Is this etching or anodizing?

Atlas Knife Company

Atlas Knife Company

Joined
Feb 16, 2010
Messages
3,668
Please take a look at the picture and tell me what you think. It was an anodizing test, but didn't quite achieve the normal results. I'm wondering if I was etching the item instead of anodizing. The strip in the middle is where I put tape to prevent anodizing for the test. TSP was used as the electrolyte at a voltage varying from 25vdc - 115vdc.

test.jpg
 
Last edited:
Anodizing is a term used to describe the build up of an oxide layer on aluminum or titanium. This is done electrolytically.
On steel we refer to terms like bluing ,heat colors.
What do you have and what are you trying to do ? Please put that info in all your posts so we don't have to guess.
 
I'd rather not mention the exact metal or process, but it is an attempt to anodize a metal that may or may not be able to be anodized. It was an electrolytically created oxide layer using 25VDC-115VDC. Perhaps I'm just bluing the metal.
 
mete said:
Anodizing is a term used to describe the build up of an oxide layer on aluminum or titanium. This is done electrolytically.
On steel we refer to terms like bluing ,heat colors.
What do you have and what are you trying to do ? Please put that info in all your posts so we don't have to guess.
Click to expand...

If you don't want to give more info, you're on your own I guess...

are you familiar with http://www.reactivemetals.com/

It has to be a reactive metal to use the procedure you are using, titanium, Niobium...etc
 
Hmmm, would I rather look stupid or look like a jerk? Fine, I'll take stupid. It's CPM-S35VN. Before you say "Are you crazy? You can't anodize stainless!" Realize that this is a new formula that contains niobium, which IS capable of being anodized. Has anyone else even TRIED to anodize it? The niobium is <1%, but it's still there. The problem is that other 99% is more conductive than the niobium. I can definitely get different colors according to the voltage, but it requires a much higher voltage than normal niobium/titanium/tantalum. My calculation is that the colors I got at 115VDC were about the same as 30VDC on pure niobium. I may need to find a way to anodize at much higher voltages, perhaps in the 220VDC range.
 
Was the pitting I see there before you started?
I've removed oxides from steel using electrolosis, and found you can oxidize if the polarity is reversed (aka anodizing).
 
It isn't pitting, just debris on the metal. I had to take about 30 pictures to get the colors to show with the poor lighting. I'll be trying some other chemical oxidizers and working on a new anodizer.
 
The appearance of the tape edge is darker. What does this look like on close examination? Is there a ridge that can be felt with your fingernail or is it a depression. If it is a ridge I would think you did some sort of deposition on the blade. Whether it was being stripped from one area and redeposited there I cannot say. If it a depression then you are etching the material. Also the taped area will be lower if you anodized and higher if etched. I am wondering if you can get any colors from this. Experimentation is what makes new advances. I had a friend who had the idea of laminating stainless to carbon steel using a tig welder to seal the joint. I told him it would not work and never gave it a thought. Well I wish I had given it a try, this was 18 years ago, I could have possibly been the first to discover the cool laminates that are so popular now. Let us know how your project turns out.
 
Thanks. I'll get out the microscope tomorrow and post some pics. My current theory is this: The 1% niobium will anodize, but I have to use enough current to get to it. Niobium is less conductive than iron. If I use enough current to get 99% of the current to the iron, 1% will make it to the niobium in the alloy. Of course the colors won't be as intense as pure element, but I should still be able to get a color change.
 
Zaph,
Your metallurgical theory and voltage calculations are specious.

If there is 1% niobium in the steel, it is not a plating on the surface. It is alloyed into the steel and is bound up with the carbon and iron. It is not elemental niobium.
Furthermore, the voltage required to anodize it would not be a linear scale with 99% going to the Fe and 1% going to the Nb..... 100% goes to both.
 
1% color change, you bet! Especially if it's something no one else has done yet.

Back to chemistry class to figure out some of this stuff, but at 200x it seems there is definitely an oxide layer deposited on the surface. I will try to find something in the 500x or 1000x rangebut that will take some time. I'm pretty sure that electrons flow at the atomic level and not the molecular level. If they did flow at the molecular level this would be an easy task as the electrons would easily flow through the niobium at the same current. The higher resistance the lower the current, IIRC.
s35vn.jpg
 
You must log in or register to reply here.
Back
Top