Physical properties of cement composites designed for aerostatic bearings

This paper investigates the physical properties of cement composites based on ordinary Portland cement (OPC) and silica particles as a potential material for porous aerostatic bearings for precision engineering applications. A full factorial design (2 2 4 1 ) was carried out to study the effects of silica properties (size and geometry) and uniaxial pressure (10 and 30 MPa) on the composite properties, namely bulk density, apparent porosity and intrinsic permeability of the ceramic composites. Scatter graphs were plotted to identify the existence of significant correlations between parameters. The cementitious composite manufactured with small silica particles, non-spherical shape and low level of compaction pressure exhibited the most appropriate properties for the proposed application. In addition, mathematical models obtained from the response-correlation plots are potentially important tools for the development and design of new composites for porous bearing applications.