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Let's talk coatings

KipNoxzema

KipNoxzema

Out of platinum, chromium, polymer, Teflon, even diamond, etc., all coatings, do you find one type of coating preferable to the others? I figure the veteran shavers might have a good read on this.
Have you ever said, "Wow, X coating is really the way to go"?
 
Uncle Brian

Uncle Brian

I guess you are talking about coatings on a DE blade? If I was gived a blind test I doubt I could tell the difference, I do however like the Astra SP blade so I guess my vote is in for Platinum.
 
Alphonse

Alphonse

I like blades based on the quality of the shave and find that all the coatings are good depending on the quality of the blade.. the 7oclock black is platinum coated and is pretty smooth and shaves. The Astra SP is also platinum, but it is not anywhere near the quality of shave of a 7oclock Black platinum. The Polsilvers are stainless and even smoother than a 7oclock black IMO and they last a few shaves longer for me. I like teflons as well, such as the Voskhods and the Sputnik teflons, and they give very smooth shaves too. Lately, I've been getting rough shaves from my beloved Personna Lab's with "comfort coating". I do not think that platinum is better than teflon or stainless.. I like them all. It's all up to the quality of the blade.
 
Uncle Brian

Uncle Brian

brother cavefish said:
do you find the Astra sp rusts or spots fast
Click to expand...

Now that you mention it I have noticed 'something' when I was changing the blade, I didn't look at it too hard as I was throwing the old one out.
I shall go look ...............
The new blade is only two shaves old and yes its got what looks like rust on it, could be some kind of stain but I think it's rust not that I'm bothered at all.
 
Rufust445

Rufust445

Except for a few carbon steel blades, every blade on the market contains chromium, 9 to 14%, alloyed in with the basic steel, and is teflon coated. When the term polymer is used, they mean teflon, or PTFE.

Chromium is the main alloy ingredient in stainless steel and it must contain at least 11% chromium to be called stainless. Blades with 9 to 11% chromium don't have the term stainless on them. When Wilkinson first began trials with stainless blades over 50 years ago, they deemed them unsuitable for the marketplace until the adapted a special teflon coating process. Stainless blades come out of the grinding/honing process rougher than bare carbon steel. The teflon fills in the microscopic gaps and chips in the stainless edge and makes it smoother.

Platinum treatment of edges is done to make the blade last longer.
 
SiBurning

SiBurning

Platinum coatings wear off after a single shave, as testified in Qualitative Analysis Of The Edge Characteristics Of Shaving Razor Blades As A Function Of Continued Use. It seems unlikely that teflon would survive a single shave. Do any manufacturers coat stainless blades with chromium, given that stainless already contains a high amount (typically 14%) of chromium? They used to do this because teflon sticks better to chromium than steel. It would still be of limited use because the underlying steel degrades from shaving.
 
brother cavefish

brother cavefish

Rufust445 said:
Except for a few carbon steel blades, every blade on the market contains chromium, 9 to 14%, alloyed in with the basic steel, and is teflon coated. When the term polymer is used, they mean teflon, or PTFE.

Chromium is the main alloy ingredient in stainless steel and it must contain at least 11% chromium to be called stainless. Blades with 9 to 11% chromium don't have the term stainless on them. When Wilkinson first began trials with stainless blades over 50 years ago, they deemed them unsuitable for the marketplace until the adapted a special teflon coating process. Stainless blades come out of the grinding/honing process rougher than bare carbon steel. The teflon fills in the microscopic gaps and chips in the stainless edge and makes it smoother.

Platinum treatment of edges is done to make the blade last longer.
Click to expand...
perfect thanks- how can one tell which ones have more %
 
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brother cavefish

brother cavefish

SiBurning said:
Platinum coatings wear off after a single shave, as testified in Qualitative Analysis Of The Edge Characteristics Of Shaving Razor Blades As A Function Of Continued Use. It seems unlikely that teflon would survive a single shave. Do any manufacturers coat stainless blades with chromium, given that stainless already contains a high amount (typically 14%) of chromium? They used to do this because teflon sticks better to chromium than steel. It would still be of limited use because the underlying steel degrades from shaving.
Click to expand...
the link does not work
 
dpm802

dpm802

Ever read the label on a pack of Derby?

CHROMIUM-CERAMIC-PLATINUM-TUNGSTEN and POLYMER COATED EDGES.

I don't know why they put so many coatings on their blades ... or how it would shave without them.

I like the way DERBY works for me (under the right conditions, in the right razor) ... but I think all these coatings are overkill.

I've never paid much attention to the individual types of coatings, one works as good as another, I suppose. But I know that I wouldn't want to shave with an uncoated blade. Even a bare stainless steel blade is kind of rough without a coating of some sort to smooth it out.
 
SiBurning

SiBurning

dpm802 said:
Ever read the label on a pack of Derby?

CHROMIUM-CERAMIC-PLATINUM-TUNGSTEN and POLYMER COATED EDGES.
Click to expand...

That's probably 2 or 3 layers of coatings.

I've been reading up on Thermal Spray Coatings. Gordon England's site has information and microscope pictures of coatings, and also hosts the Surface Engineering Forum.

From what I gather, there's a lot of alloys and multiple layers being used today. Here's a few interesting things found there. (I don't claim to understand it, so some of this might be wrong.)

  • Most PTFE used today is mixed with something, typically with some metal, possibly also with a ceramic, so it probably won't wear off after a singe shave. The PTFE sort of leeches out of the porous metal to continue to coat the surface (or something to that effect) or fill the surface irregularities. (It can be porous either from the process of spray coating or when mixed with ceramic.)
  • Chromium-oxide & ceramic are often alloyed for their hardness and wear resistance when using plasma spraying.
  • The addition of platinum to chromium makes it more malleable and less brittle (although I'm not certain of this).
  • Chromium oxide ceramic (and other similar alloys) can be ground and honed.
  • Tungsten has long been used in its pure form and coated with PTFE. The nice thing about tungsten is it's just about the hardest metal, so it doesn't wear out easily. In its pure form, it's not as brittle as in alloys. (You're probably familiar with the strength and brittleness from tungsten-steel drill bits.)
  • Many of these coatings made for wear resistance are permeable (among other things) so a sealing coating is often used underneath to prevent chemical erosion (or oxidation) to the underlying metal.
With all these options, I wonder why any blade manufacturer still uses a simple platinum coating that easily wears off in one shave. Perhaps this layer is only meant to provide chemical/oxidation resistance over long term storage.

Here's another thing that plays into this. What I've read about friction suggests that a rough edge (with irregularities of small enough size, probably below 0.5 micron) has less friction than a smooth surface because it presents less surface to the skin. I mention it here because it suggests a possible reason why the outer coating might be a porous ceramic, particularly if it's alloyed with PTFE. Of course, not all blades are made that way.

This is all so complicated. But it suggests a lot more reasons why YMMV.
 
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