Black Trivalent Chromium Electrodeposit

本工作的目标是通过从三价铬溶液中电镀来开发高级黑铬涂层。该项目将集中在积极合作的昆茨电镀公司。(KEI)麦克马斯特大学KEI致力于开发用于汽车工业的电镀黑铬保护涂层的新技术。KEI对解决用三价铬溶液的新电镀工艺替代六价铬溶液的镀铬工艺的问题感兴趣。该公司存在从Cr 3+溶液中电沉积Cr镀层的得率低和阴极析气显著的问题，导致附着力低、机械性能差、抗热震性低和耐腐蚀性差。KEI不能实现涂层的黑色，其从灰色到棕色变化。有效络合剂的使用对于从Cr ~（3+）溶液中电镀至关重要。KEI对新的络合剂和表面改性技术感兴趣，这些技术目前正在麦克马斯特大学的电化学实验室进行开发。新型络合剂的独特之处在于：对用作电镀添加剂的Cr 3+和其他金属离子具有良好的螯合作用，对Cr和Cr氧化物添加剂具有强吸附性，能够促进溶液中的离子还原并改善电荷转移。此外，新型螯合剂还能赋予涂料黑色和疏水性能.新型螯合剂的应用将使黑铬涂层具有更好的防腐蚀性能、机械性能、附着力和抗热震性。从Cr 3+溶液中开发黑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，技术转让给KEI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.