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High Performance Sprayed Coatings and Spray-Forms

Project Code: 0902-01


Evaluate cold and thermal spray deposition for repair and spray forming applications.

Evaluate the effect of post processing (eg HIPping) on spray-formed deposits prepared by cold and thermal spray processes.

Evaluate manual / portable cold spray systems (through collaboration with an equipment manufacturer).

Project Outline

Spray forming will be evaluated for both cold and HVOF spraying systems. The ability to deposit features of a practical size will be determined. Following initial trials it is intended to deposit dissimilar material additively to create functional features on a component. The mechanical and metallurgical properties of the spray formed deposits will be assessed, both in terms of as-deposited and post-processed (eg HIPping) conditions. Measurement of the residual stress fields within the spray formed material will also be considered.

The evaluation of portable cold spray systems will require collaboration with an equipment manufacturer. It is intended to deposit industrially relevant materials such as aluminium (for the repair of magnesium and TSA coatings). The performance of these deposits will be benchmarked against the Kinetics 4000 fixed system in order to understand if significant differences in quality can be observed between the fixed and portable equipment.

In all cases industrially relevant materials will be selected for all the planned work and coatings and spray-forms will be subject to metallurgical assessment using both light and electron microscopy to identify the microstructural features associated with the coatings, such as particle deformation, grain structure, porosity, and oxide content. Deposit characteristics will also be correlated to spray particle flight characteristics (velocity, temperature and size) using the SprayWatch 2i particle diagnostics system in coordination with 0902-14.

Relevant Industry Sectors

Oil and Gas, Aerospace, Electronics and Medical Equipment

Technical and Economic Benefits

The total value of UK surface engineering industry services has recently been estimated at 21.3bn, critically affecting manufactured products to the value of 143bn or 7% UK GDP (NAMTEC, Strategic Review of the SE Industry in the UK, 2006). UK thermal spraying services are estimated at around 400m, globally about 3bn. There are currently fewer than 10 cold spray coating contractors globally, but if previous business growth experience with HVOF spraying is an indicator, it is anticipated that demand for cold spray technology, cold spray-forming and related technologies will increase this number by 1-2 orders of magnitude over the next decade, generating new business to the value of 0.5-1.0bn per annum globally. Data generated by this project will help establish TWI as an authority in advanced metal spray deposition processes and assist TWI industrial members in their evaluation of this technology.

The specific technical benefits are:

Development of spray forming for low cost manufacture and repair; fabrication of components incorporating improved functional surfaces.

Further improvement to deposit integrity, properties and performance through post-deposition processing.

Life extension of high value components, reduced maintenance costs, improved reliability and improved safety.

For more information please email: