These nozzles are NOT hard enough for Carbon Fibre… They are a plated brass (or copper), and the ends of them wear off… Here is a photo of the one I used, compared to a new one…
As you can see, the tip of the nozzle is worn away, and this occurred on about 500g of CF filament, resulting in deteorating print quality and having to raise the table frequently to get first layer adhesion as it wore down…
I have located some “hardened steel nozzles” on Alibaba, and ordered them in 0.4, 0.6 and 0.8mm…
They have arrived, and I will report on how they perform after using them…
Bob