Abstract: An apparatus for classifying fine balls having diameters of 1 mm or less into those having predetermined diameter ranges, comprising a feeder for supplying fine balls, at least one rotatable cylindrical sieve constituted by a plate with a thickness of 200 ?m or less having circular holes and having a center axis inclined relative to a horizontal plane, and a container for receiving fine balls classified by subjecting the fine balls to falling from the cylindrical sieve, the fine balls being supplied from the feeder to an inlet of the rotating cylindrical sieve at its upper end, fine balls that have passed through the circular holes of the cylindrical sieve being subjected to falling to be recovered by the container, and fine balls that have not passed through the circular holes being withdrawn from an exit of the cylindrical sieve at its lower end.

Abstract: An apparatus for classifying fine balls having diameters of 1 mm or less, comprising a feeder for supplying fine balls, at least one rotatable cylindrical sieve constituted by a plate having holes and having a center axis inclined relative to a horizontal plane, and a container for receiving fine balls classified by the cylindrical sieve, the fine balls being supplied from the feeder to an inlet of the rotating cylindrical sieve at its upper end, fine balls that have passed through the holes of the cylindrical sieve being recovered by the container, and fine balls that have not passed through the holes being withdrawn from an exit of the cylindrical sieve at its lower end.

Abstract: An apparatus for producing fine metal balls comprising a crucible 3 for holding a metal melt and equipped with orifices 2 for ejecting the metal melt; a vibration rod 6 for giving vibration to the melt 1 held in the crucible 3; a vibrator 4 for giving vibration to the vibration rod 6; a means 5 for transmitting the vibration of the vibrator 4 to the vibration rod 6; and a chamber 7 in which melt droplets 9 ejected through the orifices 2 are solidified while dropping, the vibration-transmitting means 5 having one end in contact with the vibrator 4 and the other end abutting a support member 11 connected to the vibration rod 6; the vibration-transmitting means 5 having a cross section decreasing as it nears the support member 11.

Abstract: A solder ball having a diameter of 1.2 mm or less, a dispersion of a diameter distribution of 5% or less and sphericity of 0.95 or more, an area ratio of the maximum dendrite being 80% or less of a cross section including a center of the solder ball, comprises a first additional element of 0.5-8 mass % of Ag and/or 0.1-3 mass % of Cu, and 0.006-10 mass %, in total, of at least one second additional element selected from the group consisting of Bi, Ge, Ni, P, Mn, Au, Pd, Pt, S, In and Sb, the balance being substantially Sn. The solder ball is produced by a uniform droplet-spraying method comprising the steps of vibrating a melt of a solder alloy in a crucible under pressure to force the melt to drop through orifices of the crucible; permitting the melt dropping through the orifices to become spherical droplets in a non-oxidizing gas atmosphere; and rapidly solidifying them.

Abstract: An apparatus for producing fine metal balls comprising a crucible 3 for holding a metal melt and equipped with orifices 2 for ejecting the metal melt; a vibration rod 6 for giving vibration to the melt 1 held in the crucible 3; a vibrator 4 for giving vibration to the vibration rod 6; a means 5 for transmitting the vibration of the vibrator 4 to the vibration rod 6; and a chamber 7 in which melt droplets 9 ejected through the orifices 2 are solidified while dropping, the vibration-transmitting means 5 having one end in contact with the vibrator 4 and the other end abutting a support member 11 connected to the vibration rod 6; the vibration-transmitting means 5 having a cross section decreasing as it nears the support member 11.

Abstract: A solder ball having a diameter of 1.2 mm or less, a dispersion of a diameter distribution of 5% or less and sphericity of 0.95 or more, an area ratio of the maximum dendrite being 80% or less of a cross section including a center of the solder ball, comprises a first additional element of 0.5-8 mass% of Ag and/or 0.1-3 mass % of Cu, and 0.006-10 mass %, in total, of at least one second additional element selected from the group consisting of Bi, Ge, Ni, P, Mn, Au, Pd, Pt, S, In and Sb, the balance being substantially Sn. The solder ball is produced by a uniform droplet-spraying method comprising the steps of vibrating a melt of a solder alloy in a crucible under pressure to force the melt to drop through orifices of the crucible; permitting the melt dropping through the orifices to become spherical droplets in a non-oxidizing gas atmosphere; and rapidly solidifying them.

Abstract: A thin plate made of an Fe--Ni alloy for electronic parts, which has excellent softening property. The alloy consists essentially of, by weight, 32 to 40% Ni, not more than 0.1% Si, not more than 0.5% Mn and 5 to 50 ppm boron, and balance of Fe and unavoidable impurities. It comprises also trace elements which fulfill the following requirements: "S+O".ltoreq.150 ppm, Al.ltoreq.400 ppm, N.ltoreq.50 ppm, P.ltoreq.100 ppm, an element of IVa, Va and VIa Groups defined in the periodic table being not more than 2000 ppm in amount, and an atomic ratio of "B(atom. %)/N(atom. %)" being not less than 0.8, preferably more than 1.0. The invention also relates to a shadow mask made of the alloy and a cathode-ray tube comprising the shadow mask.