Microstructure and Mechanical Properties of Mica Glass-Ceramics Prepared by Pressureless Sintering a Phlogopite and Various Additives

Mica glass-ceramics were prepared by pressureless sintering with a phlogopite and various additives as raw materials. The effects of CaF2 content, Li2O content, ZrO2 content, and sintering temperature on the microstructure and mechanical properties of the mica glass-ceramics were investigated by X-ray diffraction, scanning electron microscopy, and mechanical testing, respectively. The results show that the additive of ZrO2 has the best reinforcing effect on the flexural strength of the mica glass-ceramics. The smaller powder particles and the larger forming pressure result in the larger bulk density of the mica glass-ceramics samples. The main crystallite phases of samples with ZrO2 as additive were phlogopite and quartz with sintering temperature lower than 1120 ℃. The crystal phase of glass ceramics appeared fiberform and cross arranges with good lap. The highest value of flexural strength, 63.7 MPa, was shown on sample with 10wt% ZrO2 as additive and sintering temperature of 1120 ℃.

Effects of ZrO_2 on the Microstructure of a Mica Glass-ceramic

The effects of ZrO2 on the crystallinity of mica and microstructure of a machina- ble glassceramic were studied. It was found that ZrO2 is an effective nucleation agent in mica glass- ceramics. Stabilized by Ca2+, a lot of t--ZrO2 particles precipitate from ZrO2-mica glass-ceramics. The ZrO2 particles can effectively limit the growth of mica crystal and benefit the mechanical properties of glass-ceramics.

Lanthanide doped fluorosilicate glass-ceramics:A review on experimental and theoretical progresses

Significant developments have been made in the past few decades for lanthanide(Ln)ions doped fluorosilicate glass-ceramics(Flusi-GCs).As novel generation of luminescence materials with a wide range of applications,Flusi-GCs as a single host combine the advantages of glass and ceramics/crystals as well as fluorides and silicates.In this review,the chemical design principles and experimental procedures of Flusi-GCs are summarized in detail.Flusi-GCs are categorized as those containing PbxCd_(1-x)F_(2),RF_(3)(R=Y,La,Gd),MF_(2)(M=Ca,Sr,Ba),xMF_(2)-yRF_(3)(R=Y,La-Lu),mAF-nRF_(3)(A=Li,Na,K),KTF_(3)(T=Zn,Mn)and K2 SiF6 nanocrystals(NCs).Theoretical breakthroughs mainly by molecular dynamic(MD)simulation have been recapitulated as efficient routes for composition-design,nano-crystallization-prediction,and performance-optimization of Flusi-GCs containing target fluoride NCs.Essential research progresses pertaining photonic applications have been made in random lasers,communication amplifiers,optical fibers,spectral converters,white light-emitting-diodes(WLEDs),and thermal sensors.In the end,we propose three future research directions for Flusi-GCs.

纳米二氧化硅对氟硅云母玻璃陶瓷强度的影响

目的:提高以云母为主晶相的牙科用可切削玻璃陶瓷氟硅云母玻璃陶瓷材料强度。方法:在氟硅云母玻璃原料粉中使用纳米二氧化硅(粒径7 nm),制备氟硅云母玻璃陶瓷,用扫描电镜观察其显微结构,X线衍射确定物象组成及含量,测定样本的抗弯强度和断裂韧性,并与普通氟硅云母玻璃陶瓷材料进行比较。结果:使用纳米二氧化硅(纳米组)和普通氟硅云母玻璃陶瓷材料组(微米组)的抗弯强度和断裂韧性分别增加34%和23%。纳米组的密度和收缩率高于微米组。XRD结果显示两组材料的晶相结构相同。在SEM下观察纳米组结晶更加充分,其晶粒大小相对均匀,相互交错;未晶化的玻璃成分比例较低。结论:纳米二氧化硅粉体的应用可以显著提高氟硅云母玻璃陶瓷材料的强度和断裂韧性。