What’s The Deal With Transparent Aluminum?

April 3, 2018 by Dan Maloney 138 Comments

It looks like a tube made of glass but it’s actually aluminum. Well, aluminum with an asterisk beside it — this is not elemental aluminum but rather a material made using it.

We got onto the buzz about “transparent aluminum” as a result of a Tweet from whence the image above came. This Tweet was posted by [Jo Pitesky], a Science Systems Engineer at the Jet Propulsion Lab in Pasadena. [Jo] reported that at a recent JPL technology open house she had the chance to handle a tube of material that looks for all the world like a section of glass tubing, but was billed as transparent aluminum. [Jo] tweeted this because it was an interesting artifact that few people get to play with and she’s right, this is fascinating!

The the material itself is intriguing, and I immediately had practical questions like what is this stuff? What is it good for? How is it made? And is it really aluminum rendered transparent by some science fiction process?

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Cook Up Your Own High-Temperature Superconductors

February 28, 2018 by Dan Maloney 16 Comments

It looks more like a charcoal briquette than anything, but the black brittle thing at the bottom of [Ben Krasnow]’s crucible is actually a superconducting ceramic that can levitate magnets when it’s sitting in liquid nitrogen. And with [Ben]’s help, you can make some too.

Superconductors that can work at the relatively high temperature of liquid nitrogen instead of ultracold liquid helium are pretty easy to come by commercially, so if you’re looking to just float a few magnets, it would be a lot easier to just hit eBay. But getting there is half the fun, and from the look of the energetic reaction in the video below, [Ben] had some fun with this. The superconductor in question here is a mix of yttrium, barium, and copper oxide that goes by the merciful acronym YBCO.

The easy way to make YBCO involves multiple rounds of pulverizing yttrium oxide, barium ~~chloride~~ carbonate, and copper oxide together and heating them in a furnace. That works, sort of, but [Ben] wanted more, so he performed a pyrophoric reaction instead. By boiling down an aqueous solution of the three components, a thick sludge results that eventually self-ignites in a spectacular way. The YBCO residue is cooked in a kiln with oxygen blowing over it, and the resulting puck has all the magical properties of superconductors. There’s a lot of detail in the video, and the experiments [Ben] does with his YBCO are pretty fascinating too.

Things are always interesting in [Ben Krasnow]’s life, and there seem to be few areas he’s not interested in. Of course we’ve seen his DIY CAT scanner, his ruby laser, and recently, his homemade photochromic glass.

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Your 3D Printer Could Print Stone

December 27, 2017 by Al Williams 38 Comments

Most of our 3D printers print in plastic. While metal printing exists, the setup for it is expensive and the less expensive it is, the less impressive the results are. But there are other materials available, including ceramic. You don’t see many hobby-level ceramic printers, but a company, StoneFlower, aims to change all that with a print head that fits a normal 3D printer and extrudes clay. You can see a video of the device, below. They say with some modifications, it can print other things, including solder paste.

The concept isn’t new. There are printers that can do this on the market. However, they still aren’t a common item. Partially, this is a cost issue as many of these printers are pricey. They also often require compressed air to move the viscous clay through tubes. StoneFlower has a syringe pump that doesn’t use compressed air.

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Popping The Top Of A Ceramic IC

April 7, 2017 by Al Williams 31 Comments

If you’ve ever wanted to open up an IC to see what’s inside it, you have a few options. The ceramic packages with a metal lid will succumb to a hobby knife. That’s easy. The common epoxy packages are harder, and usually require a mix of mechanical milling and the use of an acid (like fuming nitric, for example). [Robert Baruch] wanted to open a fully ceramic package so he used the “cooler” part of a MAP gas torch. If you like seeing things get hot in an open flame, you might enjoy the video below.

Spoiler alert: [Robert] found out the hard way that dropping the hot part isn’t a great idea. Also, we are not sure what the heat does if you want to do more than just inspect the die. It would be interesting to measure a junction on the die during the process to see how much heat actually goes to the device.

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History Of The Capacitor – The Modern Era

July 26, 2016 by Steven Dufresne 20 Comments

The pioneering years in the history of capacitors was a time when capacitors were used primarily for gaining an early understanding of electricity, predating the discovery even of the electron. It was also a time for doing parlor demonstrations, such as having a line of people holding hands and discharging a capacitor through them. The modern era of capacitors begins in the late 1800s with the dawning of the age of the practical application of electricity, requiring reliable capacitors with specific properties.

Leyden Jars

Marconi with transmitting apparatus, Published on LIFE [Public domain], via Wikimedia Commons

One such practical use was in Marconi’s wireless spark-gap transmitters starting just before 1900 and into the first and second decade. The transmitters built up a high voltage for discharging across a spark gap and so used porcelain capacitors to withstand that voltage. High frequency was also required. These were basically Leyden jars and to get the required capacitances took a lot of space.

Mica

In 1909, William Dubilier invented smaller mica capacitors which were then used on the receiving side for the resonant circuits in wireless hardware.

Early mica capacitors were basically layers of mica and copper foils clamped together as what were called “clamped mica capacitors”. These capacitors weren’t very reliable though. Being just mica sheets pressed against metal foils, there were air gaps between the mica and foils. Those gap allowed for oxidation and corrosion, and meant that the distance between plates was subject to change, altering the capacitance.

In the 1920s silver mica capacitors were developed, ones where the mica is coated on both sides with the metal, eliminating the air gaps. With a thin metal coating instead of thicker foils, the capacitors could also be made smaller. These were very reliable. Of course we didn’t stop there. The modern era of capacitors has been marked by one breakthrough after another for a fascinating story. Let’s take a look.

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Hackaday Prize Entry: DIY Ceramic PCBs

May 14, 2016 by Brian Benchoff 10 Comments

We’ve seen hundreds of ways to create your own PCBs at home. If you have a laser printer, you can put traces on a piece of copper clad board. If you have some hydrogen peroxide and acid, you can etch those traces. Don’t have either? Build a tiny mill and cut through the copper with a Dremel. Making your own PCBs at home is easy, provided your boards are made out of FR4 and copper sheets.

Printed circuit boards can be so much cooler than a piece of FR4, though. Ceramic PCBs are the height of board fabrication technology, producing a very hard board with near perfect electrical properties, high thermal conductivity, and a dielectric strength similar to mineral transformer oil. Ceramic PCBs are for electronics going to space or inside nuclear reactors.

For his entry into this year’s Hackaday Prize, [Chuck] is building these space grade PCBs. Not only is he tackling the hardest challenge PCB fabrication has to offer, he’s building a machine to automate the process.

The basic process of building ceramic PCBs is to create a sheet of alumina, glass powder, and binder. This sheet is first drilled out, then silver ink is printed on top. Layers of these sheets are stacked on top of each other, and the whole stack is rammed together in a press and fired in a furnace.

Instead of making his own unfired ceramic sheets, he’s just buying it off the shelf. It costs about a dollar per square inch. This material is held down on a laser cutter/inkjet combo machine with a vacuum table. It’s just a beginning, but [Chuck] has everything he needs to start his experiments in creating truly space grade PCBs.

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Good Vibrations In 3D-Printed Clay

February 20, 2016 by Elliot Williams 16 Comments

An engineer with a 3D printer wants everything to be rigid and precise. Wobble induced by flex in the z-axis feedscrews, for instance, makes telltale wavy patterns in the surface that match exactly the screw pitch. Nobody likes those, right? Certainly not an engineer!

But one man’s surface irregularity is another man’s ornamentation. The details we have are sparse, but from looking at the video (also inlined below the break) it’s clear enough: [Olivier van Herpt] and [Ricky van Broekhoven] stuck a vibrating woofer underneath the print bed of their ceramic printer, and use it to intentionally ruin their smooth surface. And they do so to great artistic effect!

We’re not suggesting that you give up entirely on your calibrations, but we do appreciate a little out-of-the-box thinking from time to time. But then our internal engineer raises his head and we wonder if they’re linking the pitch of the woofer to the feed rate of the print head. Your thoughts in the comments?

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