| The metal bond diamond abrasive tool has great advantages in hard and brittle materials processing and its application is more and more extensive.However,it also has some problems,such as poor self-sharpness,difficult finishing of grinding tools,frequent dressing and poor wettability of diamond abrasives,which limit its development and application in some aspects.Therefore,it is significant to develop a new type of metal bond diamond grinding tool with good self-sharpness and great wettability to diamond.In this paper,the Na2O-B2O3-SiO2-Al2O3 low-temperature ceramic bond was introduced into the Cu-based metal by powder metallurgy.The ceramic/Cu-based metal bond was prepared by hot pressing.The bond and abrasive samples were characterized by various equipment.The effect of process parameters and raw material components on the bond were studied,and the interface conditions of metal-ceramic and diamond-bonding agents were investigated.By analysing mechanical properties,microstructure and material composition,the corresponding mechanism was studied.Through adjusting and optimizing,a more ideal ceramic/copper-based metal bond is prepared.The results show that:?1?The optimum process parameters of ceramic/Cu-based metal bond are as follows:sintering temperature at 650?,holding time for 4.5 min and hot pressing pressure at 18.4MPa.Under this condition,the bending strength,impact strength of bond and hardness of the bond are 265 MPa,6.63 KJ/m2 and HRB109,respectively.Meanwhile,the ceramic phase and the metal phase in the bond show larger wetting angle,and the combination of them is not very good.?2?With contents of the ceramic bond increasing from 0 vol%to 60 vol%,the strength of the composite bond is gradually decreased and at the same time the hardness is increased.We also found that the bending strength decreased from 690 MPa to 190 MPa,the impact strength decreased from 72.89 KJ/m2 to 3.82 KJ/m2,and the hardness increased from HRB 94 to HRB115.Under the basic of certain strength,the introduction of hard and brittle phases was helpful to improve the self-sharpening of the bond.In this paper,the volume fraction of ceramic bond was 40%,and the corresponding mass fraction is 16.5%.At this time,the bending strength and impact strength of bond are 275 MPa and 7.8 KJ/m2,respectively,and the hardness was HRB107.?3?Fe,Co and Ni were introduced into the ceramic/Cu-based bond to optimize the formulation.By comparing the two addition methods,the best addition method is to reduce Cu plus Fe?Co or Ni?.The optimum addition amounts of Fe,Co and Ni are 12%,8%,and 8%,respectively.Appropriate amounts of Fe,Co and Ni are beneficial for increasing the bonding strength of the two phases in the bond.Co and Ni present good mutual solubility with Cu-based metal bond,and Fe present poor mutual solubility with Cu-based metal bond.?4?The optimum process parameters of the grinding tools are as follows:hot pressing temperature at 670?and holding time for 4.5 min.The bending strength and impact strength of the abrasive samples are 170 MPa and 4.41 KJ/m2,respectively.The ceramic part of the abrasive sample has a high bonding strength to diamond,and the residual particles on the diamond surface are mainly ceramic phase.The proper introduction of Ti and Cr is helpful to improve the bonding strength of the metal to the diamond. |
PDF Full Text Request