Spark plasma sintering

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Spark plasma sintering (SPS), [1] also known as field assisted sintering technique (FAST) [2] or pulsed electric current sintering (PECS), or plasma pressure compaction (P2C) [3] is a sintering technique.

Contents

The main characteristic of SPS is that the pulsed or unpulsed DC or AC current directly passes through the graphite die, as well as the powder compact, in case of conductive samples. Joule heating has been found to play a dominant role in the densification of powder compacts, which results in achieving near theoretical density at lower sintering temperature compared to conventional sintering techniques. [4] The heat generation is internal, in contrast to the conventional hot pressing, where the heat is provided by external heating elements. This facilitates a very high heating or cooling rate (up to 1000 K/min), hence the sintering process generally is very fast (within a few minutes). The general speed of the process ensures it has the potential of densifying powders with nanosize or nanostructure while avoiding coarsening which accompanies standard densification routes. This has made SPS a good method for preparation of a range of materials with enhanced magnetic, [5] magnetoelectric, [6] piezoelectric, [7] thermoelectric, [8] optical [9] or biomedical [10] properties. SPS is also used for sintering of carbon nanotubes [11] for development of field electron emission electrodes. Functioning of SPS systems is schematically explained in a video link. [12] While the term "spark plasma sintering" is commonly used, the term is misleading since neither a spark nor a plasma is present in the process. [13] It has been experimentally verified that densification is facilitated by the use of a current. SPS can be used as a tool for the creation of functionally graded soft-magnetic materials and it is useful in accelerating the development of magnetic materials. [14] It has been found that this process improves the oxidation resistance [15] and wear resistance [16] of sintered tungsten carbide composites compared to conventional consolidation methods.

A kind of sintering that involves both temperature and pressure Spark Plasma Sintering.JPG
A kind of sintering that involves both temperature and pressure

Hybrid heating

By means of a combination of the FAST/SPS method with one or several additional heating systems acting from the outside of the pressing tool systems it's possible to minimize the thermal gradients thus allowing the enhancement of the heating rates at simultaneously optimized homogeneity.[ citation needed ]

In 2012 the world's largest hybrid SPS-hot press sintering system was set up in Spain [17] and the fabrication of fully dense large ceramic blanks of up to 400mm with this system is in progress within the frame of the FP7 European Project HYMACER - Hybrid sintering and advanced machining of technical ceramics

Spark plasma sintering, also known as plasma pressure compaction (P2C) sintering, equipment are commercially available now and are no longer limited to laboratory research work. Products like body armor, rocket nozzles, carbon fiber composites and several other hybrid materials can be produced in commercial scale using these equipment. [18]

See also

Related Research Articles

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Magnetostriction is a property of magnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of materials' magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, λ. The effect was first identified in 1842 by James Joule when observing a sample of iron.

<span class="mw-page-title-main">Powder metallurgy</span> Process of sintering metal powders

Powder metallurgy (PM) is a term covering a wide range of ways in which materials or components are made from metal powders. PM processes can reduce or eliminate the need for subtractive processes in manufacturing, lowering material losses and reducing the cost of the final product.

<span class="mw-page-title-main">Tungsten carbide</span> Hard, dense and stiff chemical compound

Tungsten carbide is a chemical compound containing equal parts of tungsten and carbon atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes through sintering for use in industrial machinery, cutting tools, chisels, abrasives, armor-piercing shells and jewelry.

<span class="mw-page-title-main">Tantalum carbide</span> Chemical compound

Tantalum carbides (TaC) form a family of binary chemical compounds of tantalum and carbon with the empirical formula TaCx, where x usually varies between 0.4 and 1. They are extremely hard, brittle, refractory ceramic materials with metallic electrical conductivity. They appear as brown-gray powders, which are usually processed by sintering.

<span class="mw-page-title-main">Ferrite (magnet)</span> Ferrimagnetic ceramic material composed of rust and a metallic element

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<span class="mw-page-title-main">Zirconium carbide</span> Chemical compound

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<span class="mw-page-title-main">Barium titanate</span> Chemical compound

Barium titanate (BTO) is an inorganic compound with chemical formula BaTiO3. Barium titanate appears white as a powder and is transparent when prepared as large crystals. It is a ferroelectric, pyroelectric, and piezoelectric ceramic material that exhibits the photorefractive effect. It is used in capacitors, electromechanical transducers and nonlinear optics.

<span class="mw-page-title-main">Silicon nitride</span> Compound of silicon and nitrogen

Silicon nitride is a chemical compound of the elements silicon and nitrogen. Si
3N
4 is the most thermodynamically stable and commercially important of the silicon nitrides, and the term ″Silicon nitride″ commonly refers to this specific composition. It is a white, high-melting-point solid that is relatively chemically inert, being attacked by dilute HF and hot H
3PO
4. It is very hard. It has a high thermal stability with strong optical nonlinearities for all-optical applications.

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<span class="mw-page-title-main">Zirconium diboride</span> Chemical compound

Zirconium diboride (ZrB2) is a highly covalent refractory ceramic material with a hexagonal crystal structure. ZrB2 is an ultra-high temperature ceramic (UHTC) with a melting point of 3246 °C. This along with its relatively low density of ~6.09 g/cm3 (measured density may be higher due to hafnium impurities) and good high temperature strength makes it a candidate for high temperature aerospace applications such as hypersonic flight or rocket propulsion systems. It is an unusual ceramic, having relatively high thermal and electrical conductivities, properties it shares with isostructural titanium diboride and hafnium diboride.

<span class="mw-page-title-main">Lithium titanate</span> Chemical compound

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Hot pressing is a high-pressure, low-strain-rate powder metallurgy process for forming of a powder or powder compact at a temperature high enough to induce sintering and creep processes. This is achieved by the simultaneous application of heat and pressure.

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<span class="mw-page-title-main">Ceramic nanoparticle</span>

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Capacitor discharge sintering (CDS) is an electric current assisted sintering (ECAS) technique. The technique is based on storage of electromagnetic energy in a high voltage capacitor bank, and discharge into the sintering apparatus at low voltage and high current through step-down transformers on a pre-compacted powder compact which is kept under pressure. The sintering mould and Electrodes are similar to those employed in field assisted sintering techniques (FAST) such as spark plasma sintering and single electromagnetic pulse sintering technologies.

Ultra-high-temperature ceramics (UHTCs) are a type of refractory ceramics that that can withstand extremely high temperatures without degrading, often above 2,000 °C. They also often have high thermal conductivities and are highly resistant to thermal shock, meaning they can withstand sudden and extreme changes in temperature without cracking or breaking. Chemically, they are usually borides, carbides, nitrides, and oxides of early transition metals.

<span class="mw-page-title-main">Niobium diboride</span> Chemical compound

Niobium diboride (NbB2) is a highly covalent refractory ceramic material with a hexagonal crystal structure.

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References

  1. ↑ "Field-Assisted Sintering Technology / Spark Plasma Sintering: Mechanisms,Materials, and Technology Developments", By O. Guillon et al., Advanced Engineering Materials 2014, DOI: 10.1002/adem.201300409, http://onlinelibrary.wiley.com/doi/10.1002/adem.201300409/epdf
  2. ↑ KU Leuven - SPS process modeling
  3. ↑ 'sps-p2c
  4. ↑ Sairam, K.; Sonber, J.K.; Subramanian, C.; Fotedar, R.K.; Nanekar, P.; Hubli, R.C. (January 2014). "Influence of spark plasma sintering parameters on densification and mechanical properties of boron carbide". International Journal of Refractory Metals and Hard Materials. 42: 185–192. doi:10.1016/j.ijrmhm.2013.09.004.
  5. ↑ Aubert, A.; Loyau, V.; Mazaleyrat, F.; LoBue, M. (2017). "Uniaxial anisotropy and enhanced magnetostriction of CoFe2O4 induced by reaction under uniaxial pressure with SPS". Journal of the European Ceramic Society. 37 (9): 3101–3105. arXiv: 1803.09656 . doi:10.1016/j.jeurceramsoc.2017.03.036. S2CID   118914808.
  6. ↑ Aubert, A.; Loyau, V.; Mazaleyrat, F.; LoBue, M. (2017). "Enhancement of the Magnetoelectric Effect in Multiferroic CoFe2O4/PZT Bilayer by Induced Uniaxial Magnetic Anisotropy". IEEE Transactions on Magnetics. 53 (11): 1–5. arXiv: 1803.09677 . doi:10.1109/TMAG.2017.2696162. S2CID   25427820.
  7. ↑ Li et al, Ferroelectric and Piezoelectric Properties of Fine-Grained Na0.5K0.5NbO3 Lead-Free Piezoelectric Ceramics Prepared by Spark Plasma Sintering, Journal of the American Ceramic Society, 89, 2, 706–709, (2006)
  8. ↑ Wang; et al. (2006). "High-performance Ag[sub 0.8]Pb[sub 18+x]SbTe[sub 20] thermoelectric bulk materials fabricated by mechanical alloying and spark plasma sintering". Applied Physics Letters. 88 (9): 092104. doi:10.1063/1.2181197.
  9. ↑ Kim; et al. (2007). "Spark plasma sintering of transparent alumina". Scripta Materialia. 57 (7): 607–610. doi:10.1016/j.scriptamat.2007.06.009.
  10. ↑ Gu; et al. (2002). "Spark plasma sintering of hydroxyapatite powders". Biomaterials. 23 (1): 37–43. doi:10.1016/S0142-9612(01)00076-X. PMID   11762852.
  11. ↑ Talemi; et al. (2012). "Fusion of carbon nanotubes for fabrication of field emission cathodes". Carbon. 50 (2): 356–361. doi:10.1016/j.carbon.2011.07.058.
  12. ↑ 'SPS-How it Works?
  13. ↑ Hulbert, D. M.; Anders, A.; Dudina, D. V.; Andersson, J.; Jiang, D.; Unuvar, C.; Anselmi-Tamburini, U.; Lavernia, E. J.; Mukherjee, A. K. (2008). "The absence of plasma in spark plasma sintering". J. Appl. Phys. 104 (3): 033305–7. Bibcode:2008JAP...104c3305H. doi:10.1063/1.2963701. S2CID   54726651.
  14. ↑ V. Chaudhary, L. P. Tan, V. K. Sharma, R. V. Ramanujan, Accelerated study of magnetic Fe-Co-Ni alloys through compositionally graded spark plasma sintered samples, Journal of Alloys and Compounds, 869, 159318 (2021), https://doi.org/10.1016/j.jallcom.2021.159318
  15. ↑ Karimi, Hadi; Hadi, Morteza; Ebrahimzadeh, Iman; Farhang, Mohammad Reza; Sadeghi, Mohsen (2018-10-01). "High-temperature oxidation behaviour of WC-FeAl composite fabricated by spark plasma sintering". Ceramics International. 44 (14): 17147–17153. doi:10.1016/j.ceramint.2018.06.168. ISSN   0272-8842. S2CID   140057751.
  16. ↑ Karimi, Hadi; Hadi, Morteza (2020-08-01). "Effect of sintering techniques on the structure and dry sliding wear behavior of WC-FeAl composite". Ceramics International. 46 (11, Part B): 18487–18497. doi:10.1016/j.ceramint.2020.04.154. ISSN   0272-8842. S2CID   219077175.
  17. ↑ CINN-CSIC: Hybrid SPS-HP - Photo Gallery
  18. ↑ plasma pressure compaction
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