景德镇陶瓷工业生态化发展中存在的问题及对策研究

伴随着景德镇陶瓷工业的飞速发展,其污染问题也日益突出。在循环经济大背景下,本文对景德镇陶瓷工业生态化发展过程中存在的主要问题进行分析。从景德镇发展生态工业的原则,树立生态设计思想,建立生态技术支撑体系,发展陶瓷生态工业园、大力发展陶瓷文化创意产业及建立生态补偿机制等方面提出对策。     

CFCC用补强纤维及纤维涂层

补强纤维对连续纤维补强陶瓷复合材料(CFCC)的性能起着至关重要的作用。本文介绍了目前CFCC所用补强纤维的种类及特性,并介绍了纤维涂层在CFCC补强和增韧过程中的作用以及涂层的涂覆方法。     

陶瓷电热材料的研究与应用

本文分析了金属电热丝、电热膜、电热涂料等电热材料,重点介绍了四种陶瓷电热材料各自的研究历史、主要制备方法、电热性能方面的研究,并对各电热材料的发展进行了展望。     

工程陶瓷材料及其与金属连接工艺的研究进展

工程陶瓷材料由于具有良好的综合性能，近几年在动力工程和先进发动机上的应用愈来愈广。笔者介绍了工程陶瓷材料的分类及性能特点、陶瓷—金属的主要连接工艺，探讨了陶瓷—金属连接工艺存在的主要问题和陶瓷零部件在汽车上的应用前景。     

3D printing ceramic cores for investment casting of turbine blades,using LCD screen printers: The mixture design and characterisation

The primary objective of this study is to demonstrate the possibility of developing silica, alumina, and zircon-based photocurable ceramic suspensions that can be used for visible light photopolymerization (> 450 nm) and to optimise the binder formulations for the purpose of LCD-based ceramic 3D printing applications. Reference ceramic components for this work are ceramic cores employed in the investment casting of high-pressure turbine blades and vanes. Arguably, one of the most critical steps in photoinduced ceramic 3D printing is developing suitable ceramic suspensions, having high ceramic loading, low viscosity, and short curing times. Ceramic suspensions with four different novel binder formulations and commercial ceramic powders used in core manufacturing (SiO₂, Al₂O₃ and ZrSiO₄) were investigated to achieve the best trade-off between: (1) their curing performance (cure depth and curing speed), (2) rheological properties of the binder mixtures at the solid loadings of 60 vol.% for SiO₂, 55 vol.% for ZrSiO₄, and 45 vol.% for Al₂O₃; and (3) the green body mechanical properties of the mixtures after printing. The effect of ceramic particles on the selected binders was examined individually, and the correlation between cure depth (C_d), volumetric loading, and curing speed are evaluated. The results show all binders designed in this study provide an adequate cure depth, even at high ceramic loadings. When the curing behaviour of all unloaded binder mixtures from the previous study [1] compared with the 10 vol.% SiO₂ loaded mixtures, the cure depth of all formulated binder mixtures increased 50–55 % and the curing thickness of 60 vol.% SiO₂ loaded suspensions were still slightly higher than their unloaded counterparts. The rheology outcomes indicate that lower viscosity binders always result in lower viscosity of the ceramic loaded inks, even without taking the effect of dispersants into account. Besides, the addition of N-Vinyl-2-Pyrrolidone (NVP) monofunctional monomer to the binder mixtures significantly reduces the viscosity and changes the normally linear relationship of the mix viscosity and its silica loading content. Among the binder formulations loaded with 60 vol.% of SiO₂, the formulation providing the lowest viscosity and highest mechanical property consists of 5 wt.% of NVP, 45 wt.% of HDDA and 50 wt.% of Photocentric 34 resin. Although this binder mixture showed the highest green flexural strength when loaded by 55 vol.% ZrSiO₄, all other mixtures loaded with zircon flour also demonstrated a near-fluid behaviour, below 200 s^?1. In Al₂O₃ loaded mixtures, the HDDA di-functional binder formulations present lowest viscosity and the di- and multifunctional monomer blends (HDDA-Photocentric27) showed the highest mechanical properties when used in a 50/50 ratio. This work summarises the best binder choices for silica, alumina and zircon based ceramic suspensions used in core printing for investment casting applications through LCD screen printing.     

Binder stabilization and rheology optimization for vat-photopolymerization 3D printing of silica-based ceramic mixtures

Enhancing inlet gas temperature in aero/gas turbines to reduce their carbon-footprint, has led to a strive for better performing inlet cooling mechanism of the turbine blades. The internal cooling of the blades is made by ceramic cores in their casting process, but conventional ceramic molding has long reached its maximum possible geometrical complexity, hence shedding light on 3D printing of these cores. The objective of this study is to develop low-viscous, fully stabilized, commercially viable ink for vat-photopolymerization of silica-based ceramics. This paper investigates the best dispersion type and amount for different formulated monomer mixtures, and explains the best correlation between viscosity, solid loading, binders, dispersants, peeling forces and mechanical properties, and offers an optimized mixture to avoid the common ceramic printing issue, namely crack propagation of cores during sintering. Among five dispersant agents, the SOL20, SOL24 and FA4611 exhibited better performance than other dispersion agents, and the optimum concentration level for each binder and dispersant agent was ensured through sedimentation test. Their dispersion capability and long-term stability were further investigated to designate the best dispersion agent for each binder system. Further verification was made by sedimentation study of the samples at 40 °C for 40 days and reducing the superficial area of the used powder mixture. According to the result of the rheology analysis, the best dispersions were achieved using SOL20 for the loaded binder mixtures of M1 and M4, SOL24 for M3and FA4611 for M2. The instability of M1 and M2 with their respective dispersant agent was coordinated through the thixotropic agent of TX/2, and complete stabilization and near-Newtonian behavior were achieved. However, the research showed that the addition of TX/2 to fully stabilized M4 and M2 suspensions negatively impacts the mixtures’ rheological behavior from near-Newtonian to shear-thickening. In the final stage of this study, peeling forces, sintering and three-point bending tests were conducted to determine the final formulated suspension to print ceramic core components. M4 and SOL20 combination was selected for SiO₂-ZrSiO₄ loading and dispersing, respectively. The impact of solid loading between the range of 58 and 65 vol% on the rheological behavior of the final suspension and the mechanical properties of sintered bodies were investigated to assign an optimum solid rate. The adequate strength on sintered and degree of viscosity for ceramic vat-polymerization processing was achieved at 58 vol%. Lastly, a validation study is conducted by printing a complex ceramic core model by a commercial LCD hobby printer. This validation shows the significance of this study to scale up the manufacturing of complex-shaped ceramic cores and to revolutionize the sector, by printing inexpensive and readily available irregular-shaped (non-atomized) ceramic powder, using the most cost-effective LCD printers (non-specialized expensive ceramic printers).     

Analysis of structural and thermal properties of Li2TiO3 ceramic powders

Li₂TiO₃ ceramic powders have been developed by a solid state reaction method and those have been sintered at four different temperatures (600 °C, 700 °C, 800 °C and 900 °C) towards the optimization of sintering temperature that has been found to be at 800 °C based on the nature of the XRD profiles. The sample sintered at 800 °C has shown a good crystallinity situation from its XRD peaks and the sample is found to be in monoclinic structure which is in accordance with the reported data of JCPDS 33-0831. The SEM images for samples sintered at 600 °C, 700 °C, 800 and 900 °C, EDAX peaks, FTIR profile have been measured for the temperature optimized (800 °C) sample for understanding the structural details of Li₂TiO₃ ceramic powders. Besides these, dielectric constant, dielectric loss and a.c. conductivities have been measured for the temperature optimized sample. In order to strengthen the observations made in the XRD profiles at four different temperatures, Raman spectra of those four sintered ceramic powders have also been studied. In respect of the thermal properties, only for the as synthesized (precursor) sample, simultaneous measurement of TG-DTA profiles has been carried out for analysis.     

陶瓷纤维在陶瓷窑炉上的应用及展望

介绍了陶瓷纤维在陶瓷窑炉上的应用,并针对应用中存在的一些问题提出了看法,为陶瓷纤维的实际应用提供参考。     

陶瓷烧结新技术—微波烧结

本文综述了微波烧结陶瓷材料这一新技术在国内外的研究，应用和进展，并介绍和指出了微波烧结的原理，特点及其未来展望。