Black Trivalent Chromium Electrodeposit

这项工作的目标是从三价铬溶液中开发先进的电镀黑铬涂层。该项目将专注于昆茨电镀公司(KEI)和麦克马斯特大学的积极合作。KEI致力于开发用于汽车工业的黑色铬防护涂层电镀新技术。KEI感兴趣的是解决从六价铬溶液中取代镀铬工艺为从三价铬溶液中电镀新工艺的问题。该公司的问题是，从Cr3+溶液中电沉积的铬层产量低，阴极气体析出严重，导致附着力低，机械性能差，抗热震性差，耐腐蚀性差。Kei无法实现涂层的黑色，从灰色到棕色。使用有效的络合剂是从Cr3+溶液中电镀的关键。KEI对新的络合剂和表面修饰技术感兴趣，目前麦克马斯特大学的电化学实验室正在开发这些技术。新型络合剂的特点是：作为电镀添加剂的Cr3+与其他金属离子有良好的络合作用，对铬和铬氧化物添加剂有很强的吸附作用，能促进溶液中离子的还原和电荷转移。此外，新的螯合剂可以赋予涂料黑色和疏水性能。预计新型络合剂的应用将导致黑色铬涂层的发展，使其具有更好的防腐性能和机械性能，改善附着力和抗热震性。从Cr3+溶液中开发黑色铬涂层符合加拿大汽车工业的利益，并提供许多环境效益。该项目的好处将包括产生新的技术解决方案、向KEI转让技术和HQP培训。问题的解决将导致Kei的就业增长和收入增加。

The objective of this work is the development of advanced black chromium coatings by electroplating fromtrivalent chromium solutions. This project will be focused on active collaboration of Kuntz Electroplating Inc.(KEI) and McMaster University. KEI is working on the development of new technology for electroplating ofblack Cr protective coatings for applications in automotive industry. KEI is interested in the solving of aproblem of replacement of a Cr plating process from the hexavalent Cr solutions for a new plating processfrom the trivalent Cr solutions. The company has a problem of low electrodeposition yield of Cr coatings fromCr3+ solutions and significant cathodic gas evolution, which result in low adhesion, poor mechanicalproperties, low thermal shock resistance and poor corrosion resistance. KEI was not able to achieve black colorof the coatings, which varied from gray to brown. The use of efficient complexing agents is of criticalimportance for electroplating from Cr3+ solutions. KEI is interested in new complexing agents and surfacemodification techniques, which are currently under development in the electrochemical laboratory of McMasterUniversity. The unique features of new complexing agents are: good chelation of Cr3+ and other metal ions,which are used as plating additives, strong adsorption on Cr and Cr oxide additives, ability to facilitate ionreduction in solutions and improve charge transfer. Moreover, new chelating agents can impart black color tothe coatings and hydrophobic properties. It is expected that the application of new chelating agents will resultin the development of black Cr coatings with enhanced corrosion protection and mechanical properties,improved adhesion and thermal shock resistance. The development of black Cr coatings from Cr3+ solutionsmeets interests of Canadian automotive industry and offers many environmental benefits. The benefits of thisproject will include the generation of new technological solutions, technology transfer to KEI and HQPtraining. The resolution of the problem will result in job growth at KEI and increased revenue.