Thermal Spray in Food industry
11-19-2019, 01:20 PM,
#1
Thermal Spray in Food industry
I'm currently looking for real life examples of using Thermal spray Process in Food industry.
Ideally example of Stainless steel coating as corrosion protection on Cast part (aluminium or zinc). Surfaces coated are not normally in contact with food.
Would bead blasting Sprayed coating close up surface pores or do we still need sealants?
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11-20-2019, 07:05 AM, (This post was last modified: 11-20-2019, 07:12 AM by Vadim Verlotski.)
#2
RE: Thermal Spray in Food industry
(11-19-2019, 01:20 PM)yatuin Wrote: I'm currently looking for real life examples of using Thermal spray Process in Food industry.
Ideally example of Stainless steel coating as corrosion protection on Cast part (aluminium or zinc). Surfaces coated are not normally in contact with food.
Would bead blasting Sprayed coating close up surface pores or do we still need sealants?

There is no impermeable stainless steel coating, so be sure to seal it with a polymer. If you try to close the pores in the stainless steel coating by shot peening, your layer will break.

That's I wonder why this coating is so in demand? A thermally sprayed layer of stainless steel (no matter which thermal spraying method) has very miserable properties: coarse continuous porosity, weak adhesion, high roughness, tendency to under layer corrosion (accelerates corrosion of the substrate), low corrosion resistance (pitting) and so on. There are plenty of other thermal spray coatings that are much better. For use in the food industry, for example, the plasma coating of Al2O3 impregnated with Teflon would be much better. You can see this type of coating on any white non-stick pan.
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11-21-2019, 09:33 AM,
#3
RE: Thermal Spray in Food industry
(11-20-2019, 07:05 AM)Vadim Verlotski Wrote:
(11-19-2019, 01:20 PM)yatuin Wrote: I'm currently looking for real life examples of using Thermal spray Process in Food industry.
Ideally example of Stainless steel coating as corrosion protection on Cast part (aluminium or zinc). Surfaces coated are not normally in contact with food.
Would bead blasting Sprayed coating close up surface pores or do we still need sealants?

There is no impermeable stainless steel coating, so be sure to seal it with a polymer. If you try to close the pores in the stainless steel coating by shot peening, your layer will break.

That's I wonder why this coating is so in demand? A thermally sprayed layer of stainless steel (no matter which thermal spraying method) has very miserable properties: coarse continuous porosity, weak adhesion, high roughness, tendency to under layer corrosion (accelerates corrosion of the substrate), low corrosion resistance (pitting) and so on. There are plenty of other thermal spray coatings that are much better. For use in the food industry, for example, the plasma coating of Al2O3 impregnated with Teflon would be much better. You can see this type of coating on any white non-stick pan.
I expected that we wont get away from needing to use sealants.
Corrosion resistance is not an massive issue in environment where our products end up - its generally dry and cleaning solutions used are less aggressive than ones used in for example meat industry.
We produce currently powder coated cast aluminium equipment and Fabricated SS 304 versions and spraying stainless was first on list of possible paint alternatives. Teflon coating on top of thermal spray was further on the list mainly due to higher cost involved. Unfortunately there is very limited amount of information available regarding thermal spray coatings in food industry, especially when considering such coating as general protection barrier.
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11-21-2019, 07:04 PM,
#4
RE: Thermal Spray in Food industry
(11-21-2019, 09:33 AM)yatuin Wrote:
(11-20-2019, 07:05 AM)Vadim Verlotski Wrote:
(11-19-2019, 01:20 PM)yatuin Wrote: I'm currently looking for real life examples of using Thermal spray Process in Food industry.
Ideally example of Stainless steel coating as corrosion protection on Cast part (aluminium or zinc). Surfaces coated are not normally in contact with food.
Would bead blasting Sprayed coating close up surface pores or do we still need sealants?

There is no impermeable stainless steel coating, so be sure to seal it with a polymer. If you try to close the pores in the stainless steel coating by shot peening, your layer will break.

That's I wonder why this coating is so in demand? A thermally sprayed layer of stainless steel (no matter which thermal spraying method) has very miserable properties: coarse continuous porosity, weak adhesion, high roughness, tendency to under layer corrosion (accelerates corrosion of the substrate), low corrosion resistance (pitting) and so on. There are plenty of other thermal spray coatings that are much better. For use in the food industry, for example, the plasma coating of Al2O3 impregnated with Teflon would be much better. You can see this type of coating on any white non-stick pan.
I expected that we wont get away from needing to use sealants.
Corrosion resistance is not an massive issue in environment where our products end up - its generally dry and cleaning solutions used are less aggressive than ones used in for example meat industry.
We produce currently powder coated cast aluminium equipment and Fabricated SS 304 versions and spraying stainless was first on list of possible paint alternatives. Teflon coating on top of thermal spray was further on the list mainly due to higher cost involved. Unfortunately there is very limited amount of information available regarding thermal spray coatings in food industry, especially when considering such coating as general protection barrier.

The reason why there is little information about thermally sprayed coatings in the food industry is quite simple: there are hardly any coatings that meet the four requirements of this industry:
impermeability, corrosion resistance and suitability for food contact, good adhesion and low cost.
Plasma-sprayed ceramic coatings with a PTFE top coat are, despite relatively high costs, practically the only layer system that has found wide application in the food industry.
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