| 摘要 |
An electrodeposition process for depositing a boron-containing amorphous metallic layer onto a cathode from an electrodeposition bath having borophosphoric acid, dimethylamineborane or diethylamineborane; an ammonium salt of a hydroxycarboxylic acid or amino acid; and a source of the metallic ions. In one embodiment, tungsten-cobalt-boron amorphous alloys are deposited onto the cathode from a bath having borophosphoric acid, an ammonium salt of a hydroxycarboxylic acid or amino acid, a tungsten-containing salt and a cobalt-containing salt. In the preferred embodiment, the tungsten-containing salt is sodium tungstate, the cobalt-containing salt is cobalt sulphate, and the ammonium salt of a hydroxycarboxylic acid is ammonium citrate or ammonium tartrate. A range of bath compositions may be utilized to deposit the amorphous tungsten-cobalt-boron alloys onto the cathode, such alloys having high hardness and wear resistance and also having sufficient ductility to avoid cracking of the amorphous layer in fabrication and use. The electrodeposition process is preferably conducted at a voltage greater than the hydrogen over-voltage of the bath composition, and at a current density greater than about 20 milliamps per square centimeter.
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