Enhancement in the osteogenesis and angiogenesis of calcium phosphate cement by incorporating magnesium-containing silicates

Based on the good osteogenic and angiogenic effects of silicon and magnesium elements, three types of micro-nano magnesium-containing silicates (MS), including akermanite (Ake, Ca₂MgSi₂O₇), diopside (Dio, CaMgSi₂O₆) and forsterite (For, Mg₂SiO₄), were incorporated into calcium phosphate cement (CPC) to improve its osteogenic and angiogenic performances for clinical application. In this present work, the physicochemical properties, osteogenesis and angiogenesis of MS/CPCs (Ake/CPCs, Dio/CPCs and For/CPCs) were investigated systematically and comparatively. The results showed that all MS/CPCs had good biomineralization and significantly stimulated the osteogenic differentiation of mBMSCs and angiogenic differentiation of HUVECs, respectively. Besides, the stimulating effects were related to not only the category of MS, but also the content of MS. The For/CPCs had a good angiogenic property but their initial setting times were beyond 60 min. The Dio/CPCs showed the lowest biological performance among the three groups of MS/CPCs due to the lower ion release (Si and Mg). The Ake was the ideal modifier that could provide CPC with appropriate physicochemical properties, better osteogenesis and angiogenesis. Simultaneously, a higher addition (10 wt%) of akermanite resulted in the best potential to bone regeneration. Taken together, this research provides an effective approach to improve the overall performance of CPC, and 10Ake/CPC is of great promising prospect in bone repair.     

高频透辉石瓷

本文对透辉石矿的组成与特性进行了评述。用透辉石代替滑石时,透辉石瓷有较低的烧成温度和较宽的烧结范围,其性能符合高频电介质标准的要求。透辉石矿是高频瓷的一种实用原料。     

Modification of glass network and crystallization of CaO–Al2O3–MgO–SiO2 based glass ceramics with addition of iron oxide

Modification of glass network and crystallization process of a CaO–Al₂O₃–MgO–SiO₂ (CAMS) based glass ceramic to form diopside through addition of iron oxide were investigated using differential thermal analysis (DTA), Raman spectrum, X-ray diffraction, SEM and EBSD techniques. The experimental results showed that addition of Fe₂O₃ led to remarkable reductions in both the glass transition temperature (Tg) and crystallization temperature (Tp) of the CAMS glass ceramic. At addition level below 5 wt%, the Tg and Tp temperatures were 651°C and 903°C, respectively, and the crystallization only occurred on the surface of the glass ceramic samples. Increasing the addition level to 10 wt% and 15 wt%, not only led to reduction in the Tg and Tp temperatures to 643-641°C and 892-876°C, respectively, but also promoted the formation of crystalline diopside throughout the CAMS samples. Based on the results of Raman spectrums, it was confirmed that Fe₂O₃ addition reduced the strength of glass connection as a result of chemical reactions between the isolated Si–O tetrahedron and Fe³⁺ ion, forming Fe³⁺O₄–SiO₄, which can be regarded as Q₂ unit. And this is the first experimental evidence that proving the approach of Fe³⁺ mending glass network. Microstructural examination also identified the formation of large numbers of spherical Fe-enriched regions within the CAMS glass matrix as a result of the amorphous phase separation due to the Fe₂O₃ addition. The interfaces between the Fe-enriched regions and the glass matrix acted as preferred nucleation sites for the diopside, facilitating the crystallization. Crystallographic analysis using EBSD technique determined the <001> as the most favorite growth direction for the diopside crystals in the CAMS based glass ceramic.     

矽卡岩型透辉石矿选矿试验研究

介绍了新型陶瓷材料-透辉石矿的选矿研究现状,提出采用间接测量酸不溶CaO含量来评价和比较透辉石纯度的检测新方法,对具有代表性的西安里矽卡岩型透辉石矿进行了试验研究。经过弱磁一重选一强磁联合工艺试验,透辉石品位从原矿的40%提高到了80%,达到了透辉石工业使用要求,实现了矽卡岩型透辉石矿的回收利用。     

黄磷渣微晶玻璃制备及显微结构分析

黄磷渣是热法磷酸生产过程中排放的熔融态工业废渣。利用黄磷渣进行热态浇注成型和一定的热处理 ,分别获得黄磷渣透明玻璃样品以及微晶玻璃样品。对样品进行了 X衍射分析、电子探针和扫描电镜分析 ,确定黄磷渣微晶玻璃主晶相为硅灰石 ( Ca Si O3)和透灰石 ( Ca Mg( Si O3) 2 )。黄磷渣微晶玻璃的显微结构特征为 :细长、纤维状硅灰石组织中弥散着白亮的小颗粒状透灰石晶粒 ,硅灰石纤维状晶体的晶宽以及透灰石粒状晶体的粒径均大约为 1μm。     

Pressureless sintering and mechanical properties of SiO2–Al2O3–MgO–K2O–TiO2–F (CaO–Na2O) machinable glass–ceramics

To develop a high strength machinable glass–ceramic through pressureless sintering, the glassy compositions were obtained by mixing a mica-based frit and a frit in the SiO₂–CaO–Na₂O system. According to XRD results, the glass compositions mainly crystallized into phlogopite and diopside after sintering. The optimum sintered glass–ceramic with desirable mechanical properties, machinability and sinterability was achieved by addition of 30 wt.% SiO₂–CaO–Na₂O glass powder to 70 wt.% mica glass composition. SEM results confirmed presence of needle-like diopside crystals which played a reinforcement role to the platelet phlogopite and glassy matrix combination. The measurements showed bending strength and fracture toughness enhanced up to 144.6 ± 17.6 MPa and 1.7 ± 0.2 MPa m^1/2, respectively.     

从透辉石的结构特征探析其在陶瓷中的应用

透辉石为典型的热液接触变质矿物，系花岗岩浆与钙质白云岩接触交代的产物。多呈针柱状、柱粒状结构，富含SiO2、CaO、MgO，热性能好、烧失量低、资源丰富，是生产墙地砖的优质原料。含铁低的透辉石亦可用来生产日用细瓷，具有产品成本低、外观性能好、透光度高、机械强度高、热稳定性好等特点。     

利用硫铁矿尾矿制备微晶玻璃

以硫铁矿尾矿制备微晶玻璃,并用DTA、XRD、SEM等手段分析了微晶玻璃的相变、相组成及微观结构。结果表明,利用硫铁矿尾矿为主要原料,添加适量的其他原料,可获得主晶相为透辉石相的微晶玻璃。     

Direct ink writing of wollastonite-diopside glass-ceramic scaffolds from a silicone resin and engineered fillers

Wollastonite-diopside scaffolds have been successfully developed by direct ink writing of an ink made of silicone polymer and inorganic fillers. The main reason for using a silicone in the ink formulation consisted in its double effect, in controlling the ink rheology and in developing of wollastonite and diopside crystalline phases upon heat treatment. The obtained 3D wollastonite-diopside scaffolds featured regular geometries, and a high compressive strength (3.9–4.9 MPa) when considering the large amount of porosity (68–76 vol.%). A glass with the same oxide composition as the silicone-based ink and crystallizing into wollastonite and diopside, was produced and used as additional filler. This addition enabled the fabrication of even stronger 3D printed scaffolds (∼8 MPa for a porosity of 67 vol%), owing to the enhanced viscous flow upon firing which reduced the micro-cracks in the scaffold struts generated by the preceramic polymer decomposition. The obtained highly porous wollastonite-diopside glass-ceramic scaffolds are suitable candidates for bone tissue engineering.     

The impact of wollastonite and dolomite on chemical durability of matte fast-fired raw glazes

Controlled share of wollastonite and dolomite in the recipe was decisive for achieving raw glazes with a matte surface in a fast-firing process. The surface characteristics were studied for 25 experimental glazes containing 9–39 wt% wollastonite and 0–16 wt% dolomite. The glaze suspensions were applied on raw tiles and fired to 1215 °C in an industrial kiln. The chemical durability of the tiles was measured according to the standard ISO 10545-13. Further, the impact of exposure time on surface degradation was measured for 0.1 and 3 vol% HCl-solutions. The changes in the phase composition were studied with SEM/EDXA and XRD. The surface consisted of wollastonite and diopside, some residual quartz and corundum as well as amorphous phases. Wollastonite crystals severely decreased the durability while diopside crystals provided a durable matte surface. The results give guidelines for manufacturing matte and chemically durable fast-fired raw glazes.