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The Problem with Zirconia Ceramics
- Thread starter kleo
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Wow thanks lots of good information. I sure am curious about what they are going to do with the back... but in the end (as someone in another thread said) I'm more interested in the front 
People seem pretty convinced that the back won't be plastic, but I am not so sure.
People seem pretty convinced that the back won't be plastic, but I am not so sure.I've seen Zirconia's Mohs hardness cited as 8, which I think makes a much larger difference than potential heat issues. When you compare that to plastic (3-4 Mohs hardness) I would rather have a phone that wouldn't scratch so easily. Having such a nice piece of technology that can do all the things the iPhone can do AND stand up for itself in a fall would really mean a lot to me, and I take exceptional care of my electronics.
Second, when you quote the strength numbers you're citing tensile strength and then liken the strength to crack resistance. The only problem is it would be cracking under compression. That's like saying because carbon fiber isn't strong in compression it shouldn't be used to make Formula 1 cars.
I'm looking at a data sheet right now for CeramTec 848 Zirconia (ZrO2) and seeing that the Ultimate Tensile strength is actually 80K Psi, so your comparison is done using flawed data. This would make Zirconia the strongest of the materials you compare. Also the Compressive strength is 435K Psi, making it as strong in compression as other ceramics such as Aluminum Oxide. Compare this to the compressive strength of common plastics, which will fall between 6K and 12K Psi.
I think you may be on to something with the heat dissipation, but I guess that remains to be seen how the designers weigh one piece strong back or split materials that dissipate heat better.
After reviewing more reliable data I agree my source of data last night was incorrect. You can read more reliable data for yourself at Kyocera's website: http://americas.kyocera.com/kicc/industrial/wiremater.html
Zirconia ceramics do in fact have a higher hardness then i originally stated making them even more ideal for scratch resistance. Second the strength of these ceramics does appear to be quite a bit higher then i originally stated making them far superior to there plastic and even some metal counterparts. Does anyone know the flexural strength (3point) of stainless steel for comparison to the stated Zirconia strength of 102 KPSI. I think flexural strength is a better measurement of the durability of these materials under iPhone conditions compared to both Ultimate tensile strength and compressive strength.
Heres for zirconia ceramics!
Zirconia ceramics do in fact have a higher hardness then i originally stated making them even more ideal for scratch resistance. Second the strength of these ceramics does appear to be quite a bit higher then i originally stated making them far superior to there plastic and even some metal counterparts. Does anyone know the flexural strength (3point) of stainless steel for comparison to the stated Zirconia strength of 102 KPSI. I think flexural strength is a better measurement of the durability of these materials under iPhone conditions compared to both Ultimate tensile strength and compressive strength.
Heres for zirconia ceramics!
Zirconia as a writing surface.
I saw something over a year ago about Apple's intent to employ Zirconia in their products. When Jobs introduced the iPhone, he pointed out that he really thought a stylus was useless for a number of reasons. Using our fingers should be enough, it was implied. But "writing" with a finger just does not cut it.
What if I could use a pen or pencil? Zirconia could handle the scratches and you would not need to extend the tip of the pen. Smudges (even ink) wipes off easily. Most people carry a pen or pencil. I have used one many times on my Palm with no ill effects.
A Zirconia writing surface lets me use any writing device I have on me and moves me toward using the handwriting recognition which is already built into the OS.
I don't see them using Zircona for the shell but for a screen that can take a bit more punishment than glass can.
I saw something over a year ago about Apple's intent to employ Zirconia in their products. When Jobs introduced the iPhone, he pointed out that he really thought a stylus was useless for a number of reasons. Using our fingers should be enough, it was implied. But "writing" with a finger just does not cut it.
What if I could use a pen or pencil? Zirconia could handle the scratches and you would not need to extend the tip of the pen. Smudges (even ink) wipes off easily. Most people carry a pen or pencil. I have used one many times on my Palm with no ill effects.
A Zirconia writing surface lets me use any writing device I have on me and moves me toward using the handwriting recognition which is already built into the OS.
I don't see them using Zircona for the shell but for a screen that can take a bit more punishment than glass can.
I think ceramic zirconia in an white opaque material, you might be talking about the crystalline zirconium (ZrO2) which would be way to brittle for use as the shell but is transparent. It might work for the screen because it does tend to be harder than glass, but the hardness of glass can vary depending on how it is made so I'm not really sure how hard the iPhone's screen is. I think the major benefit of using glass is the ease of formation, making a screen out of cubic zirconium would be much more difficult.
First we should see if the new phone is actually made of the material, before critiquing it. Just my 2 cents.
I don't think anyone was actually critiquing the phone, just speculating about possible materials for its construction. I think materials science is fascinating and I would love to see more companies using high tech ceramics in their products.