected flaw echo.

Abstract: An ultrasonic testing method for detecting flaws of balls for structural members comprises rotating a ball to be tested in an ultrasonic wave transmitting medium. At least two focus-type ultrasonic probes are provided and arranged so as to cover nonoverlapping flaw-detecting regions on and/or inside the ball. Flaws in the ball are detected by sending ultrasonic waves from the probes toward the ball. An apparatus for detecting flaws of balls comprises a ball holding portion for rotatably holding the ball to be tested, at least two focus-type probes for detecting flaws and at least two probe mounting portions for mounting the probes thereof so that respective axes of the probes are each capable of being set eccentrically relative to the center of the ball and wherein the focal positions of the probes are variable.

Abstract: An ultrasonic testing method for detection of flaws in a material to be tested having a curved surface portion by use of an ultrasonic probe, wherein a center axis of curvature of the curved surface portion of the material to be tested and the center axis of the probe are set in an eccentric relationship so that the angle of refraction of an ultrasonic wave is 90.degree., and the probe comprises a tip portion having a curved surface of the same kind as the curved surface portion of the material to be tested and a radius of curvature of from 1.0 to 3.0 times the radius of curvature of the curved surface portion of the material to be tested. The method enables detection of internal flaws in, particularly, a spherical or cylindrical body formed of a ceramic and used as a bearing member.

Abstract: In a method of detecting defects formed in a surface or in the vicinity thereof of a ball of a bearing by means of an ultrasonic wave, the ball and a probe for projecting an ultrasonic wave toward the ball and receiving an ultrasonic wave reflected from the detects are arranged in water in such a manner that a center axis of the probe is deviated from a normal axis of the ball which passes through a center of the ball and extends in parallel with the center axis of the probe by such a displacement amount that the ultrasonic wave refracted by the ball propagates along the surface of ball. The ball is rotated about a horizontal axis perpendicular to the normal axis, and the ball and probe are rotated relative to each other about a center axis of the ball which is perpendicular both to the normal axis and horizontal axis of the ball, so that the whole surface of the ball is scanned automatically with the ultrasonic wave.

Abstract: An ultrasonic testing method comprises steps of transmitting an ultrasonic wave from a probe to a test article, detecting an internal flaw in the test article by a reflected flaw echo from the internal flaw, and deciding a condition of the detected flaw by comparing and analyzing frequency components of the transmitted ultrasonic wave and the reflected flaw echo. The probe has a curved tip surface which is the same kind as that of a curved incident surface of the test article and has a radius of curvature of 0.5.about.2.0 times the radius of curvature of the curved incident surface of the test article.

Abstract: An ultrasonic flaw detecting method able to detect defects of structural balls arranged in an ultrasonic transmitting medium with the aid of reflecting ultrasonic echoes transmitted from an ultrasonic flaw detecting probe immersed in the ultrasonic transmitting medium. The ball to be tested is arranged on two sets of ball driving rollers and the driving rollers are driven to rotate the ball during the test. An ultrasonic flaw detecting apparatus comprises ball driving rollers each including a shaft portion and a ball driving portion having a circular shape in a section perpendicular to the shaft portion to rotate the ball arranged on the ball driving rollers when the ball driving rollers are rotated, and an ultrasonic flaw detecting probe adapted to rotate about the ball for transmitting ultrasonic waves to the ball to scan defects of the ball.

Abstract: A ceramic radial turbine rotor made of a ceramic material having a strength s (kg/mm.sup.2) includes blade tips having a thickness t (mm). A product st.sup.2 of strength s and t.sup.2 (square of t) is representative of resistance to breakage of the rotor to foreign objects colliding against blades of the rotor. The product st.sup.2 fulfills a relation st.sup.2 .gtoreq.5.times.10.sup.4 vm+33. In this case, v is a circumferential speed of tip ends of inducers of blades of the rotating rotor when the blades are damaged by steel balls having a mass m (kg) colliding against the blades in a steel ball collision test of blades of a ceramic radial turbine rotor, and vm is a product of v and m.

Abstract: Method of effecting a spin-testing of a turbocharger rotor with its shaft portion fixed to a simulation attachment assembly consisting of components parts which include a thrust bearing, a spacer, a sleeve or compressor rotor, and a lock nut, wherein an integral composite member is formed from at least two parts of the component parts. The testing device includes the attachment assembly with the integral composite member, and a bearing housing for supporting the turbocharger rotor and the attachment assembly rotatably as a unit.

Abstract: In a method for electrolyzing water or an aqueous solution using a cation-exchange membrane provided between an anode and a cathode, the improvement wherein one or both of the anode and cathode are composed of a thin layer of an electrically conductive fibrous assembly having a rigid through-hole bearing current collector disposed on its outside surface, and the electrolysis is carried out while maintaining the two electrodes, the cation exchange membrane and the current collectors in the integrally pressed state.

Abstract: An improved cathode for the electrolysis of an aqueous solution of an alkali metal halide, which shows a reduced hydrogen overvoltage. The cathode comprises a metallic substrate and a coating of iron or both iron and cobalt electroplated thereon from a specified electroplating bath containing iron or both iron and cobalt. A method is also provided for electrolyzing an aqueous solution of an alkali metal halide using this cathode.

Abstract: A novel cathode for use in electrolysis of an aqueous solution of an alkali metal halide or water is provided which comprises a metallic cathode substrate and a powder of Raney nickel held on its surface partly embedded in a nickel layer deposited thereon from a nickel plating bath. The cathode has a considerably lower hydrogen overvoltage than ordinary cathodes. It can be produced by electrolytically depositing nickel on the surface of a metallic cathode substrate from an aqueous nickel plating bath containing a powder of Raney nickel suspended therein to form a co-deposited layer of the nickel and the Raney nickel powder.

Abstract: A method of removing mercury vapor from a gas contaminated therewith comprising washing said gas with an acid solution of divalent mercury ions, the concentration of which ranges from 0.5 to 100g per liter, at room temperature and atmospheric pressure; and rewashing the resultant gas with an acid solution of divalent mercury ions, the concentration of which ranges from 0.05 to 0.5g per liter, at room temperature and atmospheric pressure to obtain a purified gas containing mercury vapor of less than 0.01 mg/Nm.sup.3, that is, 0.001 ppm.