Multiple Applications of Silver

Medical uses of silver

Silver is used in many medical applications due to its antibacterial properties. Most medical devices, such as bandages, wound cleansers, catheters, pacemakers, valves and feeding tubes, that comes into contact with the body contain silver. The hospital also uses silver in air ducts to prevent certain conditions, such as Legionnaires Disease.

Silver for textiles

The thermal and biological properties of silver make it an ideal choice for the commercial textile industry. Silver is used in the anti-microbial properties of high-end sportswear to inhibit the growth of bacteria that can cause odors. Traditionally, silver and gold threads have been woven into clothing.

silver-for-textiles

Silver for food and water

Silver will play an important role in the food industry in the next decade. The US Food and Drug Administration has approved the addition of silver to bottled water to help kill bacteria, which opened the door for major municipalities to use white water for clean water at local communities, cities and state levels. Silver tip cutting tools are used for meat processing. It is also used in the processing of milk, cheese making and baking.

Silver superconductor

Another important use of silver is as a superconductor, mainly for large industrial and military electric motors. For a while, silver was used as a strategic reserve for military applications.

Other applications of silver

In addition to the above aspects, silver has many other uses. Silver is used as a wood preservative. Silver sputtering targets and silver evaporating materials are used for vacuum coating. The silver coating plays a key role in the solar power industry. Solar cells coated with silver absorb light and convert it into electricity.

silver-sputtering-coating

From the perspective of industrial applications, the future of silver is indeed very obvious. Many industrial applications will continue to use silver, and many new applications for silver will continue to grow at a significant rate.

Please visit https://www.sputtertargets.net/ for more information.

Deposition of silver on glass by e-beam evaporation

The case

I am attempting to use silver evaporation pellets to deposit one-micrometer thick silver layer on the glass substrate. I found that only electron beam evaporation is accessible within the facility. I tried Ag/Ti/glass but silver peels off the Titanium layer. Up to now, only Ag/Au/Ti/glass can partially work, and only 1/2 of my samples were fully coated with silver; the other half turned into blackish-rainbow color. I wonder what is wrong in the process? Should I should some intermediate layers?

deposit silver on glass substrate
deposit silver on the glass substrate

Possible Cause and Solution

The thickness of the Titanium (Ti) layer may be too large. Generally speaking, 5 to 10 nm is enough in this case.

The process is not operated in a good vacuum condition, thus the titanium layer is oxidized. In electron beam evaporation, as well as other vacuum evaporation, the vacuum degree of the evaporator is extremely important, which will greatly influence the quality of the film obtained. Thus, please make sure the vacuum chamber is well sealed before evaporating.

It is hard to avoid that the evaporated silver (as well as gold) only loosely connected to the glass substrate. Cleaning the glass with acetone and then methanol could help. Or you can just replace the glass substrate by using another transparent substrate, such as Al2O3, SiO2, AlN and Diamond. The silver layer can better deposit on those substrates mentioned above.

Other Suggestions

Titanium is an excellent adhesion layer, but it is also true that it may lose some of its adhesiveness if the vacuum is not good enough. As for its alternatives, Chromium (Cr) and Aluminum (Al) are recommended to act as the adhesion promoter.

Rising the temperature up to 100℃ in the vacuum for a few minutes may also improve the adhesion of metals.

Silver (Ag) Evaporation Materials
Silver (Ag) Evaporation Materials

For the explanation of the terminologies of vacuum coating mentioned in this passage, please refer to Terminologies of Vacuum Evaporation.

For high purity silver evaporation materials, please visit Stanford Advanced Materials.

For more news and knowledge about vacuum coating, please see SAM News.