Investigation of the substrate heating during liningby means of HVOF spraying and warm spraying

Lining still constitutes a special field of thermal spraying technology. In addition to the already industrially established technologies for linings (e.g. atmospheric plasma spraying (APS), wire arc spraying (WAS) and plasma transferred wire arc (PTWA) spraying procedures), the HVOF spraying procedures have been leading a niche existence until now, particularly for the lining of small borehole diameters (< 200 mm). One challenge during HVOF spraying lining is the heat input into the substrate by the flame jet and the hot sprayed particles. Within the framework of the executed experiments, various cooling concepts and spraying parameters in the HVOF and warm spraying processes were investigated with regard to the substrate heating during the lining. It was shown that, together with the warm spraying process, combined external and internal cooling can reduce the component heating significantly.