Blue and purple gold alloys form in the alloying systems of gold with gallium/indium and aluminium respectively and are known to be very brittle and to possess low corrosion resistance. Taking into account these drawbacks this paper describes the results of a European funded research project. The properties of the blue and purple gold alloys and coatings such as corrosion resistance, metal release rates, hardness and colour and the influence of alloying additions on these properties are presented and discussed. Surface engineering techniques and investment casting were used for manufacturing of jewellery items with selectively coated coloured surface. Coatings of AuGa2 and AuIn2 blue gold alloys were applied on 18kt gold and Sterling silver jewellery by electroplating, laser/torch cladding or dipping into liquid gallium. The suitability of blue gold coatings for jewellery purposes will be discussed in the light of reliability and feasibility. The work consists of two parts. Part I describes properties and surface processing techniques while Part II deals with investment casting and related alloy design of coloured gold alloys.

中文翻译：

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有色金金属间化合物的冶金和加工 第 I 部分：性能和表面加工

蓝色和紫色金合金分别在金与镓/铟和铝的合金系统中形成，并且已知非常脆且具有低耐腐蚀性。考虑到这些缺点，本文描述了一个欧洲资助的研究项目的结果。介绍和讨论了蓝色和紫色金合金和涂层的性能，例如耐腐蚀性、金属释放率、硬度和颜色，以及合金添加对这些性能的影响。表面工程技术和熔模铸造被用于制造具有选择性涂层彩色表面的珠宝首饰。AuGa2 和 AuIn2 蓝金合金涂层通过电镀、激光/火炬熔覆或浸入液态镓应用于 18kt 金和纯银首饰。将根据可靠性和可行性讨论蓝金涂层用于珠宝用途的适用性。作品由两部分组成。第一部分描述了性能和表面处理技术，而第二部分涉及有色金合金的熔模铸造和相关合金设计。