Hillbillysmith Posted September 7, 2012 Share Posted September 7, 2012 Alright. So we all know (our should know) that you can change a metal's color or appearance by heat and w call it anodizing or patina (can also be done by chemical but....). Stainless, for example, will change colors by welding if its not shielded completely from the atmospheric gasses while at a raised temperature..... Now, here's my question for all you intellects on here; can anybody tell me exactly what atmospheric gas, reacting at what temperature, and with what specific metal creates which color??? Hopefully i explained this well enough. For example (example only): chromium reacts with nitrogen at 875 degrees fahrenheit to create a dark blue almost violet color.... See what I'm saying? If you were able to break this down to a science, you could get amazingly beautiful designs. -Hillbilly Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted September 7, 2012 Share Posted September 7, 2012 Well as the colour is to do with the thickness of the oxide layer it's oxygen. As to temps it depends on the alloy, colours on Titanium are not the same as HC steel, Copper, etc. And while it's the same result anodizing is not the the same thing as heat colouring as in anodizing you use electricity to control the thickness of the oxide layer. Quote Link to comment Share on other sites More sharing options...
Hillbillysmith Posted September 7, 2012 Author Share Posted September 7, 2012 I stand corrected Thomas, thank you. So that narrows it down then, only oxygen is the reactive gas. Now all i have to do is figure out what alloy at certain temps turn the specific colors.... -Hillbilly Quote Link to comment Share on other sites More sharing options...
Hillbillysmith Posted September 7, 2012 Author Share Posted September 7, 2012 In all reality, i should've known it was oxygen that reacted because as you simply stated its nothing more than an oxide layer. -Hillbilly Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted September 7, 2012 Share Posted September 7, 2012 Look around the net; I know there is a full set of Ti colours by voltage posted. Someone took a bunch of identical pieces and did it as a personal project. So if you had an alloy(s) you like you could do similar as a "chart" for yourself. Quote Link to comment Share on other sites More sharing options...
IronAlchemy Posted September 7, 2012 Share Posted September 7, 2012 HillBilly - Thomas has given you the core information so I will only add a few pieces. The colors that you get from oxidation of the surface are interference colors. It is not an accident that they are the same series of colors from straw to peacock for all metals. In fact, many bird feathers have the same colors, like peacocks, because the color comes from the same mechanism. Anything from soap bubbles to oil slicks to titanium gives the same colors. The color is a function of the thickness of the oxide coating and the refractive index of the oxide. At a higher temperature, you get a thicker oxide and a different color. Likewise, at any given temperature, if you hold the temperature the oxide layer will thicken with time and the color will change. Have a look at this earlier thread that has some useful links and discussion.http://www.iforgeiro...ors#entry255109 - Doug Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted September 7, 2012 Share Posted September 7, 2012 I do not recall steel getting vibrate red or green oxide layers? Quote Link to comment Share on other sites More sharing options...
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