Hexavalent Chromium Substitution

From razor thin tool blade coatings to shiny custom motorcycle parts, hexavalent chromium (Hex-chrome) has historically been the coating of choice for a vast array of industrial applications. Hex-chrome has many advantages over other coating alternatives including hardness, corrosion resistance, coefficient of friction, process maturity, and economic factors. Existing Hex-chrome process technologies are simple and well understood in the industry. Recent reports and media coverage have brought Hex-chrome into the spotlight. Increased environmental and regulatory pressure on existing Hex-chrome has created a need for companies to investigate alternative coatings. In 1988 [15] Hexavalent Chromium was declared a carcinogen and since has received additional scrutiny and regulation. Recent advances in coating technologies and process methods look to provide feasible alternatives to existing processes while providing Hex-Chrome free options. However, evaluating these potential alternatives is difficult as information from vendors is not easily obtained the decision process is not well documented. In this project, the team provides a history of hard chromium coatings. We discuss the issues emanating from hard chromium and traditional application processes. Various alternatives are discussed in detail, many of which are considered “Nano-coatings” due to their tiny architecture and deposition methods. A criteria analysis/decision matrix is provided which provides: Multiple selection criteria/key metric scoring (harness, coefficient of friction, corrosion resistance) Consideration of cost of ownership Environmental impact factors Priority weighting of factors (cost vs. environmental) Visual results for ease of analysis, helps technology managers prepare for Hex-chrome alternative evaluation In researching this topic, the team was unable to find such a decision model. The team adds to the existing body of knowledge by establishing this model and providing guidance regarding the model inputs. Although a fully comprehensive decision matrix could not be developed, due to limitations in available data, the team provides a detailed overview of each replacement technology and guidelines for making decisions in the future when such information is available.