Wang Shoude

Influence of preparation process on piezo-conductance effect of carbon fiber sulfoaluminate cement composite

Carbon fiber sulfoaluminate cement composite was prepared by casting, extrusion, and pressing processes. Their fractional change in conductance and strain of all three kinds of the samples under uniaxial stress were investigated. And the fractional changes in conductance of all the samples under cycle stress were studied. The fractional changes in conductance of carbon fiber sulfoaluminate cement composite prepared by different preparation process were all sensitive to the stress change. This meant that carbon fiber sulfoaluminate cement composite could sense the loading stress on itself and had good piezo-conductance effects. Compared with casting process, the piezo-conductance effect of carbon fiber sulfoaluminate cement composite prepared by extrusion and pressing had good repeatability and stability. This was related to the interface structure improvement.Carbon fiber sulfoaluminate cement composite was prepared by casting, extrusion, and pressing processes. Their fractional change in conductance and strain of all three kinds of the samples under uniaxial stress were investigated. And the fractional changes in conductance of all the samples under cycle stress were studied. The fractional changes in conductance of carbon fiber sulfoaluminate cement composite prepared by different preparation process were all sensitive to the stress change. This meant that carbon fiber sulfoaluminate cement composite could sense the loading stress on itself and had good piezo-conductance effects. Compared with casting process, the piezo-conductance effect of carbon fiber sulfoaluminate cement composite prepared by extrusion and pressing had good repeatability and stability. This was related to the interface structure improvement.

Fabrication and properties of 2-2 cement based piezoelectric composites

Composites with 2–2 connectivity were fabricated from lead magnesium niobate-lead zirconate-lead titanate(PMN) and sulphoaluminate cement by cut-filling process. The influences of PMN volume fraction and water/cement ratio on the properties of the composite were investigated. The results show that the piezoelectric strain constant d 33 increase rapidly with increasing volume fraction of PMN. When the PMN volume fraction is about 0.60, the d 33 value is up to 357 pCN−1. The planar electromechanical coupling coefficient Kp of the composites is lower than that of PMN ceramic, while the thickness electromechanical coupling coefficient K t is higher than that of PMN ceramic. The water/cement ratio has little influence on piezoelectric properties of 2–2 cement based piezoelectric composite.

The Influence of Forming Pressure on Piezo-resistivity and Temperature-resistivity Effects of CFSC

Carbon fiber/sulfoaluminate cement composites (CFSC) were prepared by pressing technology; the influence of forming pressure on piezo-resistivity and temperature-resistivity effects of CFSC were studied. The studied results indicate that CFSC has good piezo-resistivity effect when the forming pressure is 7 MPa as well as 10 MPa. With the forming pressure rising, the porosity of CFSC decreases and its resistivity value decreases also. The relationship between the resistivity of CFSC and temperature could be described by a linear equation. Based on this linear equation, the surrounding temperature could be figured out if the resistivity of CFSC is already known. However, the forming pressure has no influence on the slope of this linear equation. The curves of the equations of the samples prepared under different forming pressure are parallel with each other. Only the value of the equation curve is different.Carbon fiber/sulfoaluminate cement composites (CFSC) were prepared by pressing technology; the influence of forming pressure on piezo-resistivity and temperature-resistivity effects of CFSC were studied. The studied results indicate that CFSC has good piezo-resistivity effect when the forming pressure is 7 MPa as well as 10 MPa. With the forming pressure rising, the porosity of CFSC decreases and its resistivity value decreases also. The relationship between the resistivity of CFSC and temperature could be described by a linear equation. Based on this linear equation, the surrounding temperature could be figured out if the resistivity of CFSC is already known. However, the forming pressure has no influence on the slope of this linear equation. The curves of the equations of the samples prepared under different forming pressure are parallel with each other. Only the value of the equation curve is different.