Electroplate Requirements for Decorative Chromium Deposits on Zinc Base Materials Used for Exterior Ornamentation
|Publication Date:||1 December 2017|
This SAE Standard covers the physical and performance requirements for electrodeposited copper, nickel, and chromium deposits on exterior ornamentation fabricated from die cast zinc alloys (SAE J468 alloys 903 and 925), and wrought zinc strip (ASTM B 69). This type of coating is designed to provide a high degree of corrosion resistance for automotive, truck, marine, and farm usage where a bright, decorative finish is desired.
Purpose-This document details the physical and chemical properties that are necessary to optimize coating appearance and durability of decoratively plated parts. When properly applied, the electroplate described in this document has a bright, highly reflective, and specular finish with an inherently high degree of corrosion resistance. The coating's resistance to a corrosive environment is highly dependent on the proper maintenance of the processes used to produce the coating. Since the treatment of processing variables is outside the scope of this document, it is important for applicators of this coating to develop an intimate knowledge of their process, and control all parameters that affect the quality of the end product. The use of techniques such as statistical process control (SPC), capability studies, design of experiments, process optimization, etc., are critical to produce a material of consistently high quality.
The subjects included in this document are: substrate preparation, metal finishing, plate thickness, electrochemical potential difference, ductility, chromium microdiscontinuity, accelerated corrosion, adhesion, bend testing, and sampling. The appropriate specification limits and test methods are described in each section. Where possible, the test methods specified are well established and accepted within the plating industry. In a few instances, several test methods are specified. In these cases, it is up to the purchaser and supplier to agree on the test method to be used.