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何绍华 《徐州工程学院学报》2009,24(1):11-16
传统陶瓷材料因其具有耐高温、耐腐蚀、强度高、硬度大等优点,已成为人们普遍关注的对象.但传统陶瓷的脆性问题一直是阻碍陶瓷材料发展的主要因素之一,而由纳米晶组成的陶瓷材料则具有高韧性、低温超塑性等特点.文章重点分析了纳米晶陶瓷传统成形技术的研究现状及各种技术的优缺点,并探讨纳米晶陶瓷的制备成型技术发展方向,指出使用激光成型技术制备高性能纳米晶陶瓷零件是可以期待的. 相似文献
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Işıl Damla Sener-Yamaner Atilla Sertgöz Tugba Toz-Akalın 《Journal of Adhesion Science and Technology》2013,27(1):55-70
This study evaluated the fracture resistance and marginal fit of CAD/CAM ceramic and composite inlays. Molars (N = 80) were prepared to receive Mesio-occlusal-distal (MOD) inlays and randomly divided into four groups to be restored depending on the materials: (a) HLD: heat-pressed lithium disilicate ceramic (IPS e.max Press), (b) CLD: CAD/CAM-fabricated lithium disilicate ceramic (IPS e.max CAD), (c) NC: CAD/CAM nano-ceramic resin (Lava Ultimate), (d) RC: Indirect resin composite (Filtek P60). Each group was randomly divided into two subgroups regarding the resin cement: (a) High-viscosity resin cement (Syntac, Variolink II), (b) Self-adhesive low-viscosity cement (RelyX Ultimate). After marginal gap and cement thickness measurements, specimens were loaded to fracture in a Universal Testing Machine (1 mm/min). Intact molars acted as the control group (n = 10). Data were analyzed using one-way and two-way ANOVA, Tukey’s tests (α = 0.05). Before cementation, CLD group showed significantly lower mean marginal gap (65 ± 22.4 μm) and after cementation, cement thickness was again the lowest with CLD (82.6 ± 24.6 μm) and the highest with HLD (108.4 ± 21.3 μm) (p < 0.001). The mean marginal gaps of inlays at the gingival margin were significantly higher than at the occlusal and the axial margins (p < 0.05). While material type significantly affected the mean fracture resistance (p < 0.001), the cement type had no effect on the results (p = 0.083). NC group (2486 ± 40 N) showed significantly higher mean fracture load compared to those of other three groups (1997.5 ± 60–2007 ± 30) (p < 0.05). The mean fracture resistance of control group with the intact teeth was significantly higher than those of all groups (p < 0.05) except for NC (p > 0.05). 相似文献
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The major solving ways for the material wear are surface modification and lubrication.Currently,the researches at home and abroad are all limited to the single study of either nano-lubricating oil additive or electroless deposited coating.The surface coating has high hardness and high wear resistance,however,the friction reduction performance of the coating with high hardness is not good,the thickness of the coating is limited,and the coating can not regenerate after wearing.The nano-lubricating additives have good tribological performance and self-repair function,but under heavy load,the self-repair rate to the worn surface with the nano-additives is smaller than the wearing rate of the friction pair.To solve the above problems,the Ni-W-P alloy coating and deposition process with excellent anti-wear,and suitable for industrial application were developed,the optimum bath composition and process can be obtained by studying the influence of the bath composition,temperature and PH value to the deposition rate and the plating solution stability.The tribological properties as well as anti-wear and friction reduction mechanism of wear self-repair nano-ceramic lubricating additives are also studied.The ring-block abrasion testing machine and energy dispersive spectrometer are used to explore the internal relation between the coating and the nano-lubricating oil additives,and the tribology mechanism,to seek the synergetic effect between the two.The test results show that the wear resistance of Ni-W-P alloy coating(with heat treatment and in oil with nano-ceramic additives) has increased hundreds times than 45 steel as the metal substrate in basic oil,the friction reduction performance is improved.This research breaks through the bottleneck of previous separate research of the above-mentioned two methods,and explores the combination use of the two methods in industrial field. 相似文献
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1 INTRODUCTIONHigh temperatureceramiccoatinghasemer gedinresponsetorequirementsforoxidationresistanceandcorrosionresistanceofsuperalloypartsinhightemperatureapplicationssuchasturbineblades ,andformanyapplicationsinceramiccoatings ,itisdesir abletosinteratrelativelylowtemperature .Thisgoalcanbeaccomplishedbyusingsubmicrometer particlecoating,suchasnano ceramiccoating .Buttheag glomerationcausedbythehighsurfaceenergyofthenano particlesmadeitimpossibletoshowtheadvan tageofthem ,sohomodispers… 相似文献
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纳米陶瓷粉体的应用现状与展望 总被引:2,自引:0,他引:2
纳米陶瓷粉体在精细陶瓷、功能陶瓷、生物陶瓷及精细化工材料等高技术领域中得到了广泛的应用,已成为当今发展高技术材料的基石。分析纳米陶瓷粉体的应用研究现状,对研究其发展前景具有重要的现实意义。 相似文献
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