Evaluation of crucible and investment materials for lost wax investment casting of Ti and NiTi alloys

Abstract

The aim of this study is to assess the suitability of selected commercial ceramic crucibles for the investment casting of Ti6Al4V and NiTi alloys for jewellery purposes. A commercial vacuum tilt casting machine and a centrifugal casting machine were employed to cast the alloys in cold copper moulds or in refractory investment shells. The form filling of the shell and the crucible and investment reactions were assessed by microstructural investigation, chemical analysis and hardness profiles of the as cast items as a function of shell temperature. The reaction of the alloys strongly depended on the alloy, the crucible material, the coating of the crucibles and the temperature of the ceramic shell. Optimum results were achieved with yttria and yttria coated Al titanate crucibles for Ti6Al4V and NiTi alloys respectively. Improvement of the materials and process costs is necessary to allow the competitive casting of jewellery made from titanium alloys.     

体验营销在珠宝营销中的实践

现在已经步入了体验营销时代,珠宝作为一种象征性商品,它的营销模式应区别于普通商品。珠宝的象征性体现在人们对于它寄予了一种美好的情感,珠宝的本身就具备了很多美好的寓意,而这一点正与体验营销的情感体验不谋而合。同时,由于金融危机的影响,掌握了雄厚资金及先进运营模式的国外著名珠宝公司纷纷看好中国市场,抢滩登陆。所以,改变我国珠宝业的营销模式势在必行。     

饰品用金及其新技术研究

从饰品金用量在世界金总需求中所占份额以及近年来饰品市场的迅速增长，说明金饰品工业在世界经济中的地位，介绍了饰品含金量表示法，饰品类型、典型合金成分和主要性能。以及饰品用金的新发展，如粉末金合金，电铸成型，新型高含金饰品合金９９０Ａｕ等。还讨论了金饰品市场，设计等有关问题。     

杂糅:当代首饰多元边界的承袭——《论首饰:国际当代艺术首饰简编》述评

英文著作《论首饰:国际当代艺术首饰简编》是剖析当代首饰艺术化历程多元边界的先驱之作。作者伊丽莎白·邓·伯斯特(Liesbeth den Besten)以当代首饰艺术化历程为主线,结合西方不同首饰艺术家的作品实例展开当代首饰跨越艺术、手工艺、设计和时尚四个领域的杂糅状态探析,首次呈现出国际当代首饰丰富多元的整体面貌。     

利用x荧光能谱仪对珠宝玉石进行辅助鉴定的方法研究

市场上很多常规鉴定方法无法鉴定的珠宝制品,通过了解它们的元素组成对其准确鉴定很有帮助。针对市场上常见的宝石和其仿制品通过利用x荧光能谱仪进行辅助鉴定,取得了不错的效果。     

Microblasting characteristics of jewellery models built using stereolithography apparatus (SLA)

This paper describes an investigation of the effect of the microblasting process on the surface finish of jewellery models built using stereolithography apparatus (SLA). The layering process of SLA results in visible steps on the model surface. The investigation aims to determine the significant operating parameters of the microblaster deburring process that affect the surface roughness of the SLA jewellery model, to set a practicable range for these parameters for effective deburring and establish the optimum parameters for the best surface finish. A ring model based on the British Standards 28653: 1993 is designed using the Pro-Engineer software. The experimental strategy applies techniques including the full factorial and Yates' method together with the analysis of variance on the deburred samples. The surface roughness of the ring models before and after the deburring process are then measured with a Form Talysurf surface roughness measuring machine. The information obtained is used to identify the parameters for further study. Parameters identified are different nozzle types, blasting time and pressure variation. These parameters are tested for their optimum settings and the microblasting process is found to significantly improve the surface finish by approximately 30% on both the curvature and flat features of the ring model.     

贵金属饰品材料及其制造

介绍三种新型贵金属饰品材料以及制备工艺，这三种新型材料为：贵金属造型材料，Ｓｐａｎｇｏｌｄ，一种具有奇特花纹的饰品金合金和彩色铂饰品，并阐明了这三种材料的优点和应用。