コダマ Company Overview

At Kodama Co., Ltd., we address yellow discoloration and blackening that occurs in silver-plated products, from investigating the causes to implementing discoloration prevention treatments. Silver easily reacts with hydrogen sulfide and sulfur compounds in the air, leading to the formation of black silver sulfide (Ag₂S) on the surface, which causes discoloration. Factors such as exhaust gases, rubber, cardboard, adhesives, sweat and sebum, and high-temperature and high-humidity environments also promote discoloration. As countermeasures, we propose discoloration inhibitors (anti-sulfur treatments), chromate treatments, and simple rust prevention treatments. Furthermore, the use of anti-sulfur bags, avoiding direct contact with cardboard and rubber, and storing in environments that avoid high temperature and humidity are also important packaging and storage methods. We cater to terminals, connectors, busbars, contacts, EV and automotive components, and electrical parts. We can assist with everything from prototypes to mass production for matte silver, glossy silver, hard silver, super hard silver, and partial silver plating.

At Kodama Co., Ltd., we propose the optimization of film thickness, plating range, substrate specifications, and processing lots to maintain the quality of gold plating while keeping costs down. The price of gold plating can fluctuate significantly based on surface area, film thickness, gold market prices, and quantity. By reviewing unnecessary film thickness, changing from full plating to partial gold plating, and optimizing substrate specifications and masking methods, it may be possible to reduce the amount of gold used and processing costs. We cater to electronic components, terminals, connectors, contacts, and semiconductor-related parts. We can assist with everything from prototypes to mass production, including pure gold plating, hard gold plating, partial gold plating, thick gold plating, and gold plating on SUS.

At Kodama Co., Ltd., we conduct coating hardness measurements using a micro Vickers hardness tester as part of our quality assurance for silver-plated coatings. According to JIS Z 2244 (Vickers hardness measurement test), we measured the hardness of hard silver plating and bright silver plating over a period of 10 days. The required hardness for silver plating varies depending on the application and required characteristics. In particular, for sliding parts and contact components, hardness is one of the important quality items for evaluating wear resistance and durability. 【Hardness Measurement of Silver Plating: 10-Day Actual Measurement Using Micro Vickers Hardness Tester】 Hard Silver Plating: Average Hardness: Hv184.0, Minimum Value: Hv177, Maximum Value: Hv193 Bright Silver Plating: Average Hardness: Hv120.5, Minimum Value: Hv118, Maximum Value: Hv125