Does plating darken? Causes of sulfide and prevention measures.
Plated parts can turn black over time. Have you ever experienced this? This phenomenon is common with silver and copper plating, and the cause may be sulfide formation. Sulfide formation is a chemical reaction where metals react with sulfur components to create metal sulfides. Examples: - Silver (Ag) → Silver sulfide (Ag₂S) → Blackening - Copper (Cu) → Copper sulfide (CuS, etc.) → Brown to black It gradually progresses through contact with sulfur compounds (H₂S, SO₂, etc.) in the air or surrounding materials. The causes include: - Sulfur gas in the air or polluted environments - Sulfur content in rubber, resin, adhesives, paper, and cardboard - Human sebum and high-temperature, high-humidity environments The impacts include: - Poor conductivity due to increased contact resistance - Decreased solderability - Appearance defects and reduced reliability Effective countermeasures include: - Sealed storage + use of desulfurizing agents and drying agents - Avoiding packaging materials that contain sulfur Sulfide formation can be prevented or delayed with proper management. [Nihon Denpaku Kogyo Co., Ltd.] 1-137 Nisshin-cho, Kita-ku, Saitama-shi, Saitama 331-0823 Tel: 048-665-8135 Fax: 048-665-8130
Inquire About This Product
basic information
Causes of Sulfuration and Preventive Measures
Price range
Delivery Time
Applications/Examples of results
We examined the occurrence of sulfide phenomenon with the item from the customer and considered its causes and countermeasures.
Company information
Nihon Denko Kogyo is a company that specializes in variable multi-product production, handling small lot items across a wide range of applications. We have a rich variety of plating solutions, centered around our in-house developed liquids. We propose and provide optimal specifications from the base layer to the finish, tailored to your applications and needs. We are happy to accept small lots (from 1 piece) and prototype development projects. If you are facing challenges with surface treatment, please feel free to contact us.



![[Case Study of Problem Solving] Want to switch to mercury-free products due to environmental issues.](https://image.mono.ipros.com/public/product/image/f6e/2000575726/IPROS72373036213194291779.png?w=280&h=280)
![[Case Study of Conductive Diamond Technology] Pre-treatment for Plating on PPS Resin](https://image.mono.ipros.com/public/product/image/2111902/IPROS13896057029331523361.png?w=280&h=280)