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1.
《Ceramics International》2020,46(4):4322-4328
The objective of this study was to evaluate the effect of ZnO content on the physical, mechanical and chemical properties of CaO–Al2O3–SiO2 (CAS) glass-ceramics produced from Colombian wastes, such as fly ash, granulated blast furnace slag and glass cullet. The CaO/SiO2 molar ratio of the mixtures was held constant (0.36). ZnO was added to the mixtures in proportions of 4, 7 and 10 wt%. The glass-ceramics were produced by the controlled crystallization of a parent glass. The values of crystallization temperature (Tp) show a fall up to 7 wt% and then shoots up with 10 wt% concentration of ZnO, but in general, ZnO addition lowers the temperature required for the formation of crystalline phases. In general, anorthite (CaAl2Si2O8) is the main phase observed in all heat treated samples, in addition to albite (Na(AlSi3O8)) and labradorite (Na0.45 Ca0.55 Al1.55 Si2.45 O8). The crystalline phases hardystonite (Ca2ZnSi2O7) and willemite (Zn2SiO4) were also identified in the samples with 7 and 10 wt% ZnO. The densities of the glass-ceramics were between 2658 and 2848 kg/m3, and it was found that ZnO helps to increase the density of glass-ceramics. The elastic modulus was in the 100–105 GPa range, the fracture toughness was between 0.45 and 0.64 MPa m1/2, and the Vickers microhardness was between 632 and 653 MPa. With regards to the durability, the weight loss of the glass-ceramics immersed in alkaline solution (NaOH) did not exceed 1.5 wt% after immersion for 6 h at 80 °C. The results of this study confirm that the vitrification process is a favorable option to utilize these industrial wastes.  相似文献   
2.
The oxyfluoride glass and glass-ceramics from the LiF-B2O3-SiO2 system are developed. The stable glass can be produced in the range of 20–40 mol% LiF. The effect of LiF admixture on the thermal stability of the glass as well as the thermoluminescence (TL) properties such as glow curves shape is studied. The results show that the increase of lithium fluoride content in the borosilicate glass causes efficiency enhancement of the thermoluminescence signal. We have clearly stated that the process of controlled crystallization of the oxyfluoride glasses can lead again to increased intensity of the TL process. The glass-ceramics with 40 mol% LiF reveals similar level of TL signal to commercially used doped LiF material and can be considered as active material for alpha and beta radiation detectors.  相似文献   
3.
A multi-component lithium disilicate (LD) glass-ceramic with interlocking microstructure consisting of rod-like LD crystals and glassy matrix was ion-exchanged over wide temperature and time ranges in pure NaNO3 or mixed NaNO3 and KNO3 baths below the glass transition temperature. Treatment temperature, time and salt bath dependences of surface characteristics and mechanical properties for the ion-exchanged glass-ceramic were investigated. It was found that the glass-ceramic with limited glassy matrix could be remarkably strengthened and toughened in NaNO3 bath by adjusting the treatment temperature to a moderate level, at which Li+/Na+ exchange between the glassy matrix and the salt bath could form an ion-exchanged layer with larger depth and less stress relaxation. Furthermore, by using the mixed salt bath, the undesirable exchange of K+/Na+ in pure NaNO3 bath could be limited; further enhanced strengthening effect was achieved. The results might renew the interest on strengthening LD glass-ceramics by traditional ion-exchange process.  相似文献   
4.
将煅烧后的电解锰渣作为单一的实验原料,采用烧结法,制备微晶玻璃,通过正交实验对锰渣微晶玻璃的热处理方案及性能进行探讨。实验通过DSC、XRD、SEM等方法对样品的性能进行表征,并测试了样品的体积密度、抗弯强度等性能。结果显示:不同的热处理条件下的锰渣微晶玻璃的主晶相均为透辉石(含铁),次晶相为普通辉石相。在800℃/0.5 h+980℃/1 h的热处理条件下得到的锰渣微晶玻璃的综合性能最优,其抗弯强度为106.82 MPa;体积密度为2.68 g/cm^3;维氏硬度为4.43 GPa;耐酸度为0.71%;耐碱度为0.07%。此外,锰渣微晶玻璃用作建筑材料,有非常大的应用潜力。  相似文献   
5.
烧结法制备微晶玻璃材料   总被引:7,自引:0,他引:7  
微晶玻璃是由玻璃原位析晶而获得的一种结构均匀,致密,晶粒尺寸为纳米或亚微米级的新型陶瓷复合材料。本文介绍了烧结法制备徽晶玻璃复合材料的特征、工艺原理、微观结构、性能及应用。  相似文献   
6.
Since reliable long term operation of SOFC and SOEC devices depends critically on the mechanical behavior of the sealant material, the current work focuses on the characterization of the shear strength by a torsion test of two different glass-ceramic sealants that are used to join Crofer22APU substrates in an application relevant configuration. The two glass-ceramic sealants differ in terms of characteristic temperatures and crystalline phases with possible impications on the joining behavior. Statistically identical shear stress values were measured at room temperature for joined hourglasses of different size with both sealants, thus confirming a size independence of the measured strength values. Experimental post-test examination results confirm that the interfaces play a strong role regarding the measured shear strength and provide important insights with respect to integration of metallic and glass-ceramic components in SOFC/SOEC stacks.  相似文献   
7.
Heterogeneous ion solution is an important method to improve the wanted property of polycrystalline materials. In this paper, for the purpose of infrared radiation property modification, different contents Fe2O3 were doped in MgO-Al2O3-SiO2 system glasses. The effects of Fe2O3 doping on nucleation mechanism, crystallization behaviors and especially infrared radiation properties of this cordierite-crystalline based glass-ceramics were systematically investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results show that, the doping of iron ion can promote the phase separation of this magnesium aluminosilicate glass, and therefore change the crystallization mechanism of this glass from surface crystallization to bulk crystallization. The iron ion incorporates into the crystal structure of cordierite by mean of substituting Mg2+ in M site. The substitution of Fe3+ to Mg2+ can form the vacant site of Mg2+ cations. For the effects of lattice distortion, impurity and vacancy defects which caused by the incorporation of iron ion, the infrared radiation performance of cordierite based glass-ceramics can be improved effectively.  相似文献   
8.
《Ceramics International》2023,49(16):26860-26870
The degradation of environmentally friendly CaO–Al2O3–SiO2–B2O3 (CASB) glass-ceramics, which consist of anorthite and glass phase, was investigated in three natural organic acid solutions. The results indicated that citric acid had the most significant effect on the degradation of CASB glass-ceramics. While the chemical stability of anorthite is relatively poor, the glass phase also contributed significantly to the effective degradation of CASB glass-ceramics. Subsequently, Ba2+ or Sr2+ was used for full or partial substitution of Ca2+ in CASB glass-ceramics, and the degradation-controlling mechanism of the substituted CASB glass-ceramics was further researched. The full substitution of Ca2+ in CASB glass-ceramics by the two cations resulted in the occurrence of borate [BO4] units in the glass phases, and the interlinkage of [BO4] with broken silicate [SiO4] network structures caused a complementary network effect. Consequently, the degradation of CASB glass-ceramics by organic acids was reduced due to the improvements in the chemical stability of the modified glass-ceramics. Additionally, degradation control can also be achieved based on a mixed-alkali effect, originating from the partial substitution of Ca2+ in CASB glass-ceramics by Ba2+ or Sr2+. The degradable glass-ceramics have the potential to be applied in low-temperature co-fired ceramic technology because of their good physical properties, which include a dielectric constant of 3–5, a dielectric loss as low as 10−3, a coefficient of thermal expansion of 3–9 × 10−6/°C, and an average bending strength of about 47 MPa. Noticeably, the development of the degradable glass-ceramics is helpful to the low-cost and pollution-free recycling of valuable metal electrodes, which is significant for the sustainable development of electronic packaging technologies.  相似文献   
9.
This work focuses on the joining processes of oxide-based ceramic matrix composites (Al2O3f /Al2O3-ZrO2), which are used as radiant tube furnace components in the steel industry. These components have to operate in harsh environments, and under high temperatures, and they therefore have to resist corrosion, humidity, and combustion. Two glass-ceramics systems, which have Y2Ti2O7 as their main crystalline phase, as well as specific and optimized properties to withstand severe operating conditions, including temperatures of 900 °C, are here proposed as joining materials. The adhesion of the glass-ceramics to the composite was found to be excellent after mechanical and thermal tests in which they were in direct contact with a 900 °C flame and thermal cycling of between 400 °C and 900 °C.  相似文献   
10.
高掺量赤泥-粉煤灰微晶玻璃研究   总被引:8,自引:0,他引:8  
赤泥是氧化铝生产中排放的碱性废渣,粉煤灰是燃煤电厂排放的高SiO2含量废渣.综合利用两种废渣制备高性能的微晶玻璃材料,控制SiO2含量在31%~44%,CaO含量在25%~31%,两种废渣总吃渣量能够达到90wt%以上,具有显著经济效益和环境效益.  相似文献   
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