Silver rings, bangles, and pendants are popular items at MITUBACI, but we understand that some people worry about them turning black.
In response to customer requests, MITUBACI now offers the option of "rhodium plating" to prevent discoloration.
Rhodium plating option] Start!
Charge: +3,300 yen per bottle
All silver items
You can take it home on the same day.
MITUBACI currently offers "yellow gold plating" and "pink gold plating" as an option (+3,300 yen).
Can you do silver plating?
How can I prevent silver from discoloring?
I want to use the silver color to keep the surface discoloration (sulfurization) at bay and keep it looking good for a long time!
I can't wear it every day, so when I do wear it, I want it to always look good, so I want to prevent discoloration!
I want to prevent discoloration (sulfurization) on a ring/ bangle I made for a memorial and want to keep it on display!
We have received a lot of questions and requests for the "rhodium platingWe also decided to add a
Rhodium plating has a white luster that is slightly less white than silver.
Silver has the highest reflectivity of all metals, but if left in contact with air for a long period of time, it will sulfurize and discolor. This is recommended when you want to prevent scratches and discoloration on your shiny silver items as much as possible.
We also have samples of rhodium-plated pieces available, so please take a look at them on the day of the workshop and consult with our craftsmen.
Here is a little more technical information.
What kind of material is rhodium?
Here is a brief description of rhodium.
English: Rhodium Element symbol: Rh Atomic number 45
Specific gravity 12.5, melting point 1966°C, reflectance 85% (visible wavelength range)
It is one of the white metals and is classified as a precious metal.
It is very chemically stable and insoluble in ordinary acids and alkalis. It has good corrosion and wear resistance and does not tarnish, so it is often plated on silver, white gold, and platinum products.
In particular, it is safe to assume that most K18 white gold products are rhodium plated.
MITUBACI's K18 white gold is not plated because we value the color of the base metal itself.
White gold, as close to white as possible, is used by adjusting the composition of the base metal.
■ Reflectance of precious metals
Silver: approx. 90
Platinum: approx. 70
Rhodium: approx. 85
Comparing silver and platinum, platinum has a subdued silver luster, while rhodium has a luster somewhere between silver and platinum.
Numerically, silver is the most reflective and shiny, but silver deteriorates (sulfides) over time and requires regular care to maintain its luster.
■Comparison of hardness (Vickers hardness)
Silver: 100-120HV (hardness after processing)
Rhodium: 800-1000 HV rhodium plating is effective in preventing tarnishing compared to silver, but in addition, it has about 10 times the hardness of silver, so it can be expected to prevent minor surface scratches.
Before and after rhodium plating ・Plating process
I would like to explain the difference in color between silver and rhodium after rhodium plating with pictures.
How to apply rhodium plating
Before plating, the surface is cleaned of dirt and oil.
Rinse well with water after placing in ultrasonic cleaner.
The cleaned item is placed in the beaker of the plating machine. When placed in the rhodium plating solution, bubbles will appear.
A rhodium plating film is formed on the surface of the ring by applying an electric current. You can see that the silver shine before plating has a slight yellow luster in some areas.
In the photo, you can see the color of the back of the ring better. After rhodium plating, the ring looks bluish compared to before plating.
It is the same silvery metal, but it has a different luster from both silver and platinum.
Silver jewelry holds many memories. Why not keep it beautiful longer by applying rhodium plating?
If you wish, please let our craftsman know on the day of your visit!