Mechanical Properties-oriented Optimization Of Phosphate Glass Composition

Phosphate glass has potential application value in the solidification of laser materials,slow-release materials,nuclear waste materials and other aspects due to its many advantages such as low melting temperature,ultraviolet light transmission,and low dispersion power.However,due to the P=O double bond contained in the structural unit[PO₄]of the phosphate glass,a layered or chain-like glass structure is formed.This special structure leads to its disadvantages of poor thermal and mechanical properties,which limits its scope of application.In this paper,six groups of phosphate glass samples were prepared by traditional high temperature melting methods using phosphate glass materials as the research object.The problems of crystallization,cracking and bubbles in the preparation of glass were studied,and solutions were proposed for these three problems.Subsequently,X-ray diffraction analysis?XRD?,Raman spectroscopy?Raman?,differential scanning calorimetry?DSC?,electronic tensile testing machine and digital micro-hardness tester were used to test the structure and physical properties and mechanical properties of the glass,the correlation between the composition,structure,and performance of the six groups of phosphate glass were systematically study.The effects of phosphorus content and boron oxide content on the structure and properties of phosphate glass were explored,and the differences in physical and chemical properties of six groups of borophosphate glass materials were comprehensively compared to obtained a new type of phosphate glass material with better comprehensive physical and chemical properties.The main findings are as follows:1.In view of the problem of crystallization of glass,the methods of increasing the uniformity of components and selecting a suitable molding temperature range make the experimental effect significant;the problem of cracking of the glass was solved by changing the annealing rate and annealing temperature of the glass;the problem of air bubbles in the glass during the glass preparation process in order to reduce the generation of air bubbles by appropriately increasing the melting temperature and stirring of the glass,a complete and transparent block glass sample was finally obtained.2.X-ray diffraction results showed that the amorphous structure of the glass,indicating that the addition of boron oxide has not changed the disorder of the glass;Raman results indicated that the increase in phosphorus content changed the glass structure from metaphosphate structure to pyro-phosphate structure.The introduction of appropriate boron oxide transformed the glass from a layered structure to a three-dimensional structure,and then enhanced the compactness of glass;Differential scanning calorimetry?DSC?analysis displayed that the increase in phosphorus and boron oxide improved the glass transition temperature T_g.3.The analysis of physical properties illustrated that the increase in phosphorus content reduced the density of the phosphate glass,resulting in a loose glass structure.The introduction of an appropriate amount of boron oxide increased the density of the glass,and its molar volume and density are exactly the opposite,making the glass structure densification;The analysis of mechanical properties demonstrated that the addition of phosphorus content dropped the flexural strength and micro-hardness of phosphate glass.The addition of an appropriate amount of boron oxide improved the flexural strength of the glass,Fracture toughness,and micro-hardness.All in all,boron oxide strengthened the thermo-mechanical properties of the phosphate glass.