hardness tester

[Arturas]

Hello,
I would like to know is it possible without demage to measure hardness of thermal spray coatings (cold and fused) with portable hardness device. Please recomend if yes , as there is few different methods - leeb , tdt, uci.
Best regards
Arturas

[Gordon]

Hi Arturas

Sorry for late response, this one pass me bye

Many hardness tests produce an indentation and damage which in many cases would make this a destructive test for most thermal spray coatings. Some of the portable hardness testers though do only leave relatively tiny impressions and I suppose may be ok for non-destructive testing. It will be dependent on a number of factors:

* Indentation size and damage caused
* Type of coating and hardness
* Finish requirements
* Testing before or after finishing

Fused coatings will be more tolerant than non-fused coatings. I would suggest doing tests and make a judgement from the degree of damage caused to a specific coating with respect to the coatings final function.