Adhesion of CVD coatings on new cemeted carbides
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesisAlternative title
Vidhäftning mellan keramiskt skikt och hårdmetall med alternativ bindefas (Swedish)
Steel turning inserts cemented carbides have a binder phase consisting of cobalt (Co). However, in recent years a study from the United States National Toxicity Program (NTP) found that cobalt powder is carcinogenic upon inhalation. The European Union's REACH have therefore also classified cobalt powder as carcinogenic upon inhalation. The worldwide search to find a replacement has therefore lately intensified. It is important that the alternative binder phase has no negative effects on the properties of the insert. In this thesis the adhesion between a multilayer ceramic chemical vapor deposition (CVD) coating and a cemented carbide with the alternative binder phases consisting of iron (Fe), nickel (Ni) and cobalt (Co) has been studied.
First of all, the fracture surfaces showed that the CVD coating was able to grow on all cemented carbides, regardless of which binder phase. To evaluate the adhesion, scratch tests were performed on all samples. The results from the scratch tests were not as expected. No chipping of the coating down to the cemented carbide occurred on any of the samples and the samples with the hardest cemented carbide did not get the highest critical load, which it should according to the literature if all other parameters were the same. Instead the sample with the binder phase consisting of 73 wt% iron and 27 wt% nickel had the highest critical load. This is thought to be due to that during the scratch test the binder phase in this cemented carbide would most likely transform into deformation martensite.
Place, publisher, year, edition, pages
2016. , 41 p.
UPTEC Q, ISSN 1401-5773 ; 16015
cemented carbide, adhesion, alternative binder phase, CVD coating, hard metal
Metallurgy and Metallic Materials Manufacturing, Surface and Joining Technology Other Materials Engineering Composite Science and Engineering
IdentifiersURN: urn:nbn:se:uu:diva-298648OAI: oai:DiVA.org:uu-298648DiVA: diva2:946733
Master Programme in Materials Engineering
Toller, LisaNorgren, Susanne
Kassman Rudolphi, ÅsaJacobson, Staffan