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Lely method
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<h2 id="overview">Overview</h2> <p>The Lely method produces bulk silicon carbide crystals through the process of <a href="/facts/Sublimation_(phase_transition)/KDoKokMn">sublimation</a>. Silicon carbide powder is loaded into a graphite <a href="/facts/Crucible/o7WrIqhu">crucible</a>, which is purged with <a href="/facts/Argon/QX6NRH6d">argon</a> gas and heated to approximately 2,500 °C (4,530 °F). The silicon carbide near the outer walls of the crucible sublimes and is <a href="/facts/Deposition_(phase_transition)/JweT4Eqs">deposited</a> on a graphite rod near the center of the crucible, which is at a lower temperature.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> </p><p>Several modified versions of the Lely process exist, most commonly the silicon carbide is heated from the bottom end rather than the walls of the crucible, and deposited on the lid. Other modifications include varying the temperature, <a href="/facts/Temperature_gradient/YhWj21zy">temperature gradient</a>, argon pressure, and geometry of the system. Typically, an <a href="/facts/Induction_furnace/MI49lJYl">induction furnace</a> is used to achieve the required temperatures of 1,800–2,600 °C (3,270–4,710 °F).<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>: 195 </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Acheson_process/pMN95kDB">Acheson process</a></li> <li><a href="/facts/Czochralski_method/uvSrr84x">Czochralski method</a></li> <li><a href="/facts/Sublimation_sandwich_method/7fS6a0Xv">Sublimation sandwich method</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>US 2854364, Lely, Jan Anthony, "Sublimation process for manufacturing silicon carbide crystals", published 1958-09-30, assigned to North American Philips Co., Inc. <a href="https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US2854364" target="_blank">https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US2854364</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Byrappa, Kullaiah; Ohachi, Tadashi (2003). Crystal Growth Technology. Springer Science & Business Media. ISBN 9783540003670. Retrieved 10 September 2018. <a href="9783540003670" target="_blank">9783540003670</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Byrappa, Kullaiah; Ohachi, Tadashi (2003). Crystal Growth Technology. Springer Science & Business Media. ISBN 9783540003670. Retrieved 10 September 2018. <a href="9783540003670" target="_blank">9783540003670</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Byrappa, Kullaiah; Ohachi, Tadashi (2003). Crystal Growth Technology. Springer Science & Business Media. ISBN 9783540003670. Retrieved 10 September 2018. <a href="9783540003670" target="_blank">9783540003670</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> </ol>