Metals are cool; I don’t know where we humans would be if we had never learned about how to extract, work, form, sharpen, machine, weld, cast, polish, and everything else we do with metals.
A couple, maybe more like three or four years ago, I was asked at the place I worked to put together a set of classes for non-engineers mostly to help with communication, but also at that particular company, the management thought that some familiarity with engineering topics and know-how might somehow, “educate” and help “train” people. Anyhow, I went to work on my training book, and one topic I got into was engineering materials.
Metals. I thought I pretty much knew about all you had to know for everyday design type work, and yes metals rock, but in researching closer, I found out some pretty cool, even a little bit weird stuff about ordinary metals and that’s what we talk about today. First off though, what is a “metal” precisely:
A metal (from Greek “μέταλλον” – métallon, “mine, quarry, metal”) is a material (an element, compound, or alloy) that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable — that is, they can be hammered or pressed permanently out of shape without breaking or cracking — as well as fusible (able to be fused or melted) and ductile (able to be drawn out into a thin wire). About 91 of the 118 elements in the periodic table are metals (some elements appear in both metallic and non-metallic forms). From the Wikipedia: http://en.wikipedia.org/wiki/Metal
Copper is a metal. It’s also an element. Some metals are combinations of elemental materials – for example – if you mix copper, an element, with zinc, another element, you get brass – an alloy. So metals mix it up, making new kinds of metals frequently with different properties from their base constituents. This has been understood one way or another, for thousands of years; we know more about metals now, but we don’t know it all and we are constantly discovering new things. Copper and copper alloys are often referred to as the red metals. Another alloy of copper is bronze; which classically was an alloy of copper and tin, but nowadays any copper alloy whose main alloying element is not zinc or nickel is referred to as bronze.
Ever heard of the bronze age; and how it was replaced by the iron age? About 1200 BC in the civilized world around the Mediterranean, things just started politically falling apart – there was a dark ages for about 400-500 years, people even forgot how to read and write. We don’t really know exactly what happened. The ancient trade routes were abandoned and this eventually spelled doom for bronze because while copper is relatively plentiful so is easy to get just about everywhere; tin is scarce, only shows up in a few spots and had to be traded for. No trade. No tin. No bronze. Iron was plentiful, but harder to work and in a pure form, not much harder than bronze; and while iron corrodes; bronze forms a thin, thin layer or inert patina thus resists corrosion. As long as tin was available, iron was largely ignored.
Iron is relatively plentiful and over time, some say as short as 80-100 years, a couple of working generations, smiths and metal workers figured out how to work iron – it takes a lot more heat to work iron – and it was accidentally found that by repeatedly heating iron, it was changed into something else far, far harder than iron or bronze; it was turned into steel – an alloy of iron and carbon – the carbon came from the combustion products in the fire. Carbon steel. Say good-bye to the bronze age.
Red metals were, and are still used. Remember, they don’t corrode like iron and steel implements which have to be oiled and coated and protected or they will just rust away. So everything from monuments to horse bridles kept being made from bronze and brass, but weapons and tools started getting made from iron.
“So how long would something made from bronze last?” The answer is “almost forever”. We still find bronze stuff made by the Greeks and other bronze stuff even even predating the Greeks! Let’s play the tape of time forward just to see how insane this is. I make sundials and have a nice piece of bronze I want to use for one. I anticipate it will basically last practically forever – that’s why I am using bronze. Let’s say I got myself a patch of land out in the middle of nowhere Arizona; built my sundial from bronze out there; things just start politically falling apart people stopped blogging because they forget how to read and write, hundreds of years later things get cool again; more time goes by and they find my sundial in the year 5014, 3000 years later; it would still be there. Bronze. It’s bad-ass. But it gets better.
The copper in brass is germicidal. Depending upon the type and concentration of pathogens (germs, viruses, amoebas) and the medium they are in, brass kills these microorganisms with a few minutes to eight hours of contact. The bactericidal properties of brass have been observed for centuries and were confirmed in the laboratory in 1983. Subsequent experiments by research groups around the world reconfirmed the antimicrobial efficacy of brass, as well as copper and other copper alloys. Extensive structural membrane damage to bacteria was noted after being exposed to copper.
In 2007, U.S. Department of Defense’s Telemedicine and Advanced Technologies Research Center (TATRC) began to study the antimicrobial properties of copper alloys in a multi-site clinical hospital trials. Commonly touched items, like bed rails, over-the-bed tray tables, chair arms, nurse’s call buttons, IV poles, etc, were retrofitted with copper alloys – results in 2011 indicate that the coppered rooms demonstrated a 97% reduction in surface pathogens versus the non-coppered rooms! Patients in the coppered rooms had a 40% lower risk of contracting a hospital acquired infection versus patients in non-coppered rooms. And you can Google this and get tons of confirmation. Did you know that about copper and its alloys? Why aren’t all hospitals outfitted in copper and brass? What about your house? Want to kill germs? Here’s how.
Speaking of medical stuff, have ever wondered about the metal they implant into your body, if say for example, you need that sort of thing? Dental implants, orthopedic apparatus’s, heart pacemaker cases, that stuff. The metal of choice is titanium. Why? I mean, the body rejects foreign stuff – but it’s cool with titanium. The human body actually allows bone to grow onto titanium.
“Titanium is considered the most biocompatible of all metals due to its ability to withstand attack from bodily fluids, stay inert in the human body, be compatible with bone growth and stay strong and flexible during use. The materials ability to be resistant to body environments under stress, fatigue, and in crevice conditions is due to the protective oxide film that forms naturally in the presence of oxygen. The oxide film is highly adherent, insoluble, and chemically non transportable, preventing reaction from occurring.” http://en.wikipedia.org/wiki/Titanium_biocompatibility
Metals. I have yet to even scratch the surface of the topic – more later – just touched on copper, red-alloys, iron-steel and space age titanium; but enough for now…
The image of platinum at the beginning of the blog? No reason. I just like platinum.