The present invention provides an aqueous composition comprising tin ions and at least one compound of formula I wherein X.sub.1 is selected from a linear or branched C.sub.1-C.sub.12 alkanediyl, which may optionally be interrupted by O or S or a C.sub.5 to C.sub.12 aromatic moiety, R.sup.11 is a copolymer of ethylene oxide and a further C.sub.3 to C.sub.6 alkylene oxide, wherein the content of ethylene oxide is from 5 to 30% by weight, R.sup.12 is selected from H, R.sup.11, R.sup.40, R.sup.13, R.sup.14, are (a) independently selected from H, R.sup.11, R.sup.40, or (b) may together form a divalent group X.sup.13; X.sup.13 is selected from a linear or branched C.sub.1-C.sub.12 alkanediyl, which may optionally be interrupted by O, S or NR.sup.43; R.sup.40 is H or a linear or branched C.sub.1-C.sub.20 alkyl, R.sup.43 is selected from H, R.sup.11 and a linear or branched C.sub.1-C.sub.20 alkyl. ##STR00001##

A Cu core ball and a method of manufacturing such a Cu core ball. Purity of the Cu internal ball is at least 99.9% and not greater than 99.995%. A total contained amount of Pb and/or Bi in impurity contained in the Cu ball is equal to or larger than 1 ppm. Its sphericity is at least 0.95. A solder plating film coated on the Cu ball is of Sn solder or a lead free solder alloy whose primary component is Sn. In the solder plating film, a contained amount of U is not more than 5 ppb and that of Th is not more than 5 ppb. A total alpha dose of the Cu ball and the solder plating film is not more than 0./0200 cph/cm2. An arithmetic average roughness of the Cu core ball is equal to or less than 0.3 μm.

A Cu core ball and a method of manufacturing such a Cu core ball. Purity of the Cu internal ball is at least 99.9% and not greater than 99.995%. A total contained amount of Pb and/or Bi in impurity contained in the Cu ball is equal to or larger than 1 ppm. Its sphericity is at least 0.95. A solder plating film coated on the Cu ball is of Sn solder or a lead free solder alloy whose primary component is Sn. In the solder plating film, a contained amount of U is not more than 5 ppb and that of Th is not more than 5 ppb. A total alpha dose of the Cu ball and the solder plating film is not more than 0./0200 cph/cm2. An arithmetic average roughness of the Cu core ball is equal to or less than 0.3 μm.

There are provided a press-fit terminal which has an excellent whisker resistance and a low inserting force, is unlikely to cause shaving of plating when the press-fit terminal is inserted into a substrate, and has a high heat resistance, and an electronic component using the same. A press-fit terminal comprises: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate. At least the substrate connection part has the surface structure described below, and the press-fit terminal has an excellent whisker resistance. The surface structure comprises: an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof; a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu. The A layer has a thickness of 0.002 to 0.2 μm. The B layer has a thickness of 0.001 to 0.3 μm. The C layer has a thickness of 0.05 μm or larger.

There are provided a press-fit terminal which has an excellent whisker resistance and a low inserting force, is unlikely to cause shaving of plating when the press-fit terminal is inserted into a substrate, and has a high heat resistance, and an electronic component using the same. A press-fit terminal comprises: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate. At least the substrate connection part has the surface structure described below, and the press-fit terminal has an excellent whisker resistance. The surface structure comprises: an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof; a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu. The A layer has a thickness of 0.002 to 0.2 μm. The B layer has a thickness of 0.001 to 0.3 μm. The C layer has a thickness of 0.05 μm or larger.

An article comprises a metal alloy substrate and a plated wear interface layer disposed over a surface of the metal alloy substrate. The wear interface layer has a chemical composition including between about 0.005 wt % and about 0.050 wt % of antimony (Sb), and the balance silver (Ag) and incidental impurities.

An article comprises a metal alloy substrate and a plated wear interface layer disposed over a surface of the metal alloy substrate. The wear interface layer has a chemical composition including between about 0.005 wt % and about 0.050 wt % of antimony (Sb), and the balance silver (Ag) and incidental impurities.

A method includes: agitating base members that has been immersed in an electrolytic solution inside of an electroplating tank so as to flow in a circumference direction along an inner wall of the electroplating tank; and electroplating the base members flowing along the circumference direction in the electrolytic solution inside of the electroplating tank. The flow of the base members along the circumference direction is caused by a flow of magnetic media along the circumference direction in the electrolytic solution inside of the electroplating tank or is caused by rotation of an agitation unit provided at a bottom side of the electroplating tank. At least one of the base members touches a bottom cathode, and a base member positioned upward relative to the base member touching the bottom cathode is electrically connected to the bottom cathode via at least the base member touching the bottom cathode.

A method includes: agitating base members that has been immersed in an electrolytic solution inside of an electroplating tank so as to flow in a circumference direction along an inner wall of the electroplating tank; and electroplating the base members flowing along the circumference direction in the electrolytic solution inside of the electroplating tank. The flow of the base members along the circumference direction is caused by a flow of magnetic media along the circumference direction in the electrolytic solution inside of the electroplating tank or is caused by rotation of an agitation unit provided at a bottom side of the electroplating tank. At least one of the base members touches a bottom cathode, and a base member positioned upward relative to the base member touching the bottom cathode is electrically connected to the bottom cathode via at least the base member touching the bottom cathode.

An earth bolt with a surface treatment layer are a method of surface treatment of the earth bolt are provided. The surface treatment includes a tin-zinc plated layer, a colored chromate film layer and a silicate coating layer. Since the earth bolt with the surface treatment layer has improved electro-conductivity and anti-rusting property, it may protect electrical/electronic components fitted to a vehicle from electromagnetic shock and remove noise therefrom, thereby improving reliability of a vehicle body.