Study of brazed diamond micro-powder burs fabricated using induction brazing with either an amorphous or a crystalline Ni-based filler alloy

The outcome of brazing diamond micro-powder using a crystalline Ni-based alloy is not ideal because of the relatively high melting temperature and relatively poor wetting of the crystalline Ni-based alloy toward the steel substrate. In this study, a brazed diamond micro-powder bur was fabricated using an amorphous Ni-based alloy. Fine grains with an average diameter of about 0.02-0.03 μm are formed during the heating process of the amorphous Ni-based alloy. The melting of 0.2 g filler alloy stacked at the center of a circular steel disc indicates that, after heating above the melting finish temperature for 20 s, the wetting ability i.e. wetting area of the amorphous Ni-based alloy for a steel substrate is 1.34 times larger than the wetting ability of the crystalline Ni-based alloy. Unlike diamond particle brazing using a crystalline Ni-based alloy, the diamond particles brazed with the amorphous Ni-based alloy can be better exposed and the brazed surface can also maintain its original shape. In addition, the brazed diamond micro-powder bur obtained using induction brazing with amorphous Ni-based filler alloy can be dressed more easily. The grinding efficiency of the dressed diamond micro-powder bur fabricated using induction brazing with the amorphous Ni-based filler is significantly higher than that of the dressed diamond micro-powder bur fabricated using induction brazing with a crystalline Ni-based filler alloy.