Mitsubishi Materials Corporation

Takuma Katase

Hirotaka Hirano

Akihiro Masuda

Koji Tatsumi

Kotaro Masuyama

Kanji Kuba

Tsukasa Yasoshima

Yoshihiro Yoshida

Kohei Otogawa

Any metal having a low α-ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an α-ray after heating the metal at 100° C. in an atmosphere for six hours is 0.002 cph/cmor less. Any metal of tin, silver, copper, zinc and indium each including lead as an impurity is dissolved to prepare a hydrosulfate aqueous solution of the metal and lead sulfate is precipitated and removed in the solution. The lead sulfate is precipitated in the hydrosulfate aqueous solution by adding a lead nitrate aqueous solution including lead having an α-ray emission of 10 cph/cmor less to the hydrosulfate aqueous solution, from which the lead sulfate has been removed, and, at the same time, the solution is circulated while removing the lead sulfate to electrowinning the metal using the hydrosulfate aqueous solution as an electrolytic solution.

Metal and tin alloy having low alpha-ray emission, and method for producing same

The SnAg alloy plating solution of the invention is a SnAg alloy plating solution including a water-soluble tin compound, a water-soluble silver compound, and a particular sulfide compound in an amount in the range of 0.25 mol or more and 10 mol or less with respect to 1 mol of silver in the water-soluble silver compound.

SnAg alloy plating solution

A stannous oxide powder which has a high dissolution rate into various acid solutions such as a plating solution and is particularly suitable as a Sn supply material to a plating solution, and a method for producing the stannous oxide powder are provided. The stannous oxide powder is a particle body having a plurality of plate-like protrusions protruding outward, and has an average particle size in a range of 1 &#x3bc;m to 15 &#x3bc;m.

Stannous oxide powder and method for producing stannous oxide powder

The method of producing stannous oxide includes: a Sn ion-containing acid solution forming step (S); a first neutralizing step (S), which is a step of forming Sn precipitates by adding one or more of alkaline solutions of ammonium carbonate, ammonium bicarbonate, and aqueous ammonia to the Sn ion-containing acid solution to retain pH at 3-6 therein; a Sn precipitate separating step (S); a Sn precipitate dispersing step (S), which is a step of dispersing the separated Sn precipitates in a solvent liquid to obtain a dispersion liquid; and a second neutralizing step (S), which is a step of forming SnO by adding an alkaline solution to the dispersion liquid of the Sn precipitates and then by heating, wherein Na, K, Pb, Fe, Ni, Cu, Zn, Al, Mg, Ca, Cr, Mn, Co, In, and Cd reside in the Sn ion-containing acid solution in the first neutralizing step (S).

Method of producing stannous oxide, stannous oxide, method of Sn plating solution, and method of removing impurities from Sn plating solution

An object and a problem of the present invention is to provide tin(II) oxide powder which has extremely high solubility in an acid or an acidic plating solution and excellent in storage stability in the air. The tin(II) oxide powder of the present invention is for replenishing a tin component of a tin-alloy plating solution, and comprises 100 to 5000 ppm of an antioxidant being contained in the powder with a mass ratio, and has such a dissolution rate that when 0.1 g of the tin(II) oxide powder is added to 100 ml of 100 g/L aqueous alkylsulfonic acid solution at a temperature of 25&#xb0; C. and stirred, then the powder dissolves therein within 180 seconds.

Tin(II) oxide powder for replenishing tin component of tin-alloy plating solution and method for manufacturing said powder

An object of the present invention is to provide tin(II) oxide powder which has extremely high solubility in an acid or an acidic plating solution, excellent in storage stability in the air and can heighten oxidation-preventive effect of Snion in the plating solution. The method for manufacturing tin(II) oxide powder of the present invention comprises Step () of preparing an aqueous acidic solution containing Snions, Step () of neutralizing the aqueous acidic solution by adding an aqueous alkaline solution to prepare a slurry of tin(II) hydroxide, Step () of dehydrating the prepared slurry to obtain a slurry of tin(II) oxide, Step () of separating the slurry of tin(II) oxide into a solid and a liquid to obtain tin(II) oxide, Step () of treating the obtained tin(II) oxide with an aqueous antioxidant solution, and Step () of vacuum drying the tin(II) oxide treated with the aqueous antioxidant solution.

Method for manufacturing tin(II) oxide powder for replenishing tin component of tin-alloy plating solution, and tin (II) oxide powder manufactured using said method

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Sanda, Japan

Takuma Katase