Bor karbür tozu üretiminde farklı karbon kaynaklarının faz oluşumu ve mikroyapı üzerindeki etkisi

Abstract

Bu çalışmada, bor oksit ve farklı karbon kaynaklarından hareketle bor karbür tozu üretimi amaçlanmıştır. Hammadde olarak, B2O3 ve grafit ya da aktif karbon kullanılmış olup, toz karışımları bilyalı değirmende mekanik olarak aktive edilmiştir. Mekanik olarak aktive edilen tozlar, hidrolik preste peletler haline getirilmiş ve Ar atmosferi altında 1450°C’de reaksiyona tabi tutulmuştur. Öğütme süresi/hızı, reaksiyon süresi, başlangıç toz miktarları ve farklı karbon kaynaklarının son ürün verimi ve faz yapısı üzerindeki etkisi incelenmiştir. Elde edilen toz ürünlerin karakterizasyonu, XRD, SEM ve organik element analizi yöntemleri ile gerçekleştirilmiştir. Öğütme ve presleme işlemleri sayesinde, son ürün yapısındaki kalıntı karbon miktarı önemli ölçüde azaltılmış ve teorik oluşum sıcaklığı 1360°C’ye kadar düşürülmüştür. Optimum koşullarda elde edilen tozlar, yapısında en fazla % 4 kalıntı karbon içeren ve ortalama 10 µm partikül boyutuna sahip saf bor karbür tozlarıdır.  

Keywords

• Bor karbür
• Bor oksit
• Grafit
• Aktif karbon
• Mikroyapı

The effect of different carbon sources on the phase formation and microstructure of boron carbide powders

Abstract

The objective of this study is to synthesize boron carbide powders starting with boron oxide (B2O3) and varying carbon sources such as graphite and activated carbon by using carbothermal method. Powder mixtures are mechanically activated with ball mill, pelletized in cold hydraulic press and reacted under Argon atmosphere at 1450°C. Milling speed and time; reaction duration; varying carbon source and the ratio of the starting materials are experimented to observe the results upon the phase structure and the yield of the B4C. The product characterization is carried out via XRD, SEM, particle size analyzer and organic elemental analysis methods. Mechanical pretreatment significantly reduces the amount of the unreacted carbon and lowers the reaction temperature down to 1360°C. Under the optimum conditions, the yield contains 4 % remaining carbon and approximately 10 µm boron carbide particles. 

Keywords

• Boron carbide
• Boron oxide
• Graphite
• Activated carbon
• Microstructure

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