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AssigneesSenju Metal Industry Co., Ltd., Miyazaki Prefecture
InventorsKiyoshi Torigoe, Masataka Shimizu, Kenji Yamamoto, Mitsuhiro Mizozoe, Hoshiro Takahashi, Tomohide Suzuki, Motohiro Murase
Estimating the term…
In a solder paste which is a mixture of a flux and low melting point metal particles, low melting point metal fine particles manufactured by a conventional method or apparatus therefor include particles having widely varying particle diameters. Accordingly, the solder paste could not completely fill the minute holes in a mask for application to minute solder portions by printing, or mask removability was poor. According to the present invention, a mixture of a heat resistant continuous phase liquid and coarse metal particles in molten state is passed through a porous membrane to form the coarse low melting point metal particles into fine particles with a predetermined diameter. An apparatus according to the present invention comprise a porous membrane between a heating and dispersing mechanism and a cooling mechanism, and a pressure vessel connected to the heating and dispersing mechanism for applying a high pressure to the heating and dispersing mechanism.
1-7. (canceled)
A method of manufacturing low melting point metal fine particles comprising applying a pressure to a mixture of coarse particles of a low melting point metal in a molten state and a heat resistant continuous phase liquid at a temperature of at least the melting point of the low melting point metal, the pressure being at least sufficient to force the mixture to pass through a porous membrane having at least two penetrating pores, thereby forming the liquid metal coarse particles into liquid metal fine particles, and then cooling the liquid metal fine particles and the heat resistant continuous phase liquid to a temperature equal to or lower than the melting point of the low melting point metal to obtain solid metal fine particles.
A method as claimed in claim 7 including controlling the speed of passage of the liquid metal coarse particles through the membrane such that the particle diameter of the resulting liquid metal fine particles is within a range which is of the same order or smaller than the pore diameter of the porous membrane.
A method as claimed in claim 7 including passing the liquid metal fine particles through a porous membrane to increase the uniformity of the particle diameter of the liquid metal fine particles.
A method as claimed in claim 7 wherein the heat resistant continuous phase liquid is mineral oil, vegetable oil, or a glycol.
A method as claimed in claim 7 wherein the heat resistant continuous phase liquid contains a dispersion stabilizer.
An apparatus for manufacturing low melting point metal fine particles comprising a dispersing mechanism for heating and dispersing liquid metal coarse particles in a heat resistant continuous phase liquid, a porous membrane having at least two penetrating pores, and a cooling mechanism for cooling liquid metal fine particles formed by passage of the coarse particles through the porous membrane.
Dependencies are inferred from the claim text.