Abstract: An additive for use in producing spheroidal graphite cast iron of the present invention contains a fine particle of magnesium oxide having a purity of 90 weight % or more and at least one selected from the group consisting of a graphite-spheroidizing material, an inoculant and a graphite-spheroidizing inoculant. The fine particle of highly pure magnesium oxide increases the number of nuclei in a melt, and as a result thereof, increases the graphite spheroid count of a spheroidal graphite cast iron being produced. Another additive for use in producing spheroidal graphite cast iron of the present invention contains at least one selected from the group consisting of a graphite-spheroidizing material, an inoculant and a graphite-spheroidizing inoculant, and an oxide of a metal which has, at a temperature of a melt at a time when subjected to a graphite-spheroidizing treatment, an affinity for oxygen smaller than that of a graphite-spheroidizing element being used in the graphite-spheroidizing treatment.

Abstract: Stainless steel member for semiconductor fabrication equipment having a passive state coating on the surface of the stainless steel comprising, in weight percent, 0.1% or less of C, 2.0% or less of Si, 3.0% or less of Mn, 10% or more of Ni, 15 to 25% of Cr, 1.5 to 4.5% of Mo, 0.5% or less of one or more rare earth element and Fe for substantially the whole remainder. Said passive state coating has a pitting potential of at least 900 mV (when the current density of the anode polarization curve determined with a potentiostat in 3.5% aqueous sodium chloride solution is 10 .mu.A/cm.sup.2) and has a thickness of 0.5 to 20 nm. The invention also includes a surface treatment method for the stainless steel.

Abstract: This invention provides a cermet alloy having a structure comprising a hard phase and a bonding phase, wherein the hard phase comprising carbide particles rich An TiC, those rich in WC and (Ti, W, MO)C or (Ti, W, Mo)(C, N) and the bonding phase comprising at least one of Co and Ni. Mo contents in the bonding phase satisfies the conditions: 1.0.ltoreq.Mo (wt %)/Ti (wt %) and 6 (wt %).ltoreq.Ti+Mo. The cermet alloy has superior hardness and toughness as well as improved heat resistance and is applicable as a material for a wet machining tool.

Abstract: A sintered ceramic composite comprising 35 to 80 wt. % of aluminum nitride, 2 to 60 wt. % of boron nitride, 0.1 to 25 wt. % of an oxide of magnesium, 0.5 to 20 wt. % of at least one of rare earth oxides including yttrium oxide as an optional component and 25 wt. % or less of aluminum oxide as an optional component is disclosed.

Abstract: A permanent magnet formed by a permanent magnet alloy of R--T--B system chiefly comprising a transition metal T, a rare earth element R including yttrium and boron B, and coated with a protective plating layer of Ni or an Ni alloy, wherein said protective plating layer is 30 .mu.m or less in thickness, and the inter-cell pitch in the surface of said protective plating layer is 14 .mu.m or more.

Abstract: A cermet alloy having a structure comprising a hard phase and a bonding phase, said hard phase comprising (1) at least one of MC, MN, and MCN, wherein M is at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W (2) at least one compound selected from (M,Mo)(B,C), M,Mo)(B,N) and (M,Mo)(B,CN) and (3) at least one Mo--Co--B compound; said bonding phase comprising Co. The cermet alloy has superior toughness and hardness, and can be worked by conventional sintering methods. The invention also includes a method for producing the cermet alloy.

Abstract: There can be provided a TiC-base cermet alloy whose hardness is equal to or higher than that of a Ti(C, N)-base cermet alloy and which is excellent in toughness by strengtening the binder phase of the TiC-Base cermet alloy which does not involve the problem of denifrification at the time of sintering. The titanium-carbide-base cermet alloy comprises a hard phase which contains titanium carbide as a main component and a binder phase which contains one or both of Co and Ni as main components, wherein amounts of Ti and Mo in the binder phase satisfy the conditions, by weight T: 0.85.ltoreq.Mo (wt. %)/Ti (wt. %), and 6 wt. %.ltoreq.[Ti +Mo].

Abstract: A cermet alloy having a structure comprising a hard phase and a bonding phase, said hard phase comprising (1) at least one of MC, MN and MCN, wherein M is at least one element selected from Ti, Zr, Hf, Th, V, Nb, Ta, Pa, Cr, Mo, U and W and (2) at least one W-Co-B compound; said bonding phase comprising Co. The cermet has superior toughness and hardness, and can be worked by conventional sintering methods. The invention also includes a method for producing the cermet.