| Al2O3-SiO2-CaF2-P2O5 glass powder was prepared by liquid phase precipitation method and melting-quenching-grinding method, liquid phase precipitation powder was heat-treated and melting-quenching-grinding powder was high-octane milled, respectively. The liquid phase precipitation powder, melting-quenching-grinding powder, heat-treated powder and milled powder were concreted. By means of DTA, XRD, TEM, IR, SEM and Electron Universal Testing Machine, the effect of the heat treatment on the crystallization characteristic, micro-morphology, glass structure and concreted properties of the glass powder was studied, the effect of the liquid recipe, the mass ratio of powder to liquid, granularity, stored media and stored time, on the properties of the concretion was studied, and the concreted mechanisms of the glass powder were also discussed. The main results of the thesis were showed as follow:1,The influences of the mass ratio of powder to liquid, granularity on compressive strength of concretion were proved up. The results showed that with the increasing of the ratio of powder to liquid or the diminishing of the granularity, the compressive strength of the concretion increased first and decreased afterwards. The compressive strength of concretion was the best, when the mass ratio of liquid phase powder to liquid was 0.33-0.4, the mass ratio of melting-quenching powder to liquid was 2.0-2.5 and the granularity was about 2μm.2,The influences of heat treatment process on the properties of liquid phase method powder and concretion were proved up. The results showed that heat treatment had no obvious effect on main linkage way of the system. Between 500℃and 900℃, the crystal phase CaF2 was precipitated firstly, with the rising of temperature and the prolonging of time, crystal phases such as Al2SiO5,Ca2SiO4 and Ca3(PO4)2 were precipitated sequentially and the powder was changed from dispersive spheroidic to irregular strip that linked each other, and congregated to irregular mass, gradually. The compressive strength of concretion increased gradually, then tended to unchangeableness, it was the best when the powder heated-treatment two hours at 600 3,The effect of the concreted liquid recipe, stored media and stored time, on the properties of concretion was proved up. The results showed that the compressive strength of concretion was affected by the mass ratios of molecular weight regulator and itaconic acid to acrylic acid, monomer concentration. The compressive strength of the concretion was the best when the ratio of molecular weight regulator to acrylic acid was 8-10%, the ratio of itaconic acid to acrylic acid was 14-16% and the monomer concentration was 35-40%. The compressive strength of the concretion increased with the prolonging of the stored time in liquid media, the strength of the concretion stored in silicone oil was higher than stored in water and air.4,The concreted mechanisms of Al2O3-SiO2-CaF2-P2O5 powder were discussed. In the process of solidified reaction, because of the acid hydrolyzation of Si-O-Al (Ca) and P-O-Al (Ca) bonds, the release of Ca and Al from the glass powder which reacted with the carboxylate groups to prepare a polysalt matrix. The residual glass particles, with a surrounding siliceous hydrogel, embedded in the polysalt matrix.
|
PDF Full Text Request