| Metal-based bond abrasives have good thermal conductivity and wear resistance,long service life,and can bear large grinding load,which can meet the requirements of high-speed grinding and precision grinding at present,especially in ore mining.Cutting hard and brittle materials and other fields are widely used,but metal bond abrasives have poor self-sharpening,low porosity,poor wettability with diamond,easy to cause burns and blockage of workpieces.In the process of high precision grinding,the reduction of grinding efficiency hinders its development.Ceramic/metal bond was prepared by combining ceramic bond and metal bond,taking advantage of the good self-sharpening,corrosion resistance,high strength and so on of ceramic bond diamond abrasive.In this paper,R2O-B2O3-Al2O3-SiO2 low-temperature ceramic binder was introduced into the modified Cu-Al-based binder by powder metallurgy,and the ceramic/Cu-Al-based metal binder was prepared by vacuum hot pressing sintering.Through the analysis of its phase composition,microstructure and mechanical properties,the formula was optimized and adjusted,and finally the ceramic/copper-aluminum-based metal binder with excellent comprehensive properties was prepared.When the optimum content of Al in copper-aluminum based metal binder is 40 wt.%.The density is 3.71 g/cm3,and the bending strength,impact strength and hardness are181.54 MPa,10.26 k J/m2 and 81.2 HRB respectively.Because of the poor wettability of diamond abrasives and metals added later,the basic formula of the copper-aluminum-based metal bond will be further optimized.In order to improve the mechanical properties of copper-aluminum-based binders,Y2O3,La2O3 and Ce O2 were used as additives to modify copper-aluminum-based metal binders.By comparing the modification effects of three different rare earth oxides and different addition amounts of rare earth oxides,the best additive is Y2O3,with the addition amount of 1.5 wt.%.At this time,the overall structure of the copper-aluminum-based metal binder is more uniform and dense,and the density is 4.16g/cm 3.The impact strength of the binder is 10.24 k J/m2,and the flexural strength and hardness of the binder are 229.02 MPa and 92.3 HRB,respectively,which are 26.8%and 13.7%higher than that of the copper-aluminum-based metal bond before modification.When the R2O-B2O3-Al2O3-SiO2 series low temperature vitrified bond was compounded with the modified copper-aluminum-based metal bond,the ceramic content increased from 0wt.%to 25wt.%and the optimum ceramic content was determined to be20 wt.%.At this time,the interface between the ceramic phase and the metal phase in the ceramic/copper-aluminum-based metal binder is good,with a density of 93.5%,a bending strength of 149.85 MPa,an impact strength of 6.94 k J/m2 and a hardness of 113HRB.The bending strength of the bonding agent is 16.6%lower than that without ceramic bonding agent,and its hardness was 14.8%higher than that without ceramic bonding agent. |
PDF Full Text Request