Autocatalytic silver-plating of aluminium radio frequency waveguides with autocatalytic nickel as the undercoat for space applications

• Published in: Surface topography metrology and properties Vol. 2; no. 4; pp. 45004 - 45010
• Main Authors: Shukla, Sharad, Gomathi, N, George, Rene
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.10.2014
• Subjects: aluminium; autocataltic silver plating; radio frequency waveguide
• ISSN: 2051-672X; 2051-672X
• DOI: 10.1088/2051-672X/2/4/045004

Autocatalytic plating, a technique used for evenly coating contoured items with deep cavities, such as microwave components, irrespective of shape and size of the item to be plated, was used in this work to coat a radio frequency waveguide. In this work, a process sequence was developed for autocatalytic silver plating on aluminum base material with autocatalytic nickel as the undercoat. The thickness of the deposited silver depends on variables like temperature, concentration of silver ions in the electrolyte, and the pH of the solution. The influence of these variables was studied under different process conditions. Silver-coated rectangular plates were subjected to various tests, including a bend test, a heat resistance test, a thermal cycling test, a thermo vacuum test, a solderability test, and a humidity resistance test. Autocatalytic silver-coated RF waveguide WR28 was tested for insertion loss and return loss. Autocatalytic silver-plated rectangular plates and waveguides were found to withstand a simulated space environment.