Studies Of Structure And Properties Of Decorative Opaque Glass With Low Melting Temperature

Based on Na2O-CaO-SiO2glass, adds phosphate as opacifying agents, toproduce a kind of fluorine-free decorative opaque glass with good water resistance,preferencial glossiness, whiteness above80%, thermal expansion coefficientin below75×10-7℃-1and flexural strength above100Mpa. Analysis the effect of P2O5onphase-separation of opaque glass; Analysis the effect of R2O3(R as Al, B) onmicrostructure and physical properties of opaque glass. Analysis the effect of alkalion low-melting property of opaque glass. The results show that:Alkali metal ions plays a key role on low-melting property of opaque glass.Na2O content increases from2wt%to8wt%, the degree of polarization of oxygenions increases, chemical bond strength of the network structure reduces gradually, theviscosity acti vity energies Eη reduces from244.97KJ·mol-1to219.14KJ·mol-1, andtheoretical melting temperature decreases67℃;With K2O gradually replace Na2O,the polarization effect of the former is larger than the latter, chemical bond strength ofthe network structure increases gradually,he viscosity acti vity energies Eη increasesfrom228.47KJ·mol-1to255.28KJ·mol-1, and theoretical melting temperatureincreases58℃.P2O5makes the size of phase-separation of opaque glass presenting a graduallyincreasing trend, the state of droplets become from aggregation to discrete, the shapeof droplets tends to be more complete and the regular sphere. When P2O5content is6wt%, the average size of droplets is250nm and tend to uniform, droplets present asmellow sphere; Silicon-rich phase tend to the state of disperse and independent.When P2O5content becomes from4wt%to7wt%, the whiteness increases from73.51%to82.67%; the flexural strength increases from104.56MPa to113.63MPa.A12O3makes the region of phosphorus-rich phase decreasing, but benefits toincrease the size of droplets. When A12O3content is5wt%, droplets basically stableat around200nm. A12O3content increased from2wt%to5wt%, the flexural strengthincreases from111.29MPa to114.36MPa; the thermal expansion coefficient presentsgradually increasing trend but no significant changes, keeps between73.08×10-7℃-1and75.34×10-7℃-1, Tgand Tfalso increase; the density has no significant change,keeps between2.5361g/cm3and2.5541g/cm3. B2O3plays a role in regulating the phase, resulting in hampering the aggregationof phosphorus-rich, suppressing the size of droplets, so as to adjust the effect ofopacifying. When B2O3content is6wt%, the whiteness presents better performance,which is84.27%. When B2O3content increases from2wt%to8wt%; the thermalexpansion coefficient increases from74.56×10-7℃-1to87.67×10-7℃-1, Tg and Tf alsodecreased; the density reduces from2.5422g/cm3to2.4981g/cm3.When Na2O content increases from2wt%to8wt%, the thermal expansioncoefficient increases from63.51×10-7℃-1to75.34×10-7℃-1, Tg and Tf also decrease,water resistance tends to decrease; With K2O gradually replace Na2O, the thermalexpansion coefficient decreases from75.34×10-7℃-1to70.14×10-7℃-1, Tg and Tfalso increase, water resistance has better performance when both content of themreach4wt%.