Abstract: The present invention is an electrodeposited film substantially containing no lead, characterized by applying an alloy layer or a simple metal layer with an Hv value of not less than 60 to an under layer, and an alloy layer or a simple metal layer with an Hv value of not more than 40 to an upper layer. This electrodeposited film is harmless to the human body and the environment, and superior in sliding properties.

Abstract: A synchronizer ring 1 has an annular ring body 2; a friction material 4 joined integrally to a cylindrical inner peripheral surface 3 of the ring body 2; a conical surface 5 formed on an inner surface of the friction material 4; and a plurality of annular grooves 6 formed in the conical surface 5 of the friction material 4.

Abstract: A lead-containing copper-based alloy is immersed into a weak acidic or neutral etching solution having a buffer effect which is formed by adding an organic acid into a complexing agent having a high ability to form a complexing ion with lead, and lead particles present on the surface of the lead-containing copper-based alloy are then removed. The complexing agent is one of an organic ammonium salt such as ammonium acetate, or ammonium citrate, or may be an organic sodium salt such as sodium acetate, sodium tartrate, and sodium citrate. Preferably, an immersion temperature of the alloy to the etching solution falls within a range of from 10 to 50° C. The etching solution is agitated with oxygen or a gas containing oxygen blown thereinto during the immersion of the alloy into the etching solution. An extremely low voltage of ?0.3 to +0.2 V vs. NHE is applied from outside to the lead-containing copper-based alloy as an anode.

Abstract: A synchronizer ring 1 has an annular ring body 2; a friction material 4 joined integrally to a cylindrical inner peripheral surface 3 of the ring body 2; a conical surface 5 formed on an inner surface of the friction material 4; and a plurality of annular grooves 6 formed in the conical surface 5 of the friction material 4.

Abstract: The present invention is an electrodeposited film substantially containing no lead, characterized by applying an alloy layer or a simple metal layer with an Hv value of not less than 60 to an under layer, and an alloy layer or a simple metal layer with an Hv value of not more than 40 to an upper layer. This electrodeposited film is harmless to the human body and the environment, and superior in sliding properties.

Abstract: A lead-containing copper-based alloy is immersed into a weak acidic or neutral etching solution having a buffer effect which is formed by adding an organic acid into a complexing agent having a high ability to form a complexing ion with lead, and lead particles present on the surface of the lead-containing copper-based alloy are then removed. The complexing agent is one of an organic ammonium salt such as ammonium acetate, or ammonium citrate, or may be an organic sodium salt such as sodium acetate, sodium tartrate, and sodium citrate. Preferably, an immersion temperature of the alloy to the etching solution falls within a range of from 10 to 50° C. The etching solution is agitated with oxygen or a gas containing oxygen blown thereinto during the immersion of the alloy into the etching solution. An extremely low voltage of −0.3 to +0.2 V vs. NHE is applied from outside to the lead-containing copper-based alloy as an anode.