共查询到20条相似文献,搜索用时 477 毫秒
1.
2.
3.
负压吸附涂料层透气性的测试原理及方法 总被引:3,自引:0,他引:3
提出了用负压吸附涂料层的方式测试涂料透气性的新方法,并推导出了在该方法下计算涂料透气性的数学表达式。对该方法的可靠性进行了实验验证,结果表明,该法所测数值对同一种涂料具有好的重现与稳定性;对涂料透气性的微小变化有好的敏感性;粘结剂量增加,涂料透气性下降。 相似文献
4.
5.
介绍了环境友好防腐涂料研究的背景,对环境友好防腐涂料进行了分类和定义;分别对环境友好涂料即:水性涂料、高固体分涂料、粉末涂料及辐射固化涂料的现状与研究进展进行了较详细的介绍。 相似文献
6.
讨论了稀土复合保温涂料对退火炉的节能机制,对稀土复合保温涂料作了分析,并对稀土保温涂料的节能效果从理论和实践两方面进行了对比。 相似文献
7.
8.
9.
10.
11.
Xiangfan Fang Joachim Gundlach Jannis-Jeremias Schipperges Xin Jiang 《Journal of Materials Engineering and Performance》2018,27(12):6415-6425
Hybrid casting is a well-known technology to join steel inserts and aluminum. In order to achieve a high-performance material-based joining between steel and aluminum, a new PVD Al-Si-(Fe) coating, which consists of two sub-layers, has been successfully developed for high-pressure die casting. This coating system has been investigated further in this work for the sand casting process. By extending the sand casting process to the plaster casting process with preheating possibilities for the coated steel inserts, a material-based connection between steel and aluminum with a tensile shear strength of 7.7 MPa could be created. The ductility of this connection is decreased comparing with the connection manufactured by die casting. SEM and EDS analysis and diffusion experiments show that the difference of mechanical properties between plaster and die casting is caused by the extensive diffusion and the corresponding layer growth at plaster casting. The edge separation in plaster casting is a result of the edge stresses due to the different thermal expansion of steel and aluminum which can be suppressed at high-pressure die casting. To improve the joining properties at sand casting, it is necessary to control the layer diffusion by adding other alloy elements such as Mn into the Al-Si-(Fe) coating layer. 相似文献
12.
《中国铸造》2015,(2)
Soldering is a unique casting defect associated with die casting or metal mold casting of aluminum alloys. It occurs when molten aluminum sticks or solders the surface of the die steel and remains there after the ejection of the casting, causing a surface defect and dimensional inaccuracy of the castings and increased machine downtime. Soldering occurs easily when a bare die steel mold is used for die casting of aluminum alloys. When molten aluminum comes in contact with the die steel at a temperature higher than a critical temperature, the iron and aluminum atoms diffuse into each other, forming a series of intermetallic phases and a liquid aluminum-rich fcc phase. This liquid phase exists between intermetallic phases. On cooling, the liquid fcc phase solidifi es on the intermetallic phases and grows into the casting, resulting in soldering. The critical temperature is the eutectic temperature near the aluminum corner of the phase diagram. If the die is protected using a nonreactive ceramic coating, soldering starts at locations where local coating failure occurs. Molten aluminum comes into contact with die steel through the coating failure locations and eats into the steel matrix, forming small pits. As these small pits grow, the coating is gradually removed and soldering becomes more severe. Details of die soldering step on a bare steel die and on a coated die material are discussed. 相似文献
13.
采用阿基米德法测试烧结试样密度,研究了陶土对铸钢消失模涂料烧结性的影响。结果表明,随着陶土含量和烧结温度的增加,试样体积密度都有增大趋势。陶土含量为5%时,试样在1550℃时密度显著增大,符合铸钢消失模涂料要求。另外,进行现场浇注试验,对涂片层断面进行扫描电镜分析,涂片层断面与钢水接触部分烧结良好,耐火骨料连成整片,阻止钢水进一步渗透,使涂料烧结壳从铸件表面自动剥离。 相似文献
14.
15.
16.
介绍了一种新的离心铸造用涂料的配制,测定了其有关性能。试验表明,它具有良好的工艺性能,抗热裂性能,绝热性能及发气量低等优点。可用于热模法离心铸造薄壁耐热合金钢管的生产。 相似文献
17.
18.
通过正交试验方法对水基铝矾土铸钢流涂涂料进行了研究,确定了各项工艺性能最佳的流涂涂料配方。流涂和浇注试验表明.采用流涂工艺.铸件表面质量好,提高了涂敷效率。 相似文献
19.