A tin alloy plating solution of the present invention includes (A) a soluble salt or oxide including at least a stannous salt, (B) a soluble salt of a metal nobler than tin, (C) a tin complexing agent formed of a sugar alcohol having 4 or more and 6 or less carbon atoms, (D) a free acid, and (E) an antioxidant. In addition, a content of the tin complexing agent is 0.1 g/L or more and 5 g/L or less, and a concentration of divalent tin ions (Sn.sup.2+) is 30 g/L or more.

Disclosed herein is an aqueous composition including tin ions, optionally alloy metal ions selected from the group consisting of silver, indium, and bismuth ions and at least one additive of formula L1a

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or of formula L1b

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Disclosed herein is an aqueous composition including tin ions, optionally alloy metal ions selected from the group consisting of silver, indium, and bismuth ions and at least one additive of formula L1a

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or of formula L1b

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An electrodeposit formed by using a tin or tin alloy plating bath containing a prescribed branched polyoxyalkylene compound, such as an alkylene oxide adduct of aliphatic monoamine or polyamine in which a plurality of oxyalkylene chains are bonded to a nitrogen atom of an amine structure in a molecule, or an alkylene oxide adduct of glycerin or polyglycerin in which oxyalkylene chains are respectively bonded to a plurality of oxygen atoms of an alcohol structure in a molecule, suppresses formation defect such as abnormal growth of the electrodeposit. The electrodeposit also improves yield from the viewpoint of quality control.

An electrodeposit formed by using a tin or tin alloy plating bath containing a prescribed branched polyoxyalkylene compound, such as an alkylene oxide adduct of aliphatic monoamine or polyamine in which a plurality of oxyalkylene chains are bonded to a nitrogen atom of an amine structure in a molecule, or an alkylene oxide adduct of glycerin or polyglycerin in which oxyalkylene chains are respectively bonded to a plurality of oxygen atoms of an alcohol structure in a molecule, suppresses formation defect such as abnormal growth of the electrodeposit. The electrodeposit also improves yield from the viewpoint of quality control.

The present disclosure relates to methods of monitoring the concentrations of silver ion and complexing agent in tin-silver (SnAg) electrodeposition solutions, and analysis and process control using such methods. Methods can include adding a precipitating agent to an electrodeposition solution including at least tin ions, silver ions, and complexing agent to cause a reaction between at least a portion of the precipitating agent and substantially all of the silver ions (to precipitate silver ions as a precipitant); adding a metallic salt to the electrodeposition solution to cause a reaction with substantially all of the remaining precipitating agent; measuring the endpoint of the silver ion back titration; further adding metallic salt to cause a further reaction with the complexing agent; and measuring the endpoint of the complexing agent titration.

The present disclosure relates to methods of monitoring the concentrations of silver ion and complexing agent in tin-silver (SnAg) electrodeposition solutions, and analysis and process control using such methods. Methods can include adding a precipitating agent to an electrodeposition solution including at least tin ions, silver ions, and complexing agent to cause a reaction between at least a portion of the precipitating agent and substantially all of the silver ions (to precipitate silver ions as a precipitant); adding a metallic salt to the electrodeposition solution to cause a reaction with substantially all of the remaining precipitating agent; measuring the endpoint of the silver ion back titration; further adding metallic salt to cause a further reaction with the complexing agent; and measuring the endpoint of the complexing agent titration.

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.

A technique capable of reducing the possibility of generation of a CuSb compound in an overlay and the possibility of delamination between layers. A sliding member includes: an overlay including an alloy plating film of Bi and Sb; a lining including an Al alloy; a first intermediate layer including Cu as a main component, and laminated on the lining; and a second intermediate layer including Ag as a main component, and connecting the first intermediate layer and the overlay.

This dithiapolyether diol has a halogen content of less than 10 ppm and a purity of 80% or more and is represented by the following general formula (1) or (2). In the general formula (1) or (2), x and y are arbitrary natural numbers

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