An economic and environment friendly way of recycling boron carbide waste to prepare B4C/Al composite ceramic

Recently, with the rapid growth of sapphire wafer applications, boron carbide as abrasive, has shown an increasing demand. Great amounts of boron carbide waste (low purity and small grain size with D-50 approximate to 1 mu m) are therefore produced during the production of boron carbide abrasives and barely recovered and utilized. This paper is aimed at developing an economic and environment friendly process to recycle the boron carbide waste through adding a certain amount of Al powder to prepare B4C/Al composite ceramic. Prior to the sintering process, samples were firstly mixed with different Al powder and then pelleted and dehydrated. The effects of the pelletizing factors on performances of the pellets and the ceramics were optimized as binder hydroxypropyl methylcellulose addition 0.4%, pelleting pressure 30 MPa, Al addition 9 wt%, sintering time 90 minutes. Under these conditions, the apparent porosity, bulk density, compressive strength and flexural strength of the sintered B4C/Al are 19.08%, 1.84 g/cm(3), 246.88 MPa and 71.10 MPa respectively. Al addition can not only attribute to the low-temperature liquid sintering and densification of the product, but also generation of some stable phases including AlB12, AlB12C2 and Al3BC, which in turn increase the performance of the ceramic composite.