While analyzing XRD of yttria stabilized zirconia (YSZ), I found some peaks at around 73-74. Some peaks were matching with JCPDS database of zirconia. When I saw the literature, I found researchers have pointed out those peaks as non-transformable tetragonal phase (t'-ZrO2) whose planes are (004) at around 73 and (400) at around 74. When I matched those positions with JCPDS database, no plane at 74 was found. If we take the structure of non-transformable tetragonal phase equal to that of tetragonal phase then at an angle 74 the plane is (220) in stead of (400).
I believe by "JCPDF" you mean the Powder Diffraction File (PDF) which is published by the International Center for Diffraction Data (ICDD). Many years ago this was known as the JCPDS (the ASTM Joint Committee on Powder Diffraction Standards) powder diffraction file, but that name is long out of use.
There are many entries in the PDF database for tetragonal YSZ. Note that the PDF is an edited database, with the best entries indicated by a "star" quality marker. Others are marked as lower quality. You have not told us which file number you are using for tetragonal zirconia, or what the release year is for your database.
Certainly the lower angle peak is 004 and the higher one is 220.
In the 2012 release of PDF-4, I found many starred entries for tetragonal YSZ including:
00-060-0501 through 00-060-0505. These structures are all consistent with what you are saying.
Please tell us what PDF card # you were using.
I believe by "JCPDF" you mean the Powder Diffraction File (PDF) which is published by the International Center for Diffraction Data (ICDD). Many years ago this was known as the JCPDS (the ASTM Joint Committee on Powder Diffraction Standards) powder diffraction file, but that name is long out of use.
There are many entries in the PDF database for tetragonal YSZ. Note that the PDF is an edited database, with the best entries indicated by a "star" quality marker. Others are marked as lower quality. You have not told us which file number you are using for tetragonal zirconia, or what the release year is for your database.
Certainly the lower angle peak is 004 and the higher one is 220.
In the 2012 release of PDF-4, I found many starred entries for tetragonal YSZ including:
00-060-0501 through 00-060-0505. These structures are all consistent with what you are saying.
Please tell us what PDF card # you were using.
I worked a lot with YSZ (or YPSZ if you want to stress the fact that the material is partially stabilized) in my Master thesis and I did also some quantification of the famous non-trasformable tetragonal phase. As far as I remember, there are two possible ways of describing the structure: a conventional one (the one giving the (400) and (004) peaks) and an alternative one with the new a,b axes on the base diagonals of the original cell.. You can easily find out from the cell parameters if the problem is this one or not.
Duh! I should have realized right away that this was the issue. If you redefine the basal plane axes then the 220 becomes the 400. Thanks Matteo!
Not an answer. In my question, I want to know how can I measure the diffusion in glass metal seal because I need to estimate the amount of moisture ingress in PV module for such seals
Dear Matteo/Edward, could you please refer me some resources/publications/books to get the points you people have mentioned. I would be lucky if you please elaborate in detail.
Just a rough idea of what's going one.
This is the base of your cell (is a square with edges abcd):
a---A---b
D..........B
d---C---c
If you now connect ABCD you obtain another smaller square (rotated). This is the basis of your new cell. The c axis remains the same. You just need a good crystallography book, the space groups of tetragonal zirconia and the international tables for crystallography vol. A to work out the remapping of the atoms
If you can see it, the original (larger) ascii-art drawing was:
a ______A______ b
| | |
D |______|______| B
| | |
|______|______|
d C c
it comes out good in the editing phase, but not online...
If I am not wrong it is like this one in the attachment. If the BCT structure is extended to FCT structure then 220 and 400 are same.
Matteo, out of curiosity: is that Master's thesis of yours available?
I (and others) may be interested to read it.
Think about the actual thing that is the structure defined of. Look at c/a ratio defining the tetragonility of a structure from cubic side.
c/(a*√2) ratio tend to 1.01 (but not really c/a 1.00 for cubic) for non transformable tetragonal phase at the 4-13M% of Y content in solid solution and if it gets exceed the value, transformable tetragonality of the structure confirms for less than 4M% of Y content in solid solution. This kind of inter-phase transition consumes the energy or suppress the energy and mechanism of toughening takes place if the solute atom is of Al. But if the case with Ti^+4 atom into zirconia it suppress the much less energy and cubic remains cubic or have the tendency to be transform into cubic structure of zirconia in this case temperature and oxygen vacancy matters for adjacent ion into the parents' oxygen vacancy or anionic vacancy..
one can use the following equation to define the fraction of Y atom up to 15M% Y content in solid solution
a√2 = 0.50801 + 0.03582x, c = 0.51944 + 0.03045x
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