Study On Brazing Of Diamond Powder In Furnace With Amorphous Ni-based Brazing Allooy And Processability Of Brazed Diamond Powder

Solidus temperature of crystalline Ni-based brazing alloy is high,and long time is needed when brazed diamond powder tools are fabricated by furnace brazing.This can easily lead to the thermal damage of diamond powder grits in the high temperature environment.Grinding performance of diamond powder grits can also be weakened.The amorphous Ni-based brazing alloy is chosen to fabricate brazed diamond powder tools by furnace brazing to reduce the thermal damage of diamond grits,to improve the wettability of brazing alloy towards diamond grits and to strengthen the adhesion between diamond and Ni-based brazing alloy.As a result,processing performance of the tools is improved.In this study,brazed diamond powder burs were made as an example to accomplish theoretical demonstration.The following innovative works were completed:(1)The thermal analysis curve of the Ni-based brazing alloy indicated that the range of the melting temperature of the crystalline Ni-based brazing alloy was about 933℃~1044℃.And the range of the melting temperature of the amorphous Ni-based brazing alloy was about 913℃~993℃.The narrower range of melting temperature and a faster melting rate of the amorphous Ni-based brazing alloy could effectively reduce the thermal damage of the diamond grits.(2)The study on the wettability of the Ni-based brazing alloy towards 45-steel substrate with different roughness was done.The result indicated that the wetting area of the amorphous Ni-based brazing alloy on 45-steel substrate increased first and then decreased with the increasing of the 45-steel substrate roughness.The wetting area of the crystalline brazing alloy decreased first,then increased and then decreased with the increasing of the 45-steel substrate roughness.The wetting areas of the two kinds of brazing alloy reached the maximum when the substrate roughness Ra was 0.5μm.The wetting area of the amorphous Ni-based brazing alloy showed a tendency of increasing first and then decreasing with the increasing of the brazing temperature.When the brazing temperature was 950℃,the largest wetting area was 4.9cm2.(3)The material removal rate of the diamond bur with the amorphous Ni-based brazing alloy grinding the engineering ceramic and the ZL102 aluminum alloy was respectively 1.26 times and 1.3 times of that of the diamond bur with the crystalline brazing alloy.The temperature in grinding arc-zone of the engineering ceramic and the ZL102 aluminum alloy grinded by the diamond bur with the amorphous Ni-based brazing alloy was respectively 59℃ and 70℃ lower than that grinded by the bur with the crystalline brazing alloy for 225 min grinding.(4)The diamond burs with the amorphous Ni-based brazing alloy used to grind the engineering ceramic and the ZL102 aluminum alloy for 300 min were dressed by the oilstone.The material removal rate of the dressed diamond bur with the amorphous Ni-based brazing alloy grinding the engineering ceramic and the ZL102 aluminum alloy was increased by 59% and 65% respectively.The brazing temperature of the diamond powder was lowered by the use of the amorphous Ni-based brazing alloy.The process of the brazed diamond using furnace brazing was optimized.The grinding performance of the brazed diamond powder tool fabricated by furnace brazing was promoted.This provided a theoretical and experimental basis for the widespread use of the brazed diamond powder tool fabricated by furnace brazing.