HVOF Spray Coating

[subtechy]

We use a company at the moment to repair our valve components with the above mentioned process. The most common of the coatings being tungsten carbide. Our problem is that the companies spray application can only handle outside diameters and internal diameters of fairly small depths from the end faces. The company had told us that once upon a time they used to be able to but had all kinds of problems with the angle tha coating was being applied at.
Can anybody advise of any reputable companies (preferably local....scotland) that have a successful record of HVOF applications on internal faces?
Rgds

MAB

 

[Carburize]

Most HVOF Processes need "line-of-sight" access to the area which is to be coated. Since HVOF heads tend to be fairly large there are physical limits in the size of internal surfaces which can be sucessfully coated. Check to see if there is a local facility of Praxair in your area, they will be able to advise on limits.