Abstract: A powder is hydrophilized by treating surfaces of particles with a hydrolyzable silyl group-containing acid anhydride compound, dispersing the surface treated particles in water, adding a base, and heating the dispersion for thereby hydrolyzing the acid anhydride moiety to open its ring and neutralizing the resultant carboxylic acid with the base. The hydrophilized powder is fully dispersible in aqueous media.

Abstract: A powder is hydrophilized by treating surfaces of particles with a hydrolyzable silyl group-containing acid anhydride compound, dispersing the surface treated particles in water, adding a base, and heating the dispersion for thereby hydrolyzing the acid anhydride moiety to open its ring and neutralizing the resultant carboxylic acid with the base. The hydrophilized powder is fully dispersible in aqueous media.

Abstract: A hydrolyzable group-containing organohydrogenpolysiloxane is prepared by (A) reacting (a) an organosiloxane with (b) an organosilane or organosiloxane containing a hydrolyzable group, at least one of components (a) and (b) containing hydrosilyl, in the presence of a superstrong acid catalyst, (B) adding an inorganic basic neutralizing agent and/or an adsorbent to the resulting reaction solution, and (C) removing the neutralized and/or adsorbed form of the superstrong acid catalyst. The process proceeds in an essentially non-aqueous system, and the organohydrogenpolysiloxane free of residual acidic catalyst is obtainable at low cost.

Abstract: A powder is hydrophilized by treating surfaces of particles with a hydrolyzable silyl group-containing acid anhydride compound, dispersing the surface treated particles in water, adding a base, and heating the dispersion for thereby hydrolyzing the acid anhydride moiety to open its ring and neutralizing the resultant carboxylic acid with the base. The hydrophilized powder is fully dispersible in aqueous media.

Abstract: A hydrolyzable group-containing organohydrogenpolysiloxane is prepared by (A) reacting (a) an organosiloxane with (b) an organosilane or organosiloxane containing a hydrolyzable group, at least one of components (a) and (b) containing hydrosilyl, in the presence of a superstrong acid catalyst, (B) adding an inorganic basic neutralizing agent and/or an adsorbent to the resulting reaction solution, and (C) removing the neutralized and/or adsorbed form of the superstrong acid catalyst. The process proceeds in an essentially non-aqueous system, and the organohydrogenpolysiloxane free of residual acidic catalyst is obtainable at low cost.

Abstract: A cleaning agent composition comprising a nonionic surfactant represented by the following formula (1): R1O(EO)x(PO)yH (I)(wherein R1 represents a linear or branched alkyl group having from 6 to 20 carbon atoms or a linear or branched alkenyl group having from 6 to 20 carbon atoms, EO represents an oxyethylene group, PO represents an oxypropylene group, EO and PO each is bonded by random addition or block addition, x number of EOs and y number of POs are arranged in an arbitrary order, x and y each independently represents an integer of 1 to 20, and x/(x+y) is 0.5 or more) and a quaternary ammonium hydroxide) is provided. Also, cleaning and production methods for semiconductor wafer using the cleaning agent composition and semiconductor wafer produced by the production method are provided.

Abstract: An object of the present invention is to provide a new cleaning agent composition having excellent cleaning power for the surface contamination of a semiconductor wafer or various precisely worked instruments made of glass or ceramic, which is used in the manufacture of wafer; a method for cleaning a wafer; a semiconductor wafer having a surface cleaned by a cleaning method; and a method for manufacturing a semiconductor wafer. A semiconductor wafer is cleaned using a cleaning agent composition including a specific fluorine-containing anionic surfactant, a quaternary ammonium hydroxide and/or an alkanolamine.

Abstract: An object of the present invention is to provide a new cleaning agent composition having excellent cleaning power for the surface contamination of a semiconductor wafer or various precisely worked instruments made of glass or ceramic, which is used in the manufacture of wafer; a method for cleaning a wafer; a semiconductor wafer having a surface cleaned by a cleaning method; and a method for manufacturing a semiconductor wafer. A semiconductor wafer is cleaned using a cleaning agent composition including a specific fluorine-containing anionic surfactant, a quaternary ammonium hydroxide and/or an alkanolamine.

Abstract: An object of the present invention is to provide a new cleaning agent composition having excellent cleaning power for the surface contamination of a semiconductor wafer or various precisely worked instruments made of glass or ceramic, which is used in the manufacture of wafer; a method for cleaning a wafer; a semiconductor wafer having a surface cleaned by a cleaning method; and a method for manufacturing a semiconductor wafer. A semiconductor wafer is cleaned using a cleaning agent composition including a specific fluorine-containing anionic surfactant, a quaternary ammonium hydroxide and/or an alkanolamine.

Abstract: A magnetic recording medium with improved output characteristics and durability is provided by using magnetic powder comprising iron-containing particles each of which carries a compound containing aluminum and/or a compound containing silicon in such amounts that, in the whole magnetic powder, a weight ratio of silicon to iron is from 0.010:1 to 0.150:1, a weight ratio of aluminum to iron is from 0.040:1 to 0.150:1, and a weight ratio of aluminum to silicon is from 1:1 to 15:1.

Abstract: A process for preparing ferromagnetic particles comprising metallic iron as the major component by oxidizing Fe(OH).sub.2 in an aqueous medium adjusted to a pH of not less than 11 with gaseous oxygen to produce particles of .alpha.-FeOOH, optionally followed by dehydration of the .alpha.-FeOOH particles under heating to produce particles of .alpha.-Fe.sub.2 O.sub.3, and reducing the .alpha.-FeOOH or .alpha.-Fe.sub.2 O.sub.3 particles under heating, characterized in that (1) the aqueous medium at the oxidation step comprises at least one metal compound chosen from compounds of alkaline earth metals, zinc and aluminum and (2) the coating of a silicon compound is applied to the .alpha.-FeOOH or .alpha.-Fe.sub.2 O.sub.3 particles before the reduction step, whereby the ferromagnetic particles of metallic iron having enhanced magnetic characteristics are obtained.

Abstract: A method for the production of uniform acicular metal magnetic particles comprising predominantly iron which have excellent magnetic characteristics and are useful as a recording element for a magnetic recording medium, said method comprising the steps of coating the surface of metal compound particles containing predominantly acicular iron oxyhydroxide or iron oxides with at least one member selected from the group consisting of an aluminum compound and a silicon compound, pelletizing the coated particles, and reducing the pellets with heating under reducing atmosphere, e.g. under hydrogen stream.

Abstract: A process for preparing ferromagnetic iron particles comprising metallic iron as the major component by reduction of particles of an iron oxide under heating, characterized in that the iron oxide particles are provided with a first coating layer containing at least one metal compound chosen from compounds of aluminum, zinc and alkaline earth metals at the surfaces and a second coating layer containing at least one silicon compound thereon before the reduction, whereby the coated particles are prevented from sintering and breaking upon reduction so as to give ferromagnetic particles of metallic iron having excellent magnetic characteristics.

Abstract: A method of producing ferromagnetic metal powder comprises the steps of dipping an iron compound powder in a solution in which an aluminum compound and/or a titanium compound is dissolved, removing solvent from the iron compound powder, reducing the iron compound powder in a reducing atmosphere at an elevated temperature and forming oxide layers on whole surfaces of the individual particles of the iron powder. Ferromagnetic iron powder produced according to this method has both a high coercive force and a high remanence ratio.

Abstract: A method of producing ferromagnetic iron powder comprises the steps of dipping iron compound powder in a solution in which silicone oil is dissolved, removing solvent from the iron compound powder, reducing the iron compound powder in a reducing atmosphere at an elevated temperature and forming oxide layers on whole surfaces of the individual particles of the iron compound powder. Ferromagnetic iron powder produced according to this method has both a high coercive force and a high remanence ratio.

Abstract: A magnetic recording medium or composition which comprises a ferromagnetic chromium dioxide product containing a proper quantity of tungsten alone or admixed with a member selected from the group consisting of copper and zinc, which has an excellent ferromagnetic characteristic of high coercive force.