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钎料中Ti元素含量对Si3N4/Si3N4接头界面结构及性能的影响

Effect of Ti content in composite filler on interfacial microstructure and joining property of Si3N4 brazed joint

  • 摘要: 在900℃保温10 min的工艺条件下采用Ti含量不同的AgCu+Ti+nano-Si3N4复合钎料(AgCuC)实现了Si3N4陶瓷自身的钎焊连接,并对不同Ti元素含量的接头界面组织及性能进行了分析.结果表明,接头典型界面结构为Si3N4/TiN+Ti5Si3/Ag(s,s)+Cu(s,s)+TiNP+Ti5Si3P/TiN+Ti5Si3/Si3N4.随着复合钎料中Ti元素含量的增加,钎缝中团聚的纳米Si3N4颗粒逐渐减少,母材侧的反应层厚度逐渐增加后趋于稳定.当Ti元素含量高于4%时,钎缝中形成了类似于颗粒增强金属基复合材料的界面组织;当Ti元素含量达到10%时,有少量Ti-Cu金属间化合物在钎缝中形成;钎焊接头的抗剪强度随着Ti元素含量的增加而呈现先增加后降低的变化趋势,当Ti元素含量为6%时接头的抗剪强度达到最高值,即75 MPa.

     

    Abstract: The Si3N4 ceramic was brazed using AgCu+Ti+nano-Si3N4 composite filler(AgCuC) with different Ti contentat 900 ℃ for 10 min. The interfacial microstructure and the property of brazed joints were investigated in detail. The results showed that the typical interfacial microstructure of brazed joint was Si3N4/TiN+Ti5Si3/Ag(s,s)+Cu(s,s)+TiNP+Ti5Si3P/TiN+Ti5Si3/Si3N4. As the Ti content increased, the amount of aggregated nano-Si3N4 particles in the brazing joint decreased, while the thickness of reaction layer adjacent to substrate gradually increased and then remained unchanged. An composite-like interfacial microstructure was formed in the brazing joint when Ti content was beyond 4wt.%.However, when the Ti content further increased to 10%, a small amount of Ti-Cu intermetallic compounds was formed in brazing seam. The shear strength of brazed joints increased firstly and then decreased with the increase of Ti content.And when the Ti content was 6%, the shear strength reached a maximum value of 75 MPa.

     

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