Posted by Gordon England on February 04, 2003 at 15:19:37:
In Reply to: Coating onto nitriding steel posted by Papapanos George on February 03, 2003 at 10:02:47:
: Good morning
: I would like to now why is have not good bond properties when we spray (arc,plasma,hvof) onto nitriding steel and we must removed the nitriding layer before spraying.
: Thank you
1. Nitrided surface is very hard and it is difficult to get a good grit blast etch/profile to anchor the coatings.
2. Some bond coat materials like molybdenum are not self-bonding to nitrided surfaces (particularly if white layers are retained)
To be successful in applying coatings to nitrided surfaces you will need to ensure a good sharp grit blast profile by using alumina or silicon carbide grit at high pressure.
Nickel aluminium bond coat materials are self-bonding to nitrided surfaces (removal of any white layer recommended)
Adhesion will not be as good as a soft non-nitrided steel, but should be adequate for many applications.
Regards Gordon
Follow Ups:
Surface Engineering Forum
Surface Engineering Message Board Archive
Surface Engineering Message Board Archive Index
www.gordonengland.co.uk
Please go to the new Surface Engineering Forum as this old message board is a read only archive. Please copy and paste relevant information or link to the page if you wish to reactivate a thread on the new forum.
Introducing
Nature of Thermal Spray Coatings
Surface Engineering in a Nutshell
Surface Engineering Forum
Thermal Spray Gun Repair Service
Plasma Consumable Parts
Thermal Spray Powder Supplies
Applications:
Thermal Spray Coatings on Carbon and Glass Fibre Reinforced Polymers
HVOF Coating of Paper Making Roll
Abradable Coatings
Thermal Spray Processes:
Combustion Wire Thermal Spray Process
Combustion Powder Thermal Spray Process
Arc Wire Thermal Spray Process
Plasma Thermal Spray Process
HVOF Thermal Spray Process
HVAF Thermal Spray Process
Detonation Thermal Spray Process
Plasma Flame Theory
Cold Spray Coating Process
Wear and Use of Thermal Spray Coatings
Corrosion and Use of Thermal Spray Coatings
Glossary of Thermal Spray and Surface Engineering Terms
Image Directory for Thermal Spray Coatings
Plasma Gas Flow Information
Plasma Gas Flow Correction Calculator
Contact Form
Links to other interesting sites related to thermal spray and surface engineering
Reciprocal Links
Periodic Table of the Elements
SI Units
Calculators for Conversion between Units of Measurement
Hardness Testing
Surface Engineering Message Board Archive
Surface Engineering Message Board Archive Index
Photography Gallery2
Photography Gallery3
© Copyright Gordon England