Can Titanium Be Worn with Other Metals?

June 3, 2008

I received this email:

Dear Sir,
I would like to know when titanium and gold accessories are worn together, will there be any chemical reaction affecting both metals. I am wearing a Gold Chain now and I wish to purchase a Titanium Chain but I do not know whether there will be any adverse reaction. As I know Gold and Silver accessories can’t be worn together, so how about titanium and gold?

I hadn’t previously considered that gold and silver might react on the skin. But, yes they do. It isn’t much of a reaction, but it is to the detriment of the silver.

I replied:

Titanium is safe to wear with other metals.
Titanium always has a protective oxide coating that prevents any electrolytic reaction with other metals. Basically, moisture cannot reach the metal itself in order to complete a reaction. If it is scratched, the protective coating immediately re-forms (unless in a perfectly inert atmosphere (argon, krypton, etc) or a vacuum). That’s part of why titanium is such a good candidate for medical implants.

Go ahead and try it: http://mrtitanium.com/TitaniumChains.html

In detail, any two metals in a conductive solution (impure water) will exchange ions. If the metals touch, then an electric current forms, eating away at one of the metals. That’s how a battery works. Body moisture acts as an electrolyte between silver and gold, and hydrogen is produced at the gold side, and oxygen on the silver. Silver oxide is black and soluble; it tarnishes and eventually eats into the silver.

But for the reaction to continue, neither metal can be allowed to grow a continuous, non-soluble insulating layer. Titanium and niobium grow very good insulating layers when just exposed to most electrolytes. In fact, I force this insulating layer with enough voltage to produce the colors. That’s called “anodizing.”


Hypoallergenic: Titanium versus Niobium

April 2, 2008

There is a bit of confusion about which of these metals is safer for sensitive ears, or wherever. Niobium is generally available only in a chemically pure form, whereas titanium is available both pure and in a bewildering list of alloys (such as many surgical implant grades).

I list a few of the more popular grades and designations of titanium here. Most of them are hypoallergenic. Most of the jewelry that I sell is pure grade #1 or #2 titanium. Some of my ball posts are an alloy, medical implant certified, and with no detectable trace of dreaded nickel.

The etching and anodizing process strip the few percent of non-titanium elements from the surface, and then create a protective shield of titanium dioxide.

Chemically speaking, titanium is less likely to be absorbed by biological systems than niobium. Neither should cause an immune response or allergic reaction.

But when it comes to piercings, part of the issue is abrasion. Titanium is a hard metal that could have a slightly rough surface on the microscopic scale. The act of putting it in might abrade a tight hole.

Niobium is a softer metal, so the surface will yield more to pressure. This might make it better for extremely sensitive skin. The same softness is why the initially brighter colors of niobium don’t last as long as titanium colors.

Whereas I am distinctly a titanium partisan, my colleague at Wear-Earrings-Again.com prefers niobium, from her personal experience.

When in doubt, try both. If both work, then choose only by price, color and design.


Getting started in anodizing: Mesh?

March 18, 2008

Here is a typical question that I get asked:

I would like your advice: Besides the plastic container, what else do I need to anodize titanium grade 23 or grade 5. I called Reactive Metals to buy the machine for $206 , they told me to buy a mesh but I do not know what or where to buy it. I am a little scared of getting hurt if I do not know how it really works.

Any help will be really appreciated.

Peter

The question seems to be, what is needed to get started. Peter has already bought an anodizer, a 0-150vdc voltage supply.

The “mesh” might be one of three things.

  • A large-area cathode (negative pole immersed contact) could be a mesh of titanium or even stainless steel. I use a coil of wire for this, but a plate of metal does fine. Ideally, you want to have a non-conductive porous material ( maybe a plastic mesh) between the cathode and the work piece, in case of contact. Rubber non-skid shelf liner mesh/screen is cheap and good for this.
  • A mesh basket made of niobium wire makes a good anode connection for loose parts. A titanium wire basket will work, too. Just not quite as reliable at higher voltages.
    Note: I haven’t tried this myself. I use a homemade titanium clip and the niobium clips that ReactiveMetals sells.
  • A plastic mesh basket such as a salvaged automotive windshield washer fluid filter can also be used on the anode side by running a niobium or titanium wire into the basket full of little parts.
    Note: I haven’t tried this myself, but have heard of it being used by others.

One can easily weave your own basket from titanium or niobium wire.

One important final note: If you are afraid of getting hurt, please do some more reading about electricity and safety precautions. Wear rubber gloves, and always double check where all the live contacts are when you are working. Read my old anodizing page over until you understand everything in it. It may not be complete, so do ask questions to help me fill it out.