碳化钨对放电等离子烧结氮化硅陶瓷的致密化及力学性能的影响

Effect of Tungsten Carbide on Densification and Mechanical Properties of Silicon Nitride Ceramics by Spark Plasma Sintering

摘要:

以Al2O3-Y2O3烧结助剂，采用特制的碳化钨球磨罐与球磨子，通过机械球磨的方法向氮化硅陶瓷中引入碳化钨（WC），采用放电等离子烧结技术（SPS）进行快速烧结，制备出高性能β相氮化硅陶瓷。分析了碳化钨对氮化硅陶瓷致密化及力学性能的影响，结果表明：碳化钨的引入有效地降低了β相沉淀析出并继续生长的激活能，促进了氮化硅陶瓷α相→β相转变，实现烧结试样的致密化；随着碳化钨引入量的增加，烧结试样的抗弯强度从729 MPa急剧增加至1 090 MPa，提高了49.5%。

Abstract:

The high-performance silicon nitride ceramics were prepared by spark plasma sintering (SPS) with Al₂O₃–Y₂O₃ as a sintering aid.A novel approch was adopted to fabricate the silicon nitride by introducting WC via mechanical ball milling.The effects of tungsten carbide on densification and mechanical properties of silicon nitride ceramics were inverstigated.The results show that the introduction of tungsten carbide effectively reduces the activation energy of β phase precipitation and growth, which promotes the phase transformation of silicon nitride ceramic , and the densification of sintered samples. Tungsten carbide can dissolve into the matrix lattice partly.With the increase of the amount of tungsten carbide, the flexural strength of sintered samples increased from 735.2MPa to 1091.2MPa, which increased by 48.4%.