B. Zha, X. Yuan, Xi'an Research Institute of Hi-Tech, Xi'an, China; H. Wang, Xi'an Research Institute of Hi-Tech, Xi’an, China; K. Xu, Xi'an Jiaotong University, Xi'an, China
Bonding strength is the most important property of LTHVOF sprayed copper coatings. Parameters which influce the bonding strength is flux of kerosene, nitrogen, oxygen and spray distance. Wth the increase of flux of kerosene and oxygen, bonding strength inxreased.With the increase of flux of nitrgen, bonding strength decrease. With the increase of spray distance, bonding strength firstly inxreased ,then decreased.When spray copper coatings on Aluminum substrate, the optimized spray distance is 120mm,and the flame temperature is about 873K.The obained average bonding strength is 32MPa.
Summary: Through insert nitrogen into the combustion chamber of HVOF gun,Low Temperture HVOF(LTHVOF) can be obtained,which can be used to fabricate oxide free copper coatings.Spray parameters which affect bonding strength of LTHVOF fabricated copper coatings is flux of oxgen, nitrogen,kerosene and spray distance. With the increase of flux of nitrogen and kerosene, the bonding strength of the coatings increased. However, with the increase of flux of nitrogen,the bonding strength decreased.When the spray distance increase,the bonding strength first increased,then decreased.
The average bonding strength of copper coatings sprayed on the Aluminum substrate under the optimized parameters is 32MPa.
