I try to prepare thin film of SiC material by using pulse laser deposition in vacuum and SiC disc by using 10 ton pressure,but the operation was failed. How can I get compact disc in spite I use heat treatment to the disc.Can I select a liquid do not affect on structure of SiC to obtain a hardening of the disc,Thank you.
I am sorry, I cannot help you; but can you explain the reasons why you do not want to use heat treatment?
The chemical bonds between Si and C atoms in SiC are almost 88% covalent, decreasing the atomic diffusivity and making it difficult to achieve high densification. Sintering additives are usually required to obtain high density, such as boron, carbon, aluminum - or their compounds.
Liquid phase sintering, through solution re-precipitation process, can also be employed to densify SiC based ceramics. The main advantage of this approach is the lower temperatures involved. Liquid phase is generally produced by reaction of the additives with SiO2 present on the SiC surface.
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392001000400002
The production of ceramic parts by powder metallurgy is very difficult due to the weak bond strength between the ceramic powders, resistance to deformation and brittleness. But, the following resource on the production of SiC powder metal compacts may be useful for you. Sorry, no full text. You can request by mail from the authors.
http://search.proquest.com/openview/74330458e434da31f64879697b79bbc0/1?pq-origsite=gscholar&cbl=596295
Thank you for all sending answers, but there are some interpretations.
Dear Gopikrishna Nidigonda :Are you employed the Sintering process and succeeded.
Dear Joy Rizki Pangestu Djuansjah, I used the heat treatment for this compound but it was failed.
Dear Florian Glodeanu, Thank for websit
Dear Ulas Matik, Thank for websit
Dear Xu Wang,Thank you for your description questions , I need a disc of SiC high density, no easily broken. Also I mean a liquid dont react with SiC but make a compact the grains with each other or to be hardening . SiC compound I want to be not change in structure.
What kind of powder are you using (specific surface area or particle size, alpha or beta-SiC), what temperature and atmosphere are you using to sinter? For SiC you will need 2000 oC or higher, At atmosphere and some sintering aids and will need pressure at temperature to get densities above ~95% th. May be easier to purchase a SiC pellet...
You may be able to use Si and C as addition to the SiC powder. In the laser heating the Si will become liquid and react with C and form additional SiC. The liquid phase will help the densification.
Have you try Hot Isostatic Pressing?
The powder compression and sintering are done simultaneously.
Generally speaking, sintering of bulk SiC is different from deposition of SiC. the characteristics of the final SiC will be different using the 2 different methods. However, if you just want a bulk 1cm thick SiC disc you can consider the following:
if there is no limits placed on the final grain size, you can get fairly dense SiC disc using pressureless sintering at >2200degC. If you would like a small grain size, hot pressing can be employed and the temperature can be dropped.
If secondary phase is an issue, solid state sintering will work, with a small amount of B and C. Otherwise, you will be able to get dense samples using liquid phase sintering with Al2O3+Y2O3.
Thank you Jia Hui Teo for your details, I tried compressing the mixing SiC with KBr powder with 10 tons and so on heat treatment procedures suggest 400C at 2 hr,I wait the result.
Dear Faisal Ali Mustafa
I hope you can share the result with us.
Is it work?
It's okay, I add KBr material mixing with SiC and procedure heat treatment 400C at two hr. The result that the mixed materials are compact with each other.
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