Talk:Crystal growth

Needs BIG Improvements
The article in general is very bad (I do my PhD in crystallization) and needs several sections added: - a simple description what crystal growth is and what causes it (links to other articles already existing) - a more detailed description on HOW a crystal grows (growth mechanisms)

As soon as there is some time open in my schedule, I will work on this.Necmon (talk) 11:58, 25 November 2008 (UTC)
 * Casual observer here: I agree completely, and the first introductory paragraph of Mechanisms of growth really needs to be cleaned up. It's not a good introduction at all - it's short and dense, very technical, a bit random, and only mentions vapor growth. It seems like it was written in haste. Not to mention the last sentence ends with a colon. :) This article needs help, but I'm inexperienced in editing Wikipedia even though I have some background in Crystal growth. I'd be willing to help, if needed. 2601:88:8100:7443:4DBD:72A7:ABE2:723B (talk) 04:02, 23 April 2019 (UTC)

Needs Headings
The article needs headings. I am not sure where they would go-just throwing this out there. —The preceding unsigned comment was added by 69.250.187.194 (talk) 22:17, 26 March 2007 (UTC).

Mergers

 * There a quite a few articles on aspects of crystals and Crystallization. I wonder to what degree some of these articles could be merged. For example, It seems that crystal growth is quite closely related to Crystallization (engineering aspects).


 * See also:


 * Crystal
 * Crystal structure
 * Crystallite
 * Crystallization
 * Crystal growth
 * Fractional crystallization
 * Recrystallization
 * Seed crystal
 * Single crystal


 * and articles cited therein also!
 * I suspect it would take a brave person to try and untangle/merge these articles !! -- Quantockgoblin 13:47, 23 January 2007 (UTC)


 * I would like to add that this article is now mainly about nucleation, which is a related but completely different process. Josq (talk) 00:21, 7 February 2008 (UTC)

MAIN MERGE
Reinforcing the suggestion to merge, part with Crystal growth and part with Crystallization (engineering aspects):
 * 1) Work with samples and summaries at talk pages for discuss new structure and appends at each main article;
 * 2) Work migrating and merging some content.

If this article is improved, cleaned (there are a lot of non-encyclopedic details and repeated content between articles), and make understandable to non-experts, it not need to merge with others: is a in-deep article to the "(only) crystal growth" subject.

--Krauss (talk) 01:26, 8 March 2011 (UTC)

They need to add more.
It's too short. If someone, like me, for example, was looking for info on crystals and they came here, they would want more info on crystals. Ptara517 (talk) 23:38, 4 February 2008 (UTC)

Gallery cleanup
It would be helpful to add captions to the images based on the image titles in the code of the edit window. I'll ask someone how to do that. Crystal whacker (talk) 18:16, 26 November 2008 (UTC)

Difference?
How is this topic different from grain growth? If there is little difference, perhaps they should be merged. Wizard191 (talk) 18:10, 18 January 2009 (UTC)

Original Research included in Figures
While I believe the SEM of the silver growing is very interesting in an academic perspective, I wonder if this constitutes original research. Also I am not sure how useful the caption is in describing the interesting features such as nucleation sites and lattice steps. Darkwraith (talk) 17:30, 16 February 2010 (UTC)

Is this article adequate?
What portion of the keywords that categorize the papers in The Journal of Crystal Growth published by Elsevier does this article cover? Is this sufficient for an article that a reader might think gives an indication of what someone working on "crystal growth" might be studying now, or studied in the past? For example, should the role of growing large single crystals in the development of infra-red and heat detecting semiconductor sensors be mentioned? Should mention be made of mathematical theories for rate of crystal growth? Should mention be made of relevance to space studies? And so on. Adding a long list of "see also"s without explaining why they should be seen is a cop-out. I think that one of the worst dangers of WP is the use of a phrase as the title of an article that deals with just one or two items that fall within it. Michael P. Barnett (talk) 01:13, 22 December 2010 (UTC)

Adding physical model on diffusion controlled growth
We are two students(Bachelor Physics and Chemistry Master) and we would like to update this article and add more information. We thought about adding a part to diffusion controlled growth. Thats what we would like to add:

Diffusion-control: Very commonly when the supersaturation (or degree of supercooling) is high, and sometimes even when it is not high, growth kinetics may be diffusion-controlled, which means the transport of atoms or molecules to the growing nucleus is limiting the velocity of crystal growth. Assuming the nucleus in such a diffusion-controlled system is a perfect sphere, the growth velocity, corresponding to the change of the radius with time $$ \textstyle \frac{\partial r}{\partial t} $$, can be determined with Fick’s Laws.

1. Fick' s Law:   $$J=-D \nabla c $$,

where $$ \textstyle J$$ is the flux of atoms in the dimension of $$ \textstyle \frac{[quantity]}{[time]\cdot[area]} $$, $$ \textstyle D $$ is the diffusion coefficient and $$ \textstyle \nabla c $$ is the concentration gradient.

2. Fick' s Law:   $$\frac{\partial c}{\partial t} =D \nabla^2c$$,

where $$ \textstyle \frac{\partial c}{\partial t}$$ is the change of the concentration with time. The first Law can be adjusted to the flux of matter onto a specific surface, in this case the surface of the spherical nucleus:

$$ J_{matter} = D 4 \pi \cdot r^2 \frac{\partial c}{\partial r} $$,

where $$ \textstyle J_{matter}$$ now is the flux onto the spherical surface in the dimension of $$ \textstyle \frac{[quantity]}{[time]} $$ and $$ \textstyle 4 \pi \cdot r^2$$ being the area of the spherical nucleus. $$ \textstyle J_{matter}$$ can also be expressed as the change of number of atoms in the nucleus over time, with the number of atoms in the nucleus being:

$$ N(t)=\frac{\frac{4}{3} \pi \cdot r(t)^3}{V_{at}}$$ ,

where $$ \textstyle \frac{4}{3} \pi r^3 $$ is the volume of the spherical nucleus and $$ \textstyle V_{at}$$ is the atomic volume. Therefore, the change if number of atoms in the nucleus over time will be:

$$\frac{\partial N(t)}{\partial t}=\frac{4 \pi \cdot r(t)^2}{V_at} \frac{\partial r}{\partial t}=J_{matter} $$

Combining both equations for $$ \textstyle J_{matter} $$ the following expression for the growth velocity is obtained:

$$\frac{\partial r}{\partial t}=V_{at} D \frac{\partial c}{\partial r} $$

From second Fick’s Law for spheres the equation below can be obtained:

$$ \frac{\partial c}{\partial t}=D \frac{\partial }{\partial t} (r^2 \frac{\partial c}{\partial r}) $$

Assuming that the diffusion profile does not change over time but is only shifted with the growing radius it can be said that $$ \textstyle \frac{\partial c}{\partial t}=0$$, which leads to $$ \textstyle r^2 \frac{\partial c}{\partial r}$$ being constant. This constant can be indicated with the letter $$A$$ and integrating will result in the following equation:

$$r^2 \frac{\partial c}{\partial r}=A    \Rightarrow  \frac{A}{r^2}  dr=dc   \Rightarrow   \int_{r}^{r+\delta} \frac{A}{r^2}  dr =  \int_{c_{0}}^{c_{l}} dc \Rightarrow   c_{0}-c_{l}=A[\frac{1}{r}-\frac{1}{r+ \delta}]   \Rightarrow   A=\frac{c_{0}-c_{l}}{[\frac{1}{r}-\frac{1}{r+ \delta}]} $$,

where $$ \textstyle r $$ is the radius of the nucleus, $$ \textstyle r+ \delta$$  is the distance from the nucleus where the equilibrium concentration $$ \textstyle c_{0}$$ is recovered and $$ \textstyle c_{l}$$ is the concentration right at the surface of the nucleus. Now the expression for $$ \textstyle \frac{\partial c}{\partial r} $$ can be found by:

$$ r^2 \frac{\partial c}{\partial r}=A  \Rightarrow   \frac{\partial c}{\partial r} = \frac{A}{r^2} = \frac{c_{0}-c_{l}}{[\frac{1}{r}-\frac{1}{r+\delta}] r^2 }=(c_{0}-c_{l} ) \cdot (\frac{1}{r}+\frac{1}{\delta})$$

Therefore, the growth velocity for a diffusion-controlled system can be described as:

$$ \frac{\partial r}{\partial t}= V_{at} D(c_{0}-c_{l} ) \cdot (\frac{1}{r}+\frac{1}{\delta}) $$

[Picture]

Concentration profile in a diffusion-controlled system for a spherical nucleus with radius $$ r $$, where $$ c_{s}$$ is the concentration of atoms in the solid nucleus, $$ c_{l}$$ is the concentration in the liquid right at the surface if the nucleus, $$ c_{0}$$ is the equilibrium concentration in the liquid phase and $$\textstyle r + \delta $$ is the distance from the nucleus where the equilibrium concentration $$ c_{0}$$ is recovered. FelixvF47 (talk) 14:02, 30 May 2024 (UTC)