Research On Vitrified Bond For Diamond Abrasive Tool

The vitrified bond diamond tools is becoming one of the most potential tools in modern engineering applications. In this research, the vitrified bond for diamond tool was studied, The effects of constitution and preparation process of vitrified bond on the properties of the vitrified bond for diamond tool were discussed. The main properties of the vitrified bond, including refractoriness, fluidity, bending strength and microstructure of vitrified grinding tools, were investigated by using three-point bending strength tester, scanning electron microscope (SEM) and X-ray diffraction measurements.The results were shown as follows: when the proportion coefficient(R2O+MO)/(Al2O3+B2O3)of vitrified bond from 0.916 to 1.044, the refractoriness of vitrified bond was 670℃, the fluidity was 170% at the appropriate sintering temperature 790℃, the bending strength of vitrified grinding tools was 55MPa. The introduction of AlF3 inclined to reduce the bond's refractoriness and increase its fluidity and the bending strength of grinding tools with 1% AlF3 increased to 60Mpa. Different amounts of TiO₂ were also added to the basic vitrified bond. The refractoriness of vitrified bond was increased and the fluidity kept the same level with increasing the content of TiO₂ additives and the maximum bending strength (59MPa) of the grinding tools with 1% TiO₂ was achieved.The XRD pattern showed that, the crystal phase of the basic vitrified bond decreased greatly after premelting,while the content of amorphous phase increased. IR spectroscopy showed that the glass network was mainly composed of [SiO4], [BO3], [BO4]. Because phase changed, thermal expansion coefficient decreased greatly. The process of premelting had no influence on the refractoriness, but reduced the fluidity obviously and decreased the bending strength of grinding tools, because the porosity of grinding tools with premelting was higher than that without premelting.