Precious metal switch contact component and its preparation method

A method for preparing a precious metal switch contact component is characterized by comprising the following processing steps

• 1) Printing a plating mask ink
• using a base metal sheet of 0.01-10 mm in thickness as a substrate;
• printing an ink dissolvable in a solvent, an acid solution or an alkaline solution on an upper surface of the substrate in thickness of 0.5-10 μm as a plating mask;
• leaving areas without plating mask covered with dotted, striped or latticed base metal surface, or base metal dots combined with stripes;
• printing the plating mask of thickness 0.5-10 μm on an undersurface of the substrate so as to completely cover the undersurface;
• wherein the coating on the upper surface and the undersurface of the substrate is different or identical in the material composition;
• said plating mask is an organic polymer material, ink or coating, which is water resistant but dissolvable or peeled in organic solvents, or which is acid-resistant but dissolvable or peeled in alkaline solutions, or which is alkali-resistant but dissolvable or peeled in acidic solutions;
• or the printing a plating mask ink step includes
• printing an acid- or alkaline-resistant photosensitive ink in thickness of 0.5-10 μm which is subsequently used as the plating mask, on both surfaces of the base metal sheet;
• treating both surfaces of the substrate with a photo exposure machine, and then rinsing both surfaces of the substrate with water to remove uncured photosensitive ink, so as to make a dotted, striped or latticed base metal surface exposed from the substrate;
• 2) Plating of precious metals:
• depositing a coating or plating in thickness of 0.05-5 μm of precious metals by electroplating or electroless plating on areas of the substrate surface without plating mask printed;
• or depositing a coating or plating of 0.1-20 μm thick base metal before depositing a coating or plating in thickness of 0.05-5 μm of precious metals by electroplating or electroless plating;
• 3) removing of the plating mask:
• removing the plating mask, printed on the upper surface of the substrate, by using a solvent, or an alkaline solution or an acid solution in a manner of dissolution or peeling;
• or removing cured photosensitive inks on both surfaces, when used as the plating masks by dissolution with an alkaline solution, an acidic solution or a solvent
• 4) Etching:
• using an etching solution for selective etching of the areas where the plating mask on the upper surface of the substrate has already been removed as in Step 3), or where there is no precious metal plating,
• wherein the etching depth is 5%-95% of the substrate thickness so that the precious metal plating plated on the substrate protrudes out of the upper surface of the substrate;
• wherein said etching solution is
• a cupric chloride etching solution containing hydrogen peroxide, urea hydrogen peroxide or peracetic acid, or
• a ferric chloride solution containing hydrogen peroxide, urea hydrogen peroxide or peracetic acid;
• 5) Bonding with rubber:
• removing the plating mask on the undersurface of the substrate, and then bonding the undersurface of substrate with rubber by thermal vulcanization to form a 0.25-5 mm thick laminated sheet;
• 6) Punching:
• cutting or punching the laminated sheet into cylindrical, prismatic or elliptic disks with cross-sectional areas of 0.8-80 mm2;
• and
• obtaining a precious metal switch contact component,
• wherein said precious metal is selected from gold, silver, ruthenium, rhodium, palladium, osmium, iridium, and platinum or an alloy of any of them.