Influence Of Mn To The Interfacial Reactions And Infilltration Of SiC-Cu Construction At High Temperature

Silicon carbide reinforced copper composite is increasingly favored by the researchers both at home and abroad because of its high thermal conductivity, low coefficient of thermal expansion and fine strength. SiCp/Cu composite is considered as a new generation of electronic packaging and electrical materials due to its excellent properties. Compared to other preparation methods, pressureless infiltration process is a near-net-shape process with less requirement for equipments. Nowadays, the pressurelss infiltration process for SiC/Al composite has been a mature practice, but for SiC/Cu composite there are few reports. The challenges of manufacturing SiC/Cu composite come from the bad wettability between Cu and SiC, the comparely high melting point of Cu and the poor interface bonding.In this paper, the influence of Mn to the interfacial reactions and infiltration of SiC/Cu at 1260-1350℃ in N2 was investigated. The main focus is as follows:(1)The reactions of SiC/Mn binary system, SiO2/Mn binary system and SiC/Cu/Mn ternary system were designed and researched. The mixed powders of SiC/Mn, SiO2/Mn and SiC/Cu/Mn were reacted at 1250-1350℃ in N2, respectively. The phases formed during the reaction and their micro-morphology were analyzed with optical microscopy, X-ray diffraction and scan electron microscopy. Mn reacted with SiC in nitrogen atmosphere and produced MnSiN2 on the surface of SiC particle. The decomposition reaction of SiC increased with the increasing temperature. The amount of Si3N4 and graphite produced less at 1250℃,but increased significantly as the temperature increased to 1350℃, so that the relative content of MnSiN2 decreased. Mn reacted with SiO2 at 1250℃ in N2 and produced a glassy silicate phase with low melting point.The main produced phase of SiC/Cu/Mn ternary system reacted at 1250℃ in N2 atmosphere was MnSiN2, except for SiC and Cu. In addition, there were also some Si3N4, Cu3Si and graphite phases. As the temperature increased to 1350℃, SiC decomposed seriously,and the amount of Si3N4 and graphite increased significantly. The reaction in the system performed relatively well, the different particles binded together except for a small proportion of Cu was squeezed out, indicuting that Mn is beneficial to the interfacial wetting and binding between SiC and Cu.(2)The possibility, advantages and disadvantages of using pressureless infiltration method to build SiC/Cu composite were studied and evaluated. Experimental results showed that, with the aid of Mn, both QSi3-1 copper alloy and pure Cu powder were pressureless infiltrate into SiC skeleton in N2 at 1260-1350℃.The proper process parameters for the pressureless infiltration of QSi3-1 copper alloy might be 1320℃×2h, the interfacial binding looked okey, SiC decomposed moderately, Cu demonstrates high crystallinity with finer crystalline size. The main phases were detected to be Cu3Si, MnSiN2, graphite and Si3N4, except for SiC and Cu. The proper process parameters for the pressureless infiltration of pure Cu powder might be 1350℃×1h. The main phases were determined to be Cu3Si, Si3N4, graphite and Cu2O, except for SiC and Cu.Finally, on the basis of the sμmmary of the whole experimental results, some suggestions were given for pressureless infiltration of SiC/Cu, providing some technical support to the further development of SiC/Cu composite.