FAQ on Thermal Sprayed Coatings

b) What is coating

Coating is the act of building a deposit on a substrate, (2) the spray deposit.

c) What is thermal stress

Thermal stress is stress resulting from non-uniform temperature distribution.
Thermal stress can be avoided by preheating the workpieces.

d) What are the different thermal spraying processes

e) What is a substrate

f) What are the benefits of thermal spraying over other coating technologies

g) How many coatings are there

Almost any coating material can be sprayed onto the substrate, which means that there is wide range of deposits available. On demand of our customers tailor-made powders or/and wires can be used in the spraying process.

h) Can you coat high volumes

Specific dies or tools can be produced in order to treat high-volume series of one part.

i) Can you coat complex shapes

With the use of multiple axes robots, Bekaert VDS can coat complex geometries.

j) Due to the high processing temperatures, is oxidation a problem

Oxidation can be reduced by performing the thermal spray process under protective/controlled atmosphere or by providing local protection with a shroud on the torch. The protective/controlled atmosphere can be: low pressure, argon, nitrogen, ...

k) What factors influence bond strength

Bond strength is dictated by the velocity of the particles, particle temperature, substrate roughness and reaction with the underlaying substrate. Bond strength up to 60-80 MPa is not uncommon for thermally sprayed materials. The bonding ability is material and process dependant.

l) How thick are typcial coatings deposited by thermal spray processes

Bekaert can spray coatings from 15 microns up to 10 millimeters thick. The deposited coating thickness depends of course on the application.